Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/04/12


AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
210 PM EDT FRI NOV 2 2012 .SYNOPSIS (REST OF TODAY THROUGH SUNDAY)... 18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN ACTIVE NORTHERN STREAM FLOW ACROSS THE NORTHERN TIER OF THE COUNTRY. LARGE AND DOMINANT UPPER LEVEL TROUGH ASSOCIATED WITH THE LAST REMNANTS OF SANDY IS FINALLY BEGINNING TO DE-AMPLIFY AND MOVE EASTWARD TOWARD THE CANADIAN MARITIMES. RIDGING OVER THE UPPER MIDWEST IN THE WAKE OF THIS TROUGH IS FOLLOWED CLOSELY BY ANOTHER SERIES OF SHORTWAVE IMPULSES WHICH WILL EVOLVE INTO YET ANOTHER LONGWAVE EAST COAST TROUGH BY THE EARLY PORTION OF NEXT WEEK. CURRENT EAST COAST TROUGH HAS DE-AMPLIFIED ENOUGH FOR OUR UPPER LEVEL FLOW TO TRANSITION TO A MORE ZONAL PATTERN OVER OUR FORECAST AREA. WV IMAGERY SHOWS NO LACK OF MID/UPPER LEVEL DRY AIR IN PLACE...AND THE 12Z KTBW SOUNDING SHOWS THE DRY AIR CONTINUES ALL THE WAY DOWN TO THE BOUNDARY LAYER. A VERY LOW PW VALUE OF ONLY AROUND 0.65" WAS SAMPLED...WHICH IS ONLY ABOUT 60% OF NORMAL FOR EARLY NOVEMBER. THE DRY COLUMN IS ALLOWING JUST ABOUT 100% OF THE POSSIBLE SUNSHINE/INSOLATION THIS AFTERNOON. AT THE SURFACE...HIGH PRESSURE HAS PARKED ITSELF OVER THE EASTERN GULF OF MEXICO/FL PENINSULA AND WILL BE IN CONTROL OF THE LOWER LEVELS THROUGH THE UPCOMING WEEKEND. && .SHORT TERM (TONIGHT THROUGH SUNDAY)... TONIGHT...SURFACE HIGH PRESSURE IN PLACE WILL COMBINE WITH CLEAR SKIES AND A DRY COLUMN TO RESULT IN ANOTHER COOL NIGHT AWAY FROM THE IMMEDIATE COAST. MOST LOCATION AWAY FROM THE BEACHES AND URBAN SETTINGS WILL SEE LOW TEMPS IN THE 50S...HOWEVER THE NORMALLY COLDER SPOTS UNDER RADIATIONAL COOLING MAY BRIEFLY DIP IN TO UPPER 40S TOWARD SUNRISE. SATURDAY/SATURDAY NIGHT...DRY CONDITIONS WITH NEAR ZERO RAIN CHANCES. PLENTY OF SUNSHINE AND A CONTINUED MODIFICATION TO THE AIRMASS WILL ALLOW A DECENT DIURNAL SWING IN TEMPERATURES FOR THE FIRST DAY OF THE WEEKEND. AFTER THE COOL EARLY MORNING LOWS...MOST LOCATIONS SHOULD REBOUND INTO THE LOWER 80S BY MID-AFTERNOON. IMMEDIATE COASTAL LOCATIONS WILL LIKELY END UP A COUPLE OF DEGREES COOLER WITH A DEVELOPING LIGHT AFTERNOON FLOW OFF THE NOW RELATIVELY COOLER SHELF WATERS. OVERNIGHT TEMPS BEGIN TO MODERATE WITH NO MORE 40S EXPECTED. COLDEST INLAND SPOTS SHOULD SEE LATE NIGHT READINGS GENERALLY IN THE LOWER/MID 50S. SUNDAY...UPPER LEVEL PATTERN BEGINS TO AMPLIFY INTO THE EASTERN CONUS DURING THE SECOND HALF OF THE UPCOMING WEEKEND. WEAK IMPULSE ALOFT MOVING ALONG THE NORTHERN GULF COAST WILL BE ACCOMPANIED BY A WEAK FRONTAL SYSTEM SAGGING DOWN TOWARD THE I-10 CORRIDOR. COLUMN MOISTURE AND BEST LOW LEVEL FOCUS ALONG THE FRONT LOOK TO HOLD FAR ENOUGH NORTH TO KEEP ANY SHOWERS OUT OF OUR AREA FOR THE DAYLIGHT HOURS. WILL SHOW AN INCREASE IN CLOUDS NORTH OF I-4 AS THE IMPULSE APPROACHES...BUT OTHERWISE ANOTHER DRY AND SEASONABLY WARM DAY IN THE FORECAST. BY SUNDAY NIGHT WILL INTRODUCE A SLIGHT CHANCE FOR SHOWERS UP TOWARD LEVY/CITRUS/SUMTER COUNTY AS THE FRONT SAGS JUST A BIT FURTHER SOUTH...BUT SYNOPTIC FORCING WILL BE WEAK AND KEEP ANY ACTIVITY ISOLATED IN NATURE. UPDATE TO MONDAY/TUESDAY...MADE A FEW UPDATES TO THE FORECAST DURING THE EARLY PORTION OF NEXT WEEK. THE LOW LEVEL BOUNDARY WILL REMAIN IN PLACE NEAR I-10 INTO MONDAY WHICH WILL CONTINUE THE CHANCE FOR SOME ISOLATED SHOWER OVER THE FAR NORTHERN ZONES. DURING MONDAY...GLOBAL GUIDANCE IS COMING INTO GOOD AGREEMENT IN A STRONG SHORTWAVE IMPULSE DIVING TOWARD THE GULF COAST FROM THE CENTRAL PORTION OF THE COUNTRY. CONFIDENCE IS INCREASING THAT ENERGY ALONG WITH SIGNIFICANT SYNOPTIC FORCING WILL BE APPROACHING DURING THE DAY ON TUESDAY. STILL SOME UNCERTAINLY IN THE TIMING OF ANY SHOWERS/STORM SOUTH AND EAST OF TAMPA BAY AND WILL KEEP RAIN CHANCES AROUND 30% FOR THIS FORECAST PACKAGE. HOWEVER...AROUND TAMPA BAY AND ESPECIALLY NORTHWARD UP THE NATURE COAST...RAIN CHANCES ARE LOOKING BETTER AND BETTER. HAVE RAISED POP TO AROUND 50% FOR THESE ZONES BY TUESDAY AFTERNOON...AND BASED ON THE LATEST GUIDANCE CONSENSUS... EVEN THESE NUMBERS MAY BE ON THE CONSERVATIVE SIDE. && LONG TERM (SUNDAY NIGHT - THURSDAY)... THE LONG TERM PERIOD BEGINS WITH BROAD UPPER LEVEL TROUGHING OVER THE EASTERN CONUS WITH A SHORTWAVE TROUGH OVER THE NORTHERN PLAINS. AT THE SURFACE...HIGH PRESSURE OVER THE FLORIDA PENINSULA AND GULF OF MEXICO IS BOUNDED BY A COLD FRONT TO THE NORTH THAT ON SUNDAY NIGHT STRETCHES FROM THE CAROLINAS THROUGH THE MISSISSIPPI DELTA. AS THE SHORTWAVE ALOFT PUSHES SOUTHEAST...THE LONGWAVE TROUGH WILL DEEPEN AND THE SURFACE COLD FRONT WILL MOVE ACROSS THE FLORIDA PENINSULA ON MONDAY WITH A SLIGHT INCREASE IN MOISTURE. AFTER THAT FRONT CLEARS...A STRONGER SECONDARY FRONT WILL MOVE INTO THE AREA BEHIND IT BRINGING A GOOD CHANCE OF SHOWERS TUESDAY MORNING/EARLY AFTERNOON AND A SHOT OF COOLER AND DRIER AIR BEHIND THE FRONT TUESDAY NIGHT AND WEDNESDAY. WEDNESDAY AND THURSDAY...STRONG HIGH PRESSURE BUILDS IN FROM THE GULF WITH DRY AND MORE STABLE AIR TAKING HOLD OVER THE REGION. HIGH TEMPERATURES WILL BE IN THE LOW TO MID 80S MONDAY AND TUESDAY...THEN THINGS COOL OFF BEHIND THE FRONT WITH MAX TEMPERATURES IN THE 70S WEDNESDAY AND THURSDAY. LOW TEMPERATURES AFTER THE FRONT PASSES ARE ONLY EXPECTED TO DROP DOWN TO THE UPPER 40S WEDNESDAY NIGHT IN THE USUAL COLD SPOTS. && .AVIATION... VFR CONDITIONS EXPECTED ALL AREAS TODAY. && .MARINE... A WEAK FRONTAL BOUNDARY HAS EXITED SOUTH OF THE FORECAST WATERS ALLOWING HIGH PRESSURE OVER THE CENTRAL GULF TO RIDGES TOWARD FLORIDA. THE HIGH WILL MOVE ACROSS THE STATE AND OUT OVER THE ATLANTIC BY LATE SUNDAY KEEPING WINDS AND SEAS LOW THROUGH THE UPCOMING WEEKEND. && .FIRE WEATHER... A DRY AIRMASS HAS SETTLED OVER THE REGION. THIS DRY AIRMASS WILL LINGER INTO SATURDAY...ESPECIALLY ALONG AND SOUTH OF THE I-4 CORRIDOR. A COMBINATION OF LONG DURATIONS OF LOW RELATIVE HUMIDITY AND ENERGY RELEASE COMPONENT VALUES OVER 35 ARE EXPECTED TO ONCE AGAIN RESULT IN RED FLAG CONDITIONS FOR LEE AND INLAND SARASOTA COUNTIES. CONDITIONS ARE CLOSE TO RED FLAG CRITERIA ACROSS PORTIONS OF POLK COUNTY SATURDAY AFTERNOON...AND THIS ZONE WILL NEED TO BE MONITORED CLOSELY WITH FUTURE FORECASTS. LOW LEVEL MOISTURE IS EXPECTED TO INCREASE ENOUGH BY SUNDAY TO PREVENT ANY SIGNIFICANT FIRE WEATHER CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... TPA 60 82 63 80 / 0 0 0 10 FMY 57 82 61 83 / 0 0 0 10 GIF 54 83 59 83 / 0 0 0 10 SRQ 58 80 60 80 / 0 0 0 10 BKV 48 82 52 82 / 0 0 0 10 SPG 65 80 64 78 / 0 0 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING UNTIL 7 PM EDT THIS EVENING FOR HERNANDO- LEE-PASCO-PINELLAS-POLK-SARASOTA. RED FLAG WARNING FROM 2 PM TO 6 PM EDT SATURDAY FOR LEE- SARASOTA. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA AVIATION...DAVIS LONG TERM...FLEMING
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1110 AM EDT FRI NOV 2 2012 .UPDATE (REST OF TODAY THROUGH SATURDAY)... 14Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN ACTIVE NORTHERN STREAM FLOW ACROSS THE NORTHERN TIER OF THE COUNTRY. LARGE AND DOMINANT UPPER LEVEL TROUGH ASSOCIATED WITH THE LAST REMNANTS OF SANDY IS FINALLY BEGINNING TO DE-AMPLIFY AND MOVE EASTWARD TOWARD THE CANADIAN MARITIMES. RIDGING OVER THE UPPER MIDWEST IN THE WAKE OF THIS TROUGH IS FOLLOWED CLOSELY BY ANOTHER SERIES OF SHORTWAVE IMPULSES WHICH WILL EVOLVE INTO YET ANOTHER LONGWAVE EAST COAST TROUGH BY THE EARLY PORTION OF NEXT WEEK. CURRENT EAST COAST TROUGH HAS DE-AMPLIFIED ENOUGH FOR OUR UPPER LEVEL FLOW TO TRANSITION TO A MORE ZONAL PATTERN OVER OUR FORECAST AREA. WV IMAGERY SHOWS NO LACK OF MID/UPPER LEVEL DRY AIR IN PLACE...AND THE 12Z KTBW SOUNDING SHOWS THE DRY AIR CONTINUES ALL THE WAY DOWN TO THE BOUNDARY LAYER. A VERY LOW PW VALUE OF ONLY AROUND 0.65" WAS SAMPLED...WHICH IS ONLY ABOUT 60% OF NORMAL FOR EARLY NOVEMBER. THE DRY COLUMN IS ALLOWING JUST ABOUT 100% OF THE POSSIBLE SUNSHINE/INSOLATION INTO THE AFTERNOON...SO WILL CONTINUE THE SUNNY TO MOSTLY SUNNY FORECAST. AT THE SURFACE...HIGH PRESSURE HAS PARKED ITSELF OVER THE EASTERN GULF OF MEXICO/FL PENINSULA AND WILL BE IN CONTROL OF THE LOWER LEVELS THROUGH THE UPCOMING WEEKEND. WITH THE HIGH PRESSURE IN PLACE/CLEAR SKIES AND A DRY COLUMN...IT WILL BE ANOTHER COOL NIGHT AWAY FROM THE IMMEDIATE COAST. MOST LOCATION AWAY FROM THE BEACHES AND URBAN SETTINGS WILL SEE LOW TEMPS IN THE 50S...HOWEVER THE NORMALLY COLDER SPOTS UNDER RADIATIONAL COOLING MAY BRIEFLY DIP IN TO UPPER 40S TOWARD SUNRISE. PLENTY OF SUNSHINE AND A CONTINUED MODIFICATION TO THE AIRMASS WILL ALLOW A DECENT DIURNAL SWING IN TEMPERATURES FOR THE FIRST DAY OF THE WEEKEND. AFTER THE COOL EARLY MORNING LOWS...MOST LOCATIONS SHOULD REBOUND INTO THE LOWER 80S BY MID-AFTERNOON. IMMEDIATE COASTAL LOCATIONS WILL LIKELY END UP A COUPLE OF DEGREES COOLER WITH A DEVELOPING LIGHT AFTERNOON FLOW OFF THE NOW RELATIVELY COOLER SHELF WATERS. INHERITED FORECAST IS ON TRACK AND DO NOT FORESEE ANY SIGNIFICANT CHANGES TO THE GRIDS THROUGH SATURDAY. && .AVIATION... VFR CONDITIONS EXPECTED ALL AREAS TODAY. && .MARINE... A WEAK FRONTAL BOUNDARY HAS EXITED SOUTH OF THE FORECAST WATERS ALLOWING HIGH PRESSURE OVER THE CENTRAL GULF TO RIDGES TOWARD FLORIDA. THE HIGH WILL MOVE ACROSS THE STATE AND OUT OVER THE ATLANTIC BY LATE SUNDAY KEEPING WINDS AND SEAS LOW THROUGH THE UPCOMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 61 82 63 / 0 0 0 0 FMY 81 59 83 62 / 10 0 0 0 GIF 79 57 83 59 / 0 0 0 0 SRQ 76 60 80 63 / 10 0 0 0 BKV 78 48 83 51 / 0 0 0 0 SPG 77 66 81 67 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EDT THIS EVENING FOR HERNANDO-LEE-PASCO-PINELLAS-POLK-SARASOTA. GULF WATERS...NONE. && $$ UPDATE/MARINE...MROCZKA AVIATION...DAVIS
AREA FORECAST DISCUSSION
NWS MIAMI FL
739 AM EDT FRI NOV 2 2012 .AVIATION... VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE NEXT 24 HOURS. WITH RESIDUAL MOISTURE FROM A FEW RAIN SHOWERS YESTERDAY, SOME LOCATIONS HAVE SEEN SOME FOG AND/OR LOW CIG DEVELOPMENT. THIS IS EXPECTED TO BURN OFF BY 13Z. FRONTAL BOUNDARY IS STILL EXPECTED TO CROSS THROUGH THE SOUTH FLORIDA AREA LATER THIS MORNING WHICH WILL DO LITTLE MORE THAN VEER THE WINDS AROUND TO THE NORTH THROUGH THE DAY. && .PREV DISCUSSION... /ISSUED 311 AM EDT FRI NOV 2 2012/ SHORT TERM (TODAY-SUNDAY)... THE EARLY MORNING SURFACE ANALYSIS SHOWED A WEAKENING COLD FRONT EXTENDING WEST-SOUTHWEST ACROSS THE FLORIDA PENINSULA NEAR THE LAKE REGION WITH A WEAK DEW POINT GRADIENT ACROSS THE BOUNDARY FROM NORTH TO SOUTH. OBSERVATIONS AND IR2 IMAGERY SHOWED MAINLY SCATTERED CLOUD COVERAGE ALONG AND AHEAD OF THIS BOUNDARY WITH THE BEST COVERAGE OVER THE ADJACENT GULF COASTAL WATERS. A FEW SHOWERS CONTINUE TO DEVELOP AND TRACK ESE OVER THE GULF WATERS AND OVER THE GULF COASTAL LOCATIONS AROUND NAPLES BASED ON THE LATEST RADAR LOOP. AS THE DAY CONTINUES...THE LATEST MODEL GUIDANCE INDICATES THIS BOUNDARY CONTINUING SOUTH WITH DRIER AIR AND CLEARING SKIES SPREADING SOUTH INTO THE LOCAL AREA. THE LATEST HRRR AND WRF MODEL REFLECTIVITIES DO INDICATE A FEW SHOWERS CONTINUING TO DEVELOP ALONG THIS BOUNDARY AS IT CONTINUES SOUTH TODAY. THEREFORE...WILL INCLUDE SOME CHANCE FOR A FEW SHOWERS THROUGH THE FIRST HALF OF THE DAY ACROSS THE GULF WATERS AND THE FAR SOUTHERN EXTENT OF THE FL PENINSULA. OTHERWISE...ANOTHER PLEASANT DAY IS ANTICIPATED WITH HIGHS CLIMBING BACK TO AROUND 80 DEGREES THIS AFTERNOON. A SLIGHTLY WARMER START IS EXPECTED THIS MORNING COMPARED TO THE PAST FEW DAYS DUE TO THE FRONTAL BOUNDARY PUSHING SOUTH OVER THE AREA. SATURDAY THROUGH SUNDAY...DRY CONDITIONS WILL BE EXPECTED WITH THE LOW-LEVEL WIND FLOW GRADUALLY VEERING TO THE NORTH AND NORTHEAST. MODEL PWAT VALUES ARE FORECAST TO DIP BACK TO AROUND THE HALF INCH MARK. A BLEND OF THE MODEL GUIDANCE OUTPUT HIGHS REACHING THE 80-83 DEGREE RANGE THROUGH THE AFTERNOON AND LOWS RANGING FROM THE LOWER 50S INLAND AND NORTH TO THE LOWER 60S FARTHER SOUTH AND ALONG THE COASTAL LOCATIONS EACH NIGHT. LONG TERM (SUNDAY NIGHT-THURSDAY)... THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT THROUGH THE PERIOD AND SHOWS A SHORTWAVE TROUGH DIGGING SOUTHEASTWARD ACROSS THE REGION. A FRONTAL BOUNDARY ASSOCIATED WITH THIS UPPER FEATURE IS PROGGED TO APPROACH AND MOVE THROUGH THE LOCAL AREA TUESDAY THROUGH WEDNESDAY. THE GFS/GFS ENSEMBLE MEAN/ECMWF ALL GENERALLY INDICATE THE MAIN DEEP LAYER MOISTURE AXIS ALONG AND AHEAD OF THIS FRONTAL BOUNDARY DIMINISHING OR DRYING AS THE FRONTAL BOUNDARY CONTINUES SOUTH TOWARD AND OVER THE LOCAL AREA. FOR NOW...WE WILL KEEP MAINLY A CHANCE FOR SHOWERS IN THIS PACKAGE THROUGH THE TUESDAY AND TUESDAY NIGHT PERIOD. TEMPERATURES ARE EXPECTED TO REMAIN AROUND NORMAL...EXCEPT FOR SLIGHTLY COOLER OVER THE INLAND LOCATIONS EACH NIGHT. THE LATEST TEMPERATURE GUIDANCE REALLY DOES NOT INDICATE MUCH OF A TEMPERATURE CHANGE IN THE WAKE OF THIS BOUNDARY BY THE END OF THE PERIOD...HOWEVER...ANOTHER SURGE OF DRY AIR WILL BE EXPECTED IF THIS TIMING OF THE FRONTAL BOUNDARY VERIFIES THROUGH THE MID-WEEK PERIOD. MARINE... A WEAK FRONTAL BOUNDARY WILL CONTINUE TO SHIFT SOUTH OF MARINE AREAS TODAY...WHICH WILL ALLOW THE WINDS TO SHIFT AROUND TO THE NORTH AND NORTHEAST OVER THE WEEKEND IN THE WAKE OF THE FRONT. THE BEST CHANCE FOR A FEW SHOWERS WILL REMAIN THROUGH THE MORNING HOURS TODAY ACROSS THE GULF WATERS. OTHERWISE...A DRYING TREND WILL BE EXPECTED TODAY THROUGH SATURDAY. ANOTHER FRONTAL BOUNDARY WILL APPROACH AND MOVE INTO THE AREA MONDAY THROUGH WEDNESDAY...WITH INCREASING WINDS AND SEAS POSSIBLE BY THE MID-WEEK PERIOD. FIRE WEATHER... PLENTY OF DRY AIR WILL SPREAD ACROSS THE LOCAL AREA FROM NORTH TO SOUTH TODAY IN THE WAKE OF A FRONTAL BOUNDARY. LONG DURATIONS WITH SUB 35 PERCENT RH VALUES COMBINED WITH ERC VALUES IN THE MID 20S WILL SUPPORT A FIRE DANGER STATEMENT ACROSS THE AREAS EXTENDING SOUTH FROM GLADES TO INLAND COLLIER COUNTIES THIS AFTERNOON. SIMILAR CONDITIONS WILL BE ANTICIPATED ON SATURDAY AFTERNOON BEFORE A GRADUAL MOISTENING TREND IS EXPECTED AND ANOTHER FRONTAL BOUNDARY BEGINS TO APPROACH THE REGION FROM THE NORTHWEST INTO THE UPCOMING WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 79 57 80 63 / 10 0 0 0 FORT LAUDERDALE 81 63 81 68 / 10 0 0 0 MIAMI 81 63 82 67 / 10 0 0 0 NAPLES 79 58 81 62 / 10 0 0 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...10/CD AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS MIAMI FL
311 AM EDT FRI NOV 2 2012 .SHORT TERM (TODAY-SUNDAY)... THE EARLY MORNING SURFACE ANALYSIS SHOWED A WEAKENING COLD FRONT EXTENDING WEST-SOUTHWEST ACROSS THE FLORIDA PENINSULA NEAR THE LAKE REGION WITH A WEAK DEWPOINT GRADIENT ACROSS THE BOUNDARY FROM NORTH TO SOUTH. OBSERVATIONS AND IR2 IMAGERY SHOWED MAINLY SCATTERED CLOUD COVERAGE ALONG AND AHEAD OF THIS BOUNDARY WITH THE BEST COVERAGE OVER THE ADJACENT GULF COASTAL WATERS. A FEW SHOWERS CONTINUE TO DEVELOP AND TRACK ESE OVER THE GULF WATERS AND OVER THE GULF COASTAL LOCATIONS AROUND NAPLES BASED ON THE LATEST RADAR LOOP. AS THE DAY CONTINUES...THE LATEST MODEL GUIDANCE INDICATES THIS BOUNDARY CONTINUING SOUTH WITH DRIER AIR AND CLEARING SKIES SPREADING SOUTH INTO THE LOCAL AREA. THE LATEST HRRR AND WRF MODEL REFLECTIVITIES DO INDICATE A FEW SHOWERS CONTINUING TO DEVELOP ALONG THIS BOUNDARY AS IT CONTINUES SOUTH TODAY. THEREFORE...WILL INCLUDE SOME CHANCE FOR A FEW SHOWERS THROUGH THE FIRST HALF OF THE DAY ACROSS THE GULF WATERS AND THE FAR SOUTHERN EXTENT OF THE FL PENINSULA. OTHERWISE...ANOTHER PLEASANT DAY IS ANTICIPATED WITH HIGHS CLIMBING BACK TO AROUND 80 DEGREES THIS AFTERNOON. A SLIGHTLY WARMER START IS EXPECTED THIS MORNING COMPARED TO THE PAST FEW DAYS DUE TO THE FRONTAL BOUNDARY PUSHING SOUTH OVER THE AREA. SATURDAY THROUGH SUNDAY...DRY CONDITIONS WILL BE EXPECTED WITH THE LOW-LEVEL WIND FLOW GRADUALLY VEERING TO THE NORTH AND NORTHEAST. MODEL PWAT VALUES ARE FORECAST TO DIP BACK TO AROUND THE HALF INCH MARK. A BLEND OF THE MODEL GUIDANCE OUTPUT HIGHS REACHING THE 80-83 DEGREE RANGE THROUGH THE AFTERNOON AND LOWS RANGING FROM THE LOWER 50S INLAND AND NORTH TO THE LOWER 60S FARTHER SOUTH AND ALONG THE COASTAL LOCATIONS EACH NIGHT. .LONG TERM (SUNDAY NIGHT-THURSDAY)... THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT THROUGH THE PERIOD AND SHOWS A SHORTWAVE TROUGH DIGGING SOUTHEASTWARD ACROSS THE REGION. A FRONTAL BOUNDARY ASSOCIATED WITH THIS UPPER FEATURE IS PROGGED TO APPROACH AND MOVE THROUGH THE LOCAL AREA TUESDAY THROUGH WEDNESDAY. THE GFS/GFS ENSEMBLE MEAN/ECMWF ALL GENERALLY INDICATE THE MAIN DEEP LAYER MOISTURE AXIS ALONG AND AHEAD OF THIS FRONTAL BOUNDARY DIMINISHING OR DRYING AS THE FRONTAL BOUNDARY CONTINUES SOUTH TOWARD AND OVER THE LOCAL AREA. FOR NOW...WE WILL KEEP MAINLY A CHANCE FOR SHOWERS IN THIS PACKAGE THROUGH THE TUESDAY AND TUESDAY NIGHT PERIOD. TEMPERATURES ARE EXPECTED TO REMAIN AROUND NORMAL...EXCEPT FOR SLIGHTLY COOLER OVER THE INLAND LOCATIONS EACH NIGHT. THE LATEST TEMPERATURE GUIDANCE REALLY DOES NOT INDICATE MUCH OF A TEMPERATURE CHANGE IN THE WAKE OF THIS BOUNDARY BY THE END OF THE PERIOD...HOWEVER...ANOTHER SURGE OF DRY AIR WILL BE EXPECTED IF THIS TIMING OF THE FRONTAL BOUNDARY VERIFIES THROUGH THE MID-WEEK PERIOD. && .MARINE... A WEAK FRONTAL BOUNDARY WILL CONTINUE TO SHIFT SOUTH OF MARINE AREAS TODAY...WHICH WILL ALLOW THE WINDS TO SHIFT AROUND TO THE NORTH AND NORTHEAST OVER THE WEEKEND IN THE WAKE OF THE FRONT. THE BEST CHANCE FOR A FEW SHOWERS WILL REMAIN THROUGH THE MORNING HOURS TODAY ACROSS THE GULF WATERS. OTHERWISE...A DRYING TREND WILL BE EXPECTED TODAY THROUGH SATURDAY. ANOTHER FRONTAL BOUNDARY WILL APPROACH AND MOVE INTO THE AREA MONDAY THROUGH WEDNESDAY...WITH INCREASING WINDS AND SEAS POSSIBLE BY THE MID-WEEK PERIOD. && .FIRE WEATHER... PLENTY OF DRY AIR WILL SPREAD ACROSS THE LOCAL AREA FROM NORTH TO SOUTH TODAY IN THE WAKE OF A FRONTAL BOUNDARY. LONG DURATIONS WITH SUB 35 PERCENT RH VALUES COMBINED WITH ERC VALUES IN THE MID 20S WILL SUPPORT A FIRE DANGER STATEMENT ACROSS THE AREAS EXTENDING SOUTH FROM GLADES TO INLAND COLLIER COUNTIES THIS AFTERNOON. SIMILAR CONDITIONS WILL BE ANTICIPATED ON SATURDAY AFTERNOON BEFORE A GRADUAL MOISTENING TREND IS EXPECTED AND ANOTHER FRONTAL BOUNDARY BEGINS TO APPROACH THE REGION FROM THE NORTHWEST INTO THE UPCOMING WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 79 57 80 63 / 10 0 0 0 FORT LAUDERDALE 81 63 81 68 / 10 0 0 0 MIAMI 81 63 82 67 / 10 0 0 0 NAPLES 79 58 81 62 / 10 0 0 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
510 PM CDT FRI NOV 2 2012 .DISCUSSION... 329 PM CDT MAIN FORECAST CHALLENGES ARE WITH PERSISTENT LAKE EFFECT CLOUD COVER AS WELL AS POSSIBLE LIGHT RAIN SHOWERS. CURRENT SATELLITE IMAGERY CONTINUES TO SHOW LAKE EFFECT CLOUD COVER TO MOVE DOWN LAKE MICHIGAN THIS AFTERNOON AND SPILLING INTO NORTHWEST INDIANA...AS HIGH LEVEL CLOUD COVER CONTINUES TO WORK ITS WAY EAST ACROSS NORTHERN ILLINOIS. MEANWHILE...RADAR IMAGERY DEPICTING SOME LIGHT SHOWERS ALSO STILL DEVELOPING OVER THE SOUTHERN HALF OF THE LAKE AND MOVING INTO PORTER COUNTY IN NORTHWEST INDIANA. THESE LIGHT SHOWERS ARE DUE IN PART TO A LONG FETCH DOWN THE LAKE WITH SUFFICIENT DELTA TS AND CONVERGENCE NOTED ON OBS/LATEST RAP ANALYSIS. EXPECT THESE SHOWERS TO CONTINUE THIS AFTERNOON AND POSSIBLY INTO THIS EVENING WITH A SLIGHT SHIFT MORE WESTWARD INTO LAKE COUNTY IN NORTHWEST INDIANA AS BOUNDARY LAYER SHIFTS MORE NORTH/NORTHEAST. ALTHOUGH DURING THIS TIME...LATEST FORECAST SOUNDINGS OVER THE LAKE SHOWING SOME WARMING IN THE COLUMN AND A LOWERING OF EQUILIBRIUM HEIGHTS. THIS SHOULD HELP TO STIFLE THE DEVELOPMENT WHICH WE HAVE SEEN ALL DAY...WITH ONLY PRIMARILY LAKE EFFECT CLOUD COVER CONTINUING TO DEVELOP. ALTHOUGH...THERE IS SOME HIGH RES GUIDANCE THAT DOES INDICATE SOME PERSISTENT LIGHT QPF ACROSS THE LAKE AND NEAR THE SHORES TONIGHT AND INTO SATURDAY MORNING...BUT AM NOT COMPLETELY SOLD ON THIS IDEA AS OF YET DUE TO THE PREVIOUSLY MENTIONED WARMING TRENDS. SO HAVE SLIGHT CHANCE POPS GOING INTO THIS EVENING BUT THEN DECREASE OVERNIGHT INTO SATURDAY. IF THERE WERE TO BE ANY SHOWERS TO DEVELOP IT WOULD BE IN THE FORM OF SPRINKLES...FORMING ON THE FRINGE OF BUILDING HIGH PRESSURE. CURRENT WAA ACROSS THE PLAINS WILL SLOWLY SHIFT EAST INTO CENTRAL ILLINOIS TONIGHT OUT AHEAD OF A MID LEVEL TROUGH/SURFACE LOW TO THE WEST. THIS SHOULD HELP CLOUD COVER TO CONTINUE TO SPREAD EAST ACROSS THE ENTIRE CWA TONIGHT...WITH PARTLY CLOUDY SKIES BECOMING MORE CLOUDY. IT DOES APPEAR THE EXTENT OF THE WAA IS WEAKER TONIGHT AND MORE DEFINED FURTHER SOUTH...WITH ANY PRECIP THAT DEVELOPS TONIGHT IN RESPONSE TO THIS FORCING TO STAY SOUTH OF THE CWA. THIS TROUGH/SURFACE REFLECTION WILL CONTINUE EAST ON SATURDAY WITH SOME OF THIS MOISTURE TRYING TO INCH ITS WAY FURTHER NORTH...WITH A SLIGHT CHANCE FOR SHOWERS ON SATURDAY MAINLY ACROSS THE FAR SOUTHERN TIER OF THE CWA. AS HIGHER PRESSURE BUILDS OVERHEAD THROUGH THE REMAINDER OF THE WEEKEND...EXPECT DRY CONDITIONS WITH SIMILAR TEMPS IN THE 40S FOR SATURDAY AND SUNDAY. ALTHOUGH WITH SEVERAL MID LEVEL FEATURES TRAVERSING THE REGION...SOME MID LEVEL MOISTURE SHOULD MOVE OVERHEAD AND BRING SOME CLOUDY CONDITIONS ACROSS THE CWA THIS WEEKEND. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * POTENTIAL FOR MVFR LAKE-INDUCED CLOUDS 2500-3000 FT AGL TONIGHT/SATURDAY. RATZER/IZZI //DISCUSSION...UPDATED 20Z... WINDS WHICH HAVE BEEN VARYING FROM NNW TO NE AT ORD/MDW NOW BECOMING FIRMLY NORTHEAST...WITH LAKE BREEZE BOUNDARY NOW PUSHING OR ALREADY PUSHED THROUGH PER KLOT/TORD RADARS. SHOULD CONTINUE TO SEE 030-040 DEG WINDS NEAR 10 KTS REMAINDER OF AFTERNOON WITH VFR SCT CU AND HIGH BKN/OVC HIGH CIRRUS. RATZER PREVIOUS DISCUSSION FROM 18Z... SURFACE HIGH PRESSURE WAS CENTERED OVER NORTHERN MANITOBA AT MIDDAY WITH A WEAKER HIGH PRESSURE RIDGE EXTENDING SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY. WITH TERMINALS EAST OF THE RIDGE AXIS...WINDS HAVE GENERALLY BEEN NORTHERLY...THOUGH A SHIFT TO THE NORTHEAST 020-040 DEG HAS BEEN ANTICIPATED AS THE HIGH SLOWLY BUILDS SOUTHEAST AND A PSEUDO-LAKE BREEZE DEVELOPS. LATEST SATELLITE AND SURFACE OBSERVATIONS SUGGEST THAT THIS SHIFT MAY OCCUR A LITTLE EARLIER THAN MORNING FORECASTS INDICATED...WITH RECENT ORD/MDW 1-MINUTE ASOS DATA SHOWING WINDS VARYING 340-030 DEG OVER THE PAST HOUR OR SO. LAST COUPLE OF HOURLY RUNS OF RAP MODEL ALSO SUPPORT AN EARLIER SHIFT TO NORTHEAST WINDS. THUS ANTICIPATE NORTHEAST WINDS AROUND 10 KTS TO LOCK IN DURING THE NEXT 1-2 HOURS...AND TO PREVAIL THROUGH THE TAF PERIOD. COOLER AIR ALOFT OVER THE LAKE HAS BEEN PRODUCING A FAIRLY EXTENSIVE AREA OF LAKE-INDUCED STRATOCU AT THE 2500-3000 FT AGL LEVEL. WITH LOW LEVEL WINDS SHIFTING NORTHEAST...SOME OF THIS WILL ATTEMPT OT PUSH INLAND INTO CHICAGO AREA TERMINALS. RAP/NAM/GFS GUIDANCE AND TIME/HEIGHT SECTIONS ALL INDICATE THE POTENTIAL FOR STRATOCU CEILINGS IN THE HIGH-MVFR RANGE TO DEVELOP THIS EVENING AND LINGER THOUGH MUCH OF SATURDAY...WHILE MID/HIGH LEVEL CLOUDS THICKEN AND LOWER IN ASSOCIATION WITH MID-LEVEL TROUGH APPROACHING FROM THE WEST. A FEW SPRINKLES OCCURRING WITH CURRENT LAKE-INDUCED CLOUD COVER INTO INDIANA SHOULD BE MORE LIMITED LATER TONIGHT AND SATURDAY WITH INVERSION HEIGHTS LOWERING. THEREFORE HAVE NOT INDICATED PRECIPITATION IN TAFS...THOUGH AN ISOLATED SPRINKLE NOT COMPLETELY OUT OF THE QUESTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CEILINGS AT/BELOW 3000 FT LATER TONIGHT/SATURDAY. RATZER/IZZI //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT-MONDAY...VFR. TUESDAY...SLIGHT CHC OF RAIN DURING THE DAY. WEDNESDAY...VFR. THURSDAY...VFR. MTF && .MARINE... 217 PM CDT BROAD AREA OF LOW PRESSURE CENTERED ACROSS NORTHEAST QUEBEC WILL CONTINUE TO WEAKEN THE INFLUENCE ACROSS THE WESTERN GREAT LAKES THROUGH TONIGHT INTO SATURDAY...MEANWHILE A RIDGE OF HIGH PRESSURE REMAINS CENTERED ACROSS WESTERN ONTARIO STRETCHING SOUTH THROUGH THE UPPER MISSISSIPPII VALLEY. THIS RIDGE WILL REMAIN NEARLY STATIONARY...WHICH WILL ALLOW A PROLONGED PERIOD OF NORTH FLOW ACROSS LAKE MICHIGAN. GUIDANCE HAS INDICATED THAT A DECENT GRADIENT WILL REMAIN ACROSS LAKE MICHIGAN THROUGH TONIGHT...AND POSSIBLY CONTINUE THROUGH SATURDAY. THIS WILL MOST LIKELY KEEP WINDS UP IN THE 20 TO 25 KT CATEGORY. THE COMBINATION OF CONTINUED COLD AIR...NORTH WINDS AND RELATIVELY WARM LAKE MICHIGAN WATERS WILL RESULT IN WAVES REMAINING ELEVATED. BASED ON THIS SETUP HAVE OPTED TO CONTINUE THE SMALL CRAFT ADVISORY THROUGH TONIGHT AND INTO AT LEAST MID MORNING SATURDAY. BY LATE SATURDAY MORNING WAVES IN THE NEARSHORE SHOULD SUBSIDE ENOUGH TO ALLOW THE ADVISORY TO COME DOWN. GUIDANCE WAS ALSO INDICATING THAT WINDS MAY BEGIN TO TURN NORTHEAST THROUGH A PERIOD OF TIME SATURDAY AFTERNOON/EVENING...AND DIMINISH TO SPEEDS AROUND 10 TO 20 KT. A WEAK AREA OF LOW PRESSURE IS NOW EXPECTED TO PASS WELL SOUTH OF SOUTHERN LAKE MICHIGAN...HOWEVER WINDS ACROSS THE SOUTHERN TIP OF THE LAKE MAY TURN MORE EASTERLY. IF THIS SCENARIO DEVELOPS THE WAVES MAY REMAIN CHOPPY OR CLOSE TO SMALL CRAFT CONDITIONS THROUGH SATURDAY AFTERNOON FOR THE CHICAGO HARBOR AREA. HIGH PRESSURE BY THE END OF THE WEEKEND WILL DRIFT EAST AND ALLOW WINDS TO CONTINUE TO DIMINISH AND TURN EAST THEN SOUTH BY EARLY NEXT WEEK. A LOW PRESSURE IS EXPECTED TO SLIDE ACROSS WESTERN ONTARIO WITH AN INCREASING GRADIENT AND GUSTY WINDS BY TUESDAY. THIS WILL ALLOW WAVES TO STEADILY BUILD AGAIN LATE MONDAY THROUGH TUESDAY. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 11 AM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
332 PM CDT FRI NOV 2 2012 .DISCUSSION... 329 PM CDT MAIN FORECAST CHALLENGES ARE WITH PERSISTENT LAKE EFFECT CLOUD COVER AS WELL AS POSSIBLE LIGHT RAIN SHOWERS. CURRENT SATELLITE IMAGERY CONTINUES TO SHOW LAKE EFFECT CLOUD COVER TO MOVE DOWN LAKE MICHIGAN THIS AFTERNOON AND SPILLING INTO NORTHWEST INDIANA...AS HIGH LEVEL CLOUD COVER CONTINUES TO WORK ITS WAY EAST ACROSS NORTHERN ILLINOIS. MEANWHILE...RADAR IMAGERY DEPICTING SOME LIGHT SHOWERS ALSO STILL DEVELOPING OVER THE SOUTHERN HALF OF THE LAKE AND MOVING INTO PORTER COUNTY IN NORTHWEST INDIANA. THESE LIGHT SHOWERS ARE DUE IN PART TO A LONG FETCH DOWN THE LAKE WITH SUFFICIENT DELTA TS AND CONVERGENCE NOTED ON OBS/LATEST RAP ANALYSIS. EXPECT THESE SHOWERS TO CONTINUE THIS AFTERNOON AND POSSIBLY INTO THIS EVENING WITH A SLIGHT SHIFT MORE WESTWARD INTO LAKE COUNTY IN NORTHWEST INDIANA AS BOUNDARY LAYER SHIFTS MORE NORTH/NORTHEAST. ALTHOUGH DURING THIS TIME...LATEST FORECAST SOUNDINGS OVER THE LAKE SHOWING SOME WARMING IN THE COLUMN AND A LOWERING OF EQUILIBRIUM HEIGHTS. THIS SHOULD HELP TO STIFLE THE DEVELOPMENT WHICH WE HAVE SEEN ALL DAY...WITH ONLY PRIMARILY LAKE EFFECT CLOUD COVER CONTINUING TO DEVELOP. ALTHOUGH...THERE IS SOME HIGH RES GUIDANCE THAT DOES INDICATE SOME PERSISTENT LIGHT QPF ACROSS THE LAKE AND NEAR THE SHORES TONIGHT AND INTO SATURDAY MORNING...BUT AM NOT COMPLETELY SOLD ON THIS IDEA AS OF YET DUE TO THE PREVIOUSLY MENTIONED WARMING TRENDS. SO HAVE SLIGHT CHANCE POPS GOING INTO THIS EVENING BUT THEN DECREASE OVERNIGHT INTO SATURDAY. IF THERE WERE TO BE ANY SHOWERS TO DEVELOP IT WOULD BE IN THE FORM OF SPRINKLES...FORMING ON THE FRINGE OF BUILDING HIGH PRESSURE. CURRENT WAA ACROSS THE PLAINS WILL SLOWLY SHIFT EAST INTO CENTRAL ILLINOIS TONIGHT OUT AHEAD OF A MID LEVEL TROUGH/SURFACE LOW TO THE WEST. THIS SHOULD HELP CLOUD COVER TO CONTINUE TO SPREAD EAST ACROSS THE ENTIRE CWA TONIGHT...WITH PARTLY CLOUDY SKIES BECOMING MORE CLOUDY. IT DOES APPEAR THE EXTENT OF THE WAA IS WEAKER TONIGHT AND MORE DEFINED FURTHER SOUTH...WITH ANY PRECIP THAT DEVELOPS TONIGHT IN RESPONSE TO THIS FORCING TO STAY SOUTH OF THE CWA. THIS TROUGH/SURFACE REFLECTION WILL CONTINUE EAST ON SATURDAY WITH SOME OF THIS MOISTURE TRYING TO INCH ITS WAY FURTHER NORTH...WITH A SLIGHT CHANCE FOR SHOWERS ON SATURDAY MAINLY ACROSS THE FAR SOUTHERN TIER OF THE CWA. AS HIGHER PRESSURE BUILDS OVERHEAD THROUGH THE REMAINDER OF THE WEEKEND...EXPECT DRY CONDITIONS WITH SIMILAR TEMPS IN THE 40S FOR SATURDAY AND SUNDAY. ALTHOUGH WITH SEVERAL MID LEVEL FEATURES TRAVERSING THE REGION...SOME MID LEVEL MOISTURE SHOULD MOVE OVERHEAD AND BRING SOME CLOUDY CONDITIONS ACROSS THE CWA THIS WEEKEND. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WIND SHIFTING TO NORTHEAST THIS AFTERNOON. * POTENTIAL FOR MVFR LAKE-INDUCED CLOUDS 2500-3000 FT AGL TONIGHT/SATURDAY. RATZER //DISCUSSION...UPDATED 20Z... WINDS WHICH HAVE BEEN VARYING FROM NNW TO NE AT ORD/MDW NOW BECOMING FIRMLY NORTHEAST...WITH LAKE BREEZE BOUNDARY NOW PUSHING OR ALREADY PUSHED THROUGH PER KLOT/TORD RADARS. SHOULD CONTINUE TO SEE 030-040 DEG WINDS NEAR 10 KTS REMAINDER OF AFTERNOON WITH VFR SCT CU AND HIGH BKN/OVC HIGH CIRRUS. RATZER PREVIOUS DISCUSSION FROM 18Z... SURFACE HIGH PRESSURE WAS CENTERED OVER NORTHERN MANITOBA AT MIDDAY WITH A WEAKER HIGH PRESSURE RIDGE EXTENDING SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY. WITH TERMINALS EAST OF THE RIDGE AXIS...WINDS HAVE GENERALLY BEEN NORTHERLY...THOUGH A SHIFT TO THE NORTHEAST 020-040 DEG HAS BEEN ANTICIPATED AS THE HIGH SLOWLY BUILDS SOUTHEAST AND A PSEUDO-LAKE BREEZE DEVELOPS. LATEST SATELLITE AND SURFACE OBSERVATIONS SUGGEST THAT THIS SHIFT MAY OCCUR A LITTLE EARLIER THAN MORNING FORECASTS INDICATED...WITH RECENT ORD/MDW 1-MINUTE ASOS DATA SHOWING WINDS VARYING 340-030 DEG OVER THE PAST HOUR OR SO. LAST COUPLE OF HOURLY RUNS OF RAP MODEL ALSO SUPPORT AN EARLIER SHIFT TO NORTHEAST WINDS. THUS ANTICIPATE NORTHEAST WINDS AROUND 10 KTS TO LOCK IN DURING THE NEXT 1-2 HOURS...AND TO PREVAIL THROUGH THE TAF PERIOD. COOLER AIR ALOFT OVER THE LAKE HAS BEEN PRODUCING A FAIRLY EXTENSIVE AREA OF LAKE-INDUCED STRATOCU AT THE 2500-3000 FT AGL LEVEL. WITH LOW LEVEL WINDS SHIFTING NORTHEAST...SOME OF THIS WILL ATTEMPT OT PUSH INLAND INTO CHICAGO AREA TERMINALS. RAP/NAM/GFS GUIDANCE AND TIME/HEIGHT SECTIONS ALL INDICATE THE POTENTIAL FOR STRATOCU CEILINGS IN THE HIGH-MVFR RANGE TO DEVELOP THIS EVENING AND LINGER THOUGH MUCH OF SATURDAY...WHILE MID/HIGH LEVEL CLOUDS THICKEN AND LOWER IN ASSOCIATION WITH MID-LEVEL TROUGH APPROACHING FROM THE WEST. A FEW SPRINKLES OCCURRING WITH CURRENT LAKE-INDUCED CLOUD COVER INTO INDIANA SHOULD BE MORE LIMITED LATER TONIGHT AND SATURDAY WITH INVERSION HEIGHTS LOWERING. THEREFORE HAVE NOT INDICATED PRECIPITATION IN TAFS...THOUGH AN ISOLATED SPRINKLE NOT COMPLETELY OUT OF THE QUESTION. RATZER //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN CEILINGS AT/BELOW 3000 FT LATER TONIGHT/SATURDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT-MONDAY...VFR. TUESDAY...SLIGHT CHC OF RAIN DURING THE DAY. WEDNESDAY...VFR. THURSDAY...VFR. MTF && .MARINE... 217 PM CDT BROAD AREA OF LOW PRESSURE CENTERED ACROSS NORTHEAST QUEBEC WILL CONTINUE TO WEAKEN THE INFLUENCE ACROSS THE WESTERN GREAT LAKES THROUGH TONIGHT INTO SATURDAY...MEANWHILE A RIDGE OF HIGH PRESSURE REMAINS CENTERED ACROSS WESTERN ONTARIO STRETCHING SOUTH THROUGH THE UPPER MISSISSIPPII VALLEY. THIS RIDGE WILL REMAIN NEARLY STATIONARY...WHICH WILL ALLOW A PROLONGED PERIOD OF NORTH FLOW ACROSS LAKE MICHIGAN. GUIDANCE HAS INDICATED THAT A DECENT GRADIENT WILL REMAIN ACROSS LAKE MICHIGAN THROUGH TONIGHT...AND POSSIBLY CONTINUE THROUGH SATURDAY. THIS WILL MOST LIKELY KEEP WINDS UP IN THE 20 TO 25 KT CATEGORY. THE COMBINATION OF CONTINUED COLD AIR...NORTH WINDS AND RELATIVELY WARM LAKE MICHIGAN WATERS WILL RESULT IN WAVES REMAINING ELEVATED. BASED ON THIS SETUP HAVE OPTED TO CONTINUE THE SMALL CRAFT ADVISORY THROUGH TONIGHT AND INTO AT LEAST MID MORNING SATURDAY. BY LATE SATURDAY MORNING WAVES IN THE NEARSHORE SHOULD SUBSIDE ENOUGH TO ALLOW THE ADVISORY TO COME DOWN. GUIDANCE WAS ALSO INDICATING THAT WINDS MAY BEGIN TO TURN NORTHEAST THROUGH A PERIOD OF TIME SATURDAY AFTERNOON/EVENING...AND DIMINISH TO SPEEDS AROUND 10 TO 20 KT. A WEAK AREA OF LOW PRESSURE IS NOW EXPECTED TO PASS WELL SOUTH OF SOUTHERN LAKE MICHIGAN...HOWEVER WINDS ACROSS THE SOUTHERN TIP OF THE LAKE MAY TURN MORE EASTERLY. IF THIS SCENARIO DEVELOPS THE WAVES MAY REMAIN CHOPPY OR CLOSE TO SMALL CRAFT CONDITIONS THROUGH SATURDAY AFTERNOON FOR THE CHICAGO HARBOR AREA. HIGH PRESSURE BY THE END OF THE WEEKEND WILL DRIFT EAST AND ALLOW WINDS TO CONTINUE TO DIMINISH AND TURN EAST THEN SOUTH BY EARLY NEXT WEEK. A LOW PRESSURE IS EXPECTED TO SLIDE ACROSS WESTERN ONTARIO WITH AN INCREASING GRADIENT AND GUSTY WINDS BY TUESDAY. THIS WILL ALLOW WAVES TO STEADILY BUILD AGAIN LATE MONDAY THROUGH TUESDAY. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 11 AM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1213 PM CDT FRI NOV 2 2012 .DISCUSSION... ISSUED 955 AM CDT FRI NOV 2 2012 GOING FORECAST LARGELY HAS A GOOD HANDLE ON THE TRENDS AND LITTLE CHANGE IS NEEDED THIS MORNING. THIN HIGH CLOUDS CONTINUE TO OVERSPREAD THE FORECAST AREA FROM THE NORTHWEST...WITH LATEST NAM AND RAP GUIDANCE SHOWING THESE CLOUDS THICKENING DURING THE AFTERNOON HOURS. THERE SHOULD BE ENOUGH SUNSHINE TO GET TEMPERATURES INTO THE 50-55 DEGREE RANGE OVER THE CWA...AND MAY GET A TAD HIGHER IN THE FAR SOUTHEAST WHERE THE MOST SUNSHINE WILL OCCUR. GEELHART && .AVIATION... ISSUED 1213 PM CDT FRI NOV 2 2012 LITTLE CHANGE REQUIRED TO PREVIOUS TAFS. MID AND HIGH CLOUDS WILL CONTINUE TO OVERSPREAD THE AREA THIS AFTERNOON AND SLOWLY LOWER THIS EVENING. FORECAST SOUNDINGS KEEP CEILINGS ABOVE 6000 FEET LATER IN THE PERIOD...AS LOW PRESSURE MOVES ACROSS SOUTHERN MISSOURI INTO WESTERN KENTUCKY/TENNESSEE. LIGHT SHOWERS NORTH OF THIS LOW TRACK WILL MAKE A CLOSE PASS AT KDEC/KSPI DURING ABOUT THE 10-15Z TIME FRAME...AND WILL MAINTAIN THE VCSH MENTION AT THESE SITES. CANNOT RULE OUT A SIMILAR OCCURRENCE AT KCMI...BUT DRY LOW LEVELS OF THE SOUNDINGS MAKE IT MORE UNCERTAIN AND THUS WILL LEAVE RAIN MENTION OUT OF THE KCMI TAF FOR NOW. GEELHART && .PREV DISCUSSION... ISSUED 330 AM CDT FRI NOV 2 2012 SHORT TERM...TODAY THROUGH MONDAY 00Z MODELS IN FAIR AGREEMENT NEXT FEW DAYS INCLUDING THE MAV AND MET GUIDANCE TEMPS AND WILL USE A BLEND. USED A BLEND OF THE 00Z GFS AND ECMWF MODELS FOR THE EXTENDED FORECAST. A COLD FRONT WAS PRESSING SE TOWARD THE OHIO RIVER AND SOUTHERN MO EARLY THIS MORNING WITH NNW WINDS 5-10 MPH BRINGING COOLER AND DRIER AIR BACK INTO CENTRAL IL. TEMPS WERE IN THE 30S OVER CENTRAL IL WITH GALESBURG DOWN TO 31F...AND LOW TO MID 40S IN SE IL. DEWPOINTS WERE IN THE UPPER 20S AND LOWER 30S CENTRAL IL AND MID 30S SE IL. COOLER AND DRIER AIR FROM 1031 CANADIAN HIGH PRESSURE OVER MANITOBA AND RIDGING SOUTHWARD INTO THE EASTERN PLAINS WEST OF THE MS RIVER. IR SATELLITE LOOPS SHOW CIRRUS CLOUDS SPREADING SE FROM THE NORTHERN PLAINS ACROSS IA INTO PARTS OF WESTERN IL EARLY THIS MORNING WITH CLEAR SKIES IN EASTERN IL. EXPECT INCREASING HIGH CLOUDS TODAY WITH SCATTERED MID LEVEL AND BROKEN CIRRUS CLOUDS OVERALL TODAY TO GIVE WAY TO PARTLY SUNNY SKIES. COOLER HIGHS TODAY BEHIND THE COLD FRONT IN THE LOWER 50S CENTRAL IL AND MID 50S IN SE IL. 1006 MB LOW PRESSURE OVER SE CO TO WEAKEN TO 1013 MB AS IT TRACKS ALONG THE MO/AR BORDER OVERNIGHT INTO SAT MORNING. SOME ISENTROPIC LIFT AHEAD OF A WARM FRONT SW OF IL TO SPREAD A CHANCE OF SHOWERS INTO AREAS SOUTH OF I-72 OVERNIGHT AND SHIFTING INTO SE IL SUNDAY MORNING. KEPT ISOLATED THUNDER IN FAR SW/SE AREAS OVERNIGHT INTO SUNDAY MORNING. CANADIAN HIGH PRESSURE NORTH OF IL TO KEEP NORTHERN AREAS DRIER ALONG WITH BELOW NORMAL TEMPS TO PREVAIL ACROSS AREA THIS WEEKEND. LOWS FRI NIGHT IN THE MID TO UPPER 30S. HIGHS SAT IN THE UPPER 40S AND LOWER 50S WITH MILDEST READINGS NW OF THE IL RIVER WHERE A BIT MORE SUNSHINE POSSIBLE LATER IN THE DAY. HIGHS SUNDAY IN THE LOW TO MID 50S WITH PARTLY TO MOSTLY CLOUDY SKIES. UPPER LEVEL TROF DIGS INTO THE GREAT LAKES REGION INCLUDING IL/IN BY SUNDAY AFTERNOON BUT VERY LIMITED MOISTURE AND KEEPING IT DRY. HAVE A JUST A SLIGHT CHANCE OF SHOWERS OVER FAR SW AREAS LATE SUNDAY NIGHT AND MONDAY WITH STRONGER UPPER LEVEL TROF/LOW PRESSURE MOVING SE ACROSS SW MO AND AR WHERE BEST CHANCES OF SHOWERS WILL BE TO OUR SW. LOWS SUNDAY NIGHT IN THE LOW TO MID 30S WITH COOL HIGHS MONDAY AROUND 50F. LONG TERM...MONDAY NIGHT THROUGH FRIDAY MAINTAINED DRY CONDITIONS DURING THIS TIME FRAME WITH BEST CHANCE OF SHOWERS OVER NORTHERN IL TUE. NOTICED THE ECMWF MODEL DOES BRING LIGHT QPF AS FAR SOUTH AS CENTRAL IL TUE AFTERNOON/EVENING WITH PASSAGE OF A COLD FRONT. BUT BETTER LIFT AND MOISTURE IS OVER THE GREAT LAKES REGION AND GFS KEEPS QPF NNE OF CENTRAL IL SO WILL STAY WITH ALLBLEND POPS LESS THAN 15%. IL IN A NW UPPER LEVEL FLOW DURING FIRST HALF OF NEXT WEEK WITH UPPER LEVEL TROF OVER THE EASTERN STATES AND UPPER LEVEL RIDGE IN THE WESTERN STATES. UPPER LEVEL HEIGHTS RISE OVER THE MS VALLEY DURING 2ND HALF OF NEXT WEEK WITH A WARMING TREND. ECMWF (ECE) IS 10-15F WARMER THAN GFS (MEX) BY NEXT FRI. STAYED CLOSE TO ALLBEND TEMPS DUE TO THESE DIFFERENCES WHICH GIVES HIGHS IN THE MID TO UPPER 50S THU AND LOW TO MID 60S FRI. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
957 AM CDT FRI NOV 2 2012 .DISCUSSION... ISSUED 955 AM CDT FRI NOV 2 2012 GOING FORECAST LARGELY HAS A GOOD HANDLE ON THE TRENDS AND LITTLE CHANGE IS NEEDED THIS MORNING. THIN HIGH CLOUDS CONTINUE TO OVERSPREAD THE FORECAST AREA FROM THE NORTHWEST...WITH LATEST NAM AND RAP GUIDANCE SHOWING THESE CLOUDS THICKENING DURING THE AFTERNOON HOURS. THERE SHOULD BE ENOUGH SUNSHINE TO GET TEMPERATURES INTO THE 50-55 DEGREE RANGE OVER THE CWA...AND MAY GET A TAD HIGHER IN THE FAR SOUTHEAST WHERE THE MOST SUNSHINE WILL OCCUR. GEELHART && .AVIATION... ISSUED 657 AM CDT FRI NOV 2 2012 VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE 12Z TAF PERIOD. HIGH/THIN OVERCAST WILL BE NOTED THROUGHOUT THE DAY...FOLLOWED BY A GRADUAL THICKENING/LOWERING OF THE CLOUD COVER TONIGHT. FORECAST SOUNDINGS SUGGEST CEILINGS DROPPING TO BETWEEN 6000 AND 8000FT AFTER 07Z. AS A WEAK WEATHER DISTURBANCE SKIRTS BY TO THE SOUTH...A FEW SHOWERS MAY DEVELOP AS FAR NORTH AS KSPI AND KDEC OVERNIGHT. HAVE INCLUDED VCSH AT THOSE SITES AFTER 07/08Z...WITH DRY CONDITIONS ELSEWHERE. WINDS WILL BE N AT 5 TO 10 MPH THIS MORNING...THEN WILL VEER TO E/NE THIS AFTERNOON/EVENING. BARNES && .PREV DISCUSSION... ISSUED 330 AM CDT FRI NOV 2 2012 SHORT TERM...TODAY THROUGH MONDAY 00Z MODELS IN FAIR AGREEMENT NEXT FEW DAYS INCLUDING THE MAV AND MET GUIDANCE TEMPS AND WILL USE A BLEND. USED A BLEND OF THE 00Z GFS AND ECMWF MODELS FOR THE EXTENDED FORECAST. A COLD FRONT WAS PRESSING SE TOWARD THE OHIO RIVER AND SOUTHERN MO EARLY THIS MORNING WITH NNW WINDS 5-10 MPH BRINGING COOLER AND DRIER AIR BACK INTO CENTRAL IL. TEMPS WERE IN THE 30S OVER CENTRAL IL WITH GALESBURG DOWN TO 31F...AND LOW TO MID 40S IN SE IL. DEWPOINTS WERE IN THE UPPER 20S AND LOWER 30S CENTRAL IL AND MID 30S SE IL. COOLER AND DRIER AIR FROM 1031 CANADIAN HIGH PRESSURE OVER MANITOBA AND RIDGING SOUTHWARD INTO THE EASTERN PLAINS WEST OF THE MS RIVER. IR SATELLITE LOOPS SHOW CIRRUS CLOUDS SPREADING SE FROM THE NORTHERN PLAINS ACROSS IA INTO PARTS OF WESTERN IL EARLY THIS MORNING WITH CLEAR SKIES IN EASTERN IL. EXPECT INCREASING HIGH CLOUDS TODAY WITH SCATTERED MID LEVEL AND BROKEN CIRRUS CLOUDS OVERALL TODAY TO GIVE WAY TO PARTLY SUNNY SKIES. COOLER HIGHS TODAY BEHIND THE COLD FRONT IN THE LOWER 50S CENTRAL IL AND MID 50S IN SE IL. 1006 MB LOW PRESSURE OVER SE CO TO WEAKEN TO 1013 MB AS IT TRACKS ALONG THE MO/AR BORDER OVERNIGHT INTO SAT MORNING. SOME ISENTROPIC LIFT AHEAD OF A WARM FRONT SW OF IL TO SPREAD A CHANCE OF SHOWERS INTO AREAS SOUTH OF I-72 OVERNIGHT AND SHIFTING INTO SE IL SUNDAY MORNING. KEPT ISOLATED THUNDER IN FAR SW/SE AREAS OVERNIGHT INTO SUNDAY MORNING. CANADIAN HIGH PRESSURE NORTH OF IL TO KEEP NORTHERN AREAS DRIER ALONG WITH BELOW NORMAL TEMPS TO PREVAIL ACROSS AREA THIS WEEKEND. LOWS FRI NIGHT IN THE MID TO UPPER 30S. HIGHS SAT IN THE UPPER 40S AND LOWER 50S WITH MILDEST READINGS NW OF THE IL RIVER WHERE A BIT MORE SUNSHINE POSSIBLE LATER IN THE DAY. HIGHS SUNDAY IN THE LOW TO MID 50S WITH PARTLY TO MOSTLY CLOUDY SKIES. UPPER LEVEL TROF DIGS INTO THE GREAT LAKES REGION INCLUDING IL/IN BY SUNDAY AFTERNOON BUT VERY LIMITED MOISTURE AND KEEPING IT DRY. HAVE A JUST A SLIGHT CHANCE OF SHOWERS OVER FAR SW AREAS LATE SUNDAY NIGHT AND MONDAY WITH STRONGER UPPER LEVEL TROF/LOW PRESSURE MOVING SE ACROSS SW MO AND AR WHERE BEST CHANCES OF SHOWERS WILL BE TO OUR SW. LOWS SUNDAY NIGHT IN THE LOW TO MID 30S WITH COOL HIGHS MONDAY AROUND 50F. LONG TERM...MONDAY NIGHT THROUGH FRIDAY MAINTAINED DRY CONDITIONS DURING THIS TIME FRAME WITH BEST CHANCE OF SHOWERS OVER NORTHERN IL TUE. NOTICED THE ECMWF MODEL DOES BRING LIGHT QPF AS FAR SOUTH AS CENTRAL IL TUE AFTERNOON/EVENING WITH PASSAGE OF A COLD FRONT. BUT BETTER LIFT AND MOISTURE IS OVER THE GREAT LAKES REGION AND GFS KEEPS QPF NNE OF CENTRAL IL SO WILL STAY WITH ALLBLEND POPS LESS THAN 15%. IL IN A NW UPPER LEVEL FLOW DURING FIRST HALF OF NEXT WEEK WITH UPPER LEVEL TROF OVER THE EASTERN STATES AND UPPER LEVEL RIDGE IN THE WESTERN STATES. UPPER LEVEL HEIGHTS RISE OVER THE MS VALLEY DURING 2ND HALF OF NEXT WEEK WITH A WARMING TREND. ECMWF (ECE) IS 10-15F WARMER THAN GFS (MEX) BY NEXT FRI. STAYED CLOSE TO ALLBEND TEMPS DUE TO THESE DIFFERENCES WHICH GIVES HIGHS IN THE MID TO UPPER 50S THU AND LOW TO MID 60S FRI. 07 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1139 AM MDT FRI NOV 2 2012 .UPDATE... ISSUED AT 1016 AM MDT FRI NOV 2 2012 COMPLICATED TEMPERATURE FORECAST EXPECTED TODAY AS NUMEROUS VARIABLES HAVING A LARGE IMPACT ON TEMPERATURES ACROSS REGION. TO THE NORTH...THICK MOUNTAIN CIRRUS AIDED BY PERSISTENT AREA OF ASCENT ALONG ELEVATED FRONTAL ZONE/JET STREAK HAVE HELD TEMPERATURES BACK...WITH AREAS TO THE SOUTH WARMING MUCH FASTER (ASIDE FROM FEW LOCATIONS IMPACTED BY FOG). WITH NORTHERLY WINDS INCREASING INTO THE 25 TO 30 MPH FOR A FEW HOURS CAA WILL ALSO TEMPER HIGHS SOMEWHAT...WITH TEMPS STABILIZING OR FALLING SLIGHTLY IN THE NEXT 3 HOURS. HAVE WARMED FORECAST AROUND 5 DEGREES IN AREA WITH LESS CLOUDS...BUT HAVE MAX TEMPS PEAK EARLIER AND THEN FALL A BIT SOONER THAN CLIMO SUGGESTS. WITH BREEZY/WINDY CONDITIONS AND WARMER TEMPS AM A BIT CONCERNED ABOUT FIRE WEATHER WITH AFTERNOON HUMIDITIES FALLING TO AROUND 18 PERCENT. WITH MARGINAL FIRE WX CONDITIONS POSSIBLE...CONCERN IS HEIGHTENED...BUT WITH COOLER/MORE HUMID AIR FILTERING IN FROM THE NORTH CONFIDENCE NOT HIGH ENOUGH FOR WARNING AT THIS POINT. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 305 AM MDT FRI NOV 2 2012 FORECAST CONCERNS WILL BE TEMPERATURE FORECAST INTO THE WEEKEND AND FIRE WEATHER ISSUES TODAY. SATELLITE SHOWING A VERY AMPLIFIED PATTERN OVER THE PACIFIC. THIS TRANSITIONS INTO A SPLIT FLOW OVER THE WESTERN PORTION OF NORTH AMERICA THEN TO AN AMPLIFIED TROUGH OVER EASTERN NORTH AMERICA. TROUGH APPROACHING FROM THE WEST IS SPLITTING IN TWO WITH THE STRONGER PORTION MOVING WELL TO OUR NORTH. SURFACE TROUGH AND COLD FRONT MOVING THROUGH THE AREA AT THIS TIME. MODELS DID FINE AT JET LEVEL. AT MID LEVELS...THE MODELS INITIALIZED FINE WITH A LITTLE BIT OF DIFFERENCE ON THE WESTERN TROUGH. THE NAM...GFS...AND UKMET WERE DOING BETTER WITH THAT AND OVERALL. THE RUC AND NAM WERE HANDLING THE SURFACE WIND AND FEATURES THE BEST. MODELS WERE CLOSE TO EACH OTHER ON THE LOW LEVEL THERMAL FIELD. THE CANADIAN...SREF...NAM...AND GFS WERE DOING A LITTLE BETTER. TODAY/TONIGHT...RUC IS HANDLING THE WINDS AND DEWPOINTS WELL INITIALLY THIS MORNING. IT IS BRINGING IN A LITTLE FOG INTO THE EASTERN PORTION EARLY THIS MORNING. DEWPOINT DEPRESSIONS IN THAT AREA ARE ALREADY LOW AND FOG HAS DEVELOPED NOT TOO FAR EAST OF MY AREA. SO HAVE INSERTED SOME PATCHY FOG IN THROUGH MID MORNING. RIGHT REAR QUADRANT OF THE UPPER JET WILL MOVE ACROSS THE AREA FROM LATE THIS MORNING THROUGH THE OVERNIGHT HOURS. SOUNDING PROFILES SHOW A VERY DEEP DRY LAYER SO ONLY EXPECT THICK HIGH CLOUDS AND MAYBE SOME MID CLOUDS. BY 18Z THE FRONT HAS MOVED THROUGH THE AREA ...WITH BREEZY WINDS...WITH STEADY OR FALLING 850 MB TEMPERATURES AFTER THAT. THE CLOUDS LOOK TO HANG AROUND MOST OF THE DAY AND ALSO COULD BE RATHER THICK. MADE ONLY SLIGHT ADJUSTMENTS BASED ON CHANGE IN 850 MB TEMPERATURES FROM YESTERDAY...BIAS ADJUSTMENTS AND BEST PERFORMING GUIDANCE. JET WILL KEEP SOME CLOUDS AROUND TONIGHT BUT SHOULD BE NEARLY GONE BY 12Z. LIGHT AND VARIABLE WIND FIELD IS EXPECTED BY THAT TIME. SO WOULD EXPECT PRETTY GOOD RADIATIONAL CONDITIONS. AS A RESULT TRENDED TOWARD THE COOLER GUIDANCE. HOWEVER...THEY MAY NOT BE COOL ENOUGH. SATURDAY/SATURDAY NIGHT...ABOVE MENTIONED UPPER JET EXITS THE AREA EARLY IN THE DAY. TEMPERATURE FORECAST LOOKS TO BE A LITTLE TRICKY. WILL HAVE A COOL START TO THE DAY AND WIND FIELD DOES NOT LOOK THAT STRONG...ESPECIALLY IN THE EAST...AS THE SURFACE RIDGE PULLS AWAY. ALSO THERE LOOKS TO BE VARIABLE CLOUD COVER. CLOUDS WILL INCREASE LATER IN THE MORNING INTO THE AFTERNOON AS THE NEXT SHORTWAVE APPROACHES. TEMPERATURE CHANGE AND BIAS ADJUSTMENTS SUPPORT NWP AND 2 METER TEMPERATURES AND MADE LITTLE IF ANY CHANGES FOR THE MAXES. WEAKER JET MOVES ACROSS TO THE NORTH AND EAST OF THE AREA DURING THE NIGHT. THAT COMBINED WITH ANOTHER SHORTWAVE SHOULD KEEP A DECENT AMOUNT OF CLOUDS AROUND. WIND FIELD WILL BE LIGHT IN THE EAST WITH WARM AIR ADVECTION BEGINNING IN THE WEST. SUNDAY/SUNDAY NIGHT...DUE TO THE SHARP NORTHWEST FLOW ALOFT...A SERIES OF SHORTWAVE TROUGHS...WITH THE STRONGEST ONE APPROACHING IN THE AFTERNOON WILL MOVE THROUGH THE AREA. PLAN VIEW RH AND FORECAST SOUNDINGS WOULD INDICATE A RATHER THICK MID AND UPPER LEVEL CLOUD DECK. SO DO NOT EXPECT A LOT OF SUN AND MIXING. IF THERE WERE MORE SUN...I WOULD EXPECT MORE WIND. MAY BUMP UP WINDS A LITTLE. HOWEVER MORE IMPORTANTLY WILL KEEP MAXES COOL AND BELOW THE NWP. RATHER STRONG UPPER JET DIVES DOWN THE WEST SIDE OF THE UPPER TROUGH THAT IS MOVING THROUGH THE NORTH CENTRAL PORTION OF THE COUNTRY. THE BRUNT OF THAT JET WILL AFFECT THE EASTERN HALF LATER IN THE NIGHT. MODEL SOUNDINGS SHOW A SATURATED PROFILE FROM NEAR 650 MB AND UP. WITH THE LAPSE RATES AND STRONG FORCING ALOFT WOULD NOT BE SURPRISED TO MAYBE SEE SOME SPRINKLES. HOWEVER...THIS IS TOO LOW ON THE END OF PROBABILITY TO INSERT. AT THE VERY LEAST THE CLOUDS WILL KEEP THE MINS WARMER. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 305 AM MDT FRI NOV 2 2012 A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH THE PLAINS ON MONDAY. THE PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE SHOULD STAY WELL TO THE EAST OF THE TRI-STATE REGION. HOWEVER...THIS DISTURBANCE COULD BRING SOME CLOUDS AND GUSTY WINDS FOR MONDAY. A RIDGE OF HIGH PRESSURE WILL DEVELOP OVER THE ROCKY MOUNTAINS EARLY NEXT WEEK. MODELS ARE INDICATING THAT THIS RIDGE OF HIGH PRESSURE WILL NOT LAST VERY LONG...WEAKENING AS IT MOVES TO THE EAST ON TUESDAY AND WEDNESDAY. AS THE RIDGE WEAKENS...A STRONG UPPER LEVEL TROUGH WILL DEVELOP OVER THE PACIFIC AND BEGIN MAKING ITS WAY ACROSS THE PACIFIC NORTHWEST AND ROCKY MOUNTAINS. THE GFS AND EUROPEAN MODELS INDICATE THAT THIS TROUGH MAY MOVE CLOSE ENOUGH TO THE TRI-STATE AREA TO HAVE AN IMPACT ON OUR WEATHER BY FRIDAY. UNFORTUNATELY...THERE IS SOME MODEL DISAGREEMENT BY FRIDAY. MODELS HAVE ALSO TRENDED THIS TROUGH FARTHER TO THE NORTH...THUS LEADING TO A REDUCED CHANCE FOR ANY TYPE OF SIGNIFICANT WEATHER CHANGE OR PRECIPITATION. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO RESUME ON TUESDAY. HIGH AND LOW TEMPERATURES WILL AVERAGE BETWEEN 5 AND 10 DEGREES ABOVE NORMAL. SOUTH TO SOUTHEAST WINDS IN THE LATER PORTION OF THE WORK WEEK WILL BRING AN INCREASE IN MOISTURE TO THE REGION. AS OF RIGHT NOW...NO PRECIPITATION IS EXPECTED BUT THIS COULD CHANGE DEPENDING ON THE EXACT LOCATION AND TRACK OF THE WEATHER SYSTEM MENTIONED ABOVE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1139 AM MDT FRI NOV 2 2012 VFR CONDITIONS ARE EXPECTED TO PREVAIL THRU THE TAF PERIOD AT BOTH MCK AND GLD. A COLD FRONT PUSHED THROUGH BOTH TERMINALS EARLIER TODAY BRINGING HIGH CLOUDS AND BREEZY CONDITIONS. WINDS OUT OF THE NORTH AT 20-30KTS THIS AFTERNOON WILL DIMINISH SHORTLY AFTER SUNSET THIS EVENING...BECOMING LIGHT FOR THE REST OF THE TAG PERIOD. A HIGH LEVEL BROKEN DECK WILL PERSIST INTO THE EVENING HOURS...WITH A MID LEVEL DECK DEVELOPING OVERNIGHT. SOME SIGNS ARE POINTING TO A POSSIBILITY OF MVFR VISIBILITIES AT MCK TOMORROW MORNING...SUCH AS THE SAME INDICATING GOOD LOW LEVEL MOISTURE ADVECTION NEAR THE SURFACE AND THE LATEST NAM MOS SHOWING MVFR VIS...BUT AM NOT CONFIDENT ENOUGH TO INCLUDE IT IN THE CURRENT TAF. && .FIRE WEATHER... ISSUED AT 305 AM MDT FRI NOV 2 2012 WINDS TODAY WILL BE BECOME BREEZY. AS STATED ABOVE RUC HAS THE DEWPOINTS BEST EARLY WITH BCALLBLEND DOING WELL. LOOKING UPSTREAM WILL INITIALLY HAVE THE DEWPOINTS GO UP BEFORE THE DRYING AND SUBSIDENCE KICK IN. WIND CRITERIA FOR FIRE WEATHER LOOKS TO BE REACH CRITERIA. HOWEVER...THE COOLER TEMPERATURES AND HIGHER DEWPOINTS WILL KEEP THE RHS ABOVE THE NEEDED CRITERIA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...BULLER LONG TERM...RRH AVIATION...JRM/JJM FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1025 AM MDT FRI NOV 2 2012 .UPDATE... ISSUED AT 1016 AM MDT FRI NOV 2 2012 COMPLICATED TEMPERATURE FORECAST EXPECTED TODAY AS NUMEROUS VARIABLES HAVING A LARGE IMPACT ON TEMPERATURES ACROSS REGION. TO THE NORTH...THICK MOUNTAIN CIRRUS AIDED BY PERSISTENT AREA OF ASCENT ALONG ELEVATED FRONTAL ZONE/JET STREAK HAVE HELD TEMPERATURES BACK...WITH AREAS TO THE SOUTH WARMING MUCH FASTER (ASIDE FROM FEW LOCATIONS IMPACTED BY FOG). WITH NORTHERLY WINDS INCREASING INTO THE 25 TO 30 MPH FOR A FEW HOURS CAA WILL ALSO TEMPER HIGHS SOMEWHAT...WITH TEMPS STABILIZING OR FALLING SLIGHTLY IN THE NEXT 3 HOURS. HAVE WARMED FORECAST AROUND 5 DEGREES IN AREA WITH LESS CLOUDS...BUT HAVE MAX TEMPS PEAK EARLIER AND THEN FALL A BIT SOONER THAN CLIMO SUGGESTS. WITH BREEZY/WINDY CONDITIONS AND WARMER TEMPS AM A BIT CONCERNED ABOUT FIRE WEATHER WITH AFTERNOON HUMIDITIES FALLING TO AROUND 18 PERCENT. WITH MARGINAL FIRE WX CONDITIONS POSSIBLE...CONCERN IS HEIGHTENED...BUT WITH COOLER/MORE HUMID AIR FILTERING IN FROM THE NORTH CONFIDENCE NOT HIGH ENOUGH FOR WARNING AT THIS POINT. && .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 305 AM MDT FRI NOV 2 2012 FORECAST CONCERNS WILL BE TEMPERATURE FORECAST INTO THE WEEKEND AND FIRE WEATHER ISSUES TODAY. SATELLITE SHOWING A VERY AMPLIFIED PATTERN OVER THE PACIFIC. THIS TRANSITIONS INTO A SPLIT FLOW OVER THE WESTERN PORTION OF NORTH AMERICA THEN TO AN AMPLIFIED TROUGH OVER EASTERN NORTH AMERICA. TROUGH APPROACHING FROM THE WEST IS SPLITTING IN TWO WITH THE STRONGER PORTION MOVING WELL TO OUR NORTH. SURFACE TROUGH AND COLD FRONT MOVING THROUGH THE AREA AT THIS TIME. MODELS DID FINE AT JET LEVEL. AT MID LEVELS...THE MODELS INITIALIZED FINE WITH A LITTLE BIT OF DIFFERENCE ON THE WESTERN TROUGH. THE NAM...GFS...AND UKMET WERE DOING BETTER WITH THAT AND OVERALL. THE RUC AND NAM WERE HANDLING THE SURFACE WIND AND FEATURES THE BEST. MODELS WERE CLOSE TO EACH OTHER ON THE LOW LEVEL THERMAL FIELD. THE CANADIAN...SREF...NAM...AND GFS WERE DOING A LITTLE BETTER. TODAY/TONIGHT...RUC IS HANDLING THE WINDS AND DEWPOINTS WELL INITIALLY THIS MORNING. IT IS BRINGING IN A LITTLE FOG INTO THE EASTERN PORTION EARLY THIS MORNING. DEWPOINT DEPRESSIONS IN THAT AREA ARE ALREADY LOW AND FOG HAS DEVELOPED NOT TOO FAR EAST OF MY AREA. SO HAVE INSERTED SOME PATCHY FOG IN THROUGH MID MORNING. RIGHT REAR QUADRANT OF THE UPPER JET WILL MOVE ACROSS THE AREA FROM LATE THIS MORNING THROUGH THE OVERNIGHT HOURS. SOUNDING PROFILES SHOW A VERY DEEP DRY LAYER SO ONLY EXPECT THICK HIGH CLOUDS AND MAYBE SOME MID CLOUDS. BY 18Z THE FRONT HAS MOVED THROUGH THE AREA ...WITH BREEZY WINDS...WITH STEADY OR FALLING 850 MB TEMPERATURES AFTER THAT. THE CLOUDS LOOK TO HANG AROUND MOST OF THE DAY AND ALSO COULD BE RATHER THICK. MADE ONLY SLIGHT ADJUSTMENTS BASED ON CHANGE IN 850 MB TEMPERATURES FROM YESTERDAY...BIAS ADJUSTMENTS AND BEST PERFORMING GUIDANCE. JET WILL KEEP SOME CLOUDS AROUND TONIGHT BUT SHOULD BE NEARLY GONE BY 12Z. LIGHT AND VARIABLE WIND FIELD IS EXPECTED BY THAT TIME. SO WOULD EXPECT PRETTY GOOD RADIATIONAL CONDITIONS. AS A RESULT TRENDED TOWARD THE COOLER GUIDANCE. HOWEVER...THEY MAY NOT BE COOL ENOUGH. SATURDAY/SATURDAY NIGHT...ABOVE MENTIONED UPPER JET EXITS THE AREA EARLY IN THE DAY. TEMPERATURE FORECAST LOOKS TO BE A LITTLE TRICKY. WILL HAVE A COOL START TO THE DAY AND WIND FIELD DOES NOT LOOK THAT STRONG...ESPECIALLY IN THE EAST...AS THE SURFACE RIDGE PULLS AWAY. ALSO THERE LOOKS TO BE VARIABLE CLOUD COVER. CLOUDS WILL INCREASE LATER IN THE MORNING INTO THE AFTERNOON AS THE NEXT SHORTWAVE APPROACHES. TEMPERATURE CHANGE AND BIAS ADJUSTMENTS SUPPORT NWP AND 2 METER TEMPERATURES AND MADE LITTLE IF ANY CHANGES FOR THE MAXES. WEAKER JET MOVES ACROSS TO THE NORTH AND EAST OF THE AREA DURING THE NIGHT. THAT COMBINED WITH ANOTHER SHORTWAVE SHOULD KEEP A DECENT AMOUNT OF CLOUDS AROUND. WIND FIELD WILL BE LIGHT IN THE EAST WITH WARM AIR ADVECTION BEGINNING IN THE WEST. SUNDAY/SUNDAY NIGHT...DUE TO THE SHARP NORTHWEST FLOW ALOFT...A SERIES OF SHORTWAVE TROUGHS...WITH THE STRONGEST ONE APPROACHING IN THE AFTERNOON WILL MOVE THROUGH THE AREA. PLAN VIEW RH AND FORECAST SOUNDINGS WOULD INDICATE A RATHER THICK MID AND UPPER LEVEL CLOUD DECK. SO DO NOT EXPECT A LOT OF SUN AND MIXING. IF THERE WERE MORE SUN...I WOULD EXPECT MORE WIND. MAY BUMP UP WINDS A LITTLE. HOWEVER MORE IMPORTANTLY WILL KEEP MAXES COOL AND BELOW THE NWP. RATHER STRONG UPPER JET DIVES DOWN THE WEST SIDE OF THE UPPER TROUGH THAT IS MOVING THROUGH THE NORTH CENTRAL PORTION OF THE COUNTRY. THE BRUNT OF THAT JET WILL AFFECT THE EASTERN HALF LATER IN THE NIGHT. MODEL SOUNDINGS SHOW A SATURATED PROFILE FROM NEAR 650 MB AND UP. WITH THE LAPSE RATES AND STRONG FORCING ALOFT WOULD NOT BE SURPRISED TO MAYBE SEE SOME SPRINKLES. HOWEVER...THIS IS TOO LOW ON THE END OF PROBABILITY TO INSERT. AT THE VERY LEAST THE CLOUDS WILL KEEP THE MINS WARMER. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 305 AM MDT FRI NOV 2 2012 A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH THE PLAINS ON MONDAY. THE PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE SHOULD STAY WELL TO THE EAST OF THE TRI-STATE REGION. HOWEVER...THIS DISTURBANCE COULD BRING SOME CLOUDS AND GUSTY WINDS FOR MONDAY. A RIDGE OF HIGH PRESSURE WILL DEVELOP OVER THE ROCKY MOUNTAINS EARLY NEXT WEEK. MODELS ARE INDICATING THAT THIS RIDGE OF HIGH PRESSURE WILL NOT LAST VERY LONG...WEAKENING AS IT MOVES TO THE EAST ON TUESDAY AND WEDNESDAY. AS THE RIDGE WEAKENS...A STRONG UPPER LEVEL TROUGH WILL DEVELOP OVER THE PACIFIC AND BEGIN MAKING ITS WAY ACROSS THE PACIFIC NORTHWEST AND ROCKY MOUNTAINS. THE GFS AND EUROPEAN MODELS INDICATE THAT THIS TROUGH MAY MOVE CLOSE ENOUGH TO THE TRI-STATE AREA TO HAVE AN IMPACT ON OUR WEATHER BY FRIDAY. UNFORTUNATELY...THERE IS SOME MODEL DISAGREEMENT BY FRIDAY. MODELS HAVE ALSO TRENDED THIS TROUGH FARTHER TO THE NORTH...THUS LEADING TO A REDUCED CHANCE FOR ANY TYPE OF SIGNIFICANT WEATHER CHANGE OR PRECIPITATION. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO RESUME ON TUESDAY. HIGH AND LOW TEMPERATURES WILL AVERAGE BETWEEN 5 AND 10 DEGREES ABOVE NORMAL. SOUTH TO SOUTHEAST WINDS IN THE LATER PORTION OF THE WORK WEEK WILL BRING AN INCREASE IN MOISTURE TO THE REGION. AS OF RIGHT NOW...NO PRECIPITATION IS EXPECTED BUT THIS COULD CHANGE DEPENDING ON THE EXACT LOCATION AND TRACK OF THE WEATHER SYSTEM MENTIONED ABOVE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 514 AM MDT FRI NOV 2 2012 AT KGLD...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL BECOME GUSTY AFTER A COLD FRONT MOVES THROUGH THE AREA. NEAR SUNSET THE WINDS WILL GO LIGHT AND VARIABLE. AT KMCK...LIGHT WINDS AND MORE MOIST AIR MASS WILL ALLOW FOG TO DEVELOP. AT THIS TIME MVFR VISIBILITIES ARE EXPECTED THROUGH 15Z. THE WINDS WILL BECOME GUSTY A LITTLE LATER AT KMCK. BY LATE IN THE AFTERNOON THE WINDS WILL BECOME LIGHT AND VARIABLE. && .FIRE WEATHER... ISSUED AT 305 AM MDT FRI NOV 2 2012 WINDS TODAY WILL BE BECOME BREEZY. AS STATED ABOVE RUC HAS THE DEWPOINTS BEST EARLY WITH BCALLBLEND DOING WELL. LOOKING UPSTREAM WILL INITIALLY HAVE THE DEWPOINTS GO UP BEFORE THE DRYING AND SUBSIDENCE KICK IN. WIND CRITERIA FOR FIRE WEATHER LOOKS TO BE REACH CRITERIA. HOWEVER...THE COOLER TEMPERATURES AND HIGHER DEWPOINTS WILL KEEP THE RHS ABOVE THE NEEDED CRITERIA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...BULLER LONG TERM...RRH AVIATION...BULLER FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
518 AM MDT FRI NOV 2 2012 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 305 AM MDT FRI NOV 2 2012 FORECAST CONCERNS WILL BE TEMPERATURE FORECAST INTO THE WEEKEND AND FIRE WEATHER ISSUES TODAY. SATELLITE SHOWING A VERY AMPLIFIED PATTERN OVER THE PACIFIC. THIS TRANSITIONS INTO A SPLIT FLOW OVER THE WESTERN PORTION OF NORTH AMERICA THEN TO AN AMPLIFIED TROUGH OVER EASTERN NORTH AMERICA. TROUGH APPROACHING FROM THE WEST IS SPLITTING IN TWO WITH THE STRONGER PORTION MOVING WELL TO OUR NORTH. SURFACE TROUGH AND COLD FRONT MOVING THROUGH THE AREA AT THIS TIME. MODELS DID FINE AT JET LEVEL. AT MID LEVELS...THE MODELS INITIALIZED FINE WITH A LITTLE BIT OF DIFFERENCE ON THE WESTERN TROUGH. THE NAM...GFS...AND UKMET WERE DOING BETTER WITH THAT AND OVERALL. THE RUC AND NAM WERE HANDLING THE SURFACE WIND AND FEATURES THE BEST. MODELS WERE CLOSE TO EACH OTHER ON THE LOW LEVEL THERMAL FIELD. THE CANADIAN...SREF...NAM...AND GFS WERE DOING A LITTLE BETTER. TODAY/TONIGHT...RUC IS HANDLING THE WINDS AND DEWPOINTS WELL INITIALLY THIS MORNING. IT IS BRINGING IN A LITTLE FOG INTO THE EASTERN PORTION EARLY THIS MORNING. DEWPOINT DEPRESSIONS IN THAT AREA ARE ALREADY LOW AND FOG HAS DEVELOPED NOT TOO FAR EAST OF MY AREA. SO HAVE INSERTED SOME PATCHY FOG IN THROUGH MID MORNING. RIGHT REAR QUADRANT OF THE UPPER JET WILL MOVE ACROSS THE AREA FROM LATE THIS MORNING THROUGH THE OVERNIGHT HOURS. SOUNDING PROFILES SHOW A VERY DEEP DRY LAYER SO ONLY EXPECT THICK HIGH CLOUDS AND MAYBE SOME MID CLOUDS. BY 18Z THE FRONT HAS MOVED THROUGH THE AREA ...WITH BREEZY WINDS...WITH STEADY OR FALLING 850 MB TEMPERATURES AFTER THAT. THE CLOUDS LOOK TO HANG AROUND MOST OF THE DAY AND ALSO COULD BE RATHER THICK. MADE ONLY SLIGHT ADJUSTMENTS BASED ON CHANGE IN 850 MB TEMPERATURES FROM YESTERDAY...BIAS ADJUSTMENTS AND BEST PERFORMING GUIDANCE. JET WILL KEEP SOME CLOUDS AROUND TONIGHT BUT SHOULD BE NEARLY GONE BY 12Z. LIGHT AND VARIABLE WIND FIELD IS EXPECTED BY THAT TIME. SO WOULD EXPECT PRETTY GOOD RADIATIONAL CONDITIONS. AS A RESULT TRENDED TOWARD THE COOLER GUIDANCE. HOWEVER...THEY MAY NOT BE COOL ENOUGH. SATURDAY/SATURDAY NIGHT...ABOVE MENTIONED UPPER JET EXITS THE AREA EARLY IN THE DAY. TEMPERATURE FORECAST LOOKS TO BE A LITTLE TRICKY. WILL HAVE A COOL START TO THE DAY AND WIND FIELD DOES NOT LOOK THAT STRONG...ESPECIALLY IN THE EAST...AS THE SURFACE RIDGE PULLS AWAY. ALSO THERE LOOKS TO BE VARIABLE CLOUD COVER. CLOUDS WILL INCREASE LATER IN THE MORNING INTO THE AFTERNOON AS THE NEXT SHORTWAVE APPROACHES. TEMPERATURE CHANGE AND BIAS ADJUSTMENTS SUPPORT NWP AND 2 METER TEMPERATURES AND MADE LITTLE IF ANY CHANGES FOR THE MAXES. WEAKER JET MOVES ACROSS TO THE NORTH AND EAST OF THE AREA DURING THE NIGHT. THAT COMBINED WITH ANOTHER SHORTWAVE SHOULD KEEP A DECENT AMOUNT OF CLOUDS AROUND. WIND FIELD WILL BE LIGHT IN THE EAST WITH WARM AIR ADVECTION BEGINNING IN THE WEST. SUNDAY/SUNDAY NIGHT...DUE TO THE SHARP NORTHWEST FLOW ALOFT...A SERIES OF SHORTWAVE TROUGHS...WITH THE STRONGEST ONE APPROACHING IN THE AFTERNOON WILL MOVE THROUGH THE AREA. PLAN VIEW RH AND FORECAST SOUNDINGS WOULD INDICATE A RATHER THICK MID AND UPPER LEVEL CLOUD DECK. SO DO NOT EXPECT A LOT OF SUN AND MIXING. IF THERE WERE MORE SUN...I WOULD EXPECT MORE WIND. MAY BUMP UP WINDS A LITTLE. HOWEVER MORE IMPORTANTLY WILL KEEP MAXES COOL AND BELOW THE NWP. RATHER STRONG UPPER JET DIVES DOWN THE WEST SIDE OF THE UPPER TROUGH THAT IS MOVING THROUGH THE NORTH CENTRAL PORTION OF THE COUNTRY. THE BRUNT OF THAT JET WILL AFFECT THE EASTERN HALF LATER IN THE NIGHT. MODEL SOUNDINGS SHOW A SATURATED PROFILE FROM NEAR 650 MB AND UP. WITH THE LAPSE RATES AND STRONG FORCING ALOFT WOULD NOT BE SURPRISED TO MAYBE SEE SOME SPRINKLES. HOWEVER...THIS IS TOO LOW ON THE END OF PROBABILITY TO INSERT. AT THE VERY LEAST THE CLOUDS WILL KEEP THE MINS WARMER. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 305 AM MDT FRI NOV 2 2012 A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH THE PLAINS ON MONDAY. THE PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE SHOULD STAY WELL TO THE EAST OF THE TRI-STATE REGION. HOWEVER...THIS DISTURBANCE COULD BRING SOME CLOUDS AND GUSTY WINDS FOR MONDAY. A RIDGE OF HIGH PRESSURE WILL DEVELOP OVER THE ROCKY MOUNTAINS EARLY NEXT WEEK. MODELS ARE INDICATING THAT THIS RIDGE OF HIGH PRESSURE WILL NOT LAST VERY LONG...WEAKENING AS IT MOVES TO THE EAST ON TUESDAY AND WEDNESDAY. AS THE RIDGE WEAKENS...A STRONG UPPER LEVEL TROUGH WILL DEVELOP OVER THE PACIFIC AND BEGIN MAKING ITS WAY ACROSS THE PACIFIC NORTHWEST AND ROCKY MOUNTAINS. THE GFS AND EUROPEAN MODELS INDICATE THAT THIS TROUGH MAY MOVE CLOSE ENOUGH TO THE TRI-STATE AREA TO HAVE AN IMPACT ON OUR WEATHER BY FRIDAY. UNFORTUNATELY...THERE IS SOME MODEL DISAGREEMENT BY FRIDAY. MODELS HAVE ALSO TRENDED THIS TROUGH FARTHER TO THE NORTH...THUS LEADING TO A REDUCED CHANCE FOR ANY TYPE OF SIGNIFICANT WEATHER CHANGE OR PRECIPITATION. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO RESUME ON TUESDAY. HIGH AND LOW TEMPERATURES WILL AVERAGE BETWEEN 5 AND 10 DEGREES ABOVE NORMAL. SOUTH TO SOUTHEAST WINDS IN THE LATER PORTION OF THE WORK WEEK WILL BRING AN INCREASE IN MOISTURE TO THE REGION. AS OF RIGHT NOW...NO PRECIPITATION IS EXPECTED BUT THIS COULD CHANGE DEPENDING ON THE EXACT LOCATION AND TRACK OF THE WEATHER SYSTEM MENTIONED ABOVE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 514 AM MDT FRI NOV 2 2012 AT KGLD...VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL BECOME GUSTY AFTER A COLD FRONT MOVES THROUGH THE AREA. NEAR SUNSET THE WINDS WILL GO LIGHT AND VARIABLE. AT KMCK...LIGHT WINDS AND MORE MOIST AIR MASS WILL ALLOW FOG TO DEVELOP. AT THIS TIME MVFR VISIBILITIES ARE EXPECTED THROUGH 15Z. THE WINDS WILL BECOME GUSTY A LITTLE LATER AT KMCK. BY LATE IN THE AFTERNOON THE WINDS WILL BECOME LIGHT AND VARIABLE. && .FIRE WEATHER... ISSUED AT 305 AM MDT FRI NOV 2 2012 WINDS TODAY WILL BE BECOME BREEZY. AS STATED ABOVE RUC HAS THE DEWPOINTS BEST EARLY WITH BCALLBLEND DOING WELL. LOOKING UPSTREAM WILL INITIALLY HAVE THE DEWPOINTS GO UP BEFORE THE DRYING AND SUBSIDENCE KICK IN. WIND CRITERIA FOR FIRE WEATHER LOOKS TO BE REACH CRITERIA. HOWEVER...THE COOLER TEMPERATURES AND HIGHER DEWPOINTS WILL KEEP THE RHS ABOVE THE NEEDED CRITERIA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...RRH AVIATION...BULLER FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
305 AM MDT FRI NOV 2 2012 .SHORT TERM...(TODAY THROUGH SUNDAY NIGHT) ISSUED AT 305 AM MDT FRI NOV 2 2012 FORECAST CONCERNS WILL BE TEMPERATURE FORECAST INTO THE WEEKEND AND FIRE WEATHER ISSUES TODAY. SATELLITE SHOWING A VERY AMPLIFIED PATTERN OVER THE PACIFIC. THIS TRANSITIONS INTO A SPLIT FLOW OVER THE WESTERN PORTION OF NORTH AMERICA THEN TO AN AMPLIFIED TROUGH OVER EASTERN NORTH AMERICA. TROUGH APPROACHING FROM THE WEST IS SPLITTING IN TWO WITH THE STRONGER PORTION MOVING WELL TO OUR NORTH. SURFACE TROUGH AND COLD FRONT MOVING THROUGH THE AREA AT THIS TIME. MODELS DID FINE AT JET LEVEL. AT MID LEVELS...THE MODELS INITIALIZED FINE WITH A LITTLE BIT OF DIFFERENCE ON THE WESTERN TROUGH. THE NAM...GFS...AND UKMET WERE DOING BETTER WITH THAT AND OVERALL. THE RUC AND NAM WERE HANDLING THE SURFACE WIND AND FEATURES THE BEST. MODELS WERE CLOSE TO EACH OTHER ON THE LOW LEVEL THERMAL FIELD. THE CANADIAN...SREF...NAM...AND GFS WERE DOING A LITTLE BETTER. TODAY/TONIGHT...RUC IS HANDLING THE WINDS AND DEWPOINTS WELL INITIALLY THIS MORNING. IT IS BRINGING IN A LITTLE FOG INTO THE EASTERN PORTION EARLY THIS MORNING. DEWPOINT DEPRESSIONS IN THAT AREA ARE ALREADY LOW AND FOG HAS DEVELOPED NOT TOO FAR EAST OF MY AREA. SO HAVE INSERTED SOME PATCHY FOG IN THROUGH MID MORNING. RIGHT REAR QUADRANT OF THE UPPER JET WILL MOVE ACROSS THE AREA FROM LATE THIS MORNING THROUGH THE OVERNIGHT HOURS. SOUNDING PROFILES SHOW A VERY DEEP DRY LAYER SO ONLY EXPECT THICK HIGH CLOUDS AND MAYBE SOME MID CLOUDS. BY 18Z THE FRONT HAS MOVED THROUGH THE AREA ...WITH BREEZY WINDS...WITH STEADY OR FALLING 850 MB TEMPERATURES AFTER THAT. THE CLOUDS LOOK TO HANG AROUND MOST OF THE DAY AND ALSO COULD BE RATHER THICK. MADE ONLY SLIGHT ADJUSTMENTS BASED ON CHANGE IN 850 MB TEMPERATURES FROM YESTERDAY...BIAS ADJUSTMENTS AND BEST PERFORMING GUIDANCE. JET WILL KEEP SOME CLOUDS AROUND TONIGHT BUT SHOULD BE NEARLY GONE BY 12Z. LIGHT AND VARIABLE WIND FIELD IS EXPECTED BY THAT TIME. SO WOULD EXPECT PRETTY GOOD RADIATIONAL CONDITIONS. AS A RESULT TRENDED TOWARD THE COOLER GUIDANCE. HOWEVER...THEY MAY NOT BE COOL ENOUGH. SATURDAY/SATURDAY NIGHT...ABOVE MENTIONED UPPER JET EXITS THE AREA EARLY IN THE DAY. TEMPERATURE FORECAST LOOKS TO BE A LITTLE TRICKY. WILL HAVE A COOL START TO THE DAY AND WIND FIELD DOES NOT LOOK THAT STRONG...ESPECIALLY IN THE EAST...AS THE SURFACE RIDGE PULLS AWAY. ALSO THERE LOOKS TO BE VARIABLE CLOUD COVER. CLOUDS WILL INCREASE LATER IN THE MORNING INTO THE AFTERNOON AS THE NEXT SHORTWAVE APPROACHES. TEMPERATURE CHANGE AND BIAS ADJUSTMENTS SUPPORT NWP AND 2 METER TEMPERATURES AND MADE LITTLE IF ANY CHANGES FOR THE MAXES. WEAKER JET MOVES ACROSS TO THE NORTH AND EAST OF THE AREA DURING THE NIGHT. THAT COMBINED WITH ANOTHER SHORTWAVE SHOULD KEEP A DECENT AMOUNT OF CLOUDS AROUND. WIND FIELD WILL BE LIGHT IN THE EAST WITH WARM AIR ADVECTION BEGINNING IN THE WEST. SUNDAY/SUNDAY NIGHT...DUE TO THE SHARP NORTHWEST FLOW ALOFT...A SERIES OF SHORTWAVE TROUGHS...WITH THE STRONGEST ONE APPROACHING IN THE AFTERNOON WILL MOVE THROUGH THE AREA. PLAN VIEW RH AND FORECAST SOUNDINGS WOULD INDICATE A RATHER THICK MID AND UPPER LEVEL CLOUD DECK. SO DO NOT EXPECT A LOT OF SUN AND MIXING. IF THERE WERE MORE SUN...I WOULD EXPECT MORE WIND. MAY BUMP UP WINDS A LITTLE. HOWEVER MORE IMPORTANTLY WILL KEEP MAXES COOL AND BELOW THE NWP. RATHER STRONG UPPER JET DIVES DOWN THE WEST SIDE OF THE UPPER TROUGH THAT IS MOVING THROUGH THE NORTH CENTRAL PORTION OF THE COUNTRY. THE BRUNT OF THAT JET WILL AFFECT THE EASTERN HALF LATER IN THE NIGHT. MODEL SOUNDINGS SHOW A SATURATED PROFILE FROM NEAR 650 MB AND UP. WITH THE LAPSE RATES AND STRONG FORCING ALOFT WOULD NOT BE SURPRISED TO MAYBE SEE SOME SPRINKLES. HOWEVER...THIS IS TOO LOW ON THE END OF PROBABILITY TO INSERT. AT THE VERY LEAST THE CLOUDS WILL KEEP THE MINS WARMER. .LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 305 AM MDT FRI NOV 2 2012 A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH THE PLAINS ON MONDAY. THE PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE SHOULD STAY WELL TO THE EAST OF THE TRI-STATE REGION. HOWEVER...THIS DISTURBANCE COULD BRING SOME CLOUDS AND GUSTY WINDS FOR MONDAY. A RIDGE OF HIGH PRESSURE WILL DEVELOP OVER THE ROCKY MOUNTAINS EARLY NEXT WEEK. MODELS ARE INDICATING THAT THIS RIDGE OF HIGH PRESSURE WILL NOT LAST VERY LONG...WEAKENING AS IT MOVES TO THE EAST ON TUESDAY AND WEDNESDAY. AS THE RIDGE WEAKENS...A STRONG UPPER LEVEL TROUGH WILL DEVELOP OVER THE PACIFIC AND BEGIN MAKING ITS WAY ACROSS THE PACIFIC NORTHWEST AND ROCKY MOUNTAINS. THE GFS AND EUROPEAN MODELS INDICATE THAT THIS TROUGH MAY MOVE CLOSE ENOUGH TO THE TRI-STATE AREA TO HAVE AN IMPACT ON OUR WEATHER BY FRIDAY. UNFORTUNATELY...THERE IS SOME MODEL DISAGREEMENT BY FRIDAY. MODELS HAVE ALSO TRENDED THIS TROUGH FARTHER TO THE NORTH...THUS LEADING TO A REDUCED CHANCE FOR ANY TYPE OF SIGNIFICANT WEATHER CHANGE OR PRECIPITATION. ABOVE NORMAL TEMPERATURES ARE EXPECTED TO RESUME ON TUESDAY. HIGH AND LOW TEMPERATURES WILL AVERAGE BETWEEN 5 AND 10 DEGREES ABOVE NORMAL. SOUTH TO SOUTHEAST WINDS IN THE LATER PORTION OF THE WORK WEEK WILL BRING AN INCREASE IN MOISTURE TO THE REGION. AS OF RIGHT NOW...NO PRECIPITATION IS EXPECTED BUT THIS COULD CHANGE DEPENDING ON THE EXACT LOCATION AND TRACK OF THE WEATHER SYSTEM MENTIONED ABOVE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1050 PM MDT THU NOV 1 2012 VFR CONDITIONS SHOULD PREVAIL AT BOTH KGLD AND KMCK THROUGH THE PERIOD. LOW STRATUS/FOG DEVELOPING OVER CENTRAL NEBRASKA WILL SLOWLY MOVE SOUTHWEST TOWARDS KMCK. LATEST SHORT RANGE GUIDANCE KEEPS THIS EAST OF THE TERMINAL...AND 00Z MET GUIDANCE SHOWS NO RESTRICTIONS TO VIS...SO NOT PLANNING ON ADDING MENTION TO 06Z TAFS. WINDS WILL INCREASE FRIDAY MORNING AT KGLD AND MIDDAY FRIDAY AT KMCK AS A COLD FRONT APPROACHES THE AREA...WITH DAYTIME GUSTS 22-25KT POSSIBLE. && .FIRE WEATHER... ISSUED AT 305 AM MDT FRI NOV 2 2012 WINDS TODAY WILL BE BECOME BREEZY. AS STATED ABOVE RUC HAS THE DEWPOINTS BEST EARLY WITH BCALLBLEND DOING WELL. LOOKING UPSTREAM WILL INITIALLY HAVE THE DEWPOINTS GO UP BEFORE THE DRYING AND SUBSIDENCE KICK IN. WIND CRITERIA FOR FIRE WEATHER LOOKS TO BE REACH CRITERIA. HOWEVER...THE COOLER TEMPERATURES AND HIGHER DEWPOINTS WILL KEEP THE RHS ABOVE THE NEEDED CRITERIA. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...RRH AVIATION...DR FIRE WEATHER...BULLER
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
120 PM EDT FRI NOV 2 2012 .SYNOPSIS... A REINFORCING SHOT OF COLD AIR WITH BRING SCATTERED RAIN AND SNOW SHOWERS INTO TONIGHT. CANADIAN HIGH PRESSURE WILL PROVIDE QUIET WEATHER THIS WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AREA OF CLEARING HAS FILLED IN ACROSS REGION WITH CLOUDS AND SHOWERS ARE DEVELOPING AS NEXT SHORTWAVE BRINGS COLD ADVECTION AND NORTHWEST FLOW TO REGION. ADJUSTMENT TO CLOUDS AND POPS BASED ON CURRENT RADAR AND SAT PIX. NO CHANGES TO TEMPERATURES. PREVIOUS DISCUSSION BELOW... BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT HRRR AND SREF MODEL OUTPUT SHOW A COLD UPPER LEVEL SHORT- WAVE TROUGH MOVING SOUTHEASTWARD THROUGH THE GREAT LAKES INTO TONIGHT...THAT WILL PROVIDE A REINFORCING SHOT OF COLD UNSTABLE AIR. HENCE MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS OF RAIN AND SNOW WILL CONTINUE ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. NAM AND GFS MODEL PROFILES SHOW THE SURFACE MIXED LAYER RESTRICTED TO LESS THAN 7 KFT AGL...SO PRECIPITATION AMOUNTS WILL BE LIMITED WITH SMALL AMOUNTS OF SNOW ACCUMULATION FOR THE HIGHER WV-MD MOUNTAINS. FORECASTED A CONTINUED SMALLER THAN NORMAL DIURNAL TEMPERATURE RANGE WITH HIGHS TODAY 10 TO 15 DEGREES COLDER THAN NORMAL AND LOWS TONIGHT NO MORE THAN 5 DEGREES COLDER THAN NORMAL. SURFACE WINDS WILL BE FROM THE NORTHWEST WITH POTENTIAL GUSTS TO 25 MPH. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... FLOW WILL REMAIN OUT OF THE NW FOR MOST OF SATURDAY...WITH SOME EVENTUAL WEAK WAA. SATURDAY SHOULD BE DRY...BUT WILL BE PESSIMISTIC WITH CLOUDS DUE TO THE FLOW ALOFT AND TEMPS AT 850MB REMAINING BELOW NORMAL. EXPECT LITTLE CHANGE TO TEMPS SAT. ANOTHER UL WAVE WILL SWING THROUGH SAT NIGHT/SUN MORNING... PROVIDING ANOTHER PERIOD OF CAA. THE FLOW ALOFT BEGINS TO BECOME MORE NORTHERLY BY SUNDAY AND INVERSIONS ARE VERY LOW. THIS WOULD MEAN A DRY DAY BUT MORE CLOUDS AND BELOW NORMAL TEMPS FOR SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... DRY AND CONTINUED COOL CONDITIONS UNTIL LATER TUESDAY NIGHT INTO WEDNESDAY WHEN A COLD FRONT WILL WORK ACROSS THE REGION WITH A CHANCE OF SHOWERS. AS A STORM SYSTEM DEVELOPS OFF THE EAST COAST COLD NORTHWEST FLOW WILL KEEP LOW CHANCE FOR SHOWERS INTO THURSDAY. LITTLE CHANGE TO TEMPERATURES THROUGH THE PERIOD AND WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /17Z FRIDAY THROUGH TUESDAY/... PER RECENT SURFACE RADAR AND SATELLITE DATA...EXPECT VFR STRATOCUMULUS CEILINGS ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. HOWEVER SCATTERED SHOWERS OF RAIN AND SNOW MAY CAUSE MVFR CONDITIONS AT TIMES...EAST OF KZZV. SURFACE WINDS WILL BE MAINLY FROM THE WEST AND NORTHWEST AT 10 KTS INTO TONIGHT...WITH GUSTS TO ABOUT 20 KTS AT TIMES THIS AFTERNOON. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... CONDITIONS ARE EXPECTED TO IMPROVE THIS WEEKEND AS HIGH PRES IS FORECAST TO BUILD OVR THE UPR OH VALLEY REGION. THE NEXT CHC FOR WIDESPREAD RESTRICTIONS WL COME WITH A MID WEEK LOW PRES SYSTEM. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1020 AM EDT FRI NOV 2 2012 .SYNOPSIS... AN UPPER LEVEL TROUGH...MOVING SOUTHEASTWARD THROUGH THE GREAT LAKES...WILL PROVIDE A REINFORCING SHOT OF COLD AIR TODAY...WITH SCATTERED RAIN AND SNOW SHOWERS INTO TONIGHT. CANADIAN HIGH PRESSURE WILL BRING QUIET WEATHER THIS WEEKEND...BUT MAINTAIN MAINLY CLOUDY AND CRISP CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... AREA OF CLEARING INTO EASTERN OHIO WORKING ACROSS THE NORTHERN WEST VIRGINIA PANHANDLE WILL BE SHORT LIVED BUT CHANGES MADE TO SKY GRIDS TO ACCOUNT FOR STRANGE YELLOW BALL BEING SEEN ACROSS PARTS OF REGION. EXPECT CLOUDS TO FILL BACK IN OR AFTERNOON. REMAINDER FORECAST UNCHANGED AS ANOTHER SHORTWAVE WILL MOVE SOUTH ACROSS REGION THIS AFTERNOON. PREVIOUS DISCUSSION BELOW... BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT HRRR AND SREF MODEL OUTPUT SHOW A COLD UPPER LEVEL SHORT- WAVE TROUGH MOVING SOUTHEASTWARD THROUGH THE GREAT LAKES INTO TONIGHT...THAT WILL PROVIDE A REINFORCING SHOT OF COLD UNSTABLE AIR. HENCE MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS OF RAIN AND SNOW WILL CONTINUE ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. NAM AND GFS MODEL PROFILES SHOW THE SURFACE MIXED LAYER RESTRICTED TO LESS THAN 7 KFT AGL...SO PRECIPITATION AMOUNTS WILL BE LIMITED WITH SMALL AMOUNTS OF SNOW ACCUMULATION FOR THE HIGHER WV-MD MOUNTAINS. FORECASTED A CONTINUED SMALLER THAN NORMAL DIURNAL TEMPERATURE RANGE WITH HIGHS TODAY 10 TO 15 DEGREES COLDER THAN NORMAL AND LOWS TONIGHT NO MORE THAN 5 DEGREES COLDER THAN NORMAL. SURFACE WINDS WILL BE FROM THE NORTHWEST WITH POTENTIAL GUSTS TO 25 MPH. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... FLOW WILL REMAIN OUT OF THE NW FOR MOST OF SATURDAY...WITH SOME EVENTUAL WEAK WAA. SATURDAY SHOULD BE DRY...BUT WILL BE PESSIMISTIC WITH CLOUDS DUE TO THE FLOW ALOFT AND TEMPS AT 850MB REMAINING BELOW NORMAL. EXPECT LITTLE CHANGE TO TEMPS SAT. ANOTHER UL WAVE WILL SWING THROUGH SAT NIGHT/SUN MORNING... PROVIDING ANOTHER PERIOD OF CAA. THE FLOW ALOFT BEGINS TO BECOME MORE NORTHERLY BY SUNDAY AND INVERSIONS ARE VERY LOW. THIS WOULD MEAN A DRY DAY BUT MORE CLOUDS AND BELOW NORMAL TEMPS FOR SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... DRY AND CONTINUED COOL CONDITIONS UNTIL LATER TUESDAY NIGHT INTO WEDNESDAY WHEN A COLD FRONT WILL WORK ACROSS THE REGION WITH A CHANCE OF SHOWERS. AS A STORM SYSTEM DEVELOPS OFF THE EAST COAST COLD NORTHWEST FLOW WILL KEEP LOW CHANCE FOR SHOWERS INTO THURSDAY. LITTLE CHANGE TO TEMPERATURES THROUGH THE PERIOD AND WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... PER RECENT SURFACE RADAR AND SATELLITE DATA...EXPECT VFR STRATOCUMULUS CEILINGS ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. HOWEVER SCATTERED SHOWERS OF RAIN AND SNOW MAY CAUSE MVFR CONDITIONS AT TIMES...EAST OF KZZV. SURFACE WINDS WILL BE MAINLY FROM THE WEST AND NORTHWEST AT 10 KTS INTO TONIGHT...WITH GUSTS TO ABOUT 20 KTS AT TIMES THIS AFTERNOON. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... CONDITIONS ARE EXPECTED TO IMPROVE THIS WEEKEND AS HIGH PRES IS FORECAST TO BUILD OVR THE UPR OH VALLEY REGION. THE NEXT CHC FOR WIDESPREAD RESTRICTIONS WL COME WITH A MID WEEK LOW PRES SYSTEM. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
858 AM EDT FRI NOV 2 2012 .SYNOPSIS... AN UPPER LEVEL TROUGH...MOVING SOUTHEASTWARD THROUGH THE GREAT LAKES...WILL PROVIDE A REINFORCING SHOT OF COLD AIR TODAY...WITH SCATTERED RAIN AND SNOW SHOWERS INTO TONIGHT. CANADIAN HIGH PRESSURE WILL QUIET THE WEATHER DOWN THIS WEEKEND...BUT MAINTAIN MAINLY CLOUDY AND CRISP CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... BLEND OF RECENT SURFACE RADAR AND SATELLITE DATA COUPLED WITH RECENT HRRR AND SREF MODEL OUTPUT SHOW A COLD UPPER LEVEL SHORT- WAVE TROUGH MOVING SOUTHEASTWARD THROUGH THE GREAT LAKES INTO TONIGHT...THAT WILL PROVIDE A REINFORCING SHOT OF COLD UNSTABLE AIR. HENCE MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS OF RAIN AND SNOW WILL CONTINUE ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. NAM AND GFS MODEL PROFILES SHOW THE SURFACE MIXED LAYER RESTRICTED TO LESS THAN 7 KFT AGL...SO PRECIPITATION AMOUNTS WILL BE LIMITED WITH SMALL AMOUNTS OF SNOW ACCUMULATION FOR THE HIGHER WV-MD MOUNTAINS. FORECASTED A CONTINUED SMALLER THAN NORMAL DIURNAL TEMPERATURE RANGE WITH HIGHS TODAY 10 TO 15 DEGREES COLDER THAN NORMAL AND LOWS TONIGHT NO MORE THAN 5 DEGREES COLDER THAN NORMAL. SURFACE WINDS WILL BE FROM THE NORTHWEST WITH POTENTIAL GUSTS TO 25 MPH. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... FLOW WILL REMAIN OUT OF THE NW FOR MOST OF SATURDAY...WITH SOME EVENTUAL WEAK WAA. SATURDAY SHOULD BE DRY...BUT WILL BE PESSIMISTIC WITH CLOUDS DUE TO THE FLOW ALOFT AND TEMPS AT 850MB REMAINING BELOW NORMAL. EXPECT LITTLE CHANGE TO TEMPS SAT. ANOTHER UL WAVE WILL SWING THROUGH SAT NIGHT/SUN MORNING... PROVIDING ANOTHER PERIOD OF CAA. THE FLOW ALOFT BEGINS TO BECOME MORE NORTHERLY BY SUNDAY AND INVERSIONS ARE VERY LOW. THIS WOULD MEAN A DRY DAY BUT MORE CLOUDS AND BELOW NORMAL TEMPS FOR SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... DRY AND CONTINUED COOL CONDITIONS UNTIL LATER TUESDAY NIGHT INTO WEDNESDAY WHEN A COLD FRONT WILL WORK ACROSS THE REGION WITH A CHANCE OF SHOWERS. AS A STORM SYSTEM DEVELOPS OFF THE EAST COAST COLD NORTHWEST FLOW WILL KEEP LOW CHANCE FOR SHOWERS INTO THURSDAY. LITTLE CHANGE TO TEMPERATURES THROUGH THE PERIOD AND WILL AVERAGE 5 TO 10 DEGREES BELOW NORMAL. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... PER RECENT SURFACE RADAR AND SATELLITE DATA...EXPECT VFR STRATOCUMULUS CEILINGS ACROSS THE UPPER OHIO VALLEY INTO TONIGHT. HOWEVER SCATTERED SHOWERS OF RAIN AND SNOW MAY CAUSE MVFR CONDITIONS AT TIMES...EAST OF KZZV. SURFACE WINDS WILL BE MAINLY FROM THE WEST AND NORTHWEST AT 10 KTS INTO TONIGHT...WITH GUSTS TO ABOUT 20 KTS AT TIMES THIS AFTERNOON. .OUTLOOK.../SATURDAY THROUGH TUESDAY/... CONDITIONS ARE EXPECTED TO IMPROVE THIS WEEKEND AS HIGH PRES IS FORECAST TO BUILD OVR THE UPR OH VALLEY REGION. THE NEXT CHC FOR WIDESPREAD RESTRICTIONS WL COME WITH A MID WEEK LOW PRES SYSTEM. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
736 PM EDT SAT NOV 3 2012 .SYNOPSIS... ISSUED AT 323 PM EDT SAT NOV 3 2012 QUIET WEATHER IS EXPECTED TO CONTINUE OVER THE COURSE OF THE REMAINDER OF THE WEEKEND AND THROUGH MUCH OF NEXT WEEK. HIGH PRESSURE WILL BE IN CONTROL OF THE WEATHER ACROSS THE GREAT LAKES REGION INTO MONDAY NIGHT. DRY WEATHER IS FORECAST THROUGH THAT TIME. THE ONLY CHANCE FOR PRECIPITATION THROUGH FRIDAY WILL COME TUESDAY INTO WEDNESDAY IN THE FORM OF SOME LIGHT RAIN AS A COLD FRONT MOVES THROUGH. TEMPERATURES WILL CONTINUE TO BE NEAR OR SLIGHTLY BELOW NORMAL INTO MIDWEEK WITH HIGHS IN THE 40S. SLIGHTLY WARMER WEATHER IS EXPECTED THURSDAY AND FRIDAY WITH HIGHS IN THE 50S. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 323 PM EDT SAT NOV 3 2012 CLOUD COVER ISSUES ARE THE MAIN POINT OF CONTENTION IN THE SHORT TERM. STRATOCUMULUS IS ERODING LATE THIS AFTERNOON...BUT SOME MID CLOUDS ARE NOSING IN FROM THE WEST AT THE SAME TIME. NOT CONVINCED WE WON/T SEE A REPEAT OF LAST NIGHT TONIGHT AS WEAK NORTH FLOW CONTINUES. THE AIR IS COLD ENOUGH FOR LAKE CLOUDS WITH DELTA T/S IN THE LOWER TEENS C. SO...EXPECT SOME MID CLOUDS TO BE MOVING THROUGH ESPECIALLY THIS EVENING. MUCH OF THE UPSTREAM MID DECK IS FORECAST TO DIVE SOUTHWEST OF THE AREA. THAT LEAVES THE STRATOCU POSSIBILITY. HAVE PLAYED THE FORECAST FOR BECOMING PARTLY CLOUDY TONIGHT AS THE GUIDANCE IS ALL LEANING THAT DIRECTION. WOULD NOT BE SURPRISED TO SEE THE STRATOCU SURGE AGAIN OVERNIGHT FROM THE NORTH THOUGH AS IT IS NOVEMBER IN MICHIGAN. AFTER TONIGHT...GENERALLY PARTLY CLOUDY CONDITIONS THROUGH THE REST OF THE SHORT TERM SUNDAY THROUGH MONDAY NIGHT AS RIDGING WILL MORE FIRMLY BE IN PLACE. HIGHS IN THE MID 40S THE NEXT TWO DAYS. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 323 PM EDT SAT NOV 3 2012 MAINLY DRY WX WITH A GRADUAL MODERATING TREND OF TEMPS IS ANTICIPATED FOR THE LONG RANGE FCST PERIOD. TEMPS WILL AVERAGE CLOSE TO NORMAL FOR THIS TIME OF YEAR ON TUESDAY WITH MAX TEMPS REACHING THE MID TO UPPER 40S. A WEAK LOW PRESSURE SYSTEM WILL BRING A CHC OF A FEW LIGHT RAIN SHOWERS LATE TUESDAY THROUGH TUESDAY NIGHT THAT MAY LINGER INTO WEDNESDAY. HOWEVER EVEN MOST OF THIS TIME FRAME SHOULD BE DRY. TEMPS WILL UNDERGO A MODERATING TREND MID TO LATE WEEK WITH DRY WX LATE WEDNESDAY THROUGH FRIDAY. MAX TEMPS BY THURSDAY AND FRIDAY WILL REACH THE 50S. A WARM FRONT MAY BRING A FEW LIGHT RAIN SHOWERS BY FRIDAY NIGHT AND SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 736 PM EDT SAT NOV 3 2012 I DO NOT EXPECT A SOLID CLEARING OF THE CLOUDS AT ANY OF THE TAF SITES THROUGH 00Z MONDAY. THAT IS MOSTLY DUE TO THE UPPER LOW MOVING ACROSS THE AREA TONIGHT AND INTO SUNDAY BEFORE SINKING SOUTH AND EAST OF HERE BY LATE SUNDAY. THAT SHOULD ENCOURAGE CONSIDERABLE LAYERED CLOUDS THROUGH SUNDAY. THIS IS NOT AN EASY FORECAST TO SAY THE LEAST. I AM CURRENTLY FAVORING THE RAP MODEL AS IT SHOWS THE AREAS OF LOW CLOUDS BEST OF ALL THE CURRENT MODELS. IT WOULD SUGGEST THE MVFR CIGS WILL HOLD OVER THE SE CWA MOST OF THE EVENING WHILE THEY WILL STAY OUT OF THE PICTURE NEAR THE AND WEST OF US-131. COULD SEE THE LOW CLOUDS BREAK OUT AROUND MIDNIGHT FOR A TIME AS THE UPPER JET GET CORE MOVES OVERHEAD BUT ONCE IT MOVES SOUTH AND EAST OF HERE BY 09Z OR SO I EXPECT THE LOW LEVEL FLOW TO BECOME MORE CYCLONIC AND THE LOW CLOUDS WILL MOVE BACK IN. THE PERSISTENT NORTH WINDS AND SLIGHTLY CYCLONICLY CURVED LOW LEVEL FLOW SHOULD KEEP THE STRATOCUMULUS CLOUDS AROUND THROUGH MOST OF SUNDAY.L && .MARINE... ISSUED AT 323 PM EDT SAT NOV 3 2012 RELATIVELY CALM CONDITIONS ARE EXPECTED OUT ON THE BIG LAKE THROUGH THE SHORT TERM. WINDS SHOULD BE 10-15 KNOTS OR LESS THROUGH MONDAY NIGHT. WAVES WILL GENERALLY BE 2 FEET OR LESS DURING THIS TIME FRAME. THE NEXT CHANCE FOR INCREASED WINDS AND WAVES WILL COME ON TUESDAY IN SOUTHWESTERLY FLOW AHEAD OF A COLD FRONT. && .HYDROLOGY... ISSUED AT 323 PM EDT SAT NOV 3 2012 ALL RIVER GAGING SITES ACROSS THE FORECAST AREA ARE WELL WITHIN BANK AT THIS TIME. LOOKING AT THE USGS PERCENT OF NORMAL PAGE MOST SITES IN THE AREA ARE EITHER IN THE NORMAL CATEGORY OR ARE BEGINNING TO DIP SLIGHTLY BELOW NORMAL AGAIN. THE ONLY PRECIPITATION IN THE FORECAST BETWEEN NOW AND NEXT FRIDAY IS SOME LIGHT PRECIPITATION IN THE TUES-WED TIME FRAME. THIS PRECIPITATION LOOKS TO BE LIGHT AND WILL NOT AFFECT RIVER LEVELS OR CAUSE ANY ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...DUKE SHORT TERM...DUKE LONG TERM...LAURENS AVIATION...WDM HYDROLOGY...DUKE MARINE...DUKE
AREA FORECAST DISCUSSION...CORRECTED
NWS BILLINGS MT
830 PM MDT SAT NOV 3 2012 .SHORT TERM...VALID FOR SUN AND MON... SHORTWAVE BRINGING A BIT OF WARM FRONT LIKE LIFT TO THE CENTRAL ZONES AS IT MOVES OVER A COOLER AIRMASS OVER CENTRAL AND EASTERN MONTANA. LIFT EVENTUALLY WILL BE REPLACE BY A DOWNSLOPISH WESTERLY FLOW BUT UNTIL THEN THE HRRR AND OTHER MODELS INDICATE SOME SCATTERED PRECIPITATION AND A CHANCE FOR SOME FREEZING PRECIPITATION IN PARTS OF SOUTHEAST MONTANA. UPDATED FORECAST TO SHOW THIS ACTIVITY...WHICH WILL BE MOST FAVORED IN THE EASTERN ZONES. ALSO LOWERED TEMPERATURES A BIT IN SOUTHEAST MONTANA AS TEMPERATURES ARE ALREADY AT FORECAST MINIMUMS. BORSUM PREVIOUS DISCUSSION... MODELS WERE IN GENERAL AGREEMENT WITH THE PATTERN THROUGH THE SHORT-TERM PERIOD...SO USED A BLEND OF THE MODELS FOR THE FORECAST. SHOWERS WERE SEEN ON RADAR MOVING INTO NW MT THIS AFTERNOON. THIS PRECIPITATION WAS ASSOCIATED WITH SHORTWAVE ENERGY MOVING E INTO THE AREA ON PACIFIC FLOW. THE SHORTWAVE ENERGY WILL PUSH SE INTO THE FORECAST AREA TONIGHT AND MOVE THROUGH THE SE ZONES ON SUN...DRAGGING A SURFACE LOW AND COLD FRONT THROUGH THIS AREA. THE STRONGEST ENERGY WILL REMAIN E OF THE AREA. MODELS SHOWED LIMITED LOW TO MID LEVEL MOISTURE WITH THIS SYSTEM...SO HAD MAINLY MOUNTAIN POPS TONIGHT...AND SLIGHT CHANCE OVER AREAS AWAY FROM DOWNSLOPE FLOW ON SUN. AN INCREASING PRESSURE GRADIENT WILL KEEP WIND SPEEDS UP FROM KBIL W TONIGHT. IT WILL BECOME WINDY FROM THE W AND NW ON SUN AS THE FRONT MOVES THROUGH THE AREA. BUFKIT SHOWED MIXING DOWN OF 20 TO 30 KT WINDS...ESPECIALLY E OF KBIL...SO HAVE REFLECTED THESE STRONG WINDS IN THE GRIDS. MIXING SUPPORTED THE GOING HIGH TEMPERATURE FORECAST...EXCEPT FOR THE FAR EASTERN ZONES WHERE MIXING WILL BE TO ONLY 800 MB. HAVE LOWERED TEMPERATURES IN THIS AREA. IN ADDITION...LOW-LEVEL MOISTURE AND WIND FIELDS INDICATED THAT THE STRATUS OVER THE FAR NE ZONES THIS AFTERNOON WILL PUSH FURTHER W TONIGHT AND LINGER INTO SUN MORNING...SO HAVE REFLECTED THIS CLOUD COVER IN THE SKY GRIDS. ALSO ADDED PATCHY FOG OVER AREAS MAINLY E OF KBIL LATE TONIGHT INTO SUN MORNING. BRIEF UPPER RIDGING WILL MOVE OVER THE AREA SUN NIGHT BEFORE FAST PACIFIC FLOW OVERTAKES THE REGION AGAIN ON MON. ANOTHER SHORTWAVE WILL PUSH THROUGH ALBERTA AND SASKATCHEWAN ON MON...PUSHING A BACKDOOR COLD FRONT TOWARD THE FORECAST AREA. THIS FRONT WILL SAG INTO THE AREA MON NIGHT. A FEW RAIN AND SNOW SHOWERS WILL LINGER OVER THE MOUNTAINS FROM THE SUN SYSTEM ON SUN NIGHT...OTHERWISE IT WILL BE MAINLY DRY THROUGH MON NIGHT. THE UPPER RIDGE ON SUN NIGHT WILL CAUSE A STRONG LEE TROUGH TO DEVELOP OVER THE AREA WITH WINDY CONDITIONS IN THE GAP FLOW AREAS. AT THIS TIME...THE ORIENTATION OF THE PRESSURE GRADIENT DID NOT SUPPORT A WIND HIGHLIGHT. IT WILL BE WINDY AND WARM ACROSS THE ENTIRE AREA ON MON AHEAD OF THE COLD FRONT. MIXING WILL BE TO NEAR 700 MB EXCEPT A BIT LOWER IN THE FAR E. HAVE RAISED TEMPERATURES A FEW DEGREES ACROSS THE AREA. THE WINDS WILL DECREASE MON NIGHT AS THE FRONT SETTLES INTO THE REGION. MIN TEMPERATURES LOOKED REASONABLE THROUGH THE PERIOD AND WILL BE ABOVE NORMAL. ARTHUR .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... CONFIDENCE IN A SHARP CHANGE TO COLD WEATHER WITH A PERIOD OF SNOW FROM FRI INTO NEXT WEEKEND IS INCREASING. HOWEVER...GIVEN A COUPLE KEY DIFFERENCES IN HOW THE GFS AND ECMWF AND THEIR ENSEMBLES CARRY A 500-HPA TROUGH EASTWARD ACROSS THE ROCKIES IN THAT PERIOD...IT/S IMPORTANT FOR US TO STRESS SOME UNCERTAINTY IN THE DETAILS OF THIS WHOLE PATTERN CHANGE. THUS...WHILE WE ARE ADVERTISING THE RISK FOR SIGNIFICANT IMPACTS BY NEXT FRI AND SAT...WE HAVE DECIDED TO AVOID GETTING INTO MUCH DETAIL IN OUTLOOKS AND RELATED ITEMS FOR NOW. IT IS WORTH NOTING THAT PART OF THE ATTENTION-GRABBER IN THE FORECAST WILL BE THE RAPID SLIDE FROM HIGHS ON WED...WHEN MID AND UPPER 60S F ARE NOW ADVERTISED. THE 12 UTC GFS AND ECMWF AGREE THAT WESTERLY LOW- AND MID-LEVEL FLOW WILL BE IN PLACE WITH 850-HPA TEMPERATURES OF +13 TO +16 C. OUR FORECAST LAGGED THE COLD SIDE OF THE GUIDANCE ENVELOPE BY AT LEAST 5 F...AND IN A CASE LIKE THIS MOS NUMBERS ARE LIKELY POORLY INFLUENCED BY CLIMATOLOGY TO BEGIN WITH. THUS...EVEN THOUGH WE INCREASED WED HIGHS BY ABOUT 10 F IN MOST AREAS...WE MAY STILL BE TOO COOL. IN CONTRAST...WE MAY BE TOO WARM WITH HIGHS FOR THU...WHEN THE 12 UTC MODELS ALL SHOW EAST-NORTHEAST WINDS...WHICH ARE APT TO ALLOW SHALLOW COOL AIR TO BACK INTO THE AREA. WHERE FRI AND SAT ARE CONCERNED...THE 00 UTC GFS ENSEMBLE RELATIVE MEASURE OF PREDICTABILITY /RMOP/ VALUES TIED TO THE 500-HPA TROUGH INCREASED QUITE A BIT OVER THE LAST 24 HOURS. HOWEVER...THE 12 UTC GFS CLOSES OFF A 500-HPA LOW OVER WY /AND THUS GENERATES A DYNAMIC AND SLOW-MOVING WINTER STORM OVER THE REGION/...WHILE THE ECMWF IS MUCH FURTHER NORTHWEST WITH THAT MID-LEVEL LOW. THE ECMWF SOLUTION IS LESS VIGOROUS WITH A SURFACE LOW IN THE NORTHERN PLAINS BECAUSE ITS DYNAMICS ARE THUS DISPLACED TO THE NORTHWEST. THAT IS MERELY A GOOD EXAMPLE OF THE SUBTLE SYNOPTIC INTERACTIONS THAT ARE FAR FROM BEING IRONED OUT...BUT WHICH COULD GREATLY INFLUENCE THE FORECAST. NOTE THOUGH THAT BOTH THE GFS AND ECMWF IDEAS PRESENT SNOW FOR FRI NIGHT INTO SAT...AND THERE IS MODEST CLUSTERING WITH GFS ENSEMBLES FOR MOISTURE IN THAT PERIOD TOO...SO THAT MAY BE OUR BEST SHOT FOR ANY ACCUMULATIONS. SCHULTZ && .AVIATION... AN AREA OF MVFR-IFR CIGS ACROSS NORTHEAST MONTANA AND WESTERN NORTH DAKOTA MAY CREEP BACK INTO KBHK AND KMLS TONIGHT PER EASTERLY SURFACE WINDS...BUT THE POTENTIAL FOR THESE LOWER CIGS WILL END WITH A SHIFT TO WEST WINDS AFTER 09Z TONIGHT. A PACIFIC DISTURBANCE APPROACHING FROM THE WEST WILL BRING SOME LIGHT PRECIPITATION TO THE REGION LATER TONIGHT INTO EARLY SUNDAY... ESPECIALLY FROM KBIL EASTWARD WHERE LOCAL MVFR DUE TO THE SHOWER ACTIVITY IS POSSIBLE. LIGHT FREEZING RAIN IS A POSSIBILITY AT KBHK AS WELL. VFR WILL PREVAIL OTHERWISE ACROSS THE LOWER ELEVATIONS...AND THE MOUNTAINS WILL BE OBSCURED AT TIMES. GUSTY SW WINDS WILL DEVELOP AT KLVM TONIGHT WITH GUSTS OF 30-40 KTS EXPECTED LATER TONIGHT THROUGH SUNDAY. GUSTY NW WINDS WILL DEVELOP ACROSS THE LOWER ELEVATIONS ON SUNDAY AFTER 15Z...WITH GUSTS OF 20-30 KTS. JKL && .PRELIMINARY POINT TEMP/POPS... SUN MON TUE WED THU FRI SAT ----------------------------------------------------------- BIL 043/058 043/063 041/061 042/067 038/045 033/033 018/020 21/N 00/N 10/B 00/B 12/W 35/S 54/S LVM 039/057 043/065 040/062 038/063 035/044 030/031 014/018 22/W 01/N 00/N 00/N 24/W 66/S 54/S HDN 039/061 039/065 039/061 039/069 037/049 033/040 021/024 22/W 00/N 10/B 00/B 11/B 35/O 55/S MLS 035/052 035/061 036/055 040/065 038/046 033/039 022/023 32/W 00/B 11/B 10/B 12/W 34/O 55/S 4BQ 035/058 037/062 039/059 038/066 036/051 033/046 024/026 22/W 00/B 10/B 10/B 10/B 23/R 55/S BHK 031/050 032/060 036/053 037/060 035/044 030/037 021/027 32/W 00/B 11/B 11/B 11/B 23/S 55/S SHR 036/058 037/064 038/063 038/068 035/051 032/045 020/023 12/W 10/B 10/B 00/U 10/B 23/O 54/S && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
929 AM MDT FRI NOV 2 2012 .SHORT TERM...VALID FOR TDY AND SAT... UPDATE TO ZFP WITH NO UPDATE TO WRKAFP. BASE OF UPPER TROUGH WAS OVER S SASKATCHEWAN THIS MORNING PER WATER VAPOR IMAGERY. WATER VAPOR AND RADAR ALSO SHOWED A WAVE ROTATING TOWARD THE FORECAST AREA FROM N CENTRAL MT WITH SHOWERS ASSOCIATED WITH IT. LATEST WRF AND RAP MODELS KEPT CYCLONIC FLOW OVER THE AREA INTO THIS EVENING WITH 850-700 MB MOISTURE AND 100-200 J/KG CAPE. THUS HAVE ADDED A SLIGHT CHANCE OF SHOWERS TO THE FORECAST FOR MOST AREAS THIS AFTERNOON AND TAPERED OFF THE POPS FROM W TO E THIS EVENING. TEMPERATURE FORECAST WAS ON TRACK BASED ON CURRENT TEMPERATURES AND EXPECTED MIXING. WINDS WILL INCREASE FROM THE NW THIS AFTERNOON AS THE SHORTWAVE MOVES INTO THE AREA. ARTHUR .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... MODELS APPEAR TO BE IN RATHER GOOD AGREEMENT THROUGH MUCH OF THE EXTENDED FORECAST PERIOD WITH NO SIGNIFICANT DIFFERENCES UNTIL AROUND DAY 7. THE GENERAL WEATHER SET UP FOR THE EARLY PART OF THE WEEK IS A LARGE RIDGE OFF THE CALIFORNIA COAST WHICH GRADUALLY SLIDES EAST AND DOMINATES THE SOUTHWESTERN UNITED STATES. THIS WILL RESULT IN ANTI CYCLONIC FLOW OVER OUR REGION THROUGH MID WEEK. HOWEVER...THERE IS A CLIPPER TYPE WAVE THAT TRACKS ACROSS EASTERN MONTANA SUNDAY PRODUCING COOLER TEMPS...BREEZY CONDITIONS AND A CHANCE OF SHOWERS. OTHERWISE WE EXPECT TEMPERATURES TO BE SEASONABLY MILD. 500MB HEIGHTS DO BEGIN TO LOWER AROUND WEDNESDAY AS AN UPPER TROUGH DEVELOPS OFF THE BRITISH COLUMBIAN COAST AND DROPS INTO THE PACIFIC NW. THIS WILL BRING A SLIGHT CHANCE OF SHOWERS TO OUR REGION...AFFECTING MAINLY THE WESTERN FACING HIGHER TERRAIN. TEMPERATURES WILL REMAIN RELATIVELY MILD THOUGH AS WE WILL REMAIN ON THE WARM SIDE OF THIS WEATHER SYSTEM THROUGH AT LEAST MID WEEK. AT THIS TIME THE PROGGS SHOW COLDER AIR AND MOISTURE ASSOCIATED WITH THIS TROUGH AFFECTING OUR FORECAST AREA AROUND THURSDAY OR FRIDAY WITH THE ECMWF BEING THE FASTER SOLUTION. WHILE I EXPECT TO SEE THE TIMING OF THIS WEATHER SYSTEM VARY FROM RUN TO RUN IN THE MODEL CYCLES AS THIS IS STILL A WEEK AWAY...IT DOES SEEM THE MODELS ARE LATCHING ON TO SOMETHING. HAVE COLLABORATED WITH NEIGHBORING OFFICES TO INTRODUCE SOME HIGHER POPS FOR DAYS 7 AND 8 AT THIS TIME. BT && .AVIATION... ISOLATED SHOWERS WILL OCCUR OVER MUCH OF THE AREA THIS AFTERNOON AND TAPER OFF FROM W TO E THIS EVENING. BRIEF MVFR CONDITIONS AND GUSTY WINDS WILL BE POSSIBLE WITH THE SHOWERS. EXPECT LOCALIZED TO AREAS OF MOUNTAIN OBSCURATION THROUGH THIS EVENING. VFR WILL PREVAIL OVER THE REGION LATE TONIGHT THROUGH SAT MORNING. ARTHUR && .PRELIMINARY POINT TEMP/POPS... TDY SAT SUN MON TUE WED THU ------------------------------------------------------- BIL 055 033/057 042/058 044/064 046/059 041/058 039/055 2/W 11/B 11/B 00/B 11/B 00/B 22/W LVM 054 030/057 037/058 044/063 043/062 038/060 037/053 1/E 11/B 21/N 01/N 12/W 01/B 24/W HDN 060 029/059 037/060 039/066 043/058 037/060 036/058 2/W 11/B 02/W 10/B 12/W 11/B 11/B MLS 053 029/053 036/055 035/061 040/054 035/054 035/052 3/W 21/B 02/W 10/B 11/B 22/W 22/W 4BQ 057 029/057 033/057 037/061 042/056 037/059 036/054 2/W 21/B 02/W 10/B 00/B 11/B 10/B BHK 053 028/052 032/053 031/055 037/052 032/052 032/047 3/W 21/B 02/W 11/B 00/B 22/W 22/W SHR 057 030/057 035/057 037/061 040/060 037/061 035/060 1/B 11/B 01/B 00/B 01/U 00/B 10/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
532 PM CDT FRI NOV 2 2012 .AVIATION...00Z TAF. THE ONLY POINT OF INTEREST IS THE FIRST COUPLE HOURS OF THE TAF. A NARROW LINGERING MVFR CEILING JUST SHY OF 2K IS IN THE KEARNEY AREA...AND MAY SLIP INTO KGRI EARLY THIS EVENING. TOO MUCH HIGH CLOUDINESS TO GET A FEEL FOR JUST HOW IT IS MOVING. FOR NOW INCLUDED A TEMPO PERIOD OF A BRIEF CEILING EARLY THIS EVENING. OTHERWISE...WEAK HIGH PRESSURE WILL GRADUALLY BUILD INTO THE AREA. THICKER HIGH CLOUDS WILL THIN BY LATE THIS EVENING...AND VFR CONDITIONS ARE FORECAST THROUGHOUT. && .PREV DISCUSSION... /ISSUED 250 PM CDT FRI NOV 2 2012/ SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS INDICATES LONG WAVE TROUGHING OVER THE EASTERN ONE-THIRD OF THE CONUS...AND A RIDGE AXIS EXTENDING FROM NEW MEXICO INTO THE NORTHERN PLAINS. TWO MID LEVEL SHORTWAVES...ONE OVER THE NORTHERN PLAINS AND THE OTHER OVER THE SOUTHWESTERN CONUS...ARE ALSO NOTED...WITH ZONAL MID AND UPPER LEVEL FLOW PERSISTING ACROSS THE CENTRAL PLAINS. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM WYOMING...EAST/NORTHEAST ACROSS THE NORTHERN PLAINS AND THEN SOUTHEAST ACROSS THE MISSISSIPPI VALLEY ON INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW REMAINS FAIRLY WEAK OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 70KTS NEAR 200MB PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL MOISTURE AHEAD OF THE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...WITH THIS INCREASED MID LEVEL MOISTURE EXTENDING FROM THE FOUR-CORNERS REGION...EAST/NORTHEAST ACROSS THE CENTRAL ROCKY MOUNTAIN RANGE AND ON INTO THE CENTRAL PLAINS. PLENTY OF MID AND HIGH LEVEL CLOUDS ARE NOTED INFILTRATING THE CENTRAL PLAINS AS A RESULT. AT THE SURFACE A WEAK AREA OF LOW PRESSURE EXISTS OVER SOUTH CENTRAL KANSAS...WITH A WEAK FRONTAL BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS PORTIONS OF CENTRAL AND EASTERN KANSAS. AN INVERTED TROUGH IS ALSO NOTED EXTENDING NORTH FROM THE SURFACE LOW INTO NORTH CENTRAL KANSAS AND SOUTH CENTRAL NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR CWA REMAINS SPLIT AS A RESULT...WITH AN EAST/SOUTHEAST WIND ACROSS THE SOUTHEASTERN HALF OF THE CWA...AND A NORTH/NORTHWEST WIND FARTHER NORTHWEST. LOW LEVEL THERMAL ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER PORTIONS OF CENTRAL AND EASTERN KANSAS...IS PROMOTING ISENTROPIC UPGLIDE AND SATURATION ALONG THE 290-300K SURFACES...PER RAP ANALYSIS DATA. THIS SATURATION HAS RESULTED IN STRATUS ACROSS NORTHWESTERN PORTIONS OF THE CWA THIS AFTERNOON...WHERE CEILINGS IN THE 1000-2000FT AGL PERSIST. GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE MID LEVEL SHORT WAVE OVER THE NORTHERN PLAINS WILL CONTINUE MOVING EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS. ANY DPVA AND MID LEVEL THERMAL ADVECTION IN ASSOCIATION WITH THIS SYSTEM SHOULD REMAIN WELL NORTH/NORTHEAST OF OUR AREA. IN ADDITION...THE MID LEVEL SHORT WAVE CURRENTLY OVER THE SOUTHWESTERN CONUS IS EXPECTED TO WEAKEN THROUGH THE NEXT 24 HOURS...THUS PRESENTING LITTLE IF ANY OMEGA TO OUR AREA ONCE IT NEARS THE REGION. GIVEN THE OVERALL LACK IN KINEMATIC FORCING OVER OUR AREA THROUGH THE NEXT 24 HOURS...OPTED TO KEEP THE FORECAST DRY FOR TONIGHT AND TOMORROW. GUIDANCE ALSO SUGGESTS THE SURFACE HIGH...CURRENTLY OVER SOUTH CENTRAL KANSAS...WILL PUSH OFF TO THE EAST/SOUTHEAST TONIGHT...THUS ALLOWING WEAK SURFACE RIDGING INTO OUR AREA OVERNIGHT TONIGHT INTO SATURDAY MORNING. ISENTROPIC UPGLIDE SHOULD DISSIPATE ACROSS OUR AREA LATER TONIGHT AS THE LOW LEVEL BAROCLINIC ZONE OVER CENTRAL AND EASTERN PORTIONS OF KANSAS PUSHES OFF TO THE EAST/SOUTHEAST ALONG WITH THE SURFACE LOW. THIS SHOULD BRING AN END TO THE STRATUS CURRENTLY OVER NORTHWESTERN PORTIONS OF OUR CWA. ALSO...THE INCREASED MID LEVEL MOISTURE...BEING USHERED INTO OUR AREA FROM THE SOUTHWEST BY THE SOUTHWESTERN CONUS MID LEVEL SHORT WAVE...IS EXPECTED TO DISSIPATE THROUGH THE NEXT 24 HOURS AS THE SHORT WAVE ALSO DISSIPATES. GIVEN AL THIS...A CLEARING TREND SHOULD BE OBSERVED ACROSS OUR AREA THROUGH THE NEXT 12 OR SO HOURS...WITH MOSTLY CLEAR SKIES EXPECTED THEREAFTER. WENT AHEAD AND KEPT THE INCREASED CLOUD COVER GOING IN THE FORECAST FOR NORTHWESTERN PORTIONS OF THE CWA THROUGH THIS EVENING TO ACCOUNT FOR THE CURRENT STRATUS...WITH MOSTLY CLEAR SKIES FORECAST ACROSS MOST ALL OF THE CWA 06Z ONWARD. THE COMBINATION OF CLEARING SKIES...A DECREASING LOW LEVEL WIND FIELD...AND THE INFLUX OF A COOLER AND DRIER LOW LEVEL AIRMASS INTO OUR AREA AS THE WEAK SURFACE RIDGE INFILTRATES THE REGION...WILL PROMOTE A CHILLY NIGHT ACROSS THE CWA WITH ~30-DEGREE TEMPERATURE DROP-OFFS LIKELY ACROSS MUCH OF THE AREA. THE ONLY EXCEPTION MAY BE ACROSS OUR NORTHWESTERN CWA WHERE LINGERING CLOUDS MAY LIMIT TEMPERATURE DROP-OFFS FROM REACHING THEIR FULL POTENTIAL. MET/NAM GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON THIS AND OPTED TO PLAY CLOSE TO THIS GUIDANCE FOR LOWS TONIGHT...WHICH PRESENTS TEMPERATURES RANGING FROM THE MID-20S TO THE MID-30S. THE SURFACE RIDGE SHOULD PASS OFF TO THE EAST OF OUR AREA SATURDAY AFTERNOON...THUS ALLOWING FOR WEAK LOW LEVEL RETURN FLOW BY LATE IN THE DAY. WITH MOSTLY CLEAR SKIES AND A FAIRLY DRY LOW LEVEL AIRMASS...SATURDAY TEMPERATURE-RISES ON THE ORDER OF 25-30 DEGREES SEEM REASONABLE...WHICH PRESENTS SATURDAY HIGH TEMPERATURES GENERALLY IN THE MID TO UPPER 50S. LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. MOST DAYS WILL SEE ABOVE NORMAL HIGH TEMPERATURES EXCEPT FOR TUESDAY. IN ADDITION...OUTSIDE OF A FEW ISOLATED SPRINKLES IT SHOULD BE A DRY PERIOD. SATURDAY NIGHT...A WEAK SHORTWAVE TROUGH WILL TRACK SOUTHEAST THROUGH IOWA...AND CLOUDS WILL INCREASE OVERNIGHT ACROSS IOWA AND NEBRASKA. A FEW SPRINKLES MAY EXTEND AS FAR WEST AS CENTRAL NEBRASKA...BUT MOST AREAS WILL REMAIN DRY. WE CAME VERY CLOSE TO PULLING THE SPRINKLES OUT OF THE FORECAST...BUT WILL LEAVE THEM IN THE FORECAST THROUGH ONE MORE MODEL CYCLE. SUNDAY...A WEAK RIDGE IN THE GENERALLY NORTHWEST FLOW REGIME WILL BE PASSING THROUGH DURING THE DAY AND THE SFC WIND WILL BE LIGHT...BUT WITH A SOUTHWESTERLY COMPONENT THROUGH MOST OF THE DAY. THEREFORE...EXPECT SUNDAY WILL BE A FEW DEGREES WARMER THAN SATURDAY AND ABOVE NORMAL WITH HIGH TEMPERATURES IN THE 60S. SUNDAY NIGHT...THE NEXT SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST FLOW WILL SWING INTO NEBRASKA. THIS WILL BRING DOWN A COLD FRONT AND A CHANCE OF MORE SPRINKLES. CLOUDS WILL HELP TO KEEP LOW TEMPERATURES UP A BIT WITH UPPER 30S TO LOWER 40S EXPECTED. MONDAY...COOLER AIR WILL CONTINUE TO FILTER IN BEHIND THE SUNDAY NIGHT SHORTWAVE/COLD FRONT. TEMPERATURES AT 850MB MAY FALL TO AROUND 0C ACROSS EASTERN ZONES AND EXPECT SFC TEMPERATURES TO BE AROUND 10 DEGREES COOLER THAN ON SUNDAY WITH HIGHS IN THE 50S. TUESDAY THROUGH FRIDAY...AN UPPER RIDGE WILL BUILD ACROSS THE PLAINS AS A LARGE UPPER TROUGH BEGINS TO DIG OVER THE WESTERN CONUS. THIS WILL BE A WARM AND DRY WEATHER PATTERN FOR OUR FORECAST AREA WITH HIGHS GENERALLY IN THE 60S. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
250 PM CDT FRI NOV 2 2012 .SHORT TERM...THROUGH 00Z SUNDAY. MORNING UPPER AIR ANALYSIS INDICATES LONG WAVE TROUGHING OVER THE EASTERN ONE-THIRD OF THE CONUS...AND A RIDGE AXIS EXTENDING FROM NEW MEXICO INTO THE NORTHERN PLAINS. TWO MID LEVEL SHORTWAVES...ONE OVER THE NORTHERN PLAINS AND THE OTHER OVER THE SOUTHWESTERN CONUS...ARE ALSO NOTED...WITH ZONAL MID AND UPPER LEVEL FLOW PERSISTING ACROSS THE CENTRAL PLAINS. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM WYOMING...EAST/NORTHEAST ACROSS THE NORTHERN PLAINS AND THEN SOUTHEAST ACROSS THE MISSISSIPPI VALLEY ON INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW REMAINS FAIRLY WEAK OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 70KTS NEAR 200MB PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL MOISTURE AHEAD OF THE MID LEVEL SHORT WAVE OVER THE SOUTHWESTERN CONUS...WITH THIS INCREASED MID LEVEL MOISTURE EXTENDING FROM THE FOUR-CORNERS REGION...EAST/NORTHEAST ACROSS THE CENTRAL ROCKY MOUNTAIN RANGE AND ON INTO THE CENTRAL PLAINS. PLENTY OF MID AND HIGH LEVEL CLOUDS ARE NOTED INFILTRATING THE CENTRAL PLAINS AS A RESULT. AT THE SURFACE A WEAK AREA OF LOW PRESSURE EXISTS OVER SOUTH CENTRAL KANSAS...WITH A WEAK FRONTAL BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS PORTIONS OF CENTRAL AND EASTERN KANSAS. AN INVERTED TROUGH IS ALSO NOTED EXTENDING NORTH FROM THE SURFACE LOW INTO NORTH CENTRAL KANSAS AND SOUTH CENTRAL NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR CWA REMAINS SPLIT AS A RESULT...WITH AN EAST/SOUTHEAST WIND ACROSS THE SOUTHEASTERN HALF OF THE CWA...AND A NORTH/NORTHWEST WIND FARTHER NORTHWEST. LOW LEVEL THERMAL ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER PORTIONS OF CENTRAL AND EASTERN KANSAS...IS PROMOTING ISENTROPIC UPGLIDE AND SATURATION ALONG THE 290-300K SURFACES...PER RAP ANALYSIS DATA. THIS SATURATION HAS RESULTED IN STRATUS ACROSS NORTHWESTERN PORTIONS OF THE CWA THIS AFTERNOON...WHERE CEILINGS IN THE 1000-2000FT AGL PERSIST. GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST THE MID LEVEL SHORT WAVE OVER THE NORTHERN PLAINS WILL CONTINUE MOVING EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS. ANY DPVA AND MID LEVEL THERMAL ADVECTION IN ASSOCIATION WITH THIS SYSTEM SHOULD REMAIN WELL NORTH/NORTHEAST OF OUR AREA. IN ADDITION...THE MID LEVEL SHORT WAVE CURRENTLY OVER THE SOUTHWESTERN CONUS IS EXPECTED TO WEAKEN THROUGH THE NEXT 24 HOURS...THUS PRESENTING LITTLE IF ANY OMEGA TO OUR AREA ONCE IT NEARS THE REGION. GIVEN THE OVERALL LACK IN KINEMATIC FORCING OVER OUR AREA THROUGH THE NEXT 24 HOURS...OPTED TO KEEP THE FORECAST DRY FOR TONIGHT AND TOMORROW. GUIDANCE ALSO SUGGESTS THE SURFACE HIGH...CURRENTLY OVER SOUTH CENTRAL KANSAS...WILL PUSH OFF TO THE EAST/SOUTHEAST TONIGHT...THUS ALLOWING WEAK SURFACE RIDGING INTO OUR AREA OVERNIGHT TONIGHT INTO SATURDAY MORNING. ISENTROPIC UPGLIDE SHOULD DISSIPATE ACROSS OUR AREA LATER TONIGHT AS THE LOW LEVEL BAROCLINIC ZONE OVER CENTRAL AND EASTERN PORTIONS OF KANSAS PUSHES OFF TO THE EAST/SOUTHEAST ALONG WITH THE SURFACE LOW. THIS SHOULD BRING AN END TO THE STRATUS CURRENTLY OVER NORTHWESTERN PORTIONS OF OUR CWA. ALSO...THE INCREASED MID LEVEL MOISTURE...BEING USHERED INTO OUR AREA FROM THE SOUTHWEST BY THE SOUTHWESTERN CONUS MID LEVEL SHORT WAVE...IS EXPECTED TO DISSIPATE THROUGH THE NEXT 24 HOURS AS THE SHORT WAVE ALSO DISSIPATES. GIVEN AL THIS...A CLEARING TREND SHOULD BE OBSERVED ACROSS OUR AREA THROUGH THE NEXT 12 OR SO HOURS...WITH MOSTLY CLEAR SKIES EXPECTED THEREAFTER. WENT AHEAD AND KEPT THE INCREASED CLOUD COVER GOING IN THE FORECAST FOR NORTHWESTERN PORTIONS OF THE CWA THROUGH THIS EVENING TO ACCOUNT FOR THE CURRENT STRATUS...WITH MOSTLY CLEAR SKIES FORECAST ACROSS MOST ALL OF THE CWA 06Z ONWARD. THE COMBINATION OF CLEARING SKIES...A DECREASING LOW LEVEL WIND FIELD...AND THE INFLUX OF A COOLER AND DRIER LOW LEVEL AIRMASS INTO OUR AREA AS THE WEAK SURFACE RIDGE INFILTRATES THE REGION...WILL PROMOTE A CHILLY NIGHT ACROSS THE CWA WITH ~30-DEGREE TEMPERATURE DROP-OFFS LIKELY ACROSS MUCH OF THE AREA. THE ONLY EXCEPTION MAY BE ACROSS OUR NORTHWESTERN CWA WHERE LINGERING CLOUDS MAY LIMIT TEMPERATURE DROP-OFFS FROM REACHING THEIR FULL POTENTIAL. MET/NAM GUIDANCE SEEMS TO HAVE A GOOD HANDLE ON THIS AND OPTED TO PLAY CLOSE TO THIS GUIDANCE FOR LOWS TONIGHT...WHICH PRESENTS TEMPERATURES RANGING FROM THE MID-20S TO THE MID-30S. THE SURFACE RIDGE SHOULD PASS OFF TO THE EAST OF OUR AREA SATURDAY AFTERNOON...THUS ALLOWING FOR WEAK LOW LEVEL RETURN FLOW BY LATE IN THE DAY. WITH MOSTLY CLEAR SKIES AND A FAIRLY DRY LOW LEVEL AIRMASS...SATURDAY TEMPERATURE-RISES ON THE ORDER OF 25-30 DEGREES SEEM REASONABLE...WHICH PRESENTS SATURDAY HIGH TEMPERATURES GENERALLY IN THE MID TO UPPER 50S. .LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. MOST DAYS WILL SEE ABOVE NORMAL HIGH TEMPERATURES EXCEPT FOR TUESDAY. IN ADDITION...OUTSIDE OF A FEW ISOLATED SPRINKLES IT SHOULD BE A DRY PERIOD. SATURDAY NIGHT...A WEAK SHORTWAVE TROUGH WILL TRACK SOUTHEAST THROUGH IOWA...AND CLOUDS WILL INCREASE OVERNIGHT ACROSS IOWA AND NEBRASKA. A FEW SPRINKLES MAY EXTEND AS FAR WEST AS CENTRAL NEBRASKA...BUT MOST AREAS WILL REMAIN DRY. WE CAME VERY CLOSE TO PULLING THE SPRINKLES OUT OF THE FORECAST...BUT WILL LEAVE THEM IN THE FORECAST THROUGH ONE MORE MODEL CYCLE. SUNDAY...A WEAK RIDGE IN THE GENERALLY NORTHWEST FLOW REGIME WILL BE PASSING THROUGH DURING THE DAY AND THE SFC WIND WILL BE LIGHT...BUT WITH A SOUTHWESTERLY COMPONENT THROUGH MOST OF THE DAY. THEREFORE...EXPECT SUNDAY WILL BE A FEW DEGREES WARMER THAN SATURDAY AND ABOVE NORMAL WITH HIGH TEMPERATURES IN THE 60S. SUNDAY NIGHT...THE NEXT SHORTWAVE TROUGH EMBEDDED WITHIN THE NORTHWEST FLOW WILL SWING INTO NEBRASKA. THIS WILL BRING DOWN A COLD FRONT AND A CHANCE OF MORE SPRINKLES. CLOUDS WILL HELP TO KEEP LOW TEMPERATURES UP A BIT WITH UPPER 30S TO LOWER 40S EXPECTED. MONDAY...COOLER AIR WILL CONTINUE TO FILTER IN BEHIND THE SUNDAY NIGHT SHORTWAVE/COLD FRONT. TEMPERATURES AT 850MB MAY FALL TO AROUND 0C ACROSS EASTERN ZONES AND EXPECT SFC TEMPERATURES TO BE AROUND 10 DEGREES COOLER THAN ON SUNDAY WITH HIGHS IN THE 50S. TUESDAY THROUGH FRIDAY...AN UPPER RIDGE WILL BUILD ACROSS THE PLAINS AS A LARGE UPPER TROUGH BEGINS TO DIG OVER THE WESTERN CONUS. THIS WILL BE A WARM AND DRY WEATHER PATTERN FOR OUR FORECAST AREA WITH HIGHS GENERALLY IN THE 60S. && .PREV DISCUSSION... /ISSUED 1218 PM CDT FRI NOV 2 2012/ AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS. MID AND HIGH LEVEL CLOUDS WILL PERSIST THROUGH THE TAF PERIOD...BUT NOTHING BELOW 15000FT AGL CURRENTLY FORECAST. THE SURFACE WIND WILL REMAIN GENERALLY LIGHT AND VARIABLE THROUGH THE NEXT 24 HOURS. VISIBILITY RESTRICTION IS NOT ANTICIPATED THROUGH 18Z SATURDAY. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM/AVIATION...BRYANT LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1244 PM CDT FRI NOV 2 2012 .UPDATE...MIDDAY SURFACE ANALYSIS INDICATES AN AREA OF LOW PRESSURE OVER SOUTH CENTRAL KANSAS...WITH AN INVERTED SURFACE TROUGH EXTENDING NORTH OF THE LOW THROUGH NORTH CENTRAL KANSAS AND SOUTH CENTRAL NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR CWA REMAINS SPLIT AS A RESULT...WITH AN EAST/SOUTHEAST WIND ACROSS THE SOUTHEASTERN HALF OF THE CWA...AND A NORTH/NORTHWEST WIND FARTHER NORTHWEST. ALSO...INCREASING MID LEVEL MOISTURE...AHEAD OF THE MID LEVEL SHORT WAVE CURRENTLY OVER THE SOUTHWESTERN CONUS...CONTINUES TO PROMOTE DENSE MID TO HIGH LEVEL CLOUD COVER ACROSS NORTHWESTERN PORTIONS OF THE CWA. VISIBLE SATELLITE IMAGERY INDICATES THIS IS A TREND WHICH WILL CONTINUE THROUGH MUCH OF THE AFTERNOON. THE INCREASED CLOUD COVER...WORKING IN CONCERT WITH WEAK LOW LEVEL COLD AIR ADVECTION DUE TO THE MORE NORTHERLY LOW LEVEL WIND FIELD...WILL LIKELY KEEP TEMPERATURES SOMEWHAT COOLER ACROSS OUR NORTHWEST THAN WHAT WAS PREVIOUSLY FORECAST. WENT AHEAD AND DECREASED AFTERNOON TEMPERATURES A TOUCH ACROSS NORTHWESTERN PORTIONS OF THE CWA AS A RESULT. AFTERNOON HIGHS IN THE UPPER 40S TO MID 50S ARE NOW FORECAST FOR THE MOST PART ACROSS THE NORTHWESTERN-HALF OF THE CWA...WITH UPPER 50S TO MID 60S STILL EXPECTED FARTHER SOUTHEAST. && .PREV DISCUSSION... /ISSUED 1218 PM CDT FRI NOV 2 2012/ AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS. MID AND HIGH LEVEL CLOUDS WILL PERSIST THROUGH THE TAF PERIOD...BUT NOTHING BELOW 15000FT AGL CURRENTLY FORECAST. THE SURFACE WIND WILL REMAIN GENERALLY LIGHT AND VARIABLE THROUGH THE NEXT 24 HOURS. VISIBILITY RESTRICTION IS NOT ANTICIPATED THROUGH 18Z SATURDAY. PREV DISCUSSION... /ISSUED 1014 AM CDT FRI NOV 2 2012/ UPDATE... MORNING UPPER AIR ANALYSIS INDICATES LONG-WAVE TROUGHING OVER THE EASTERN ONE-THIRD OF THE CONUS...AND A RIDGE AXIS EXTENDING FROM NEW MEXICO INTO THE NORTHERN PLAINS. TWO MID LEVEL SHORT-WAVES...ONE OVER MONTANA AND THE OTHER OVER NEVADA...ARE ALSO NOTED. ZONAL FLOW PERSISTS ACROSS THE CENTRAL PLAINS AS A RESULT. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM WYOMING...EAST/NORTHEAST ACROSS THE NORTHERN PLAINS AND THEN SOUTHEAST ACROSS THE MISSISSIPPI VALLEY ON INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW REMAINS FAIRLY WEAK OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 70KTS NEAR 200MB PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL MOISTURE AHEAD OF THE MID LEVEL SHORTWAVE OVER NEVADA...WITH THIS INCREASED MID LEVEL MOISTURE EXTENDING FROM THE FOUR-CORNERS REGION...EAST/NORTHEAST ACROSS THE CENTRAL ROCKY MOUNTAIN RANGE AND ON INTO THE CENTRAL PLAINS. PLENTY OF MID AND HIGH LEVEL CLOUDS ARE NOTED INFILTRATING THE CENTRAL PLAINS AS A RESULT. AT THE SURFACE A WEAK AREA OF LOW PRESSURE EXISTS OVER WESTERN KANSAS...WITH A WEAK FRONTAL BOUNDARY EXTENDING EAST FROM THE LOW ACROSS PORTIONS OF CENTRAL KANSAS INTO EASTERN KANSAS...AND ALSO SOUTHWEST OF THE LOW INTO SOUTHWESTERN KANSAS ON INTO NORTHEASTERN NEW MEXICO. AN INVERTED TROUGH IS ALSO NOTED EXTENDING NORTH FROM THE SURFACE LOW ACROSS PORTIONS OF NORTHWESTERN KANSAS AND WESTERN NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE EAST/NORTHEAST AS A RESULT. THERMAL ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL KANSAS...IS PROMOTING ISENTROPIC UPGLIDE AND SATURATION ALONG THE 285-290K SURFACES...PER RAP ANALYSIS DATA. THIS SATURATION HAS RESULTED IN STRATUS DEVELOPMENT ACROSS PORTIONS OF THE CWA THIS MORNING...PRIMARILY ACROSS WESTERN AND NORTHERN PORTIONS OF THE CWA WHERE CEILINGS REMAIN IN THE 200-500FT AGL RANGE. MODEST POOLING OF LOW LEVEL MOISTURE TO THE NORTH OF THE LOW LEVEL BAROCLINIC ZONE AND EAST OF THE INVERTED SURFACE TROUGH IS HELPING PROMOTE VERY LOW SURFACE DEWPOINT DEPRESSIONS AS TEMPERATURES REMAIN IN THE UPPER 30S. FOG IS PERSISTING ACROSS PORTIONS OF THE AREA AS A RESULT...PRIMARILY SOUTH OF I-80 AND WEST OF HIGHWAY 281. THAT BEING SAID...FOG CONTINUES TO DISSIPATE THIS MORNING WITH THE VISIBILITY IMPROVING INTO THE 5-10SM FOR MOST LOCATIONS. GIVEN ALL THIS...WENT AHEAD AND REMOVED FOG FROM THE FORECAST FOR THIS MORNING. PREV DISCUSSION... /ISSUED 523 AM CDT FRI NOV 2 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. MAIN CHALLENGES INCLUDE SKY COVER AND PERHAPS QUICK SHOTS AT VERY LIGHT PRECIPITATION COMING UP. WE START TODAY OFF WITH A STATIONARY SURFACE BOUNDARY TO THE SOUTHWEST AND PLENTY OF CIRRUS WITH SOME MID-LEVEL SKY COVER HERE AND THERE. ALSO HAVE SOME REDUCED VISIBILITY SHOWING UP WITHIN LIGHT UPSLOPE FLOW...ESPECIALLY ON THE NEBRASKA SIDE OF THE CWA. EARLIER...ORD WAS DOWN TO ONE HALF MILE VISIBILITY...BUT MOST LOCATIONS ARE UP TO AROUND 3 TO 5 MILES ON THE NEBRASKA SIDE...WITH AN EXCEPTION HERE OR THERE A BIT BELOW. ANY FOG SHOULD BURN OFF BY MID-MORNING. UPPER LEVEL FLOW IS IN TRANSITION FOR US TODAY AS A RIDGE SLIPS TO THE EAST AND SHORTWAVE TROUGH ABOUT TO SKIRT THE NORTHERN PLAINS...ALLOWING COOLER AIR TO SPILL DOWN INTO OUR AREA. I HAVE DECREASED TEMPERATURES TODAY COMPARED TO THE PREVIOUS FORECAST DUE TO THE INCREASED SKY COVER AND COOLER AIR ADVECTING IN FROM THE NORTH. UPPER LEVEL FLOW WILL BE NORTHWEST FOR TONIGHT. THE REAR RIGHT QUADRANT OF THE UPPER LEVEL JET STREAK SHOULD EVENTUALLY SHIFT TO THE EAST AND WILL ALLOW A GENERAL CLEARING OF HIGH LEVEL SKY CLOUDINESS. THEN WE GET INTO A SCENARIO OF QUICK-MOVING SHORTWAVE TROUGHS WITHIN NORTHWEST FLOW...WITH A FOCUS OF ENERGY FARTHER NORTHEAST OF THE CWA. ALSO...LOW TO MID-LEVELS WILL BE QUITE DRY. WITH THESE THINGS IN MIND...THE MOST I WOULD GENERALLY EXPECT IS SPRINKLES FOR SATURDAY NIGHT AND SUNDAY NIGHT FOR SOME OF THE CWA AS THESE WAVES MOVE BY. LONG TERM...MONDAY THROUGH THURSDAY. MAIN FORECAST CONCERN WILL BE TEMPERATURES. NORTHWEST FLOW IS EXPECTED ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THIS PERIOD. ON MONDAY THERE IS AN UPPER WAVE JUST TO THE EAST OF THE FORECAST AREA PUSHING A FEW CLOUDS INTO THE EASTERN PORTION OF THE AREA IN THE MORNING. TEMPERATURES WILL BE NEAR NORMAL. MONDAY NIGHT THROUGH WEDNESDAY NIGHT THERE IS A LITTLE WARM ADVECTION AND TEMPERATURES WILL BE ABOVE NORMAL. BY THURSDAY THE UPPER FLOW BECOMES MORE ZONAL. A SURFACE LOW ACROSS KANSAS WILL ALLOW FOR EAST WINDS ACROSS THE AREA AND BRING IN SOME LOW LEVEL MOISTURE AND SOME CLOUDS AND TEMPERATURES WILL BE A BIT COOLER BUT STILL ABOVE NORMAL. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ 1244 PM UPDATE/AVIATION/1014 AM UPDATE...BRYANT SHORT TERM...HEINLEIN LONG TERM/AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1218 PM CDT FRI NOV 2 2012 .AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE NEXT 24 HOURS. MID AND HIGH LEVEL CLOUDS WILL PERSIST THROUGH THE TAF PERIOD...BUT NOTHING BELOW 15000FT AGL CURRENTLY FORECAST. THE SURFACE WIND WILL REMAIN GENERALLY LIGHT AND VARIABLE THROUGH THE NEXT 24 HOURS. VISIBILITY RESTRICTION IS NOT ANTICIPATED THROUGH 18Z SATURDAY. && .PREV DISCUSSION... /ISSUED 1014 AM CDT FRI NOV 2 2012/ UPDATE... MORNING UPPER AIR ANALYSIS INDICATES LONG-WAVE TROUGHING OVER THE EASTERN ONE-THIRD OF THE CONUS...AND A RIDGE AXIS EXTENDING FROM NEW MEXICO INTO THE NORTHERN PLAINS. TWO MID LEVEL SHORT-WAVES...ONE OVER MONTANA AND THE OTHER OVER NEVADA...ARE ALSO NOTED. ZONAL FLOW PERSISTS ACROSS THE CENTRAL PLAINS AS A RESULT. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM WYOMING...EAST/NORTHEAST ACROSS THE NORTHERN PLAINS AND THEN SOUTHEAST ACROSS THE MISSISSIPPI VALLEY ON INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW REMAINS FAIRLY WEAK OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 70KTS NEAR 200MB PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL MOISTURE AHEAD OF THE MID LEVEL SHORTWAVE OVER NEVADA...WITH THIS INCREASED MID LEVEL MOISTURE EXTENDING FROM THE FOUR-CORNERS REGION...EAST/NORTHEAST ACROSS THE CENTRAL ROCKY MOUNTAIN RANGE AND ON INTO THE CENTRAL PLAINS. PLENTY OF MID AND HIGH LEVEL CLOUDS ARE NOTED INFILTRATING THE CENTRAL PLAINS AS A RESULT. AT THE SURFACE A WEAK AREA OF LOW PRESSURE EXISTS OVER WESTERN KANSAS...WITH A WEAK FRONTAL BOUNDARY EXTENDING EAST FROM THE LOW ACROSS PORTIONS OF CENTRAL KANSAS INTO EASTERN KANSAS...AND ALSO SOUTHWEST OF THE LOW INTO SOUTHWESTERN KANSAS ON INTO NORTHEASTERN NEW MEXICO. AN INVERTED TROUGH IS ALSO NOTED EXTENDING NORTH FROM THE SURFACE LOW ACROSS PORTIONS OF NORTHWESTERN KANSAS AND WESTERN NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE EAST/NORTHEAST AS A RESULT. THERMAL ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL KANSAS...IS PROMOTING ISENTROPIC UPGLIDE AND SATURATION ALONG THE 285-290K SURFACES...PER RAP ANALYSIS DATA. THIS SATURATION HAS RESULTED IN STRATUS DEVELOPMENT ACROSS PORTIONS OF THE CWA THIS MORNING...PRIMARILY ACROSS WESTERN AND NORTHERN PORTIONS OF THE CWA WHERE CEILINGS REMAIN IN THE 200-500FT AGL RANGE. MODEST POOLING OF LOW LEVEL MOISTURE TO THE NORTH OF THE LOW LEVEL BAROCLINIC ZONE AND EAST OF THE INVERTED SURFACE TROUGH IS HELPING PROMOTE VERY LOW SURFACE DEWPOINT DEPRESSIONS AS TEMPERATURES REMAIN IN THE UPPER 30S. FOG IS PERSISTING ACROSS PORTIONS OF THE AREA AS A RESULT...PRIMARILY SOUTH OF I-80 AND WEST OF HIGHWAY 281. THAT BEING SAID...FOG CONTINUES TO DISSIPATE THIS MORNING WITH THE VISIBILITY IMPROVING INTO THE 5-10SM FOR MOST LOCATIONS. GIVEN ALL THIS...WENT AHEAD AND REMOVED FOG FROM THE FORECAST FOR THIS MORNING. PREV DISCUSSION... /ISSUED 523 AM CDT FRI NOV 2 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. MAIN CHALLENGES INCLUDE SKY COVER AND PERHAPS QUICK SHOTS AT VERY LIGHT PRECIPITATION COMING UP. WE START TODAY OFF WITH A STATIONARY SURFACE BOUNDARY TO THE SOUTHWEST AND PLENTY OF CIRRUS WITH SOME MID-LEVEL SKY COVER HERE AND THERE. ALSO HAVE SOME REDUCED VISIBILITY SHOWING UP WITHIN LIGHT UPSLOPE FLOW...ESPECIALLY ON THE NEBRASKA SIDE OF THE CWA. EARLIER...ORD WAS DOWN TO ONE HALF MILE VISIBILITY...BUT MOST LOCATIONS ARE UP TO AROUND 3 TO 5 MILES ON THE NEBRASKA SIDE...WITH AN EXCEPTION HERE OR THERE A BIT BELOW. ANY FOG SHOULD BURN OFF BY MID-MORNING. UPPER LEVEL FLOW IS IN TRANSITION FOR US TODAY AS A RIDGE SLIPS TO THE EAST AND SHORTWAVE TROUGH ABOUT TO SKIRT THE NORTHERN PLAINS...ALLOWING COOLER AIR TO SPILL DOWN INTO OUR AREA. I HAVE DECREASED TEMPERATURES TODAY COMPARED TO THE PREVIOUS FORECAST DUE TO THE INCREASED SKY COVER AND COOLER AIR ADVECTING IN FROM THE NORTH. UPPER LEVEL FLOW WILL BE NORTHWEST FOR TONIGHT. THE REAR RIGHT QUADRANT OF THE UPPER LEVEL JET STREAK SHOULD EVENTUALLY SHIFT TO THE EAST AND WILL ALLOW A GENERAL CLEARING OF HIGH LEVEL SKY CLOUDINESS. THEN WE GET INTO A SCENARIO OF QUICK-MOVING SHORTWAVE TROUGHS WITHIN NORTHWEST FLOW...WITH A FOCUS OF ENERGY FARTHER NORTHEAST OF THE CWA. ALSO...LOW TO MID-LEVELS WILL BE QUITE DRY. WITH THESE THINGS IN MIND...THE MOST I WOULD GENERALLY EXPECT IS SPRINKLES FOR SATURDAY NIGHT AND SUNDAY NIGHT FOR SOME OF THE CWA AS THESE WAVES MOVE BY. LONG TERM...MONDAY THROUGH THURSDAY. MAIN FORECAST CONCERN WILL BE TEMPERATURES. NORTHWEST FLOW IS EXPECTED ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THIS PERIOD. ON MONDAY THERE IS AN UPPER WAVE JUST TO THE EAST OF THE FORECAST AREA PUSHING A FEW CLOUDS INTO THE EASTERN PORTION OF THE AREA IN THE MORNING. TEMPERATURES WILL BE NEAR NORMAL. MONDAY NIGHT THROUGH WEDNESDAY NIGHT THERE IS A LITTLE WARM ADVECTION AND TEMPERATURES WILL BE ABOVE NORMAL. BY THURSDAY THE UPPER FLOW BECOMES MORE ZONAL. A SURFACE LOW ACROSS KANSAS WILL ALLOW FOR EAST WINDS ACROSS THE AREA AND BRING IN SOME LOW LEVEL MOISTURE AND SOME CLOUDS AND TEMPERATURES WILL BE A BIT COOLER BUT STILL ABOVE NORMAL. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION/UPDATE...BRYANT SHORT TERM...HEINLEIN LONG TERM/AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1014 AM CDT FRI NOV 2 2012 .UPDATE... MORNING UPPER AIR ANALYSIS INDICATES LONG-WAVE TROUGHING OVER THE EASTERN ONE-THIRD OF THE CONUS...AND A RIDGE AXIS EXTENDING FROM NEW MEXICO INTO THE NORTHERN PLAINS. TWO MID LEVEL SHORT-WAVES...ONE OVER MONTANA AND THE OTHER OVER NEVADA...ARE ALSO NOTED. ZONAL FLOW PERSISTS ACROSS THE CENTRAL PLAINS AS A RESULT. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM WYOMING...EAST/NORTHEAST ACROSS THE NORTHERN PLAINS AND THEN SOUTHEAST ACROSS THE MISSISSIPPI VALLEY ON INTO THE MID-ATLANTIC. TROPOSPHERIC FLOW REMAINS FAIRLY WEAK OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 70KTS NEAR 200MB PER 12Z SOUNDING DATA FROM KLBF. WATER VAPOR IMAGERY INDICATES INCREASED VALUES OF MID LEVEL MOISTURE AHEAD OF THE MID LEVEL SHORTWAVE OVER NEVADA...WITH THIS INCREASED MID LEVEL MOISTURE EXTENDING FROM THE FOUR-CORNERS REGION...EAST/NORTHEAST ACROSS THE CENTRAL ROCKY MOUNTAIN RANGE AND ON INTO THE CENTRAL PLAINS. PLENTY OF MID AND HIGH LEVEL CLOUDS ARE NOTED INFILTRATING THE CENTRAL PLAINS AS A RESULT. AT THE SURFACE A WEAK AREA OF LOW PRESSURE EXISTS OVER WESTERN KANSAS...WITH A WEAK FRONTAL BOUNDARY EXTENDING EAST FROM THE LOW ACROSS PORTIONS OF CENTRAL KANSAS INTO EASTERN KANSAS...AND ALSO SOUTHWEST OF THE LOW INTO SOUTHWESTERN KANSAS ON INTO NORTHEASTERN NEW MEXICO. AN INVERTED TROUGH IS ALSO NOTED EXTENDING NORTH FROM THE SURFACE LOW ACROSS PORTIONS OF NORTHWESTERN KANSAS AND WESTERN NEBRASKA. THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM THE EAST/NORTHEAST AS A RESULT. THERMAL ADVECTION ACROSS THE LOW LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL KANSAS...IS PROMOTING ISENTROPIC UPGLIDE AND SATURATION ALONG THE 285-290K SURFACES...PER RAP ANALYSIS DATA. THIS SATURATION HAS RESULTED IN STRATUS DEVELOPMENT ACROSS PORTIONS OF THE CWA THIS MORNING...PRIMARILY ACROSS WESTERN AND NORTHERN PORTIONS OF THE CWA WHERE CEILINGS REMAIN IN THE 200-500FT AGL RANGE. MODEST POOLING OF LOW LEVEL MOISTURE TO THE NORTH OF THE LOW LEVEL BAROCLINIC ZONE AND EAST OF THE INVERTED SURFACE TROUGH IS HELPING PROMOTE VERY LOW SURFACE DEWPOINT DEPRESSIONS AS TEMPERATURES REMAIN IN THE UPPER 30S. FOG IS PERSISTING ACROSS PORTIONS OF THE AREA AS A RESULT...PRIMARILY SOUTH OF I-80 AND WEST OF HIGHWAY 281. THAT BEING SAID...FOG CONTINUES TO DISSIPATE THIS MORNING WITH THE VISIBILITY IMPROVING INTO THE 5-10SM FOR MOST LOCATIONS. GIVEN ALL THIS...WENT AHEAD AND REMOVED FOG FROM THE FORECAST FOR THIS MORNING. && .PREV DISCUSSION... /ISSUED 620 AM CDT FRI NOV 2 2012/ AVIATION...12Z TAF. CIRRUS CONTINUES ACROSS THE KGRI TERMINAL AREA THIS MORNING AND WILL CONTINUE FOR MUCH OF THE PERIOD. IT SHOULD GRADUALLY DIMINISH LATER THIS AFTERNOON AND EVENING. THE VISIBILITY CONTINUES TO BE RESTRICTED BY SOME LIGHT FOG/MIST THIS MORNING BUT VISIBILITY SHOULD IMPROVE AFTER THE SUN COMES UP. EXPECT MVFR VISIBILITIES WITH THIS. PREV DISCUSSION... /ISSUED 523 AM CDT FRI NOV 2 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT. MAIN CHALLENGES INCLUDE SKY COVER AND PERHAPS QUICK SHOTS AT VERY LIGHT PRECIPITATION COMING UP. WE START TODAY OFF WITH A STATIONARY SURFACE BOUNDARY TO THE SOUTHWEST AND PLENTY OF CIRRUS WITH SOME MID-LEVEL SKY COVER HERE AND THERE. ALSO HAVE SOME REDUCED VISIBILITY SHOWING UP WITHIN LIGHT UPSLOPE FLOW...ESPECIALLY ON THE NEBRASKA SIDE OF THE CWA. EARLIER...ORD WAS DOWN TO ONE HALF MILE VISIBILITY...BUT MOST LOCATIONS ARE UP TO AROUND 3 TO 5 MILES ON THE NEBRASKA SIDE...WITH AN EXCEPTION HERE OR THERE A BIT BELOW. ANY FOG SHOULD BURN OFF BY MID-MORNING. UPPER LEVEL FLOW IS IN TRANSITION FOR US TODAY AS A RIDGE SLIPS TO THE EAST AND SHORTWAVE TROUGH ABOUT TO SKIRT THE NORTHERN PLAINS...ALLOWING COOLER AIR TO SPILL DOWN INTO OUR AREA. I HAVE DECREASED TEMPERATURES TODAY COMPARED TO THE PREVIOUS FORECAST DUE TO THE INCREASED SKY COVER AND COOLER AIR ADVECTING IN FROM THE NORTH. UPPER LEVEL FLOW WILL BE NORTHWEST FOR TONIGHT. THE REAR RIGHT QUADRANT OF THE UPPER LEVEL JET STREAK SHOULD EVENTUALLY SHIFT TO THE EAST AND WILL ALLOW A GENERAL CLEARING OF HIGH LEVEL SKY CLOUDINESS. THEN WE GET INTO A SCENARIO OF QUICK-MOVING SHORTWAVE TROUGHS WITHIN NORTHWEST FLOW...WITH A FOCUS OF ENERGY FARTHER NORTHEAST OF THE CWA. ALSO...LOW TO MID-LEVELS WILL BE QUITE DRY. WITH THESE THINGS IN MIND...THE MOST I WOULD GENERALLY EXPECT IS SPRINKLES FOR SATURDAY NIGHT AND SUNDAY NIGHT FOR SOME OF THE CWA AS THESE WAVES MOVE BY. LONG TERM...MONDAY THROUGH THURSDAY. MAIN FORECAST CONCERN WILL BE TEMPERATURES. NORTHWEST FLOW IS EXPECTED ACROSS THE CENTRAL PLAINS THROUGH MUCH OF THIS PERIOD. ON MONDAY THERE IS AN UPPER WAVE JUST TO THE EAST OF THE FORECAST AREA PUSHING A FEW CLOUDS INTO THE EASTERN PORTION OF THE AREA IN THE MORNING. TEMPERATURES WILL BE NEAR NORMAL. MONDAY NIGHT THROUGH WEDNESDAY NIGHT THERE IS A LITTLE WARM ADVECTION AND TEMPERATURES WILL BE ABOVE NORMAL. BY THURSDAY THE UPPER FLOW BECOMES MORE ZONAL. A SURFACE LOW ACROSS KANSAS WILL ALLOW FOR EAST WINDS ACROSS THE AREA AND BRING IN SOME LOW LEVEL MOISTURE AND SOME CLOUDS AND TEMPERATURES WILL BE A BIT COOLER BUT STILL ABOVE NORMAL. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...BRYANT SHORT TERM...HEINLEIN LONG TERM/AVIATION...JCB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
352 AM CDT FRI NOV 2 2012 .DISCUSSION... THERE IS GOOD OVERALL AGREEMENT FROM THE DIFFERENT MODEL SOLUTIONS TONIGHT AS THE GENERAL PATTERN SHIFTS FROM RIDGING OVER THE CENTRAL PLAINS TO BEING DEEP INTO NORTHWEST FLOW FOR MUCH OF NEXT WEEK. THE UPPER LEVEL PATTERN THIS MORNING SHOWS THE LARGE UPPER LOW /FORMALLY KNOWN AS SANDY/ REMAINING OVER ONTARIO...KEEPING LONGWAVE TROUGHING ACROSS THE EASTERN CONUS. RIDGING WAS OBSERVED OVER THE PLAINS...WHILE A SHORTWAVE TROUGH WAS OBSERVED OVER THE NORTHERN ROCKIES WITH RIDGING ON THE WEST COAST. FURTHER UPSTREAM...A STRONG LOW PRESSURE SYSTEM WAS SEEN IN THE GULF OF ALASKA. PLENTIFUL MOISTURE WAS SEEN FROM THE WATER VAPOR IMAGERY ROUNDING THE TOP OF THE RIDGE...BRINGING QUITE A BIT OF HIGH CLOUDS ACROSS NEBRASKA THIS MORNING. LOCALLY...A SURFACE LOW WAS OVER EASTERN WYOMING...WITH A WEAK FRONT EXTENDING INTO SOUTHWEST NEBRASKA. AHEAD OF THIS FRONT...MOISTURE IN THE LOW LEVELS AGAIN WAS TRAPPED UNDER THE INVERSION ACROSS NORTH CENTRAL NEBRASKA...WHICH HAS LED TO LOWERED CEILINGS AND SOME VISIBILITY RESTRICTIONS. THIS AREA WAS FAIRLY NARROW AFFECTION LOCATIONS BETWEEN HIGHWAYS 83 AND 281. .SHORT TERM...TODAY THROUGH SUNDAY NIGHT THE PRIMARY CONCERNS THIS PERIOD DEAL WITH FOG/STRATUS AND ITS DISSIPATION TODAY...LEADING TO QUESTIONABLE HIGHS. ALSO...SEVERAL FRONTS WILL MOVE THROUGH THE AREA OVER THE NEXT SEVERAL DAYS TO IMPACT TEMPERATURES AND POSSIBLY BRING A CHANCE FOR PRECIPITATION SUNDAY AND SUNDAY NIGHT. THE FOG/STRATUS ON THURSDAY MORNING STAYED IN PLACE THROUGH A GOOD PORTION OF THE AFTERNOON WHICH KEPT TEMPERATURES DOWN. AS THIS MOISTURE HAS DEVELOPED INTO VERY LOW CEILINGS AGAIN THIS MORNING...DESPITE THE AMOUNT OF HIGH CLOUDS ACROSS THE REGION...AM QUITE CONCERNED WITH THE SPEED OF DISSIPATION TODAY. THE MODELS THAT HAVE PICKED UP ON THIS MOISTURE DO PUSH IT OUT BY 18Z...AND WITH THE SHORTWAVE TROUGH OVER MONTANA MOVING INTO THE DAKOTAS...BELIEVE THAT WILL BE ENOUGH TO PUSH THE SURFACE FRONT EAST AND THROUGH THE FORECAST AREA BY EARLY IN THE AFTERNOON. THIS SHOULD SCOUR OUT THE MOISTURE AND GET CLOUD COVER TO DIMINISH. DID ADJUST TEMPERATURES...ESPECIALLY WHERE CLOUDS WILL STICK AROUND LONGER...BUT MAY NOT BE COOL ENOUGH IF CLOUDS REMAIN INTO THE MID AFTERNOON. ALTHOUGH THERE IS MOISTURE IN THE LOW LEVELS...THE REMAINDER OF THE COLUMN WILL BE QUITE DRY SO DO NOT ANTICIPATE ANY PRECIPITATION TO DEVELOP WITH FRONTAL PASSAGE TODAY. THE EAST COAST TROUGH /WHICH MODELS ARE SLOWLY MIGRATING EAST/ WILL DIVERT THE SHORTWAVE OVER THE DAKOTAS TO THE SOUTH ON SATURDAY...SO IT IS EXPECTED TO DROP INTO IOWA THROUGH SATURDAY NIGHT. BELIEVE IF ANY PRECIPITATION DOES ACCOMPANY THIS SYSTEM...IT WILL STAY WELL EAST OF THE FORECAST AREA SO HAVE A DRY FORECAST THROUGH SATURDAY NIGHT. BUT IF THE LONG-WAVE STAYS FURTHER WEST THE SHORTWAVE COULD TRAVEL MORE SOUTH INTO EASTERN NEBRASKA...WHICH WOULD BE THE ONLY CHANCE FOR ANY OF THE FORECAST AREA TO GET RAIN WITH THIS PARTICULAR SYSTEM. THIS IS NOT THE MOST LIKELY SOLUTION SO AGAIN...HAVE A DRY FORECAST. THE NEXT SHORTWAVE TROUGH TO PASS ACROSS THE PLAINS WILL COME FROM THE GULF OF ALASKA SYSTEM...MOVE ACROSS THE NORTHERN ROCKIES AND INTO THE PLAINS ON SUNDAY. THE PATH OF THIS SYSTEM IS DIRECTLY OVER NEBRASKA SO IF THE FORECAST AREA HAS A SHOT FOR SOME PRECIPITATION...THIS WOULD BE THE SYSTEM TO DO IT. HOWEVER...THE PLACEMENT OF THE UPPER JET WOULD KEEP THE BEST DYNAMICS ACROSS EASTERN NEBRASKA. AS THE MODEL SOLUTIONS ARE IN GOOD AGREEMENT THOUGHT THERE IS ENOUGH OF A POSSIBILITY TO ADD A SLIGHT CHANCE FOR RAIN ACROSS PARTS OF NORTH CENTRAL NEBRASKA SUNDAY NIGHT. AHEAD OF THIS SYSTEM...SHOULD SEE WARM-AIR ADVECTION ON SUNDAY SO HIGHS IN THE 50S AND 60S ARE ATTAINABLE EVEN WITH INCREASING CLOUD COVER. .LONG TERM...MONDAY THROUGH THURSDAY AS THE SHORTWAVE TROUGH OVER NEBRASKA DIGS INTO THE DEEP SOUTH EARLY IN THE WEEK...THE UPPER LEVEL FLOW WILL BECOME HIGHLY AMPLIFIED...PUTTING THE LOCAL AREA IN DEEP NORTHWEST FLOW AS A STRONG RIDGE SETS UP OVER THE WEST COAST. AS WAS MENTIONED EARLIER...THE MODELS HAVE GOOD AGREEMENT WITH THIS FLOW PATTERN SO HAVE DECENT CONFIDENCE ON THIS PORTION OF THE FORECAST. AS THE MIDDLE OF THE WEEK COMES...THE GULF OF ALASKA SYSTEM IS PROJECTED TO MOVE INTO THE PACIFIC NORTHWEST AND WEST COAST. THIS WILL CAUSE RIDGING TO BUILD OVER THE PLAINS FOR THE MIDDLE TO LATER PARTS OF THE WEEK. THIS SHOULD BRING BACK TEMPERATURES ABOVE NORMAL...IN THE 60S TO POSSIBLY 70S. DON/T HAVE 70S IN THE FORECAST YET BUT WILL CONTINUE TO MONITOR FOR THE NEED IN COMING FORECASTS. AS THE RIDGE BUILDS...DRY AIR WILL STAY IN PLACE SO NO FURTHER RAIN CHANCES FOR MONDAY THROUGH THURSDAY. && .AVIATION...FOR THE KLBF AND KVTN TERMINALS THROUGH 12Z SATURDAY. PATCHY FOG MAY IMPACT THE KLBF AND KVTN TERMINALS THROUGH 15Z THIS MORNING WITH VSBYS DOWN AS LOW AS 3SM AT THE KVTN TERMINAL AND 5SM AT THE KLBF TERMINAL. ABUNDANT MID AND HIGH LEVEL CLOUDINESS IS EXPECTED THIS MORNING...WHICH WILL LIMIT ANY DEVELOPMENT OF DENSE FOG. BASED ON THE LATEST NAM AND RAP SOLNS...THE THREAT FOR STRATUS DEVELOPMENT AND CIGS BLO 1000 FT AGL IS ACROSS PORTIONS OF NORTH CENTRAL AND CENTRAL NEBRASKA...WITH LITTLE OR NO THREAT OF STRATUS AT THE KLBF TERMINAL. FOR THE KVTN TERMINAL...WILL HOLD OFF MENTION OF STRATUS TILL NEAR FCST ISSUANCE AND WAIT TO SEE IF IT SPREADS SOUTH INTO NRN NEBRASKA FROM SRN SD. UPPER LEVEL CLOUDINESS IS EXPECTED TO PERSIST ACROSS WESTERN AND NORTH CENTRAL NEBRASKA...WITH BROKEN CIGS AOA 20000 FT AGL LIKELY THIS AFTERNOON AND EVENING...BEFORE SCATTERING OUT OVERNIGHT. WINDS TODAY WILL BE NORTHERLY AT 10 TO 20 KTS...BECOMING LIGHT AND VARIABLE TONIGHT. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...BROOKS AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1127 PM EDT SAT NOV 3 2012 .SYNOPSIS... A PERSISTENT UPPER TROUGH TONIGHT WILL GRADUALLY YIELD TO HIGH PRESSURE APPROACHING FROM THE UPPER LAKES TOMORROW. LIGHT RAIN OR SNOW SHOWERS WILL LINGER TONIGHT...BUT THEN END SUNDAY AS MORNING CLOUDS GIVE WAY TO SOME PARTIAL SUNSHINE. DRY WEATHER WILL LAST THROUGH THE FIRST HALF OF NEXT WEEK...ALTHOUGH IT WILL STILL BE CHILLY WITH BELOW AVERAGE TEMPERATURES. && .NEAR TERM /THROUGH SUNDAY/... REGIONAL RADARS THIS LATE EVENING DISPLAY JUST ISOLATED LIGHT PRECIPITATION IN THE FORM OF RAIN NEAR THE LAKES AND INLAND AND HIGHER ELEVATION SNOW. A SHORTWAVE ON WATER VAPOR IMAGERY IS NEARING THE EASTERN END OF LAKE ONTARIO...WHICH MAY ENHANCE COVERAGE AREA OF LIGHT PRECIPITATION LATER TONIGHT ACROSS THE NORTHERN FINGER LAKES AND EASTERN LAKE ONTARIO REGION. OTHERWISE MUCH OF THE TIME TONIGHT WILL BE DRY. LATER TONIGHT WARMER AIR ALOFT WILL BUILD IN FROM THE WEST. BUFKIT FORECAST SOUNDINGS FROM THE NAM AND RAP WARM THE 700-850MB LAYER...WITH THE COLDEST TEMPERATURES BENEATH THIS LAYER -6C TO -8C. WITH THE MOISTURE PROFILES WELL BELOW THE SNOW GROWTH ZONE...THIS PROFILE SHOULD NOT BE COLD ENOUGH TO SUPPORT SNOW...WITH ANY PRECIPITATION LIKELY TO FALL AS A LIGHT SLEET OR DRIZZLE. FORTUNATELY...THE SHALLOW MOISTURE LAYER AND LIMITED INSTABILITY WILL LIMIT THE CHANCE FOR PRECIPITATION...WITH ONLY A SLIGHT CHANCE OF MEASURABLE PRECIPITATION. THE PROBLEM THIS POSES...IS THAT AS THE SURFACE TEMPERATURES DROP BELOW FREEZING...SOME PATCHY FREEZING DRIZZLE CANNOT BE RULED OUT ACROSS UPSLOPE REGIONS IN THE SOUTHERN TIER. CONFIDENCE IN THIS OCCURRING REMAINS LOW AND WILL JUST INCLUDE SLIGHT CHANCE WORDING. LOWS TONIGHT WILL RANGE FROM THE UPPER 20S ACROSS THE INLAND SOUTHWESTERN NEW YORK AND HIGHER ELEVATIONS OF THE NORTH COUNTRY...TO MID 30S NEAR THE IMMEDIATE LAKE SHORELINE. ON SUNDAY...SURFACE HIGH PRESSURE WILL FINALLY START TO MAKE A MEANINGFUL PUSH INTO THE REGION. DESPITE THIS...A CONTINUED NORTHWESTERLY FLOW OFF THE LAKES WILL LIKELY KEEP CLOUDS IN FOR THE MORNING HOURS...AND WELL INTO THE AFTERNOON. EXPECT SOME BREAKS OF SUN FOR MOST LOCATIONS...BUT THESE MAY NOT BE ALL THAT LONG. HOWEVER...THE DRYING AIR SHOULD CAUSE ANY LINGERING SHOWERS TO TAPER OFF BY LATE MORNING. TEMPERATURES WILL STAY ON THE COOL SIDE...WITH HIGHS IN THE UPPER 30S TO LOWER 40S. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... THE SHORT TERM PERIOD LOOKS RELATIVELY QUIET AS A DRY AIR MASS GAINS CONTROL INTO THE GREAT LAKES AND OHIO VALLEY...COURTESY OF CANADIAN HIGH PRESSURE BUILDING SOUTHWARD INTO THE REGION. THERE COULD BE SOME MINOR LAKE RESPONSE SUNDAY NIGHT WITHIN WEAK NORTHWEST LOW LEVEL FLOW...THOUGH OVERALL DRY AMBIENT AIR AND RELATIVELY LOW LAKE DELTA T/S WOULD SUGGEST ONLY AN INCREASE IN LAKE CLOUDS SOUTHEAST OF LAKE ONTARIO AND ALONG THE SOUTHERN TIER. WESTERN AND CENTRAL NEW YORK WILL BE IN BETWEEN SYSTEMS ON MONDAY AND TUESDAY WITH SHORTWAVE RIDGING AND RESULTING SURFACE HIGH PRESSURE ENSURING A FAIR...ALBEIT CHILLY DAYS. MODEL CROSS SECTIONAL FIELDS WOULD SUGGEST MOSTLY SUNNY DAYS APART FROM SOME DIURNAL STRATOCU...ESPECIALLY MONDAY. 850 MB TEMPERATURES AROUND -6C WOULD SUGGEST HIGHS STRUGGLING TO GET OUT OF THE 30S MONDAY. MONDAY NIGHT LOOKS TO BE A GOOD RADIATIONAL COOLING NIGHT WITH OVERNIGHT LOWS DROPPING INTO THE 20S...WITH A FEW TEENS ACROSS THE NORMALLY COLDER INTERIOR SECTIONS OF THE SOUTHERN TIER AND EAST OF LAKE ONTARIO. TEMPERATURES LOOK A FEW DEGREES WARMER FOR TUESDAY...BUT PROBABLY NO WARMER THAN THE LOWER 40S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... LATEST MEDIUM RANGE GUIDANCE CONTINUING TO SUGGEST THAT CONDITIONS WILL BE FAVORABLE FOR SIGNIFICANT CYCLOGENESIS OFF THE CAROLINA COAST AT THE START OF THE PERIOD. CONFIDENCE HAS INCREASED THAT A DEEP NORTHEAST COASTAL STORM WILL EVOLVE IN THE LATE WEDNESDAY THROUGH THURSDAY TIME FRAME...ALTHOUGH THERE STILL REMAINS DIFFERENCES IN TIMING AND STRENGTH OF THE OVERALL SYSTEM. 12Z GFS FASTER IN MOVING THE COASTAL STORM NORTHWARD THAN THE ECMWF. THE ECMWF REMAINS FARTHER WEST THAN THE GFS...ALTHOUGH THE 12Z GFS HAS MOVED LEFT FROM PREVIOUS RUNS. DESPITE THE CONTINUED MODEL DIFFERENCES...STILL FEEL THAT WESTERN NEW YORK WILL HAVE A LIMITED PRECIPITATION OR WIND THREAT FROM THIS SYSTEM...HOWEVER CENTRAL NEW YORK...ESPECIALLY THE NORTH COUNTRY COULD STILL HAVE SEVERAL SIGNIFICANT IMPACTS...INCLUDING HEAVY RAINFALL...ACCUMULATING HIGHER ELEVATIONS SNOWS AND A WIND POTENTIAL. THIS SYSTEM STILL BEARS WATCHING FOR THAT PORTION OF OUR FORECAST AREA. ONCE THE NORTHEAST COASTAL LOW LIFTS OUT...A BURGEONING PACIFIC CLOSED LOW COMBINED WITH A DIGGING TROUGH OVER THE WESTERN CONUS WILL PROMOTE QUICKLY BUILDING MID LEVEL HEIGHTS AND ANTICYCLONIC VORTICITY ADVECTION INTO THE OHIO VALLEY AND GREAT LAKES. EXPECT DRY CONDITIONS WITH MODERATING TEMPERATURES IN THE FRIDAY THROUGH SATURDAY TIME FRAME...WITH ABOVE NORMAL READINGS LIKELY BY THE WEEKEND. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... AT 03Z VFR/MVFR FLIGHT CONDITIONS WERE FOUND ACROSS THE REGION WITH A NORTHWEST FLOW. MUCH OF THE TAF REGION IS DRY WITH JUST VERY LIGHT PRECIPITATION CROSSING THE AREA. A SHORTWAVE DIVING SOUTHEASTWARD LATER TONIGHT MAY BRING LIGHT PRECIPITATION NEAR KART LATER OVERNIGHT...OTHERWISE WILL HAVE THE TAF SITES DRY. MVFR FLIGHT CONDITIONS THROUGH MUCH OF THE NIGHT WILL BECOME VFR EARLY SUNDAY AS DRIER AIR BEHIND AN UPPER LEVEL TROUGH DROPS INTO THE REGION. THOUGH VFR...EXPECT A LOW CIG IN THE VFR FLIGHT RANGE THROUGH MUCH OF THE DAYLIGHT HOURS...LIFTING HIGHER TOWARDS THE END OF THE TAF PERIOD. WINDS WILL CONTINUE FROM THE NORTHWEST THROUGH THE TAF PERIOD. OUTLOOK... SUNDAY THROUGH WEDNESDAY...MAINLY VFR. THURSDAY...MVFR/VFR. A CHANCE OF RAIN OR SNOW. && .MARINE... NORTHWEST WINDS ACROSS LAKE ONTARIO WILL CONTINUE THE SMALL CRAFT FROM NEAR HAMLIN BEACH TO THE EASTERN WATERS OF LAKE ONTARIO. THESE WINDS WILL CONTINUE TO DIMINISH OVERNIGHT WITH WAVES FALLING TO BELOW SCA BY MID SUNDAY MORNING. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS THE WATERS...AND CONTINUE TO INFLUENCE THE REGION THROUGH MID-WEEK. THIS WILL LIKELY KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA DURING THE PERIOD. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST SUNDAY FOR LOZ043-044. SMALL CRAFT ADVISORY UNTIL 3 AM EST SUNDAY FOR LOZ045. && $$ SYNOPSIS...APFFEL/THOMAS NEAR TERM...APFFEL/THOMAS SHORT TERM...TMA LONG TERM...TMA AVIATION...THOMAS MARINE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
746 PM EDT SAT NOV 3 2012 .SYNOPSIS... A PERSISTENT UPPER TROUGH WILL GRADUALLY YIELD TO HIGH PRESSURE APPROACHING FROM THE UPPER LAKES. LIGHT RAIN OR SNOW SHOWERS WILL LINGER TONIGHT...BUT THEN END SUNDAY AS MORNING CLOUDS GIVE WAY TO SOME PARTIAL SUNSHINE. DRY WEATHER WILL LAST THROUGH THE FIRST HALF OF NEXT WEEK...ALTHOUGH IT WILL STILL BE CHILLY WITH BELOW AVERAGE TEMPERATURES. && .NEAR TERM /THROUGH SUNDAY/... REGIONAL RADARS THIS EVENING DISPLAYING JUST LIGHT PRECIPITATION WITH SFC OBS CONFIRMING BOTH LIGHT RAIN AND LIGHT SNOW PRESENT. ACTIVITY IS MOST PERSISTENT ACROSS UPSLOPE AREAS ON A NORTHWEST FLOW...AND SOUTH AND EAST OF LAKE ONTARIO WHERE AN UPPER LEVEL SHORTWAVE NEARING LAKE ONTARIO IS PROVIDING FOR ADDITIONAL LIFT. WILL CONTINUE WITH THE CHC POPS WITH ACTIVITY SLOWLY DIMINISHING LATER OVERNIGHT ACROSS THE SOUTHERN TIER AS DRIER AND WARMER AIR PUSHES INTO THE REGION. LATER TONIGHT WARMER AIR ALOFT WILL BUILD IN FROM THE WEST. BUFKIT FORECAST SOUNDINGS FROM THE NAM AND RAP WARM THE 700-850MB LAYER...WITH THE COLDEST TEMPERATURES BENEATH THIS LAYER -6C TO -8C. THIS SHOULD NOT BE COLD ENOUGH TO SUPPORT SNOW...WITH ANY PRECIPITATION LIKELY TO FALL AS A LIGHT SLEET OR DRIZZLE. FORTUNATELY...THE SHALLOW MOISTURE LAYER AND LIMITED INSTABILITY WILL LIMIT THE CHANCE FOR PRECIPITATION...WITH ONLY A SLIGHT CHANCE OF MEASURABLE PRECIPITATION. THE PROBLEM THIS POSES...IS THAT IF SURFACE TEMPERATURES DROP BELOW FREEZING...SOME PATCHY FREEZING DRIZZLE CANNOT BE RULED OUT ACROSS UPSLOPE REGIONS IN THE SOUTHERN TIER. CONFIDENCE IN THIS OCCURRING IS FAR SHY OF ANY HEADLINES...BUT IT WARRANT MONITORING OVERNIGHT. COLD AIR WILL HANG IN A BIT LONGER TO THE EAST...WITH PRECIPITATION FALLING AS EITHER RAIN OR SNOW. IN GENERAL...FEEL MOS NUMBERS ARE TOO COLD FOR TONIGHT`S LOWS...WITH PERSISTENT CLOUD COVER LIKELY TO REMAIN ACROSS MOST OF THE REGION. THERE STILL SHOULD BE SUB-FREEZING TEMPERATURES ACROSS INTERIOR SECTIONS AND HIGHER TERRAIN...WITH LOCATIONS NEAR THE LAKES NORTH OF I-90 AND WEST OF I-81 LIKELY TO REMAIN ABOVE FREEZING. THIS SAID...ANY LOCALIZED CLEARING WOULD ALLOW TEMPERATURES TO DROP SEVERAL DEGREES BELOW THE FORECAST. ON SUNDAY...SURFACE HIGH PRESSURE WILL FINALLY START TO MAKE A MEANINGFUL PUSH INTO THE REGION. DESPITE THIS...A CONTINUED NORTHWESTERLY FLOW OFF THE LAKES WILL LIKELY KEEP CLOUDS IN FOR THE MORNING HOURS...AND WELL INTO THE AFTERNOON. EXPECT SOME BREAKS OF SUN FOR MOST LOCATIONS...BUT THESE MAY NOT BE ALL THAT LONG. HOWEVER...THE DRYING AIR SHOULD CAUSE ANY LINGERING SHOWERS TO TAPER OFF BY LATE MORNING. TEMPERATURES WILL STAY ON THE COOL SIDE...WITH HIGHS IN THE UPPER 30S TO LOWER 40S. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... THE SHORT TERM PERIOD LOOKS RELATIVELY QUIET AS A DRY AIR MASS GAINS CONTROL INTO THE GREAT LAKES AND OHIO VALLEY...COURTESY OF CANADIAN HIGH PRESSURE BUILDING SOUTHWARD INTO THE REGION. THERE COULD BE SOME MINOR LAKE RESPONSE SUNDAY NIGHT WITHIN WEAK NORTHWEST LOW LEVEL FLOW...THOUGH OVERALL DRY AMBIENT AIR AND RELATIVELY LOW LAKE DELTA T/S WOULD SUGGEST ONLY AN INCREASE IN LAKE CLOUDS SOUTHEAST OF LAKE ONTARIO AND ALONG THE SOUTHERN TIER. WESTERN AND CENTRAL NEW YORK WILL BE IN BETWEEN SYSTEMS ON MONDAY AND TUESDAY WITH SHORTWAVE RIDGING AND RESULTING SURFACE HIGH PRESSURE ENSURING A FAIR...ALBEIT CHILLY DAYS. MODEL CROSS SECTIONAL FIELDS WOULD SUGGEST MOSTLY SUNNY DAYS APART FROM SOME DIURNAL STRATOCU...ESPECIALLY MONDAY. 850 MB TEMPERATURES AROUND -6C WOULD SUGGEST HIGHS STRUGGLING TO GET OUT OF THE 30S MONDAY. MONDAY NIGHT LOOKS TO BE A GOOD RADIATIONAL COOLING NIGHT WITH OVERNIGHT LOWS DROPPING INTO THE 20S...WITH A FEW TEENS ACROSS THE NORMALLY COLDER INTERIOR SECTIONS OF THE SOUTHERN TIER AND EAST OF LAKE ONTARIO. TEMPERATURES LOOK A FEW DEGREES WARMER FOR TUESDAY...BUT PROBABLY NO WARMER THAN THE LOWER 40S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... LATEST MEDIUM RANGE GUIDANCE CONTINUING TO SUGGEST THAT CONDITIONS WILL BE FAVORABLE FOR SIGNIFICANT CYCLOGENESIS OFF THE CAROLINA COAST AT THE START OF THE PERIOD. CONFIDENCE HAS INCREASED THAT A DEEP NORTHEAST COASTAL STORM WILL EVOLVE IN THE LATE WEDNESDAY THROUGH THURSDAY TIME FRAME...ALTHOUGH THERE STILL REMAINS DIFFERENCES IN TIMING AND STRENGTH OF THE OVERALL SYSTEM. 12Z GFS FASTER IN MOVING THE COASTAL STORM NORTHWARD THAN THE ECMWF. THE ECMWF REMAINS FARTHER WEST THAN THE GFS...ALTHOUGH THE 12Z GFS HAS MOVED LEFT FROM PREVIOUS RUNS. DESPITE THE CONTINUED MODEL DIFFERENCES...STILL FEEL THAT WESTERN NEW YORK WILL HAVE A LIMITED PRECIPITATION OR WIND THREAT FROM THIS SYSTEM...HOWEVER CENTRAL NEW YORK...ESPECIALLY THE NORTH COUNTRY COULD STILL HAVE SEVERAL SIGNIFICANT IMPACTS...INCLUDING HEAVY RAINFALL...ACCUMULATING HIGHER ELEVATIONS SNOWS AND A WIND POTENTIAL. THIS SYSTEM STILL BEARS WATCHING FOR THAT PORTION OF OUR FORECAST AREA. ONCE THE NORTHEAST COASTAL LOW LIFTS OUT...A BURGEONING PACIFIC CLOSED LOW COMBINED WITH A DIGGING TROUGH OVER THE WESTERN CONUS WILL PROMOTE QUICKLY BUILDING MID LEVEL HEIGHTS AND ANTICYCLONIC VORTICITY ADVECTION INTO THE OHIO VALLEY AND GREAT LAKES. EXPECT DRY CONDITIONS WITH MODERATING TEMPERATURES IN THE FRIDAY THROUGH SATURDAY TIME FRAME...WITH ABOVE NORMAL READINGS LIKELY BY THE WEEKEND. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AT 00Z VFR/MVFR FLIGHT CONDITIONS WERE FOUND ACROSS THE REGION WITH A NORTHWEST FLOW ACROSS THE LAKES THAT CONTINUE TO PRODUCE FINE PRECIPITATION THROUGH THE OVERNIGHT...NEAR THE SOUTHERN TIER...AND AREAS SOUTH AND EAST OF LAKE ONTARIO. PRECIPITATION WILL END FIRST ACROSS THE WESTERN SOUTHERN TIER...AND LATER ACROSS AREAS SOUTH AND EAST OF LAKE ONTARIO AS AN UPPER LEVEL SHORTWAVE DROPS ACROSS THE LAKE. MVFR FLIGHT CONDITIONS TOWARDS MORNING WILL BECOME VFR EARLY SUNDAY AS DRIER AIR BEHIND AN UPPER LEVEL TROUGH DROPS INTO THE REGION. THOUGH VFR...EXPECT A LOW CIG IN THE VFR FLIGHT RANGE THROUGH MUCH OF THE DAYLIGHT HOURS...LIFTING HIGHER TOWARDS THE END OF THE TAF PERIOD. WINDS WILL CONTINUE FROM THE NORTHWEST THROUGH THE TAF PERIOD. OUTLOOK... SUNDAY THROUGH WEDNESDAY...MAINLY VFR. THURSDAY...MVFR/VFR. A CHANCE OF RAIN OR SNOW. && .MARINE... MARGINAL SCA CONDITIONS PERSIST ON LAKE ONTARIO...WITH 15 TO 20 KNOT WINDS MAINTAINING SOME 5 FOOT WAVES ON ITS SOUTH SHORES. WINDS WILL GRADUALLY DIMINISH AND SHIFT MORE TO THE NORTH TONIGHT...WHICH SHOULD EVENTUALLY ALLOW THE HEADLINES TO BE DROPPED. AFTER THIS...HIGH PRESSURE WILL BUILD ACROSS THE WATERS...AND CONTINUE TO INFLUENCE THE REGION THROUGH MID-WEEK. THIS WILL LIKELY KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA DURING THE PERIOD. && .CLIMATE... OUR WRITTEN OCTOBER CLIMATE SUMMARIES FOR BOTH BUFFALO AND ROCHESTER CAN BE FOUND UNDER THE CLM PRODUCT ON OUR WEBPAGE UNDER LOCAL CLIMATE. SOME HIGHLIGHTS INCLUDE: FOR BUFFALO WE HAD THE 2ND MOST MEASURABLE PRECIPITATION DAYS IN OCTOBER`S RECORDED HISTORY (SINCE 1871) WITH 22 OF THE 31 DAYS MEASURING PRECIPITATION. THE ALL-TIME RECORD WAS SET BACK IN 1890 WITH 25 DAYS. FOR A 6TH STRAIGHT MONTH WE HAD A MONTH FINISH WITH ABOVE NORMAL TEMPERATURES...WITH BUFFALO`S 52.2F SETTING THE MONTH 1.4F ABOVE NORMAL. FOR ROCHESTER WE HAD A TIE FOR 6TH GREATEST NUMBER OF DAYS WITH MEASURABLE PRECIPITATION...WITH 18 DAYS. THE RECORD FOR THE MONTH OF OCTOBER IS 21 DAYS WHICH WAS SET BACK IN THE YEAR 1988. LIKE BUFFALO ROCHESTER ALSO HAS HAD 6 STRAIGHT MONTHS FINISH WITH ABOVE NORMAL WARMTH. THE 52.8F DEGREES WAS 2.2F ABOVE THE NORM. OVER AN 8 DAY PERIOD...OCTOBER 26TH THROUGH NOVEMBER 2ND...BUFFALO HAS RECEIVED AT LEAST A TENTH OF AN INCH OF PRECIPITATION. THESE 8 CONSECUTIVE DAYS TIES A RECORD FOR GREATEST NUMBER OF CONSECUTIVE DAYS WITH AT LEAST A TENTH OF AN INCH OF PRECIPITATION. THE LAST OCCURRENCE WAS IN JANUARY 1999. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST SUNDAY FOR LOZ043-044. SMALL CRAFT ADVISORY UNTIL 3 AM EST SUNDAY FOR LOZ042-045. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL/THOMAS SHORT TERM...TMA LONG TERM...TMA AVIATION...THOMAS MARINE...APFFEL/TMA CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
818 AM EDT FRI NOV 2 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE CAROLINAS FROM THE NORTHWEST TONIGHT AND SATURDAY. A WEAK LOW PRESSURE SYSTEM WILL TRACK SLOWLY EAST THROUGH THE CAROLINAS SATURDAY NIGHT THROUGH MONDAY. && .NEAR TERM /TODAY/... AS OF 645 AM FRIDAY... ONCE AGAIN...QUITE VARIABLE TEMPERATURES ACROSS CENTRAL NORTH CAROLINA EARLY THIS MORNING UNDER CLEAR SKIES...WITH MANY LOCATIONS AROUND FREEZING...AND JUST AS MANY LOCATIONS AROUND 35 DEGREES. ONE OBSERVATION FROM SILER CITY NOTED 28 DEGREES. WILL CONTINUE THE FREEZE WARNING UNTIL 8 AM EXCEPT IN THE IMMEDIATE TRIAD WHERE CLOUDS HAVE MOVED IN. THE PRIMARY AREAS OF CONCERN WILL BE RURAL AREAS. OTHERWISE...WATER VAPOR IMAGERY INDICATES A MODEST MID-LEVEL SHORTWAVE WHICH WILL MOVE PRIMARILY OVER VIRGINIA AND NORTHERN PARTS OF NORTH CAROLINA...ACCOMPANIED BY THE RIGHT ENTRANCE REGION OF AN 85KT 500MB JET...AND THE STRONGEST POTENTIAL VORTICITY ON THE 1.5PVU SURFACE FORECAST THROUGH SATURDAY NIGHT ALONG WITH A VERY MODEST INCREASE IN 850MB THETA-E. THE NAM AND THE GFS ARE SIMILAR IN THE SENSIBLE WEATHER FOR TODAY...WITH THE GFS A LITTLE MORE ROBUST WITH THE DEPTH OF MOISTURE TO NEAR THE -10C LEVEL ON ITS BUFR SOUNDINGS PARTICULARLY TOWARD KRDU AND AREAS NORTH. THE LATEST HRRR WRF SHOWS THE POTENTIAL FOR A FEW ECHOES TOWARD THE VIRGINIA BORDER...COINCIDENT WITH WHERE THE GFS ACTUALLY FORECASTS THE BEST COMBINATION OF HIGHER 700MB MOISTURE AND 850MB MOISTURE BETWEEN ABOUT 15Z AND 18Z. WITH THE APPROACH OF THE MID-LEVEL DYNAMICS AND THE SURFACE FRONT...THERE MAY BE A FEW SPRINKLES MAINLY FROM KTDF TO KIXA OR SO LATE IN THE MORNING AND EARLY THIS AFTERNOON BEFORE BROKEN-TO-OVERCAST MOSTLY MID-LEVEL CLOUDS DEPART. FOLLOWING THAT...THERE LIKELY WILL BE A PERIOD DURING THE AFTERNOON WHERE THERE IS ENOUGH MIXING TO ALLOW FOR SURFACE WIND GUSTS FROM NEAR 20 MPH...POSSIBLY TO 25 MPH AS THE 925MB WINDS WILL BE IN THAT RANGE THIS AFTERNOON. ANTICIPATING THE INCREASE IN MID-LEVEL CLOUDS THIS MORNING...PLAN TO FORECAST HIGHS NEAR OR SLIGHTLY BELOW THE COOLER MET GUIDANCE...55 TO 60 NORTH AND LOWER TO MID 60S SOUTH...WARMEST IN THE SOUTHWEST PIEDMONT. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 305 AM FRIDAY... GUIDANCE TEMPERATURES ARE WARMER TONIGHT THAN MANY OF THE CENTRAL NORTH CAROLINA TEMPERATURES EARLY THIS MORNING...AND THE NAM AND GFS AGREE THAT THERE SHOULD BE SLIGHTLY HIGHER MID-LEVEL MOISTURE... ESPECIALLY ABOVE 700MB...AND SLIGHTLY GREATER WINDS NEAR THE INVERSION WHICH COULD PROMPT JUST A TOUCH BETTER OVERNIGHT MIXING. UNDER A MAINLY CLEAR SKY...WITH A FEW MID- OR MOSTLY HIGH-LEVEL CLOUDS POSSIBLY BECOMING SCATTERED WEST LATE...WOULD ANTICIPATE THE POTENTIAL FOR SCATTERED FROST OVERNIGHT PRIMARILY IN SHELTERED AND RURAL AREAS. COORDINATED WITH ADJACENT OFFICES AND WILL ALLOW THE NEXT SHIFT TO COORDINATE ANY HEADLINES AND THE STATUS OF FROST AND FREEZE ISSUANCES IN TIME FOR THE LATE AFTERNOON FORECAST ISSUANCE. UNDER HIGH PRESSURE SATURDAY...AS K INDICES ARE NEGATIVE AND WITH AN INCREASE IN MID- AND MOSTLY HIGH-LEVEL CLOUDS FROM THE WEST LATE...1000-850MB THICKNESSES SUPPORT HIGHS NEAR THE GENERALLY COOLER MAV GUIDANCE. FOR SATURDAY NIGHT...THE NAM AND THE GFS ARE VERY SIMILAR IN MOST OF THE PARAMETERS SAVE THE MOISTURE. THERE APPEARS TO BE LIMITED SUPPORT FOR LIFT IN PRESSURE LEVEL OR ISENTROPIC FIELDS...AND THE GFS...WHILE INCREASING MOISTURE FOR CLOUDS...DOES NOT PROVIDE FOR SUFFICIENT MOISTURE FOR PRECIPITATION. ON THE OTHER HAND...THE NAM HAS MUCH STRONGER MOISTURE ADVECTION...INCREASING 850MB THETA-E... AND INCREASING THE PRECIPITABLE WATER VALUES TO AT OR JUST ABOVE AN INCH...COMPARED TO THE 0.75 INCH AVERAGE OF THE GFS BETWEEN 06Z AND 12Z SUNDAY. MID-LEVEL FRONTOGENESIS IS WEAK AS WELL...BUT IT IS HARD TO IGNORE THE VERY HIGH CHANCES OF RAIN ON THE NAM...AS WELL AS THE LIGHT QPF FORECAST BY THE 12Z ECMWF AND THE LATEST SREF. AS A SURFACE WAVE MOVES TOWARD CENTRAL NORTH CAROLINA FROM THE WEST...WILL FORECAST A CHANCE OF LIGHT RAIN MAINLY WEST OF U.S. 1 AND SLIGHT CHANCES TO THE EAST OF THERE AFTER MIDNIGHT SUNDAY...WITH THE HIGHEST QPF FOR NOW UNDER A TENTH-INCH IN THE SOUTHWEST PIEDMONT. OVERNIGHT LOWS SATURDAY NIGHT SHOULD BE MOSTLY IN THE MID 30S TO NEAR 40...EXCEPT FLIRTING WITH THE LOWER 30S IN THE TYPICALLY COOLER LOCATIONS OF THE NORTHEAST PIEDMONT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 310 AM FRIDAY... SUNDAY AND SUNDAY NIGHT... THE LEAD SHORTWAVE IN A SERIES OF SHORTWAVES TO IMPACT THE EXTENDED PERIOD FORECAST WILL APPROACH THE OH VALLEY REGION SUNDAY. HIGH PRESSURE RIDGING INTO THE AREA FROM CENTRAL CANADA WILL WEAKEN WHILE A WEAK AREA OF LOW PRESSURE FORMS ALONG A FRONTAL ZONE STRETCHING FROM AR TO GA. WEAK HEIGHT FALLS AND ISENTROPIC LIFT SUGGEST SOME PRECIP IN THE VICINITY OF THE FRONT AS IT PUSHES NORTHEAST INTO SC SUNDAY INTO SUNDAY NIGHT. THE GFS SHOWS MORE QPF OVER CENTRAL NC DURING THIS PERIOD...ALTHOUGH THE CROSS-FRONTAL FLOW AND ISENTROPIC LIFT IS RATHER WEAK AND BRIEF...SO PREFER TO KEEP LOW END CHANCE POPS CONFINED TO THE NC/SC BORDER COUNTIES AND SLIGHT CHANCE TO THE NORTH....MORE LIKE THE ECMWF/NAM. TEMPS ARE ALSO A BIT UNCERTAIN SUNDAY DUE TO THE PROXIMITY OF THE FRONT AND POSSIBLE PRECIP...AND THIS IS MANIFEST IN A WIDE RANGE IN THE SREF MEMBERS. STATISTICAL GUIDANCE MOSTLY SHOWS UPPER 60S IN THE SOUTH TO UPPER 50S IN THE NORTH...ALTHOUGH IT IS POSSIBLE THAT A LACK OF PRECIP AND POTENTIAL FOR BREAKS IN CLOUD COVER COULD CAUSE TEMPS IN THE NORTH TO BE HIGHER. WILL STICK WITH A BLEND OF THE MET AND MAV FOR NOW...WITH 57-67 NORTH TO SOUTH. LOWS SUNDAY NIGHT IN THE MID TO UPPER 30S. MONDAY THROUGH THURSDAY... A LARGE 1025MB+ HIGH PRESSURE IS FORECAST TO SHIFT ACROSS THE GREAT LAKES MONDAY THROUGH TUESDAY AND EXTEND SOUTH INTO CENTRAL NC WHILE THE AFOREMENTIONED FRONTAL ZONE REMAINS MOSTLY STATIONARY OVER SC/GA. MODELS ARE IN RELATIVELY GOOD AGREEMENT ON A SECOND SHORTWAVE MOVING OUT OF THE NORTHERN ROCKIES AND DIGGING ALL THE WAY INTO THE GULF COAST STATES MONDAY NIGHT...THEN SWINGING ACROSS THE SOUTHEAST AND LIFTING NORTHEAST ALONG THE EAST COAST. THIS SCENARIO WOULD LEAD TO A COASTAL LOW OFF THE SC COAST TUESDAY THAT DEEPENS TO THE NORTHEAST ALONG THE COAST AND EVENTUALLY BECOMES A NOR`EASTER AS YET ANOTHER PIECE OF POLAR ENERGY LINKS UP WITH THE SYSTEM OVER MID ATLANTIC COAST ON WEDNESDAY. THIS SEEMS PLAUSIBLE GIVEN THE CURRENT NEGATIVE PHASE OF THE NAO IS FORECAST TO WEAKEN NEXT WEEK...ALTHOUGH MODELS HAVE WAVERED A BIT ON HOW CLOSE TO THE COAST THE LOW WOULD TRACK. HAVE ADDED LOW POPS TO THE FORECAST FOR TUESDAY/TUESDAY NIGHT GIVEN THE MODEL CONSISTENCY...WITH MOSTLY CLOUDY SKIES AND HIGHS IN THE 50S MONDAY THROUGH WEDNESDAY....A GOOD 10-15 DEGREES BELOW NORMAL. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 645 AM FRIDAY... VFR CONDITIONS WILL CONTINUE THROUGH THE 12Z VALID TAF PERIOD. THE BROKEN-TO-OVERCAST MID-LEVEL CLOUDS WILL CONTINUE TO MOVE IN FROM THE NORTHWEST DURING THE MORNING...MOVING AWAY DURING THE EARLY AFTERNOON. THERE MAY BE A FEW SPRINKLES OR VIRGA PARTICULARLY TOWARD THE VIRGINIA BORDER. AFTER THE CLOUDS DEPART...THERE SHOULD BE PERIODS OF SURFACE WIND GUSTS FROM THE WEST-NORTHWEST TO NORTHWEST AROUND 20KT UNTIL DIURNAL MIXING SUBSIDES LATE IN THE DAY. BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS WILL CONTINUE INTO SATURDAY NIGHT. BY SUNDAY MORNING...AHEAD OF A LOW PRESSURE SYSTEM... A CHANCE OF LIGHT RAIN MOVES INTO CENTRAL NORTH CAROLINA...BUT CURRENTLY THE MOST LIKELY CATEGORY OF AVIATION CONDITIONS IS EXPECTED TO BE MVFR. THE POTENTIAL OF IFR CONDITIONS INCREASES LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING...AND AGAIN FOR TUESDAY NIGHT...DEPENDING ON THE TRACK OF SURFACE LOW PRESSURE THAT WILL MOVE OVER OR NEAR THE CAROLINAS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF SHORT TERM...DJF LONG TERM...SMITH AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
645 AM EDT FRI NOV 2 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE CAROLINAS AND SOUTHERN VIRGINIA THIS EVENING AND TONIGHT BEHIND A WEAK COLD FRONT THAT MOVES THROUGH THE REGION. THE HIGH WILL DRIFT OFFSHORE LATE SATURDAY. A LOW PRESSURE SYSTEM AND AN ASSOCIATED COLD FRONT ARE EXPECTED TO AFFECT OUR AREA SUNDAY INTO MONDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 645 AM FRIDAY... ONCE AGAIN...QUITE VARIABLE TEMPERATURES ACROSS CENTRAL NORTH CAROLINA EARLY THIS MORNING UNDER CLEAR SKIES...WITH MANY LOCATIONS AROUND FREEZING...AND JUST AS MANY LOCATIONS AROUND 35 DEGREES. ONE OBSERVATION FROM SILER CITY NOTED 28 DEGREES. WILL CONTINUE THE FREEZE WARNING UNTIL 8 AM EXCEPT IN THE IMMEDIATE TRIAD WHERE CLOUDS HAVE MOVED IN. THE PRIMARY AREAS OF CONCERN WILL BE RURAL AREAS. OTHERWISE...WATER VAPOR IMAGERY INDICATES A MODEST MID-LEVEL SHORTWAVE WHICH WILL MOVE PRIMARILY OVER VIRGINIA AND NORTHERN PARTS OF NORTH CAROLINA...ACCOMPANIED BY THE RIGHT ENTRANCE REGION OF AN 85KT 500MB JET...AND THE STRONGEST POTENTIAL VORTICITY ON THE 1.5PVU SURFACE FORECAST THROUGH SATURDAY NIGHT ALONG WITH A VERY MODEST INCREASE IN 850MB THETA-E. THE NAM AND THE GFS ARE SIMILAR IN THE SENSIBLE WEATHER FOR TODAY...WITH THE GFS A LITTLE MORE ROBUST WITH THE DEPTH OF MOISTURE TO NEAR THE -10C LEVEL ON ITS BUFR SOUNDINGS PARTICULARLY TOWARD KRDU AND AREAS NORTH. THE LATEST HRRR WRF SHOWS THE POTENTIAL FOR A FEW ECHOES TOWARD THE VIRGINIA BORDER...COINCIDENT WITH WHERE THE GFS ACTUALLY FORECASTS THE BEST COMBINATION OF HIGHER 700MB MOISTURE AND 850MB MOISTURE BETWEEN ABOUT 15Z AND 18Z. WITH THE APPROACH OF THE MID-LEVEL DYNAMICS AND THE SURFACE FRONT...THERE MAY BE A FEW SPRINKLES MAINLY FROM KTDF TO KIXA OR SO LATE IN THE MORNING AND EARLY THIS AFTERNOON BEFORE BROKEN-TO-OVERCAST MOSTLY MID-LEVEL CLOUDS DEPART. FOLLOWING THAT...THERE LIKELY WILL BE A PERIOD DURING THE AFTERNOON WHERE THERE IS ENOUGH MIXING TO ALLOW FOR SURFACE WIND GUSTS FROM NEAR 20 MPH...POSSIBLY TO 25 MPH AS THE 925MB WINDS WILL BE IN THAT RANGE THIS AFTERNOON. ANTICIPATING THE INCREASE IN MID-LEVEL CLOUDS THIS MORNING...PLAN TO FORECAST HIGHS NEAR OR SLIGHTLY BELOW THE COOLER MET GUIDANCE...55 TO 60 NORTH AND LOWER TO MID 60S SOUTH...WARMEST IN THE SOUTHWEST PIEDMONT. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 305 AM FRIDAY... GUIDANCE TEMPERATURES ARE WARMER TONIGHT THAN MANY OF THE CENTRAL NORTH CAROLINA TEMPERATURES EARLY THIS MORNING...AND THE NAM AND GFS AGREE THAT THERE SHOULD BE SLIGHTLY HIGHER MID-LEVEL MOISTURE... ESPECIALLY ABOVE 700MB...AND SLIGHTLY GREATER WINDS NEAR THE INVERSION WHICH COULD PROMPT JUST A TOUCH BETTER OVERNIGHT MIXING. UNDER A MAINLY CLEAR SKY...WITH A FEW MID- OR MOSTLY HIGH-LEVEL CLOUDS POSSIBLY BECOMING SCATTERED WEST LATE...WOULD ANTICIPATE THE POTENTIAL FOR SCATTERED FROST OVERNIGHT PRIMARILY IN SHELTERED AND RURAL AREAS. COORDINATED WITH ADJACENT OFFICES AND WILL ALLOW THE NEXT SHIFT TO COORDINATE ANY HEADLINES AND THE STATUS OF FROST AND FREEZE ISSUANCES IN TIME FOR THE LATE AFTERNOON FORECAST ISSUANCE. UNDER HIGH PRESSURE SATURDAY...AS K INDICES ARE NEGATIVE AND WITH AN INCREASE IN MID- AND MOSTLY HIGH-LEVEL CLOUDS FROM THE WEST LATE...1000-850MB THICKNESSES SUPPORT HIGHS NEAR THE GENERALLY COOLER MAV GUIDANCE. FOR SATURDAY NIGHT...THE NAM AND THE GFS ARE VERY SIMILAR IN MOST OF THE PARAMETERS SAVE THE MOISTURE. THERE APPEARS TO BE LIMITED SUPPORT FOR LIFT IN PRESSURE LEVEL OR ISENTROPIC FIELDS...AND THE GFS...WHILE INCREASING MOISTURE FOR CLOUDS...DOES NOT PROVIDE FOR SUFFICIENT MOISTURE FOR PRECIPITATION. ON THE OTHER HAND...THE NAM HAS MUCH STRONGER MOISTURE ADVECTION...INCREASING 850MB THETA-E... AND INCREASING THE PRECIPITABLE WATER VALUES TO AT OR JUST ABOVE AN INCH...COMPARED TO THE 0.75 INCH AVERAGE OF THE GFS BETWEEN 06Z AND 12Z SUNDAY. MID-LEVEL FRONTOGENESIS IS WEAK AS WELL...BUT IT IS HARD TO IGNORE THE VERY HIGH CHANCES OF RAIN ON THE NAM...AS WELL AS THE LIGHT QPF FORECAST BY THE 12Z ECMWF AND THE LATEST SREF. AS A SURFACE WAVE MOVES TOWARD CENTRAL NORTH CAROLINA FROM THE WEST...WILL FORECAST A CHANCE OF LIGHT RAIN MAINLY WEST OF U.S. 1 AND SLIGHT CHANCES TO THE EAST OF THERE AFTER MIDNIGHT SUNDAY...WITH THE HIGHEST QPF FOR NOW UNDER A TENTH-INCH IN THE SOUTHWEST PIEDMONT. OVERNIGHT LOWS SATURDAY NIGHT SHOULD BE MOSTLY IN THE MID 30S TO NEAR 40...EXCEPT FLIRTING WITH THE LOWER 30S IN THE TYPICALLY COOLER LOCATIONS OF THE NORTHEAST PIEDMONT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 310 AM FRIDAY... SUNDAY AND SUNDAY NIGHT... THE LEAD SHORTWAVE IN A SERIES OF SHORTWAVES TO IMPACT THE EXTENDED PERIOD FORECAST WILL APPROACH THE OH VALLEY REGION SUNDAY. HIGH PRESSURE RIDGING INTO THE AREA FROM CENTRAL CANADA WILL WEAKEN WHILE A WEAK AREA OF LOW PRESSURE FORMS ALONG A FRONTAL ZONE STRETCHING FROM AR TO GA. WEAK HEIGHT FALLS AND ISENTROPIC LIFT SUGGEST SOME PRECIP IN THE VICINITY OF THE FRONT AS IT PUSHES NORTHEAST INTO SC SUNDAY INTO SUNDAY NIGHT. THE GFS SHOWS MORE QPF OVER CENTRAL NC DURING THIS PERIOD...ALTHOUGH THE CROSS-FRONTAL FLOW AND ISENTROPIC LIFT IS RATHER WEAK AND BRIEF...SO PREFER TO KEEP LOW END CHANCE POPS CONFINED TO THE NC/SC BORDER COUNTIES AND SLIGHT CHANCE TO THE NORTH....MORE LIKE THE ECMWF/NAM. TEMPS ARE ALSO A BIT UNCERTAIN SUNDAY DUE TO THE PROXIMITY OF THE FRONT AND POSSIBLE PRECIP...AND THIS IS MANIFEST IN A WIDE RANGE IN THE SREF MEMBERS. STATISTICAL GUIDANCE MOSTLY SHOWS UPPER 60S IN THE SOUTH TO UPPER 50S IN THE NORTH...ALTHOUGH IT IS POSSIBLE THAT A LACK OF PRECIP AND POTENTIAL FOR BREAKS IN CLOUD COVER COULD CAUSE TEMPS IN THE NORTH TO BE HIGHER. WILL STICK WITH A BLEND OF THE MET AND MAV FOR NOW...WITH 57-67 NORTH TO SOUTH. LOWS SUNDAY NIGHT IN THE MID TO UPPER 30S. MONDAY THROUGH THURSDAY... A LARGE 1025MB+ HIGH PRESSURE IS FORECAST TO SHIFT ACROSS THE GREAT LAKES MONDAY THROUGH TUESDAY AND EXTEND SOUTH INTO CENTRAL NC WHILE THE AFOREMENTIONED FRONTAL ZONE REMAINS MOSTLY STATIONARY OVER SC/GA. MODELS ARE IN RELATIVELY GOOD AGREEMENT ON A SECOND SHORTWAVE MOVING OUT OF THE NORTHERN ROCKIES AND DIGGING ALL THE WAY INTO THE GULF COAST STATES MONDAY NIGHT...THEN SWINGING ACROSS THE SOUTHEAST AND LIFTING NORTHEAST ALONG THE EAST COAST. THIS SCENARIO WOULD LEAD TO A COASTAL LOW OFF THE SC COAST TUESDAY THAT DEEPENS TO THE NORTHEAST ALONG THE COAST AND EVENTUALLY BECOMES A NOR`EASTER AS YET ANOTHER PIECE OF POLAR ENERGY LINKS UP WITH THE SYSTEM OVER MID ATLANTIC COAST ON WEDNESDAY. THIS SEEMS PLAUSIBLE GIVEN THE CURRENT NEGATIVE PHASE OF THE NAO IS FORECAST TO WEAKEN NEXT WEEK...ALTHOUGH MODELS HAVE WAVERED A BIT ON HOW CLOSE TO THE COAST THE LOW WOULD TRACK. HAVE ADDED LOW POPS TO THE FORECAST FOR TUESDAY/TUESDAY NIGHT GIVEN THE MODEL CONSISTENCY...WITH MOSTLY CLOUDY SKIES AND HIGHS IN THE 50S MONDAY THROUGH WEDNESDAY....A GOOD 10-15 DEGREES BELOW NORMAL. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 645 AM FRIDAY... VFR CONDITIONS WILL CONTINUE THROUGH THE 12Z VALID TAF PERIOD. THE BROKEN-TO-OVERCAST MID-LEVEL CLOUDS WILL CONTINUE TO MOVE IN FROM THE NORTHWEST DURING THE MORNING...MOVING AWAY DURING THE EARLY AFTERNOON. THERE MAY BE A FEW SPRINKLES OR VIRGA PARTICULARLY TOWARD THE VIRGINIA BORDER. AFTER THE CLOUDS DEPART...THERE SHOULD BE PERIODS OF SURFACE WIND GUSTS FROM THE WEST-NORTHWEST TO NORTHWEST AROUND 20KT UNTIL DIURNAL MIXING SUBSIDES LATE IN THE DAY. BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS WILL CONTINUE INTO SATURDAY NIGHT. BY SUNDAY MORNING...AHEAD OF A LOW PRESSURE SYSTEM... A CHANCE OF LIGHT RAIN MOVES INTO CENTRAL NORTH CAROLINA...BUT CURRENTLY THE MOST LIKELY CATEGORY OF AVIATION CONDITIONS IS EXPECTED TO BE MVFR. THE POTENTIAL OF IFR CONDITIONS INCREASES LATE SUNDAY NIGHT INTO EARLY MONDAY MORNING...AND AGAIN FOR TUESDAY NIGHT...DEPENDING ON THE TRACK OF SURFACE LOW PRESSURE THAT WILL MOVE OVER OR NEAR THE CAROLINAS. && .RAH WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR NCZ007>011- 024>028-038>043-073>078-083>086-088-089. && $$ SYNOPSIS...BLS/DJF/VINCENT NEAR TERM...DJF SHORT TERM...DJF LONG TERM...BLS AVIATION...DJF
AREA FORECAST DISCUSSION
NWS MEDFORD OR
823 PM PDT SAT NOV 3 2012 .SHORT TERM...A WEAK WARM FRONT IS MOVING TOWARDS THE COAST THIS EVENING AND WILL LIFT NORTH SUNDAY MORNING. SOME AREAS OF LIGHT RAIN ARE EXPECTED WITH THE FRONT ALONG THE COAST AND INLAND INTO DOUGLAS COUNTY. LOW CLOUDS ARE SPREADING INTO THE COOS AND DOUGLAS COAST THIS EVENING AND SOME VERY LIGHT RAIN AMOUNTS HAVE BEEN REPORTED ALONG THE COASTAL HEADLANDS. EXPECT INCREASING LOW CLOUDS LATE THIS EVENING THROUGH EARLY SUNDAY MORNING ALONG THE COAST ALONG WITH AREAS OF LIGHT RAIN. INLAND...AREAS OF LIGHT RAIN ARE EXPECTED TO MAINLY ONLY SPREAD INTO DOUGLAS COUNTY TONIGHT INTO SUNDAY MORNING. THE RUC SEEMS TO HAVE A GOOD HANDLE ON THE CURRENT FRONTAL POSITION AND AREAS OF LOWER CLOUDS AND POSSIBLE RAIN...SO HAVE UPDATED THE WEATHER FORECAST BASED ON THE LATEST RUN AND HAVE INCREASED THE AREAS FOR SLIGHT CHANCE OF RAIN ALONG THE COAST AND INTO DOUGLAS COUNTY. MID LEVEL AND HIGH CLOUDS ARE ALSO SPREADING INLAND ACROSS THE AREA. THIS CLOUD DECK IS EXPECTED TO KEEP VALLEY FOG TO A MINIMUM LATE TONIGHT INTO SUNDAY MORNING. DEWPOINTS ARE HIGH THOUGH SO EXPECT A CHANCE FOR PATCHY FOG FOR MOST INLAND WEST SIDE VALLEYS LATE TONIGHT INTO EARLY SUNDAY MORNING. && .AVIATION...A WARM FRONT WILL LINGER OVER THE OREGON COAST TONIGHT WITH A MIXTURE OF IFR AND MVFR CEILINGS AND VISIBILITIES EXTENDING FROM THE COAST INTO JOSEPHINE AND DOUGLAS COUNTIES. THE RAIN AND IFR CONDITIONS WILL BE MOST PREVALENT NORTH OF CAPE BLANCO. ELSEWHERE...CONDITIONS WILL PRIMARILY REMAIN VFR. BUT, LOW CLOUDS AND PATCHY VALLEY FOG WILL PRODUCE LATE NIGHT AND EARLY MORNING MVFR CONDITIONS IN JACKSON, NORTHERN KLAMATH AND WESTERN SISKIYOU COUNTIES AS WELL AS AREAS OF OBSCURATIONS OVER WEST SIDE MOUNTAINS AND OVER THE CASCADES. CONDITIONS WILL BEGIN TO IMPROVE AROUND 18Z ON SUNDAY MORNING WITH CEILINGS EXPECTED TO LIFT TO MVFR AT THE COAST AND DISSIPATE INLAND. && .PREV DISCUSSION... /ISSUED 217 PM PDT SAT NOV 3 2012/ SHORT TERM...THE CURRENT WATER VAPOR IMAGE SHOWS ANOTHER DISTURBANCE MOVING TOWARDS THE FORECAST AREA WITH RIDGING BUILDING UPSTREAM. THIS SHOULD RESULT IN THE PRECIPITATION BEING CONFINED TO COOS AND NORTHWEST DOUGLAS COUNTIES. HOWEVER COULD NOT RULE OUT SOME SPRINKLES ALONG THE SOUTH COAST. BECAUSE OF THAT KEPT A SLIGHT CHANCE IN. ELSEWHERE IT WILL REMAIN DRY WITH PLENTY OF CLOUD COVER MAINLY OVER THE NORTHERN HALF OF THE AREA TONIGHT. IF THERE`S SUFFICIENT CLOUD COVER TONIGHT...THEN THE OPPORTUNITY FOR FOG TO DEVELOP IN THE WEST SIDE VALLEYS WILL BE LESS. ANY VALLEY FOG SHOULD BREAK UP FOLLOWED BY PARTLY CLOUDY SKIES WEST OF THE CASCADES. MEANWHILE SKIES WILL END UP MOSTLY CLEAR EAST OF THE CASCADES SUNDAY AFTERNOON. THE UPPER RIDGE BUILDS OVER THE AREA SUNDAY AND REMAINS IN CONTROL THROUGH TUESDAY RESULTING IN DRY AND STABLE CONDITIONS. THIS WILL RESULT IN A DECENT SUBSIDENCE INVERSION DEVELOPING SUNDAY NIGHT. THIS WILL RESULT IN AN INVERSION IN THE WESTSIDE VALLEYS WITH FOG LIKELY LATE AT NIGHT INTO MOST OF THE MORNING HOURS MONDAY. ABOVE THE FOG LAYER...TEMPERATURES COULD EASILY GET INTO THE 70S AND IN THE 60S IN THE VALLEY DUE TO THE FOG/LOW CLOUD POTENTIAL AND LITTLE IF ANY AFTERNOON MIXING. EXPECT SIMILAR CONDITIONS MONDAY NIGHT THROUGH TUESDAY. THE UPPER RIDGE BEGINS TO FLATTEN OUT TUESDAY NIGHT AS AN UPPER LOW FROM THE GULF OF ALASKA MOVES SOUTHWARD. THE UPPER LOW IS PROJECTED TO MOVE SOUTH DURING THE DAY WEDNESDAY WITH A SURFACE COLD FRONT MOVING INT THE AREA BRINGING A CHANCE OF PRECIPITATION WEST OF THE CASCADES AND MAINLY NORTH OF THE UMPQUA DIVIDE. -PETRUCELLI LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY. OPERATIONAL MODEL...ENSEMBLE...AND REFORECAST ANALOG SOLUTIONS ALL POINT TOWARDS THE WEATHER PATTERN BECOMING SHARPLY COOLER BY WEDNESDAY AFTERNOON AND WETTER BY THURSDAY. THERE IS REMARKABLE AGREEMENT AMONGST THE MODELS ON THE TIMING AND MAGNITUDE OF COOLING AT THE 850MB ALL THE WAY THROUGH SATURDAY. A RELATIVELY DRY COLD FRONT WILL SWEEP THROUGH THE AREA ON WEDNESDAY...GENERATING THE CHANCE FOR SOME LIGHT RAIN BOTH WEST AND EAST OF THE CASCADES. THE MORE SIGNIFICANT DYNAMICS...CLOSER TO THE LOW CENTER DIVING IN FROM THE NORTHWEST...ARRIVES THURSDAY. WE HAVE INCREASED POPS SIGNIFICANTLY FOR THURSDAY...AND WITH SNOW LEVELS AROUND 4000 FEET...WINTER WEATHER IMPACTS ARE LIKELY TO OCCUR ON SOME MOUNTAIN PASSES. A TRANSITION TOWARD ISOLATED TO SCATTERED SHOWERS OCCURS ON FRIDAY...BUT COLD AIR CONTINUES TO FUNNEL INTO THE REGION...AND HIGH TEMPERATURES ARE LIKELY TO STAY IN THE 40S WEST OF THE CASCADES AND 30S EAST OF THE CASCADES. THIS WOULD BE THE COLDEST DAY OF THE FALL THUS FAR. FURTHER DRYING IS EXPECTED ON SATURDAY...BUT BELOW NORMAL TEMPERATURES SHOULD CONTINUE. LOOKING FARTHER OUT...THE ECMWF SUGGESTS THAT AFTER BRIEF DRYING LATE IN THE WEEKEND...A BUILDING RIDGE NEAR 150W WOULD PLACE OUR FORECAST AREA IN A CONTINUED COOL AND UNSETTLED PATTERN. -KEENE && .MFR WATCHES/WARNINGS/ADVISORIES... OR...NONE. CA...NONE. PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM PST SUNDAY FOR PZZ350-356. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM PST SUNDAY FOR PZZ370-376. $$ CC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1053 PM MDT THU NOV 1 2012 .AVIATION...06Z TAFS AREA OF LIFR CIGS/VSBY WILL PERSIST THROUGH THE NIGHT ALONG THE NORTH AND EAST SLOPES OF THE BLACK HILLS AND ADJACENT PLAINS. MVFR/IFR CIGS WILL ALSO LINGER FROM KPHP-K2WX THROUGH THE NIGHT. CONDITIONS WILL IMPROVE LATE TONIGHT/FRIDAY MORNING. && .PREV DISCUSSION... /ISSUED 853 PM MDT THU NOV 1 2012/ DISCUSSION...VISIBILITY HAS DROPPED BELOW 1/2 MILE ALONG NOTHERN AND EASTERN SLOPES OF THE BLACK HILLS AND ADJACENT PLAINS. 00Z NAM/00Z RAP KEEP BL-875MB WINDS E-NE THROUGH MUCH OF THE NIGHT...WITH NORTHWEST WINDS NOT ARRIVING UNTIL LATE TONIGHT. THIS WILL KEEP DENSE FOG ALONG THE I-90 CORRIDOR. WILL ISSUE DENSE FOG ADVISORY FOR THE REMAINDER OF THE NIGHT. PREV DISCUSSION... /ISSUED 641 PM MDT THU NOV 1 2012/ WINDS HAVE TURNED NORTHEAST IN THE RAPID CITY AREA...WITH LOW STRATUS/FOG MOVING BACK INTO THE AREA. THE NARROW AXIS OF LOW CIGS/FOG FROM KICR-KRAP/KPHP-K2WX WILL PERSIST THROUGH THIS EVENING UNTIL THE WINDS BECOME NORTHWEST. 18Z NAM/21Z RUC SUGGEST THAT THE WINDS MIGHT REMAIN LIGHT EASTERLY UNTIL MIDNIGHT. FORECAST UPDATED TO ADD SOME FOG THROUGH THIS EVENING. PREV DISCUSSION... /ISSUED 247 PM MDT THU NOV 1 2012/ LONG WAVE RIDGE NEAR 108W HAS SHARPEND AND IS MOVING SLOWLY EASTWARD. SHORT WAVE TROF IS MOVING ACROSS THE RIDGE. IT WILL DIG SE WARD ON FRIDAY AND BE FOLLOWED BY A WEAKER SHORT WAVE TROF FRIDAY NIGHT INTO SATURDAY MORNING. FORCING FOR ASCENT HAS PRODUCED HIGH CLOUDS ABOVE OUR STRATUS AND FOG LAYER TODAY WITH THE FIRST WAVE. WEAK FORCING FOR ASCENT WILL ACCOMPANY THE SECOND WAVE GIVING A SLIGHT CHANCE FOR SHOWERS OVER NORTHERN PORTIONS OF THE CWA FRIDAY NIGHT AND SATURDAY MORNING. TRIMMED POPS SLIGHTLY FOR THIS SYSTEM. A COUPLE OF WEAK SURGES OF COOLER AIR WILL CROSS THE CWA TONIGHT ACCOMPANIED BY WEAK WIND SHIFTS. STAYED CLOSE TO GUIDANCE ON TEMPERATURES DURING THE SHORT RANGE PERIOD AFTER ADJUSTING FOR THIS AFTERNOONS RETARDED TEMPERATURE RISE. EXTENDED...UPPER LEVEL RIDGING WILL DOMINATE THE WESTERN CONUS EARLY NEXT WEEK...THEN THE CENTRAL CONUS BY MIDWEEK. THIS WILL BRING GENERALLY DRY WEATHER AND NEAR TO ABOVE AVERAGE TEMPERATURES FOR THE EXTENDED. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...DENSE FOG ADVISORY UNTIL 6 AM MDT FRIDAY FOR BUTTE-CUSTER CO PLAINS-HERMOSA FOOT HILLS-NORTHERN FOOT HILLS-NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-RAPID CITY-SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS. WY...DENSE FOG ADVISORY UNTIL 6 AM MDT FRIDAY FOR NORTHEASTERN CROOK. && $$ SHORT TERM...07 LONG TERM....WFO UNR AVIATION...07
AREA FORECAST DISCUSSION
NWS SPOKANE WA
247 PM PDT Fri Nov 2 2012 .SYNOPSIS... A drying and warming trend will slowly return to much of the Columbia Basin courtesy of a strengthening ridge of high pressure. Weak systems brushing the ridge will bring some light rain at times to the Cascades and mountains near the Canadian border. Much cooler and unsettled weather will likely arrive by the end of the week. Temperatures will likely be cold enough that most of the precipitation will fall as snow. && .DISCUSSION... Tonight and tomorrow...Satellite and radar data from this afternoon indicated an occluded front spreading rain into southwest Washington and northwest Oregon. Models agree that this front will stretch and weaken as it moves east of the Cascades tonight with chances for measurable rain decreasing quickly east of the Cascades. However models do show some differences as to how quickly this rain will taper off. The NAM shows 850mb winds backing to the south-southeast with rain spreading into Wenatchee early this evening with a quarter inch of rain...while GFS/ECMWF only have .02-.04 inches for Wenatchee. With HRRR also supporting the GFS/ECMWF forecast was weighted strongly towards the GFS/ECMWF solution. These solutions supports around a tenth of an inch of rain for the East Slopes of the Cascades tonight, a few hundredths for the Wenatchee area, Okanogan Valley, and northern mountains, with sprinkles elsewhere. The next wave noted on water vapor satellite near 40N/150W as of 2 PM today will move rapidly east with a moist zonal flow across the area on Saturday. Most of the energy from this wave will move north across southern British Columbia with the westerly flow Saturday rain and high mountain snow along the Cascade crest...with a secondary max in precipitation chances over the mountains of NE Washington and North Idaho. Any rain that falls on Saturday away from the Cascade crest will be light with amounts less than a tenth of an inch. JW Saturday night through Monday...Model guidance in fairly good agreement that a dirty ridge axis will remain fixed over the Inland NW through most of this period. The ridge promises to keep plenty of clouds and moisture locked over the region...however precipitation chances will become lower with time from south to north as the pattern buckles slightly on Sunday and Monday with a very strong upper level low shifting into the Gulf of Alaska. The models have been having difficulties timing the drying trend. The 12z NAM suggested the warm front would deliver widespread rain to most of the forecast area on Sunday and this notion had some support from the SREF. Now the NAM has backed off on that scenario and joined other drier models which kept the bulk of the precipitation focused near the north Cascade Crest and over locations just south of the Canadian border through Sunday night. Precipitation amounts from the front will be light...much less than a tenth of an inch in most cases. Meanwhile...snow levels will remain higher than all but the highest mountain peaks. ..so winter travel conditions are not expected. By Monday...the warm front will move into BC...while the trailing cold front will push into the north Cascades and NE Washington by late in the day. The front is expected to weaken significantly as another low deepens over the Gulf of Alaska. Again most of the precipitation from this front should be focused near the north Cascades and northern WA/ID mountains. Precipitation amounts will still be light. As for temperatures...the warm front will continue to deliver unseasonably mild temperatures with daytime highs surging well into the 50s to lower 60s...with nighttime lows holding well above freezing. Monday`s cold front could take a few degrees off the high temperatures...however the weaker the front, the less likely that cooling will occur. Fog could become Sunday night/Monday south of highway 2 as the mid/upper clouds begin to thin. If fog does become widespread and thick it would have a dramatic impact on the temperatures...and we would fall well short of the forecast high temperatures on Monday. The mid 50s to mid 60s in the forecast could easily turn out being about 10 degrees too warm. fx Monday night through Friday...Interval starts out with very low amplitude ridge that is easily over-topped with moisture rich disturbances that flattens out and becomes more zonal on Tuesday and by Wednesday a larger area of low pressure drops down from the Gulf of Alaska in a northwest to southeast trajectory and pushes the moisture rich jet stream to the south and east into and through the weekend. The above scenario should result in a generally cloudy forecast with a rain shadow keeping some of the lowlands in the lee of the Cascade crest dry Monday night into Wednesday evening with the periphery or mountain areas up north and in Northern Idaho holding onto varying pop for mostly rain as snow levels remain well above what would be considered lodge level (well above 3800-4800 ft MSL). The moisture rich baroclinic band oriented alongside the jet stream sags southeast through the area but the flow now appears in the models as having too much of a southwest orientation...and as such the lee side rain-shadow will work to inhibit precipitation processes for much of lowland Eastern Washington while pops in north Idaho may continue to hold a substantial increase and QPF amounts in the forecast may show an increase as well. By either late Thursday or Friday the cold conditionally unstable air-mass to the north of the jet stream should be overhead of Eastern Washington and Northern Idaho with weak southwest flow at lower levels thus a transition to further decreased pops and qpf and precipitation depicted as a more showery type with low snow levels (low wet bulb zero heights with the conditionally unstable air-mass could allow for snow to reach many valley locations but it would depend on time of day and pavement temperatures as to how long it would linger on surfaces) Temperatures near or slightly on the warm side of normal into Wednesday still make sense considering the jet stream placement is either north of the area or overhead and the cooling trend afterword with the jet stream to the south and cooler conditionally unstable air-mass overhead for later Thursday and Friday. /Pelatti && .AVIATION... 00Z TAFS: Currently clouds are on the increase for sites closer to th Cascades while the eastern TAF sites begin to clear out. Have a chance for VCSH for EAT around 02Z as a weak system moves over the Cascade crest. As the system moves to the east..only expect clouds for eastern TAF sites. Lowered CIGS to MVFR for KSFF and KGEG sites as the system moves from east to west. Have included fog for sites KEAT..KMWH..KCOE and KLWS but confidence is low as to whether cloud cover could limit this. Due to fog went ahead and lowerd VIS to have IFR conditions for identified sites. /Fliehman && .PRELIMINARY POINT TEMPS/POPS... Spokane 42 55 44 56 45 59 / 10 20 20 20 10 10 Coeur d`Alene 41 54 43 56 44 58 / 10 30 30 20 10 10 Pullman 44 58 45 57 46 62 / 10 20 10 20 10 0 Lewiston 44 60 47 61 48 64 / 0 10 10 20 0 0 Colville 44 54 43 57 43 61 / 30 40 40 40 20 20 Sandpoint 42 52 44 54 41 58 / 10 50 60 50 20 20 Kellogg 38 47 42 50 43 55 / 0 30 30 30 10 20 Moses Lake 42 58 45 61 45 60 / 20 20 10 10 0 0 Wenatchee 44 55 48 61 46 59 / 50 20 10 10 10 10 Omak 45 55 44 59 43 59 / 40 30 20 20 10 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1114 AM MDT FRI NOV 2 2012 .AVIATION...18Z TAF ISSUANCE... FOG AND LOW CLOUDS HAVE ERODED OVER THE CWA AS OF 1630Z AND WERE CURRENTLY NORTH AND EAST OF THE NORTHEAST CORNER OF THE CWA. VFR CONDITIONS WILL BE WIDESPREAD OVER THE CWA INTO THE MID PART OF NEXT WEEK. && .PREVIOUS DISCUSSION.../ISSUED AT 508 AM MDT FRI NOV 2 2012/... .AVIATION...12Z TAFS CHADRON REMAINS DOWN IN VLIFR FOG/STRATUS. LATEST HRRR GUIDANCE SHOWING LOW CEILINGS TO CONTINUE UNTIL 15Z. THIS LINES UP WELL WITH OTHER GUIDANCE SUGGESTING A MORE FAVORABLE DOWNSLOPING WIND TO BREAK UP THE FOG AROUND THAT TIME. ELSEWHERE...VFR CONDITIONS EXPECTED. CLAYCOMB && .PREV DISCUSSION... /ISSUED 324 AM MDT FRI NOV 2 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT... WATER VAPOR IMAGERY SHOWS A SHORTWAVE CURRENTLY MOVING OVER MONTANA WITH MID-AND-HIGH LEVEL MOISTURE OVER THE CWA. A WEAK COLD FRONT ASSOCIATED WITH THIS SHORTWAVE IS CURRENTLY NEAR CASPER AND IS PROGGED TO MOVE SOUTHEAST OVER THE PLAINS THIS MORNING. KCDR HAS REPORTED SOME FOG OVER THE PAST FEW HOURS. LAPS ANALYSIS SHOWS THE NORTHERN HALF OF THE NEBRASKA PANHANDLE EXPERIENCING WEAK NORTHEAST FLOW DUE TO A SFC HIGH IN THE DAKOTAS. THE HRRR MODEL INDICATES LIFR CONDITIONS OVER EXTREME NORTHERN DAWES COUNTY THROUGH 15Z...SO INCLUDED FOG IN THE FCST THROUGH EARLY MORNING. ANY FOG SHOULD DISSIPATE AFTER THE FROPA AND WITH DRY AIR ADVECTION. OTHERWISE...TEMPS WILL BE COOLER TODAY WITH 700MB TEMPS AT -1C (DOWN FROM 5C THIS PAST AFTN). PRESSURE RISES ARE NOT THAT IMPRESSIVE BEHIND THE FRONT...SO WIND GUSTS THIS MORNING SHOULD GENERALLY BE BELOW 30 KTS. HIGH LEVEL CLOUDS WILL PROGRESS EASTWARD OUT OF THE CWA BY LATE MORNING AS THE AREA EXPERIENCES SUBSIDENCE BEHIND THE SHORTWAVE. FAIRLY QUIET WEATHER THROUGH THE WEEKEND AS THE STRONGER LLVL AND MIDLEVEL FLOW REMAINS TO THE NORTH ALONG WITH BETTER MOISTURE. THE MODELS ARE IN AGREEMENT IN DROPPING A SHORTWAVE SOUTHEAST ACROSS MONTANA AND INTO THE DAKOTAS ON SUNDAY. NORTHWESTERLY 700MB WINDS APPROACH 40 KTS OVER THE NEBRASKA PANHANDLE ON SUNDAY AFTN SO BREEZY CONDITIONS CAN BE EXPECTED. THE SHORTWAVE WILL BRING A REINFORCING SHOT OF COOLER AIR...WITH 700MB TEMPS STAYING BETWEEN 0C AND -3C THROUGH THE WEEKEND. POPS WILL BE SLIM TO NONE WITH THE BEST MIDLEVEL MOISTURE ASSOCIATED WITH THE SHORTWAVE LARGELY REMAINING OVER CENTRAL SOUTH DAKOTA/NEBRASKA. LONG TERM...MONDAY THROUGH FRIDAY EXTENDED PRETTY QUIET WITH THE ONLY FORECAST PROBLEM BEING A BACKDOOR FRONT OVER SOUTH DAKOTA. THE FRONT SAGS SOUTHWEST INTO NORTHEASTERN WYOMING AND THE NORTHERN PANHANDLE TUESDAY...BUT THEN RETREATS NORTHEAST WEDNESDAY. THIS FRONT COULD POSE PROBLEMS WITH TEMPERATURES IF IT STALLS OUT OVER OUR EASTERN CWFA. THERE IS LOTS OF LOW CLOUDS BEHIND THE FRONT WHICH IF THE FRONT DOES STALL...WE COULD BE TOO HIGH ON OUR TEMPERATURES. FRONT MAKES A GOOD PUSH SOUTHWEST THURSDAY AND IS FORECAST TO BE UP AGAINST THE LARAMIE RANGE. THIS WOULD BE A GOOD SETUP FOR FOG/STRATUS OUT IN THE PANHANDLE. NEXT CHANCE FOR PRECIP LOOKS TO BE FRIDAY. SOME MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE FRONT AND ASSOCIATED PRECIP. THE GFS MUCH SLOWER AND WEAKER WITH THE FRONT WHILE THE ECMWF BRINGS THE FRONT IN FROM THE NORTH DURING THE DAY FRIDAY. WILL NEED TO MONITOR THIS FEATURE AS THE WEEK PROGRESSES. && FIRE WEATHER... A WEAK COLD FRONT WILL PASS OVER THE REGION THIS MORNING BRINGING A BRIEF PERIOD OF BREEZY NORTHERLY WINDS ALONG WITH COOLER TEMPERATURES TODAY. AFTERNOON RELATIVE HUMIDITY VALUES ARE EXPECTED TO BE IN THE 30-40 PERCENT RANGE. WINDS WILL GENERALLY REMAIN BELOW 15 MPH ON SATURDAY WITH WEAK PRESSURE GRADIENTS OVER THE REGION. WEST-TO-NORTHWEST WINDS WILL INCREASE SLIGHTLY ON SUNDAY WITH OCCASIONAL GUSTS TO 25 MPH DURING THE AFTERNOON. WITH MINIMUM HUMIDITIES ABOVE 25 PERCENT THROUGH THE WEEKEND...FIRE WEATHER CONCERNS WILL BE MINIMAL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM/FIRE WEATHER...FINCH LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
508 AM MDT FRI NOV 2 2012 .AVIATION...12Z TAFS CHADRON REMAINS DOWN IN VLIFR FOG/STRATUS. LATEST HRRR GUIDANCE SHOWING LOW CEILINGS TO CONTINUE UNTIL 15Z. THIS LINES UP WELL WITH OTHER GUIDANCE SUGGESTING A MORE FAVORABLE DOWNSLOPING WIND TO BREAK UP THE FOG AROUND THAT TIME. ELSEWHERE...VFR CONDITIONS EXPECTED. CLAYCOMB && .PREV DISCUSSION... /ISSUED 324 AM MDT FRI NOV 2 2012/ SHORT TERM...TODAY THROUGH SUNDAY NIGHT... WATER VAPOR IMAGERY SHOWS A SHORTWAVE CURRENTLY MOVING OVER MONTANA WITH MID-AND-HIGH LEVEL MOISTURE OVER THE CWA. A WEAK COLD FRONT ASSOCIATED WITH THIS SHORTWAVE IS CURRENTLY NEAR CASPER AND IS PROGGED TO MOVE SOUTHEAST OVER THE PLAINS THIS MORNING. KCDR HAS REPORTED SOME FOG OVER THE PAST FEW HOURS. LAPS ANALYSIS SHOWS THE NORTHERN HALF OF THE NEBRASKA PANHANDLE EXPERIENCING WEAK NORTHEAST FLOW DUE TO A SFC HIGH IN THE DAKOTAS. THE HRRR MODEL INDICATES LIFR CONDITIONS OVER EXTREME NORTHERN DAWES COUNTY THROUGH 15Z...SO INCLUDED FOG IN THE FCST THROUGH EARLY MORNING. ANY FOG SHOULD DISSIPATE AFTER THE FROPA AND WITH DRY AIR ADVECTION. OTHERWISE...TEMPS WILL BE COOLER TODAY WITH 700MB TEMPS AT -1C (DOWN FROM 5C THIS PAST AFTN). PRESSURE RISES ARE NOT THAT IMPRESSIVE BEHIND THE FRONT...SO WIND GUSTS THIS MORNING SHOULD GENERALLY BE BELOW 30 KTS. HIGH LEVEL CLOUDS WILL PROGRESS EASTWARD OUT OF THE CWA BY LATE MORNING AS THE AREA EXPERIENCES SUBSIDENCE BEHIND THE SHORTWAVE. FAIRLY QUIET WEATHER THROUGH THE WEEKEND AS THE STRONGER LLVL AND MIDLEVEL FLOW REMAINS TO THE NORTH ALONG WITH BETTER MOISTURE. THE MODELS ARE IN AGREEMENT IN DROPPING A SHORTWAVE SOUTHEAST ACROSS MONTANA AND INTO THE DAKOTAS ON SUNDAY. NORTHWESTERLY 700MB WINDS APPROACH 40 KTS OVER THE NEBRASKA PANHANDLE ON SUNDAY AFTN SO BREEZY CONDITIONS CAN BE EXPECTED. THE SHORTWAVE WILL BRING A REINFORCING SHOT OF COOLER AIR...WITH 700MB TEMPS STAYING BETWEEN 0C AND -3C THROUGH THE WEEKEND. POPS WILL BE SLIM TO NONE WITH THE BEST MIDLEVEL MOISTURE ASSOCIATED WITH THE SHORTWAVE LARGELY REMAINING OVER CENTRAL SOUTH DAKOTA/NEBRASKA. LONG TERM...MONDAY THROUGH FRIDAY EXTENDED PRETTY QUIET WITH THE ONLY FORECAST PROBLEM BEING A BACKDOOR FRONT OVER SOUTH DAKOTA. THE FRONT SAGS SOUTHWEST INTO NORTHEASTERN WYOMING AND THE NORTHERN PANHANDLE TUESDAY...BUT THEN RETREATS NORTHEAST WEDNESDAY. THIS FRONT COULD POSE PROBLEMS WITH TEMPERATURES IF IT STALLS OUT OVER OUR EASTERN CWFA. THERE IS LOTS OF LOW CLOUDS BEHIND THE FRONT WHICH IF THE FRONT DOES STALL...WE COULD BE TOO HIGH ON OUR TEMPERATURES. FRONT MAKES A GOOD PUSH SOUTHWEST THURSDAY AND IS FORECAST TO BE UP AGAINST THE LARAMIE RANGE. THIS WOULD BE A GOOD SETUP FOR FOG/STRATUS OUT IN THE PANHANDLE. NEXT CHANCE FOR PRECIP LOOKS TO BE FRIDAY. SOME MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE FRONT AND ASSOCIATED PRECIP. THE GFS MUCH SLOWER AND WEAKER WITH THE FRONT WHILE THE ECMWF BRINGS THE FRONT IN FROM THE NORTH DURING THE DAY FRIDAY. WILL NEED TO MONITOR THIS FEATURE AS THE WEEK PROGRESSES. && FIRE WEATHER... A WEAK COLD FRONT WILL PASS OVER THE REGION THIS MORNING BRINGING A BRIEF PERIOD OF BREEZY NORTHERLY WINDS ALONG WITH COOLER TEMPERATURES TODAY. AFTERNOON RELATIVE HUMIDITY VALUES ARE EXPECTED TO BE IN THE 30-40 PERCENT RANGE. WINDS WILL GENERALLY REMAIN BELOW 15 MPH ON SATURDAY WITH WEAK PRESSURE GRADIENTS OVER THE REGION. WEST-TO-NORTHWEST WINDS WILL INCREASE SLIGHTLY ON SUNDAY WITH OCCASIONAL GUSTS TO 25 MPH DURING THE AFTERNOON. WITH MINIMUM HUMIDITIES ABOVE 25 PERCENT THROUGH THE WEEKEND...FIRE WEATHER CONCERNS WILL BE MINIMAL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM/FIRE WEATHER...FINCH LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
324 AM MDT FRI NOV 2 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT... WATER VAPOR IMAGERY SHOWS A SHORTWAVE CURRENTLY MOVING OVER MONTANA WITH MID-AND-HIGH LEVEL MOISTURE OVER THE CWA. A WEAK COLD FRONT ASSOCIATED WITH THIS SHORTWAVE IS CURRENTLY NEAR CASPER AND IS PROGGED TO MOVE SOUTHEAST OVER THE PLAINS THIS MORNING. KCDR HAS REPORTED SOME FOG OVER THE PAST FEW HOURS. LAPS ANALYSIS SHOWS THE NORTHERN HALF OF THE NEBRASKA PANHANDLE EXPERIENCING WEAK NORTHEAST FLOW DUE TO A SFC HIGH IN THE DAKOTAS. THE HRRR MODEL INDICATES LIFR CONDITIONS OVER EXTREME NORTHERN DAWES COUNTY THROUGH 15Z...SO INCLUDED FOG IN THE FCST THROUGH EARLY MORNING. ANY FOG SHOULD DISSIPATE AFTER THE FROPA AND WITH DRY AIR ADVECTION. OTHERWISE...TEMPS WILL BE COOLER TODAY WITH 700MB TEMPS AT -1C (DOWN FROM 5C THIS PAST AFTN). PRESSURE RISES ARE NOT THAT IMPRESSIVE BEHIND THE FRONT...SO WIND GUSTS THIS MORNING SHOULD GENERALLY BE BELOW 30 KTS. HIGH LEVEL CLOUDS WILL PROGRESS EASTWARD OUT OF THE CWA BY LATE MORNING AS THE AREA EXPERIENCES SUBSIDENCE BEHIND THE SHORTWAVE. FAIRLY QUIET WEATHER THROUGH THE WEEKEND AS THE STRONGER LLVL AND MIDLEVEL FLOW REMAINS TO THE NORTH ALONG WITH BETTER MOISTURE. THE MODELS ARE IN AGREEMENT IN DROPPING A SHORTWAVE SOUTHEAST ACROSS MONTANA AND INTO THE DAKOTAS ON SUNDAY. NORTHWESTERLY 700MB WINDS APPROACH 40 KTS OVER THE NEBRASKA PANHANDLE ON SUNDAY AFTN SO BREEZY CONDITIONS CAN BE EXPECTED. THE SHORTWAVE WILL BRING A REINFORCING SHOT OF COOLER AIR...WITH 700MB TEMPS STAYING BETWEEN 0C AND -3C THROUGH THE WEEKEND. POPS WILL BE SLIM TO NONE WITH THE BEST MIDLEVEL MOISTURE ASSOCIATED WITH THE SHORTWAVE LARGELY REMAINING OVER CENTRAL SOUTH DAKOTA/NEBRASKA. .LONG TERM...MONDAY THROUGH FRIDAY EXTENDED PRETTY QUIET WITH THE ONLY FORECAST PROBLEM BEING A BACKDOOR FRONT OVER SOUTH DAKOTA. THE FRONT SAGS SOUTHWEST INTO NORTHEASTERN WYOMING AND THE NORTHERN PANHANDLE TUESDAY...BUT THEN RETREATS NORTHEAST WEDNESDAY. THIS FRONT COULD POSE PROBLEMS WITH TEMPERATURES IF IT STALLS OUT OVER OUR EASTERN CWFA. THERE IS LOTS OF LOW CLOUDS BEHIND THE FRONT WHICH IF THE FRONT DOES STALL...WE COULD BE TOO HIGH ON OUR TEMPERATURES. FRONT MAKES A GOOD PUSH SOUTHWEST THURSDAY AND IS FORECAST TO BE UP AGAINST THE LARAMIE RANGE. THIS WOULD BE A GOOD SETUP FOR FOG/STRATUS OUT IN THE PANHANDLE. NEXT CHANCE FOR PRECIP LOOKS TO BE FRIDAY. SOME MODEL DIFFERENCES BETWEEN THE GFS AND ECMWF ON THE MOVEMENT OF THE FRONT AND ASSOCIATED PRECIP. THE GFS MUCH SLOWER AND WEAKER WITH THE FRONT WHILE THE ECMWF BRINGS THE FRONT IN FROM THE NORTH DURING THE DAY FRIDAY. WILL NEED TO MONITOR THIS FEATURE AS THE WEEK PROGRESSES. && .AVIATION...06Z TAFS VFR CONDITIONS EXPECTED. THE EXCEPTION BEING CHADRON WHERE FAVORABLE NORTHEAST FLOW HAS CAUSED DENSE FOG TO FORM. LATEST HRRR GUIDANCE SHOWING THIS FOG PERSISTING UNTIL 13Z OR SO WHEN DOWNSLOPING NORTHWEST WINDS ARE FORECAST. ELSEWHERE...MID/HIGH LEVEL CLOUDS EARLY THIS MORNING...GIVING WAY TO SCATTERED CLOUDS BY SUNRISE. && .FIRE WEATHER... A WEAK COLD FRONT WILL PASS OVER THE REGION THIS MORNING BRINGING A BRIEF PERIOD OF BREEZY NORTHERLY WINDS ALONG WITH COOLER TEMPERATURES TODAY. AFTERNOON RELATIVE HUMIDITY VALUES ARE EXPECTED TO BE IN THE 30-40 PERCENT RANGE. WINDS WILL GENERALLY REMAIN BELOW 15 MPH ON SATURDAY WITH WEAK PRESSURE GRADIENTS OVER THE REGION. WEST-TO-NORTHWEST WINDS WILL INCREASE SLIGHTLY ON SUNDAY WITH OCCASIONAL GUSTS TO 25 MPH DURING THE AFTERNOON. WITH MINIMUM HUMIDITIES ABOVE 25 PERCENT THROUGH THE WEEKEND...FIRE WEATHER CONCERNS WILL BE MINIMAL. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM/FIRE WEATHER...FINCH LONG TERM/AVIATION...CLAYCOMB
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
410 AM EST SUN NOV 4 2012 ...DENSE FOG TO AFFECT MOST OF THE FORECAST AREA THIS MORNING... ...HIGH RAIN CHANCES LATE MON NIGHT INTO TUESDAY... .CURRENTLY...WEAK BROAD HIGH PRES IS OVER THE ERN GULF OF MEXICO PRODUCING A WEAK WLY FLOW OVER THE REGION AND ADVECTION OF MOISTURE OFF THE GULF OF MEXICO AGAIN LATE TONIGHT. STRONG INVERSION PRESENT PER HRRR GUIDANCE SOUNDINGS OVER THE AREA AND AS A RESULT ADVECTIVE FOG EVENT TONIGHT WITH FOG LIKELY TO BE WIDESPREAD INTO THE MID MORNING HOURS OVER S HALF OF THE FORECAST AREA. A DENSE FOG ADVISORY HAS BEEN ISSUED FOR NE FL...AND MAY BE EXPANDED IN SE GA LATER THIS MORNING. TEMPS MOSTLY IN THE 50S...WITH COUPLE OF LOWER 60S READINGS IN OVER PARTS OF SE GA. FURTHER N...SFC LOW IS OVER ERN TN VALLEY AREA WITH TRAILING COLD FRONT TO CENTRAL MS AND NRN LA WITH SCT CONVECTION ALONG THE BOUNDARY OVER WRN AL TO NE LA. && .SHORT TERM... TODAY...EARLY MORNING FOG AND STRATUS WILL AFFECT A LARGE PERCENTAGE OF THE FORECAST AREA THROUGH MID MORNING BEFORE BURNING OFF. SFC FLOW WILL PREVAIL W TO SW TODAY AHEAD OF THE APPROACHING FRONT FROM THE NW. THE FRONT WILL MOVE INTO SE GA BY LATE AFTN PROVIDING A FOCUS FOR MAINLY ISOLATED CONVECTION OVER GA AFTER ABOUT 3 PM. AN ISOLATED STRONG STORM POSSIBLE IN SE GA PER SPC OUTLOOK BUT OVERALL THREAT LOOKS LIMITED OWING TO RATHER WEAK INSTABILITY. PWATS REMAINING GENERALLY 1 INCH OR LESS. TONIGHT...BOTH NAM AND GFS SIMILAR IN TIMING THE FRONT PUSHING SWD INTO THE FORECAST AREA TO A LINE FROM ABOUT SAINT AUGUSTINE TO GAINESVILLE BY 12Z MONDAY. RAIN CHANCES GENERALLY 30-40% IN SE GA AND 20-30% IN NE FL AS THE UPPER SUPPORT REMAINS WEAK AS THE FRONTAL SYSTEM DIPS SWD. SLIGHT THUNDER CHANCES NEAR THE SE GA COAST AND COASTAL WATERS. LATE IN THE NIGHT...ADVECTIVE FOG POSSIBLE ONCE AGAIN OFF THE GULF BUT FURTHER S MAINLY FROM GNV-ST AUGUSTINE SWD. LOWS IN THE 50S EXPECTED. MONDAY...THE COLD FRONT IS LIKELY TO MOVE INTO N CENTRAL FL WITH SFC HIGH PRES MOVING IN FROM THE NE. ONLY SLIGHT RAIN CHANCES DUE TO LINGERING FRONT NEAR THE AREA OVER THE S ZONES. HIGHS FALL BACK INTO THE 70S MOST AREAS WITH POSSIBLE NEAR 80 DEG READINGS EXTREME S ZONES AS THE FRONT PUSHES DOWN THROUGH N AND CENTRAL FL. MONDAY NIGHT...RAPID CHANGES UNDERWAY AS STRONG POSITIVE TILT SHORTWAVE TROUGH MOVES IN FROM THE MS VALLEY AND INTO THE SE STATES. THIS WILL GENERATE BROAD SFC LOW OVER THE NERN GULF ALONG THE BAROCLINIC ZONE AND IMPRESSIVE Q-VECTOR CONVERGENCE FIELD MOVING INTO THE OUR CWA BY 12Z TUE. ANTICIPATE POPS INCREASE TO NEAR 50-60% FROM W TO E BY EARLY MORNING HOURS. TUESDAY...BOTH GFS AND ECMWF MOVE STRONG 500 MB TROUGH JUST W OF THE AREA TO THE SE U.S. COAST BY TUE EVENING. SFC LOW PROGGED TO BE IN THE FL PANHANDLE TUE MORNING WITH WARM FRONT EXTENDING EWD OVER OUR NE FL AND INTO THE ATLC. SFC LOW EXPECTED TO SHIFT EWD QUICKLY AND OFF THE COAST BY LATER IN THE DAY...AND TAKE OFF TO THE NE WITH TRAILING FRONT PUSHING SEWD OF THE AREA IN THE AFTN. CONFIDENCE HAS RISEN WITH LIKELY POPS OVER THE ENTIRE FCST AREA...AND MAY BE BUMPED TO CATEGORICAL POPS (AT LEAST 80%) IN LATER FCSTS. WHILE THUNDERSTORM POTENTIAL REMAINS LIMITED DUE TO WEAK INSTABILITY...STRONG LIFT AND COLD TEMPS ALOFT AT -18C SUGGEST INCLUDING SLIGHT TSTMS CHANCE OVER AT LEAST THE SRN 2/3RDS OF THE AREA. TEMPS MAY HOLD STEADY IN THE 60S TO NEAR 70...BUT COULD HOLD IN THE UPPER 50S N ZONES IF CLOUDS ARE SLOWER TO CLEAR OUT. TUE NIGHT...LOW POPS RESERVED FOR EARLY EVENING OVER THE ERN ZONES AS WRAP AROUND PRECIP IS POSSIBLE. AS LOW PRES MOVES NE OF THE AREA HIGH PRES WILL BUILD IN WITH COLDER TEMPS EXPECTED IN THE 40S. WIND CHILLS IN THE 30S POSSIBLE OVER SE GA. && .LONG TERM...WED-SAT. DEEP LAYER TROUGH OVER THE ERN U.S. EXPECTED TO SHIFT EWD ALLOWING STACKED HIGH PRES RIDGE TO MOVE INTO THE ERN U.S. BY EARLY SAT. THE SFC HIGH LOCATED OVER MS VALLEY WED AND EARLY THU WILL PRODUCE OCNL BREEZY NW FLOW THEN SFC HIGH PROGGED TO MOVE OFFSHORE BY LATE FRI THROUGH SAT RESULTING VEERING/WEAK WINDS. TEMPS EXPECTED TO BE BELOW NORMAL SEVERAL DEGS WED AND THU WITH A MODERATING TREND BY FRI AND SAT AS UPPER RIDING MOVES INTO THE FORECAST AREA. WIDESPREAD LOW TEMPS IN THE 40S EXPECTED WED...THU AND FRI MORNINGS. POPS WILL BE 10% OR LESS DURING THE PERIOD. && .AVIATION... DENSE FOG BANK FROM THE GULF OF MEXICO WILL CONTINUE TO SPREAD EAST ACROSS NORTHEAST FLORIDA EARLY THIS MORNING. ONGOING VLIFR CONDITIONS AT GNV AND VQQ WILL CONTINUE UNTIL ABOUT MID MORNING. DENSE FOG BANK WILL REACH JAX AND CRG JUST PRIOR TO SUNRISE WITH POOR CONDITIONS EXPECTED AT THOSE TERMINALS FOR A PERIOD OF SEVERAL HOURS BEYOND SUNRISE. CONDITIONS WILL IMPROVE MID MORNING WITH VFR CONDITIONS THEN EXPECTED THROUGH THIS EVENING. ANOTHER ROUND OF DENSE FOG WILL BE MOST LIKELY AT GNV TONIGHT WITH THE LATEST DATA SUGGESTING DENSE FOG WILL REMAIN JUST SOUTH OF THE JACKSONVILLE TERMINALS. && .MARINE... HIGH PRESSURE WILL SHIFT EAST OF THE AREA TODAY. SOUTHWEST WINDS WILL INCREASE BY THIS EVENING AS THE GRADIENT TIGHTENS AHEAD OF AN APPROACHING COLD FRONT. WINDS WILL NEAR CAUTION SPEEDS OFFSHORE TONIGHT AND A SCEC HEADLINE WILL PROBABLY BE NEEDED. WINDS WILL VEER TO THE NORTH AND INCREASE TO 15 TO 20 KNOTS BEHIND THE FRONT ON MONDAY. A SURFACE LOW WILL DEVELOP ALONG THE CENTRAL GULF OF MEXICO MONDAY NIGHT AND THEN MOVE ACROSS THE NORTHERN FLORIDA WATERS ON TUESDAY. NORTHERLY WINDS WILL INCREASE TO SCA LEVELS ACROSS THE SOUTHERN GEORGIA WATERS ON THE NORTH SIDE OF THE LOW TUESDAY AFTERNOON. THESE CONDITIONS WILL THEN SPREAD SOUTH ACROSS THE FLORIDA WATERS TUESDAY EVENING AS THE LOW PULLS OFF TO THE NORTHEAST AND A STRONG COLD FRONT CONTINUES TO SHIFT SOUTH ACROSS THE AREA. RIP CURRENTS: LOW RISK TODAY AN INCREASE TO MODERATE RISK BY TUESDAY DUE TO INCREASING ONSHORE WINDS. && .PRELIMINARY POINT TEMPS/POPS... AMG 83 52 71 51 / 30 40 10 60 SSI 79 58 70 56 / 20 40 20 60 JAX 83 57 73 55 / 10 20 20 50 SGJ 81 59 74 59 / 10 20 20 40 GNV 82 56 77 54 / 0 20 20 50 OCF 83 57 80 55 / 0 20 20 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR ALACHUA-BAKER- BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST-HAMILTON- MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION. GA...NONE. AM...NONE. && $$ SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
447 AM EST SUN NOV 4 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 443 AM EST SUN NOV 4 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A LONGWAVE PATTERN WITH A MID/UPPER LEVEL RIDGE INTO THE WRN CONUS AND A TROUGH OVER THE EAST. A SHRTWV TROUGH WAS LOCATED OVER NE IA WHILE A RIDGE EXTENDED FROM NORTH DAKOTA INTO NE MANITOBA LEAVING WEAK NRLY FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES EXTENDED FROM NRN MANITOBA AND NW ONTARIO THROUGH WRN LAKE SUPERIOR INTO WI RESULTING IN ACYC NRLY FLOW ACROSS LAKE SUPERIOR AND UPPER MI. SHALLOW MOISTURE TRAPPED BELOW A 2K-3K FT INVERSION WITH 925 MB TEMPS TO AROUND -6C HAS PROVIDED ENOUGH INSTABILITY TO SUPPORT ISOLATED LAKE EFFECT FLURRIES INTO N CNTRL UPPER MI. OTHERWISE...IR LOOP SHOWED LOW CLOUDS ACROSS NRN ONTARIO THROUGH THE CWA. SATELLITE TRENDS AND MODELS 925 RH SUGGEST THAT...SIMILAR TO YESTERDAY...THE LOW CLOUDS WILL PERSIST OVER THE AREA GIVEN LITTLE CHANGE IN THE TEMP PROFILE AND ONLY A GRADUAL WIND SHIFT. THERE MAY BE SOME AFTERNOON CLEARING AGAIN OVER THE SOUTHWEST...WHERE MIXING MAY HELP PUSH THE EDGE OF THE CLOUDS BACK TO THE NORTHEAST. EVEN THOUGH INSTABILITY AND THE WIND FIELDS REMAIN WEAK...SOME ISOLATED/INTERMITTENT FLURRIES WILL REMAIN POSSIBLE OVER N CNTRL UPPER MI INTO THIS EVENING AS WINDS GRADUALLY VEER TO THE EAST...PER HIGH RES MODELS. THE CLOUDS SHOULD ALSO KEEP TEMPS IN A NARROW RANGE WITH HIGHS TODAY ONLY INTO THE MID AND UPPER 30S NORTH TO AROUND 40 SOUTH. WITH LINGERING CLOUDS TONIGHT...EXPECT MIN READINGS TOWARD THE HIGHER END OF GUIDANCE IN THE UPPER 20S TO AROUND 30. HOWEVER... IF SOME CLEARING DEVELOPS OVER THE SW TEMPS COULD FALL OFF QUICKLY TO NEAR 20. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 443 AM EST SUN NOV 4 2012 THE 500MB WAVE CURRENTLY OVER SW CANADA WILL BE OVER THE CENTRAL PLAINS BY DAYBREAK MONDAY...WITH A REINFORCING LOW SWINGING OVER SE CANADA FROM HUDSON BAY. IN BETWEEN THESE 2 SYSTEMS UPPER MI WILL REMAIN UNDER HIGH PRESSURE AT THE SFC AND ALOFT. SW WINDS WILL BE ON THE INCREASE MONDAY NIGHT /850MB WINDS OF 20-30KTS WITH 850MB TEMPS RISING FROM -6C TO -2C/...IN ADVANCE OF THE NEARING LOW FROM THE NW. PRECIPITATION WILL BEGIN LATE MONDAY EVENING...AND BECOME LIKELY ACROSS THE ENTIRE AREA AROUND DAYBREAK TUESDAY. AROUND AN INCH OF WET SNOW WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY MORNING OVER THE HIGHER TERRAIN OF MQT...AND SE BARAGA...AND NE IRON COUNTIES...WITH THE HELP OF A POCKET OF COOLER AIR WITH SFC TEMPS EXPECTED TO REMAIN IN THE 30S THROUGH THE DAY TUESDAY. S WINDS OFF LAKE MI COULD BECOME BREEZY AT TIMES OVER THE E HALF NEAR THE GREAT LAKES SHORELINES...BUT BELOW ANY ADVISORY VALUES. THE BULK OF THE MOISTURE SHOULD EXIT TUESDAY EVENING AS THE S EXTENT OF THE ELONGATED LOW STRETCHING FROM NE MANITOBA THROUGH E LAKE SUPERIOR EXITS EASTWARD AND TEMPORARILY GETS REPLACED BY A RIDGE FROM THE SW. WHILE TIMING OF THE VARIOUS FCST MODELS IS STILL A LITTLE UNCERTAIN...THEY ARE CONSISTENT WITH THE 500MB LOW OR TROUGH DIGGING ACROSS THE UPPER GREAT LAKES TUESDAY NIGHT AND INTENSIFYING OFF THE MID ATLANTIC AS IT MERGES WITH ANOTHER WAVE ON THE S EDGE OF THE LARGER TROUGH THAT COVERS THE E HALF OF THE NATION. LAKE EFFECT/LAKE ENHANCED CLOUDS AND PRECIP SHOULD LINGER INTO WEDNESDAY...WITH THE POTENTIAL FOR BOTH RAIN AND SNOW CONTINUING. OTHERWISE FOR THE END OF THE WORK WEEK...WITH HIGH PRESSURE OVERHEAD IN BETWEEN A STRONGER SYSTEM OFF THE EASTERN SEABOARD AND ANOTHER LOW DEVELOPING OFF THE ROCKIES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 125 AM EDT SUN NOV 4 2012 WITH LIGHT NNE FLOW OFF LK SUP ON SRN FLANK OF HI PRES IN ONTARIO AND SHARP SUBSIDENCE INVRN SHOWN ON SEVERAL LOCAL 00Z RAOBS...EXPECT MVFR CIGS TO DOMINATE THIS FCST PERIOD. THE BEST CHC FOR VFR CONDITIONS WL BE SUN AFTN AT IWD...WHERE THE COMBINATION OF DIURNAL HEATING/DOWNSLOPING NE FLOW WL HAVE A BETTER CHC OF DISSIPATING THE LO CLD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST SUN NOV 4 2012 AS HIGH PRESSURE OVER NORTHWEST ONTARIO SLIDES SOUTHEAST THROUGH THE UPPER GREAT LAKES THROUGH MONDAY...EXPECT WINDS TO BE LIGHT AND LESS THAN 15KTS. A LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA ON TUESDAY WILL SWEEP A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION AND BRING INCREASING SOUTHWESTERLY WINDS TO 20-30 KTS. A WEAK HIGH PRESSURE RIDGE WILL THEN SLIDE INTO THE UPPER GREAT LAKES WEDNESDAY AFTERNOON AND REMAIN INTO FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
116 AM EDT SUN NOV 4 2012 .AVIATION... //DISCUSSION... PERIOD OF STRATUS EROSION SEEMS TO HAVE ENDED AND CIGS BETWEEN 2500 AND 3500 FEET AS FILLING BACK IN WITHIN LIGHT WIND REGIME AND MOST LIKELY AN ASSIST BY WEAK VVELS IN ADVANCE OF APPROACHING SHORTWAVE. WILL DO AN ABOUT FACE AND INCLUDE MVFR CIGS INTO THE 12Z-14Z PERIOD AND THEN BRING SOME CLEARING...OF LOWER LEVEL MOISTURE...IN THE WAKE OF THIS WAVE. THIS IS SOMEWHAT IFFY GIVEN CONTINUED LIGHT NORTH FLOW. AT DTW...SCT-BKN 3000-3500 FOOT STRATUS WILL LIKELY FILL IN FURTHER OVERNIGHT AND PERSIST INTO SUNDAY MORNING BEFORE BREAKING UP AGAIN SOMEWHAT WITHIN WEAK SUBSIDENCE IN WAKE OF A PASSING SHORTWAVE WHICH WILL PROGRESS THROUGH THE OHIO VALLEY DURING THE DAY. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET AT TIMES INTO EARLY SUNDAY MORNING. && .PREV DISCUSSION...ISSUED 337 PM EDT SAT NOV 3 2012 SHORT TERM...THIS EVENING AND TONIGHT A STABLE SURFACE RIDGE WILL MAINTAIN A FIRM GRASP OF SOUTHEASTERN MICHIGAN THROUGHOUT THE NIGHT. NAM AND RAP ARE SHOWING A RIBBON OF VORTICITY ENERGY SHEARING OUT OF THE ND/MN ANOMALY...STRINGING INTO SOUTHERN LOWER MICHIGAN FROM THE WEST. MODEL SOLUTIONS ARE ALSO DEPICTING A WING OF 700-500MB FRONTOGENSIS SLIDING OVER THE CWA. THIS FORCING IS NOW DRIVING THE REFLECTIVITY RETURNS OVER PORTIONS OF SOUTHERN WISCONSIN/ILLINOIS/LAKE MICHIGAN. FORECAST SOUNDINGS SHOW A SATURATED/WEAK LAPSE RATE LAYER BETWEEN 15-20 KFT AGL OVERNIGHT DUE TO THIS FORCING...NECESSITATING AN INCREASED MENTION OF CLOUDS. A DEEP DRY SLAB WILL REMAIN IN PLACE BETWEEN 4-15 KFT AGL...WITH NO REAL SHOT AT ANY PRECIPITATION. THIS IS IN AGREEMENT WITH THE LACK OF SFC HYDROMETEORS BEING REPORTED IN UPSTREAM OBSERVATIONS. GIVEN THE PERSISTENCE OF THE NORTHERLY FLOW TRAJECTORY...WILL BUMP TEMPERATURES UPWARD A DEGREE OR TWO FOR THE FAR EASTERN CWA. TEMPERATURES LAST NIGHT WERE ABLE TO HANG ON FOR A FEW LOCATIONS...MOST NOTABLY THE BULK OF THE THUMB. OTHERWISE...DO NOT WANT TO GET TOO CARRIED AWAY WITH RAISING MINIMUMS...GIVEN THE COLD SURFACE RIDGE AND NOTHING MORE THAN HIGH CLOUD CONCERNS. LONG TERM...SUNDAY THROUGH NEXT SATURDAY A SURFACE RIDGE LOCATED OVER THE WESTERN GREAT LAKES WILL MAINTAIN CONTROL OVER THE WEATHER ACROSS THE REGION THROUGH THE PERIOD AS IT SLOWLY MOVES EAST THROUGH THE GREAT LAKES THROUGH MONDAY. COOL AIR ALOFT COMBINED WITH SINKING MOTION FROM THE HIGH WILL KEEP MIXING HEIGHTS SHALLOW DURING THIS PERIOD...MAINTAINING COLDER THAN NORMAL TEMPERATURES THROUGH EARLY NEXT WEEK. ONE INTERESTING FEATURE THE NWP MODELS CONTINUE TO KEY IN ON IS LAKE EFFECT OVER SOUTHERN LAKE HURON BRINGING LIGHT PRECIPITATION TO THE THUMB REGION SUNDAY THROUGH MONDAY. HOWEVER CLOSER INSPECTION SHOWS A VERY SHALLOW INVERSION LEVEL AROUND 3-4K FEET WITH ABUNDANT DRY AIR ABOVE 850 MB. THE SHALLOW INVERSION HEIGHTS...DRY AIR AND RATHER UNIMPRESSIVE DELTA T VALUES LEND ITSELF TO A CONTINUED DRY FORECAST WITH INCREASED CLOUDINESS OVER THIS AREA BEING THE EXPECTED RESULT OF THE FLOW OFF LAKE HURON DURING THIS PERIOD. AS THE HIGH MOVES OFF TO THE EAST...A TROUGH WILL DIG INTO THE WESTERN GREAT LAKES REGION ON TUESDAY...TRACKING THROUGH THE CENTRAL GREAT LAKES TUESDAY NIGHT AND LIFTING OUT ON WEDNESDAY. THIS SHORTWAVE WILL BE OF PACIFIC ORIGIN...WITH NO WAY TO TAP INTO THE MOISTURE FROM THE LARGE NOREASTER TRACKING ALONG THE ATLANTIC SEABOARD DURING THIS SAME TIME PERIOD. THEREFORE WILL CONTINUE TO MAINTAIN LOW CHANCY POPS DURING THIS PERIOD AS THIS SYSTEM WILL BE SEVERELY MOISTURE STARVED. TEMPERATURES WILL CONTINUE TO BE ON THE COOL SIDE AS THE SYSTEM FAILS TO PULL IN WARMER AIR FROM THE SOUTH INTO THE CENTRAL GREAT LAKES. LARGE SCALE RIDGING WILL DOMINATE THE WEATHER ACROSS THE GREAT LAKES DURING THE LATE PART OF THE WORK WEEK AND INTO EARLY NEXT WEEKEND...KEEPING THE WEATHER DRY. THE RIDGING WILL ALSO PULL IN SOME WARMER AIR FROM THE WEST AS 850 MB TEMPERATURES WARM FROM THE SINGLE DIGITS BELOW ZERO TO THE SINGLE DIGITS ABOVE ZERO AND EVENTUALLY AROUND +10 CELSIUS BY SATURDAY. THIS WILL BRING A GRADUAL WARMUP THROUGH EARLY NEXT WEEKEND AS NEXT SATURDAYS HIGHS ARE FORECAST TO EXCEED NORMAL LEVELS. MARINE... NORTHERLY WINDS WILL DECREASE TO 15 KNOTS OR BELOW BY LATE EVENING...HOWEVER GIVEN THE CONTINUED NORTHERLY DIRECTION...WAVE HEIGHTS WILL BE SLOW TO SUBSIDE. WAVE HEIGHTS LOOK TO FALL BELOW 5 FEET OVERNIGHT. FAIRLY QUIET CONDITIONS ARE THEN EXPECTED LATE SUNDAY THROUGH MONDAY AS THE HIGH SINKS DOWN OVER THE AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT SANILAC...UNTIL 4 AM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....DG SHORT TERM...CB LONG TERM....KURIMSKI MARINE.......CB YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
141 AM CST SUN NOV 4 2012 .SHORT TERM...THROUGH TUESDAY 141 AM CST SUN NOV 4 2012 MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES TONIGHT INTO MONDAY MORNING AND AGAIN MONDAY NIGHT INTO TUESDAY. SURFACE ANALYSIS THIS MORNING SHOWS A LARGE AREA OF HIGH PRESSURE REMAINS ANCHORED OVER WESTERN ONTARIO WITH THE RIDGE AXIS SOUTH INTO THE REGION. WATER VAPOR SATELLITE THIS MORNING SHOWS AN UPPER LEVEL LOW OVER SOUTHEAST MINNESOTA. LOCAL RADAR AND SURFACE OBS INDICATE A LITTLE BIT OF LIGHT PRECIPITATION IS HITTING THE GROUND ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA. THIS ACTIVITY IS MOVING TO THE SOUTHEAST AND BASED ON THE 04.03Z HRRR AND 04.00Z HI-RES ARW AND NMM...THIS ACTIVITY SHOULD BE SOUTH OF THE FORECAST AREA BY 12Z AND AT THIS POINT...DO NOT PLAN TO INCLUDE ANY MENTION OF THIS IN THE TODAY PORTION OF THE FORECAST. THE NEXT SHORT WAVE TROUGH CAN BE SEEN MOVING ACROSS SOUTHERN ALBERTA AND SASKATCHEWAN. THIS WAVE IS EXPECTED TO ADVANCE QUICKLY INTO THE REGION ON THE FAST NORTHWEST FLOW ALOFT. AS THE WAVE APPROACHES THE REGION...ANOTHER UPPER LEVEL LOW IS EXPECTED TO FORM AND PASS OVER MINNESOTA INTO IOWA WITH THE BULK OF THE SHORT WAVE TROUGH TRACKING TO THE WEST OF THE UPPER LEVEL LOW. IN FACT...THE 04.00Z GFS SHOWS ALL OF THE PV ADVECTION IN THE 500-300 MB LAYER STAYING OVER THE MISSOURI RIVER VALLEY. THE WAVE DOES GET CLOSE ENOUGH TO PRODUCE SOME WEAK QG CONVERGENCE IN THE 1000-500 MB LAYER FOR AREAS ALONG AND WEST OF THE MISSISSIPPI RIVER. THE BEST ISENTROPIC UP GLIDE WILL REMAIN WELL TO THE WEST OF THE AREA...BUT AROUND 1 TO 2 UBAR/S DOES GET INTO THE I35 CORRIDOR ON THE 285K SURFACE. NOT EXPECTING THIS WAVE TO PRODUCE A LOT OF PRECIPITATION FOR THE FORECAST AREA...BUT COULD SEE ANOTHER ROUND OF VERY LIGHT RAIN SNEAK INTO THE SOUTHWEST SECTIONS OF THE FORECAST AREA AND WILL HAVE RAIN CHANCES ALONG AND SOUTHWEST OF A ROCHESTER TO ELKADER LINE. SOME OF THIS LIGHT RAIN COULD LINGER INTO MONDAY MORNING BEFORE MOVING AWAY FROM THE AREA. WITH THE NORTHWEST FLOW ALOFT...YET ANOTHER WAVE WILL QUICKLY ADVANCE TOWARD THE REGION FOR MONDAY NIGHT AND TUESDAY. THIS WAVE LOOKS LIKE IT WILL START OUT FARTHER NORTH COMING OUT OF CENTRAL ALBERTA AND SASKATCHEWAN WHICH WILL TAKE IT FARTHER NORTHEAST THAN THE PREVIOUS TWO WAVES. THE MODELS HAVE BEEN FAIRLY CONSISTENT SHOWING THIS WAVE TRACKING RIGHT OVER THE AREA WITH THE GFS INDICATING UP TO 16 PVU/S OF VORTICITY ADVECTION COMING ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY MORNING. THE QG RESPONSE FROM THIS WAVE IS EXPECTED TO BE MODERATE IN STRENGTH BUT VERY DEEP EXTENDING FROM 1000 UP TO 300 MB. VERY LITTLE IF ANY FRONTOGENESIS IS EXPECTED WITH THIS SYSTEM AND THE ISENTROPIC RESPONSE IS ONLY AROUND 2 UBAR/S ON THE 285K SURFACE. EXPECT THAT THIS SYSTEM WILL BE ABLE TO PRODUCE SOME PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING. HAVE RAISED THE PRECIPITATION CHANCES TO 50 PERCENT ACROSS THE FAR NORTH AND EXTENDED THE 20 PERCENT CHANCES SOUTH TO COVER THE REMAINDER OF THE AREA. RAISED THE CHANCES TO 60 AND 70 PERCENT ACROSS THE EAST FOR TUESDAY MORNING WITH 30 AND 40 PERCENT CHANCES BACK ACROSS THE WEST. LOOKING AT THE FORECAST SOUNDINGS...EXPECTING MOST OF THIS PRECIPITATION TO FALL AS RAIN AS THE WARM AIR ADVECTION AHEAD OF THE WAVE SHOULD WARM THE LOW LEVEL TEMPERATURES ENOUGH TO KEEP THINGS LIQUID. HOWEVER...CAN NOT TOTALLY RULE SOME SNOW MIXING IN SO PLAN TO HAVE A LITTLE MIX FOR A WHILE. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 141 AM CST SUN NOV 4 2012 MEDIUM RANGE MODELS IN VERY GOOD AGREEMENT THIS MORNING SHOWING THE UPPER LEVEL RIDGE OVER THE ROCKIES WILL SLIDE EAST ACROSS THE MIDWEST BEHIND THE TUESDAY SYSTEM. THIS RIDGING IS EXPECTED TO SLIDE EAST PAST THE REGION THURSDAY NIGHT AND FRIDAY ALLOWING SOUTHWEST FLOW ALOFT TO DEVELOP AS AN UPPER LEVEL LOW MOVES ACROSS THE NORTHERN ROCKIES ONTO THE HIGH PLAINS BY SATURDAY. AT THE SURFACE...CYCLOGENESIS SHOULD TAKE PLACE IN THE LEE OF THE ROCKIES FRIDAY NIGHT WITH THE LOW ADVANCING NORTHEAST INTO MINNESOTA SATURDAY. STILL SIGNIFICANT DIFFERENCES ON WHERE THE WARM FRONT DEVELOPS WITH THE SURFACE LOW. THE GFS HAS THE WARM FRONT ALONG THE IOWA/MISSOURI BORDER AND SHOWS PRECIPITATION DEVELOPING NORTH OF THIS ALREADY FRIDAY WHILE THE 04.00Z ECMWF CONTINUES TO SHOW THE WARM FRONT WELL TO THE NORTH WITH ANY PRECIPITATION ACROSS SOUTHERN CANADA. THESE DIFFERENCES THEN CONTINUE THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS BEING MUCH WETTER WHILE THE ECMWF KEEPS THE AREA IN THE WARM SECTOR AND DOES NOT DEVELOP ANY PRECIPITATION UNTIL FRIDAY NIGHT INTO SATURDAY AS THE SURFACE LOW AND COLD FRONT STARTS TO APPROACH. NO CHANGES PLANNED TO THE MODEL CONSENSUS GRIDS AT THIS POINT WHICH FAVOR THE DRIER ECMWF SOLUTION. && .AVIATION... 1025 PM CDT SAT NOV 3 2012 AN AREA OF PCPN WAS TRACKING SOUTHEAST ACROSS SOUTHERN MN...AND WILL MOVE ACROSS IOWA DURING THE OVERNIGHT HOURS. IT WAS MOSTLY -RA...BUT WILL MIX WITH SOME -SN AS TEMPS CONTINUE TO COOL. VSBYS WERE MOSTLY P6SM WITH ANY PCPN...WITH ONLY MINOR IF ANY ACCUMULATIONS. LATEST RAP13/HRRR/NAM12 CONTINUE TO KEEP THE BULK OF THE PCPN SOUTHWEST OF KLSE...BUT COULD MOVE ACROSS KRST. WILL CONTINUE -SH THERE...AND LEAVE KLSE PCPN FREE FOR NOW. FOR CIGS...SUB 3 KFT CLOUDS ARE ASSOCIATED WITH MUCH OF THE PCPN...WITH INCREASING LOW LEVEL RH AND BUFKIT SOUNDINGS SUPPORTING THESE LOWER CIGS. DAYTIME MIXING SHOULD PUSH CIG HEIGHTS UP DURING THE DAY ON SUN. THAT SAID...ANOTHER SHORTWAVE TROUGH WILL PUSH ACROSS THE REGION FOR LATE SUN NIGHT/MONDAY. SATURATION IS DEEPER AND MORE WIDESPREAD WITH THIS FEATURE...AND A PROLONGED PERIOD OF MVFR CIGS - OR CLOSE TO IT - LOOKS LIKELY FOR MONDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 141 AM CST SUN NOV 4 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
744 AM CST SUN NOV 4 2012 .UPDATE... LATEST RAP TRENDS INDICATES THE PRECIP OVER THE NORTHEAST HALF OF THE CWFA WILL RAPIDLY DISSIPATE OVER THE NEXT COUPLE OF HOURS DUE TO A LACK OF CONVERGENCE. ACROSS THE SOUTHEAST HALF OF THE CWFA CONVERGENCE IS PROGGED TO INCREASE EVEN AS THE OVERALL FORCING DECREASES. THUS PRECIPITATION WILL LINGER LONGER ACROSS ROUGHLY THE SOUTH HALF THAN THE NORTH HALF THE REMAINDER OF THE MORNING. THE ENDING OF PRECIPITATION SHOULD ALLOW TEMPERATURES TO SLOWLY RISE. SOME BREAKS MAY DEVELOP IN THE CLOUDS LATER TODAY AS SUBSIDENCE DEVELOPS BEHIND THE DEPARTING SHORTWAVE. ..08.. && .PREV DISCUSSION... /ISSUED 555 AM CST SUN NOV 4 2012/ UPDATE... TRENDS FROM THE 06Z WRF AND THE RAP MODEL WITH INPUT FROM AREA RADARS INDICATE AN ADJUSTMENT SOUTHWARD IS NEEDED FOR THE CURRENT POPS THIS MORNING. BOTH THE WRF AND RAP MODELS INDICATE THE OVERALL FORCING WILL BEGIN TO RAPIDLY WEAKEN AFTER 12Z. THE PRECIPITATION SO FAR HAS BEEN VERY SPOTTY AND WITH THE FORCING PROGGED TO GET WEAKER THE AREAL COVERAGE WILL DECREASE OVER THE NEXT SEVERAL HOURS. SUBSIDENCE BEHIND THE SHORTWAVE MAY ALLOW THE CLOUDS TO BREAK UP AROUND MID DAY AND INTO THE AFTERNOON. HOWEVER...THE DENSE CI/CS SHIELD FROM THE NEXT SYSTEM SHOULD ALSO BE ARRIVING AT THAT TIME. AT THE VERY BEST SOME EXTREMELY FILTERED SUN MAY BE POSSIBLE. A MORE LIKELY SCENARIO IS CONTINUED CLOUD COVER. IF THE LATTER SCENARIO OCCURS IT WOULD HAVE A NEGATIVE IMPACT ON TEMPERATURES. BASED ON AN APPROXIMATED ARRIVAL OF MID DAY FOR THE CLOUD SHIELD OF THE NEXT SYSTEM...MAX TEMPERATURES WERE LOWERED A FEW DEGREES TO GIVE HIGHS IN THE 45 TO 50 DEGREE RANGE. ..08.. AVIATION... MAINLY VFR WX WILL BE SEEN THROUGH 12Z/05 AS A WEAK UPPER LEVEL DISTURBANCE MOVES THROUGH THE AREA. THERE MAY BE SOME SPRINKLES OR -SHRA AT KCID/KDBQ/KMLI AS THE DISTURBANCE PASSES THROUGH. THERE MAY OR MAY NOT BE SOME MVFR VSBYS AT KBRL AROUND SUNRISE. AFT 06Z/05 YET ANOTHER UPPER LEVEL DISTURBANCE WILL MOVE THROUGH IOWA BUT ALL TAF SITES SHOULD REMAIN VFR. ..08.. PREV DISCUSSION... /ISSUED 303 AM CST SUN NOV 4 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS A VERY WEAK LOW NEAR KORC. TROFS EMANATED FROM THE LOW INTO SOUTHWEST MINNESOTA...INTO SOUTHERN IOWA...AND BACK WEST INTO NEBRASKA. DEW POINTS AROUND THE LOW AND TROFS WERE IN THE 30S WHILE 20S WERE IN THE GREAT LAKES REGION. DEW POINTS IN THE 40S AND 50S WERE ACROSS THE TENNESSEE VALLEY AND DEEP SOUTH. SATELLITE/RADAR TRENDS SHOW CLOUDS ASSOCIATED WITH THE UPPER LEVEL WAVE MOVING INTO THE AREA WITH PLENTY OF VIRGA ON RADAR. HOWEVER... PRECIPITATION WAS REACHING THE GROUND AND WAS MEASURABLE IN SPOTS. SHORT TERM...TODAY AND TONIGHT... THE CURRENT WAVE MOVING INTO THE AREA IS BEST DEPICTED USING THE 290K THETA SFC CONDENSATION PRESSURE DEFICITS/FORCING FROM THE WRF. THE TREND WITH THE OVERALL FORCING IS TO RAPIDLY WEAKEN PRIOR TO SUNRISE AND DURING THE MORNING HOURS AS THE SYSTEM ENCOUNTERS DRIER AIR OVER THE AREA. USING THE ABOVE APPROACH IN CONCERT WITH IMPLIED FORCING FROM THE TRACK OF THE VORT MAX SUGGESTS THE NORTHERN HALF SHOULD SEE SPRINKLES WITH SOME VERY LIGHT RAIN IN THE PRE-DAWN HOURS WITH THE AREAL COVERAGE SHRINKING AFTER SUNRISE AS THE FORCING COLLAPSES. THERE IS A CONCERN...WHICH THE WRF 290K THETA SFC SHOWED...THAT SPRINKLES OR VERY LIGHT RAIN MAY DEVELOP ACROSS THE SOUTHERN HALF OF THE CWFA PRIOR TO SUNRISE ON THE LEADING EDGE OF THE WEAKENING FORCING. CURRENTLY RADAR SHOWS ECHOES INCREASING AND MOVING INTO THE SOUTHERN HALF OF THE CWFA. THESE ECHOES ARE LIKELY A COMBINATION OF CLOUDS/VIRGA BUT NO SFC STATION IS REPORTING PRECIPITATION. THIS SITUATION WILL NEED TO BE MONITORED CLOSELY FOR POTENTIAL PRECIPITATION THROUGH SUNRISE AND INTO THE MORNING. BASED ON THE TRENDS IN FORCING...THE AFTERNOON HOURS LOOK TO BE DRY ACROSS THE AREA AS SUBSIDENCE MOVES IN BEHIND THE SHORT WAVE. THERE SHOULD BE SOME PARTIAL CLEARING THAT DEVELOPS DURING THE AFTERNOON WHICH WOULD ALLOW TEMPERATURES TO BE SIMILAR TO YESTERDAY. IF CLOUDS HOLD INTO THE AFTERNOON THEN THE CURRENT UPPER 40S/LOWER 50S FOR HIGHS WILL BE TOO WARM. QUIET AND DRY CONDITIONS SHOULD BE SEEN DURING THE EARLY EVENING WHILE THE NEXT...MORE SUBSTANTIAL...SHORTWAVE DROPS SOUTHEAST FROM THE NORTHERN PLAINS. THE OVERALL FORCING AND LOWERING OF CONDENSATION PRESSURE DEFICITS SUGGEST SPRINKLES/VERY LIGHT RAIN SHOULD BEGIN MOVING INTO THE FAR SOUTHWEST/WEST DURING THE LATE EVENING HOURS. AFTER MIDNIGHT THE FORCING INCREASES AND ROUGHLY THE SOUTHWEST THIRD TO WESTERN HALF OF THE CWFA SHOULD SEE SPRINKLES/LIGHT RAIN. THE FAR SOUTHWEST PART OF THE CWFA APPEARS TO HAVE THE BEST CHANCE OF SEEING MEASURABLE RAIN. 08 LONG TERM...MONDAY THROUGH NEXT SATURDAY... CLIPPER SYSTEM TO SHIFT SOUTH OF REGION ON MON WITH RAIN MAINLY WEST OF KIIB-KGBG LINE TAPERING OFF BY MIDDAY. CLOUDS REMAIN IN WAKE BUT LIKELY TO SEE SOME BREAKS IN AFTERNOON WITH SUBSIDENCE. SIDED TOWARD COOL SIDE OF GUIDANCE FOR HIGHS ACROSS THE SOUTH/WEST CWA WHERE LIKELY TO SEE MORE CLOUDINESS LINGER WHILE OPTED FOR BLEND ELSEWHERE WITH POTENTIAL FOR MORE PEAKS OF SUNSHINE. NEXT IN SERIES OF CLIPPER SYSTEMS PROGGED TO DIVE DOWN THROUGH THE GREAT LAKES TUE-TUE NGT. DIFFLUENT FLOW ALOFT... DECENT ELEVATED MOISTURE ADVECTION AND LIFT ATTENDANT TO LEFT EXIT REGION OF 110-120 KT H3 JET SUPPORT BAND OF PCPN SWEEPING ACROSS CWA TUE AM EXITING DURING THE AFTN. HAVE RAISED POPS ALL AREAS WITH LIKELY POPS NORTHEAST HALF OF CWA... BUT IF FORCING SIGNAL REMAINS THEN WOULD NEED TO RAISE POPS FURTHER TO LIKELY TO CATEGORICAL OVER GOOD PORTION OF CWA FOR MAINLY FIRST HALF OF DAY TUE. LIMITED MOISTURE AND SPEED OF SYSTEM TO KEEP PCPN AMOUNTS LIGHT AND GENERALLY FROM A FEW HUNDREDTHS TO AROUND 0.1 INCH. HIGHS TUE REMAIN BELOW NORMAL IN THE 40S TO L50S WITH THE COOLEST READINGS LIKELY TO BE IN THE N/E CWA. WED-FRI... MAINLY DRY WITH WARMING TREND ESPECIALLY THU-FRI WHEN TEMPS EXPECTED TO BE AT OR ABOVE NORMAL... AS UPPER LEVEL RIDGING BUILDS INTO THE REGION. NEXT WEEKEND CONTINUES TO LOOK INCREASINGLY UNSETTLED/WET WITH POTENTIAL FOR PERIOD OF MODERATE TO LOCALLY HEAVY RAINS... AS UPPER LEVEL ENERGY EJECTS FROM THE SOUTHWEST CONUS AND INTERACTS WITH GULF MOISTURE. TEMPS TO START OUT THE WEEKEND ABOVE NORMAL BUT LIKELY TO RETURN NEAR TO BELOW NORMAL BY EARLY NEXT WEEK WITH PASSAGE OF COLD FRONT. 05 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
555 AM CST SUN NOV 4 2012 .UPDATE... TRENDS FROM THE 06Z WRF AND THE RAP MODEL WITH INPUT FROM AREA RADARS INDICATE AN ADJUSTMENT SOUTHWARD IS NEEDED FOR THE CURRENT POPS THIS MORNING. BOTH THE WRF AND RAP MODELS INDICATE THE OVERALL FORCING WILL BEGIN TO RAPIDLY WEAKEN AFTER 12Z. THE PRECIPITATION SO FAR HAS BEEN VERY SPOTTY AND WITH THE FORCING PROGGED TO GET WEAKER THE AREAL COVERAGE WILL DECREASE OVER THE NEXT SEVERAL HOURS. SUBSIDENCE BEHIND THE SHORTWAVE MAY ALLOW THE CLOUDS TO BREAK UP AROUND MID DAY AND INTO THE AFTERNOON. HOWEVER...THE DENSE CI/CS SHIELD FROM THE NEXT SYSTEM SHOULD ALSO BE ARRIVING AT THAT TIME. AT THE VERY BEST SOME EXTREMELY FILTERED SUN MAY BE POSSIBLE. A MORE LIKELY SCENARIO IS CONTINUED CLOUD COVER. IF THE LATTER SCENARIO OCCURS IT WOULD HAVE A NEGATIVE IMPACT ON TEMPERATURES. BASED ON AN APPROXIMATED ARRIVAL OF MID DAY FOR THE CLOUD SHIELD OF THE NEXT SYSTEM...MAX TEMPERATURES WERE LOWERED A FEW DEGREES TO GIVE HIGHS IN THE 45 TO 50 DEGREE RANGE. ..08.. && .AVIATION... MAINLY VFR WX WILL BE SEEN THROUGH 12Z/05 AS A WEAK UPPER LEVEL DISTURBANCE MOVES THROUGH THE AREA. THERE MAY BE SOME SPRINKLES OR -SHRA AT KCID/KDBQ/KMLI AS THE DISTURBANCE PASSES THROUGH. THERE MAY OR MAY NOT BE SOME MVFR VSBYS AT KBRL AROUND SUNRISE. AFT 06Z/05 YET ANOTHER UPPER LEVEL DISTURBANCE WILL MOVE THROUGH IOWA BUT ALL TAF SITES SHOULD REMAIN VFR. ..08.. && .PREV DISCUSSION... /ISSUED 303 AM CST SUN NOV 4 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS A VERY WEAK LOW NEAR KORC. TROFS EMANATED FROM THE LOW INTO SOUTHWEST MINNESOTA...INTO SOUTHERN IOWA...AND BACK WEST INTO NEBRASKA. DEW POINTS AROUND THE LOW AND TROFS WERE IN THE 30S WHILE 20S WERE IN THE GREAT LAKES REGION. DEW POINTS IN THE 40S AND 50S WERE ACROSS THE TENNESSEE VALLEY AND DEEP SOUTH. SATELLITE/RADAR TRENDS SHOW CLOUDS ASSOCIATED WITH THE UPPER LEVEL WAVE MOVING INTO THE AREA WITH PLENTY OF VIRGA ON RADAR. HOWEVER... PRECIPITATION WAS REACHING THE GROUND AND WAS MEASURABLE IN SPOTS. SHORT TERM...TODAY AND TONIGHT... THE CURRENT WAVE MOVING INTO THE AREA IS BEST DEPICTED USING THE 290K THETA SFC CONDENSATION PRESSURE DEFICITS/FORCING FROM THE WRF. THE TREND WITH THE OVERALL FORCING IS TO RAPIDLY WEAKEN PRIOR TO SUNRISE AND DURING THE MORNING HOURS AS THE SYSTEM ENCOUNTERS DRIER AIR OVER THE AREA. USING THE ABOVE APPROACH IN CONCERT WITH IMPLIED FORCING FROM THE TRACK OF THE VORT MAX SUGGESTS THE NORTHERN HALF SHOULD SEE SPRINKLES WITH SOME VERY LIGHT RAIN IN THE PRE-DAWN HOURS WITH THE AREAL COVERAGE SHRINKING AFTER SUNRISE AS THE FORCING COLLAPSES. THERE IS A CONCERN...WHICH THE WRF 290K THETA SFC SHOWED...THAT SPRINKLES OR VERY LIGHT RAIN MAY DEVELOP ACROSS THE SOUTHERN HALF OF THE CWFA PRIOR TO SUNRISE ON THE LEADING EDGE OF THE WEAKENING FORCING. CURRENTLY RADAR SHOWS ECHOES INCREASING AND MOVING INTO THE SOUTHERN HALF OF THE CWFA. THESE ECHOES ARE LIKELY A COMBINATION OF CLOUDS/VIRGA BUT NO SFC STATION IS REPORTING PRECIPITATION. THIS SITUATION WILL NEED TO BE MONITORED CLOSELY FOR POTENTIAL PRECIPITATION THROUGH SUNRISE AND INTO THE MORNING. BASED ON THE TRENDS IN FORCING...THE AFTERNOON HOURS LOOK TO BE DRY ACROSS THE AREA AS SUBSIDENCE MOVES IN BEHIND THE SHORT WAVE. THERE SHOULD BE SOME PARTIAL CLEARING THAT DEVELOPS DURING THE AFTERNOON WHICH WOULD ALLOW TEMPERATURES TO BE SIMILAR TO YESTERDAY. IF CLOUDS HOLD INTO THE AFTERNOON THEN THE CURRENT UPPER 40S/LOWER 50S FOR HIGHS WILL BE TOO WARM. QUIET AND DRY CONDITIONS SHOULD BE SEEN DURING THE EARLY EVENING WHILE THE NEXT...MORE SUBSTANTIAL...SHORTWAVE DROPS SOUTHEAST FROM THE NORTHERN PLAINS. THE OVERALL FORCING AND LOWERING OF CONDENSATION PRESSURE DEFICITS SUGGEST SPRINKLES/VERY LIGHT RAIN SHOULD BEGIN MOVING INTO THE FAR SOUTHWEST/WEST DURING THE LATE EVENING HOURS. AFTER MIDNIGHT THE FORCING INCREASES AND ROUGHLY THE SOUTHWEST THIRD TO WESTERN HALF OF THE CWFA SHOULD SEE SPRINKLES/LIGHT RAIN. THE FAR SOUTHWEST PART OF THE CWFA APPEARS TO HAVE THE BEST CHANCE OF SEEING MEASURABLE RAIN. 08 LONG TERM...MONDAY THROUGH NEXT SATURDAY... CLIPPER SYSTEM TO SHIFT SOUTH OF REGION ON MON WITH RAIN MAINLY WEST OF KIIB-KGBG LINE TAPERING OFF BY MIDDAY. CLOUDS REMAIN IN WAKE BUT LIKELY TO SEE SOME BREAKS IN AFTERNOON WITH SUBSIDENCE. SIDED TOWARD COOL SIDE OF GUIDANCE FOR HIGHS ACROSS THE SOUTH/WEST CWA WHERE LIKELY TO SEE MORE CLOUDINESS LINGER WHILE OPTED FOR BLEND ELSEWHERE WITH POTENTIAL FOR MORE PEAKS OF SUNSHINE. NEXT IN SERIES OF CLIPPER SYSTEMS PROGGED TO DIVE DOWN THROUGH THE GREAT LAKES TUE-TUE NGT. DIFFLUENT FLOW ALOFT... DECENT ELEVATED MOISTURE ADVECTION AND LIFT ATTENDANT TO LEFT EXIT REGION OF 110-120 KT H3 JET SUPPORT BAND OF PCPN SWEEPING ACROSS CWA TUE AM EXITING DURING THE AFTN. HAVE RAISED POPS ALL AREAS WITH LIKELY POPS NORTHEAST HALF OF CWA... BUT IF FORCING SIGNAL REMAINS THEN WOULD NEED TO RAISE POPS FURTHER TO LIKELY TO CATEGORICAL OVER GOOD PORTION OF CWA FOR MAINLY FIRST HALF OF DAY TUE. LIMITED MOISTURE AND SPEED OF SYSTEM TO KEEP PCPN AMOUNTS LIGHT AND GENERALLY FROM A FEW HUNDREDTHS TO AROUND 0.1 INCH. HIGHS TUE REMAIN BELOW NORMAL IN THE 40S TO L50S WITH THE COOLEST READINGS LIKELY TO BE IN THE N/E CWA. WED-FRI... MAINLY DRY WITH WARMING TREND ESPECIALLY THU-FRI WHEN TEMPS EXPECTED TO BE AT OR ABOVE NORMAL... AS UPPER LEVEL RIDGING BUILDS INTO THE REGION. NEXT WEEKEND CONTINUES TO LOOK INCREASINGLY UNSETTLED/WET WITH POTENTIAL FOR PERIOD OF MODERATE TO LOCALLY HEAVY RAINS... AS UPPER LEVEL ENERGY EJECTS FROM THE SOUTHWEST CONUS AND INTERACTS WITH GULF MOISTURE. TEMPS TO START OUT THE WEEKEND ABOVE NORMAL BUT LIKELY TO RETURN NEAR TO BELOW NORMAL BY EARLY NEXT WEEK WITH PASSAGE OF COLD FRONT. 05 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
645 AM EST SUN NOV 4 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 443 AM EST SUN NOV 4 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A LONGWAVE PATTERN WITH A MID/UPPER LEVEL RIDGE INTO THE WRN CONUS AND A TROUGH OVER THE EAST. A SHRTWV TROUGH WAS LOCATED OVER NE IA WHILE A RIDGE EXTENDED FROM NORTH DAKOTA INTO NE MANITOBA LEAVING WEAK NRLY FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES EXTENDED FROM NRN MANITOBA AND NW ONTARIO THROUGH WRN LAKE SUPERIOR INTO WI RESULTING IN ACYC NRLY FLOW ACROSS LAKE SUPERIOR AND UPPER MI. SHALLOW MOISTURE TRAPPED BELOW A 2K-3K FT INVERSION WITH 925 MB TEMPS TO AROUND -6C HAS PROVIDED ENOUGH INSTABILITY TO SUPPORT ISOLATED LAKE EFFECT FLURRIES INTO N CNTRL UPPER MI. OTHERWISE...IR LOOP SHOWED LOW CLOUDS ACROSS NRN ONTARIO THROUGH THE CWA. SATELLITE TRENDS AND MODELS 925 RH SUGGEST THAT...SIMILAR TO YESTERDAY...THE LOW CLOUDS WILL PERSIST OVER THE AREA GIVEN LITTLE CHANGE IN THE TEMP PROFILE AND ONLY A GRADUAL WIND SHIFT. THERE MAY BE SOME AFTERNOON CLEARING AGAIN OVER THE SOUTHWEST...WHERE MIXING MAY HELP PUSH THE EDGE OF THE CLOUDS BACK TO THE NORTHEAST. EVEN THOUGH INSTABILITY AND THE WIND FIELDS REMAIN WEAK...SOME ISOLATED/INTERMITTENT FLURRIES WILL REMAIN POSSIBLE OVER N CNTRL UPPER MI INTO THIS EVENING AS WINDS GRADUALLY VEER TO THE EAST...PER HIGH RES MODELS. THE CLOUDS SHOULD ALSO KEEP TEMPS IN A NARROW RANGE WITH HIGHS TODAY ONLY INTO THE MID AND UPPER 30S NORTH TO AROUND 40 SOUTH. WITH LINGERING CLOUDS TONIGHT...EXPECT MIN READINGS TOWARD THE HIGHER END OF GUIDANCE IN THE UPPER 20S TO AROUND 30. HOWEVER... IF SOME CLEARING DEVELOPS OVER THE SW TEMPS COULD FALL OFF QUICKLY TO NEAR 20. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 443 AM EST SUN NOV 4 2012 THE 500MB WAVE CURRENTLY OVER SW CANADA WILL BE OVER THE CENTRAL PLAINS BY DAYBREAK MONDAY...WITH A REINFORCING LOW SWINGING OVER SE CANADA FROM HUDSON BAY. IN BETWEEN THESE 2 SYSTEMS UPPER MI WILL REMAIN UNDER HIGH PRESSURE AT THE SFC AND ALOFT. SW WINDS WILL BE ON THE INCREASE MONDAY NIGHT /850MB WINDS OF 20-30KTS WITH 850MB TEMPS RISING FROM -6C TO -2C/...IN ADVANCE OF THE NEARING LOW FROM THE NW. PRECIPITATION WILL BEGIN LATE MONDAY EVENING...AND BECOME LIKELY ACROSS THE ENTIRE AREA AROUND DAYBREAK TUESDAY. AROUND AN INCH OF WET SNOW WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY MORNING OVER THE HIGHER TERRAIN OF MQT...AND SE BARAGA...AND NE IRON COUNTIES...WITH THE HELP OF A POCKET OF COOLER AIR WITH SFC TEMPS EXPECTED TO REMAIN IN THE 30S THROUGH THE DAY TUESDAY. S WINDS OFF LAKE MI COULD BECOME BREEZY AT TIMES OVER THE E HALF NEAR THE GREAT LAKES SHORELINES...BUT BELOW ANY ADVISORY VALUES. THE BULK OF THE MOISTURE SHOULD EXIT TUESDAY EVENING AS THE S EXTENT OF THE ELONGATED LOW STRETCHING FROM NE MANITOBA THROUGH E LAKE SUPERIOR EXITS EASTWARD AND TEMPORARILY GETS REPLACED BY A RIDGE FROM THE SW. WHILE TIMING OF THE VARIOUS FCST MODELS IS STILL A LITTLE UNCERTAIN...THEY ARE CONSISTENT WITH THE 500MB LOW OR TROUGH DIGGING ACROSS THE UPPER GREAT LAKES TUESDAY NIGHT AND INTENSIFYING OFF THE MID ATLANTIC AS IT MERGES WITH ANOTHER WAVE ON THE S EDGE OF THE LARGER TROUGH THAT COVERS THE E HALF OF THE NATION. LAKE EFFECT/LAKE ENHANCED CLOUDS AND PRECIP SHOULD LINGER INTO WEDNESDAY...WITH THE POTENTIAL FOR BOTH RAIN AND SNOW CONTINUING. OTHERWISE FOR THE END OF THE WORK WEEK...WITH HIGH PRESSURE OVERHEAD IN BETWEEN A STRONGER SYSTEM OFF THE EASTERN SEABOARD AND ANOTHER LOW DEVELOPING OFF THE ROCKIES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 644 AM EST SUN NOV 4 2012 WITH LIGHT NNE FLOW OFF OF LAKE SUPERIOR ON THE SOUTHERN FLANK OF HIGH PRES IN ONTARIO AND A SHARP SUBSIDENCE INVERSION...EXPECT MVFR CIGS TO PERSIST THIS FCST PERIOD. THE BEST CHANCE FOR VFR CONDITIONS WILL BE THIS AFTERNOON AT IWD...WHERE THE COMBINATION OF DIURNAL HEATING AND DOWNSLOPING NE FLOW WILL HAVE A BETTER CHANCE OF DISSIPATING THE LOW CLOUDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST SUN NOV 4 2012 AS HIGH PRESSURE OVER NORTHWEST ONTARIO SLIDES SOUTHEAST THROUGH THE UPPER GREAT LAKES THROUGH MONDAY...EXPECT WINDS TO BE LIGHT AND LESS THAN 15KTS. A LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA ON TUESDAY WILL SWEEP A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION AND BRING INCREASING SOUTHWESTERLY WINDS TO 20-30 KTS. A WEAK HIGH PRESSURE RIDGE WILL THEN SLIDE INTO THE UPPER GREAT LAKES WEDNESDAY AFTERNOON AND REMAIN INTO FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 AM CST SUN NOV 4 2012 .SHORT TERM...THROUGH TUESDAY 141 AM CST SUN NOV 4 2012 MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES TONIGHT INTO MONDAY MORNING AND AGAIN MONDAY NIGHT INTO TUESDAY. SURFACE ANALYSIS THIS MORNING SHOWS A LARGE AREA OF HIGH PRESSURE REMAINS ANCHORED OVER WESTERN ONTARIO WITH THE RIDGE AXIS SOUTH INTO THE REGION. WATER VAPOR SATELLITE THIS MORNING SHOWS AN UPPER LEVEL LOW OVER SOUTHEAST MINNESOTA. LOCAL RADAR AND SURFACE OBS INDICATE A LITTLE BIT OF LIGHT PRECIPITATION IS HITTING THE GROUND ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA. THIS ACTIVITY IS MOVING TO THE SOUTHEAST AND BASED ON THE 04.03Z HRRR AND 04.00Z HI-RES ARW AND NMM...THIS ACTIVITY SHOULD BE SOUTH OF THE FORECAST AREA BY 12Z AND AT THIS POINT...DO NOT PLAN TO INCLUDE ANY MENTION OF THIS IN THE TODAY PORTION OF THE FORECAST. THE NEXT SHORT WAVE TROUGH CAN BE SEEN MOVING ACROSS SOUTHERN ALBERTA AND SASKATCHEWAN. THIS WAVE IS EXPECTED TO ADVANCE QUICKLY INTO THE REGION ON THE FAST NORTHWEST FLOW ALOFT. AS THE WAVE APPROACHES THE REGION...ANOTHER UPPER LEVEL LOW IS EXPECTED TO FORM AND PASS OVER MINNESOTA INTO IOWA WITH THE BULK OF THE SHORT WAVE TROUGH TRACKING TO THE WEST OF THE UPPER LEVEL LOW. IN FACT...THE 04.00Z GFS SHOWS ALL OF THE PV ADVECTION IN THE 500-300 MB LAYER STAYING OVER THE MISSOURI RIVER VALLEY. THE WAVE DOES GET CLOSE ENOUGH TO PRODUCE SOME WEAK QG CONVERGENCE IN THE 1000-500 MB LAYER FOR AREAS ALONG AND WEST OF THE MISSISSIPPI RIVER. THE BEST ISENTROPIC UP GLIDE WILL REMAIN WELL TO THE WEST OF THE AREA...BUT AROUND 1 TO 2 UBAR/S DOES GET INTO THE I35 CORRIDOR ON THE 285K SURFACE. NOT EXPECTING THIS WAVE TO PRODUCE A LOT OF PRECIPITATION FOR THE FORECAST AREA...BUT COULD SEE ANOTHER ROUND OF VERY LIGHT RAIN SNEAK INTO THE SOUTHWEST SECTIONS OF THE FORECAST AREA AND WILL HAVE RAIN CHANCES ALONG AND SOUTHWEST OF A ROCHESTER TO ELKADER LINE. SOME OF THIS LIGHT RAIN COULD LINGER INTO MONDAY MORNING BEFORE MOVING AWAY FROM THE AREA. WITH THE NORTHWEST FLOW ALOFT...YET ANOTHER WAVE WILL QUICKLY ADVANCE TOWARD THE REGION FOR MONDAY NIGHT AND TUESDAY. THIS WAVE LOOKS LIKE IT WILL START OUT FARTHER NORTH COMING OUT OF CENTRAL ALBERTA AND SASKATCHEWAN WHICH WILL TAKE IT FARTHER NORTHEAST THAN THE PREVIOUS TWO WAVES. THE MODELS HAVE BEEN FAIRLY CONSISTENT SHOWING THIS WAVE TRACKING RIGHT OVER THE AREA WITH THE GFS INDICATING UP TO 16 PVU/S OF VORTICITY ADVECTION COMING ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY MORNING. THE QG RESPONSE FROM THIS WAVE IS EXPECTED TO BE MODERATE IN STRENGTH BUT VERY DEEP EXTENDING FROM 1000 UP TO 300 MB. VERY LITTLE IF ANY FRONTOGENESIS IS EXPECTED WITH THIS SYSTEM AND THE ISENTROPIC RESPONSE IS ONLY AROUND 2 UBAR/S ON THE 285K SURFACE. EXPECT THAT THIS SYSTEM WILL BE ABLE TO PRODUCE SOME PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING. HAVE RAISED THE PRECIPITATION CHANCES TO 50 PERCENT ACROSS THE FAR NORTH AND EXTENDED THE 20 PERCENT CHANCES SOUTH TO COVER THE REMAINDER OF THE AREA. RAISED THE CHANCES TO 60 AND 70 PERCENT ACROSS THE EAST FOR TUESDAY MORNING WITH 30 AND 40 PERCENT CHANCES BACK ACROSS THE WEST. LOOKING AT THE FORECAST SOUNDINGS...EXPECTING MOST OF THIS PRECIPITATION TO FALL AS RAIN AS THE WARM AIR ADVECTION AHEAD OF THE WAVE SHOULD WARM THE LOW LEVEL TEMPERATURES ENOUGH TO KEEP THINGS LIQUID. HOWEVER...CAN NOT TOTALLY RULE SOME SNOW MIXING IN SO PLAN TO HAVE A LITTLE MIX FOR A WHILE. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 141 AM CST SUN NOV 4 2012 MEDIUM RANGE MODELS IN VERY GOOD AGREEMENT THIS MORNING SHOWING THE UPPER LEVEL RIDGE OVER THE ROCKIES WILL SLIDE EAST ACROSS THE MIDWEST BEHIND THE TUESDAY SYSTEM. THIS RIDGING IS EXPECTED TO SLIDE EAST PAST THE REGION THURSDAY NIGHT AND FRIDAY ALLOWING SOUTHWEST FLOW ALOFT TO DEVELOP AS AN UPPER LEVEL LOW MOVES ACROSS THE NORTHERN ROCKIES ONTO THE HIGH PLAINS BY SATURDAY. AT THE SURFACE...CYCLOGENESIS SHOULD TAKE PLACE IN THE LEE OF THE ROCKIES FRIDAY NIGHT WITH THE LOW ADVANCING NORTHEAST INTO MINNESOTA SATURDAY. STILL SIGNIFICANT DIFFERENCES ON WHERE THE WARM FRONT DEVELOPS WITH THE SURFACE LOW. THE GFS HAS THE WARM FRONT ALONG THE IOWA/MISSOURI BORDER AND SHOWS PRECIPITATION DEVELOPING NORTH OF THIS ALREADY FRIDAY WHILE THE 04.00Z ECMWF CONTINUES TO SHOW THE WARM FRONT WELL TO THE NORTH WITH ANY PRECIPITATION ACROSS SOUTHERN CANADA. THESE DIFFERENCES THEN CONTINUE THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS BEING MUCH WETTER WHILE THE ECMWF KEEPS THE AREA IN THE WARM SECTOR AND DOES NOT DEVELOP ANY PRECIPITATION UNTIL FRIDAY NIGHT INTO SATURDAY AS THE SURFACE LOW AND COLD FRONT STARTS TO APPROACH. NO CHANGES PLANNED TO THE MODEL CONSENSUS GRIDS AT THIS POINT WHICH FAVOR THE DRIER ECMWF SOLUTION. && .AVIATION...TODAY AND TONIGHT 520 AM CDT SUN NOV 4 2012 MOISTURE/CLOUDS IN THE 900MB TO ABOUT 800MB LAYER /ROUGHLY 2K-6K FT/ WILL BE PROBLEMATIC TODAY AND TONIGHT. DEEPER/LOWER OF THIS MOISTURE RESIDES WEST OF THE TAF SITES THIS MORNING. ISOTHERMAL OR WEAK INVERSIONS THRU ABOUT 800MB ALONG WITH WEAK FLOW IN THE SFC-700MB LAYER AND ANOTHER SHORTWAVE TO PASS JUST WEST OF THE FCST AREA TONIGHT...LOOK TO KEEP THIS MOISTURE OVER THE AREA TODAY AND SLOWLY ADVECT IT EASTWARD TONIGHT. WITH SOME DIURNAL WARMING/MIXING... MAINLY VFR CIGS EXPECTED TODAY. WITH THE ADVECTION OF THE DEEPER MOISTURE EAST TONIGHT AND DIURNAL COOLING...CIGS LOOK TO LOWER INTO THE 2K-3K FT RANGE BY LATER TONIGHT INTO MON MORNING. BOUNDARY LAYER MOISTURE TRAPPING AND THE LIGHT WINDS RESULTING IN SOME MVFR VSBYS IN BR WEST OF THE MS RIVER EARLY THIS MORNING. THIS WILL IMPROVE WITH DIURNAL WARMING/MIXING THIS MORNING...BUT RETURN TONIGHT AT SITES LIKE KRST WITH THE PASSING SHORTWAVE...INCREASE OF MOISTURE AND BOUNDARY LAYER COOLING. WEAK LIFT WITH THE PASSING SHORTWAVE AND THE DEEPER MOISTURE MAY BE ENOUGH FOR PATCHY -RA/-DZ TO AGAIN SPREAD ACROSS SOUTHEAST MN/NORTHEAST IA LATE TONIGHT. ADDED VCSH TO KRST AFTER 06Z FOR NOW. && .ARX WATCHES/WARNINGS/ADVISORIES... 141 AM CST SUN NOV 4 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM....04 AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
223 PM EST SUN NOV 4 2012 .SHORT TERM /TODAY THROUGH TUESDAY/... LATEST RAP ANALYSIS OVER THE LOCAL AREA SHOWS SURFACE BASED CAPE HAS INCREASED TO BETWEEN 500 J/KG AND 750 J/KG OVER THE SOUTHERN TIER WITH MIXED CAPE VALUES CONSIDERABLY LOWER. BAND OF PRE- FRONTAL -RA CONTINUES TO MAKE STEADY PROGRESS INTO NORTH CENTRAL GEORGIA BUT NO CONVECTIVE ELEMENTS OF NOTE WITH THIS ACTIVITY THUS FAR. INTO THE BETTER INSTABILITY HOWEVER...STARTING TO SEE SOME MORE ORGANIZED ACTIVITY. HOWEVER...FEEL BY THE TIME STRONG OR SEVERE COULD BE REALIZED...BEST LIFT WILL HAVE SHIFTED EAST OUT OF THE AREA THIS EVENING. WILL LIKELY SCALE BACK THE HWO AND ONGOING GRAPHICAST ONCE DEVELOPING LINE SHIFTS EAST. MONDAY LOOKS TO BE THE ONLY SHORT TERM DAY WITH FAIRLY BENIGN CONDITIONS AS HIGH CENTERED OVER CANADA HAS ENOUGH WEAK RIDGING SOUTH INTO THE OUR AREA TO PRODUCE A POP FREE DAY. CLOUDS HOWEVER WILL BECOME PLENTIFUL DURING THE DAY HAS MID AND HIGH LEVEL MOISTURE MAKES A RAPID RETURN TO THE NORTHWEST HALF OF THE REGION. THESE CLOUDS WILL PLAY AN IMPORTANT ROLE AS THEIR ARRIVAL PRIOR TO SUNSET WILL RESULT IN MINS TUESDAY MORNING NOT REACHING THEIR FULL POTENTIAL. THIS WILL BE CRUCIAL AS PRECIP BEGINS TO OVERSPREAD THE AREA IN EARNEST JUST PRIOR TO DAYBREAK TUESDAY AS CLOSED UPPER LOW ROTATES THROUGH THE DEEP SOUTH. NAM12 IS BY FAR THE MOST AGGRESSIVE IN DYNAMICALLY COOLING THE COLUMN...TAKING THE 850MB TEMP FROM +2C TO -1C IN A MATTER OF TWO HOURS. NOT COMPLETELY OUR OF THE QUESTION WITH SUCH A DYNAMIC SYSTEM TO SEE THIS TYPE OF COOLING ALOFT...BUT JUST CANNOT SEEM TO GET SURFACE TEMPS COLD ENOUGH TO ALLOW ANY FROZEN PRECIP TO REACH THE GROUND. THIS IS TRUE EVEN IN THE MOUNTAINS AND WILL KEEP FORECAST ALL LIQUID THIS RUN BUT WILL NEED TO BE MONITORED CLOSELY WITH SUBSEQUENT CYCLES. AS FAR AS THE THUNDER POTENTIAL...BEST SURFACE INSTABILITY SHOULD REMAIN SOUTH OF THE AREA...BUT GIVEN THE AMOUNT OF ISENTROPIC UPGLIDE JUST NORTH OF THE LOW...WILL NEED TO KEEP ISOLATED THUNDER MENTION FOR THE SOUTHERN TIER. DEESE .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... GFS AND ECMWF CONTINUE IN ARE IN FAIRLY DECENT AGREEMENT THROUGH THE EXTENDED...AND FOR THE MOST PART AFTER THE SYSTEM EXITS TUESDAY NIGHT THE EXTENDED SHOULD BE DRY WITH A GRADUAL WARMING TREND AS THE MIDLEVEL RIDGE BUILDS IN FROM THE GULF. CORRESPONDING SURFACE HIGH PRESSURE PUSHES THROUGH THE SOUTHEAST THURSDAY INTO FRIDAY...ANCHORING ITSELF IN THE WESTERN ATLANTIC BY SATURDAY BUT WITH STRONG RIDGING REMAINING IN PLACE. HAVE MADE NO SUBSTANTIVE CHANGES TO THE EXTENDED AT THIS TIME. TDP PREV DISCUSSION... /ISSUED 326 AM EST SUN NOV 4 2012/ BIG FORECAST STORY THROUGH THE EXTENDED IS LOW PRESSURE SYSTEM IMPACTING THE AREA TUESDAY THROUGH WEDNESDAY. MODELS CONTINUE TO SUGGEST DEEPENING OF THE LOW OVER THE SOUTHERN ALABAMA AND THE FLORIDA PANHANDLE TUESDAY MORNING THROUGH EARLY AFTERNOON. AS A RESULT OF THE PROJECTED TRACK...EXPECT BEST RAIN CHANGES TO INITIALLY BE ACROSS WESTERN GA LATE ON MONDAY INTO EARLY MORNING TUESDAY...THEN TRANSITIONING TO THE SOUTHERN 2/3 OF THE FORECAST AREA BY TUESDAY MORNING. PREVIOUS MODEL RUNS HAD SUGGESTED MORE ORGANIZED DEVELOPMENT TO OUR SOUTH IN THE FORM OF A SQUALL...CUTTING OFF THE AREA FROM MOISTURE SOURCE...BUT HAVE OPTED TO INCREASE POPS CONSIDERABLY DUE TO THE AGREEMENT WITH THE LATEST MODEL RUNS OF THE NORTHERN MOISTURE PROGRESSION. LITTLE OVERALL INSTABILITY WITH THIS SYSTEM HAS LIMITED THE MENTION OF THUNDER IN THE FORECAST...THOUGH DID KEEP MENTION OF ISOLATED CONVECTION IN THE FAR SE CWA TUESDAY LATE MORNING THROUGH EARLY AFTERNOON. CENTER OF THE SURFACE LOW TRACKS ACROSS NORTHERN FLORIDA INTO TUESDAY NIGHT...AND EMERGES OFF THE GEORGIA AND CAROLINA COASTS BY WEDNESDAY MORNING. HIGH PRESSURE BUILDS IN BEHIND THE LOW AND ASSOCIATED FRONT...KEEPING THE REMAINDER OF THE LONG TERM FORECAST DRY. COOLER TEMPERATURES IN THE MIDDLE OF THE WEEK WILL GRADUALLY WARM BY THE WEEKEND. 31 && AVIATION... 18Z UPDATE... BAND OF INTERMITTENT -RA AHEAD OF A COLD FRONT IS CURRENTLY PUSHING THROUGH THE ATL AREA TERMINALS. NO REDUCTIONS TO VSBY OR CIG NOTED WITH THIS ACTIVITY BUT HAVE NOTED SOME CIG REDUCTIONS TO MVFR IN ITS WAKE. WILL CARRY -RA FOR ATL FOR THE NEXT COUPLE OF HOURS FOLLOWED WITH A TEMPO FOR BKN025. FURTHER SOUTH OVER MCN AND CSG...PROSPECTS FOR TSRA APPEAR TO BE WANING BUT DEVELOPMENT JUST SOUTH OF THE AREA WARRANTS KEEPING VCTS FOR NOW. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON CIG AND WIND SHIFT MONDAY. HIGH ON REMAINING ELEMENTS. DEESE && .PRELIMINARY POINT TEMPS/POPS... ATHENS 74 44 62 42 / 30 5 0 50 ATLANTA 73 43 64 46 / 30 0 0 60 BLAIRSVILLE 63 37 57 40 / 20 0 0 50 CARTERSVILLE 68 38 63 41 / 20 0 0 60 COLUMBUS 79 44 69 48 / 30 20 0 80 GAINESVILLE 69 45 60 44 / 20 0 0 50 MACON 83 43 68 44 / 30 30 0 80 ROME 67 36 64 40 / 20 0 0 60 PEACHTREE CITY 73 37 65 40 / 40 0 0 70 VIDALIA 86 54 68 49 / 30 40 0 70 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE LONG TERM....TDP AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
203 PM CST SUN NOV 4 2012 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE MADE SOME TWEAKS TO GOING FORECAST MAINLY WITH RESPECT TO CLOUD COVER AND PRECIP TRENDS FOR TODAY. MORNING RAOB ANALYSIS AND GOES WATER VAPOR IMAGERY INDICATE MID- LEVEL SHORT WAVE PROPAGATING SOUTHEAST ACROSS THE AREA. THIS WAVE SEEMS A BIT DISJOINTED WITH BETTER LOW LEVEL WARM ADVECTION FORCING LINGERING TO THE WEST ACROSS IA...WHERE REGIONAL RADAR MOSAIC INDICATES SOME WEAK RETURNS. GUIDANCE MAINTAINS THIS THROUGH THE AFTERNOON...WITH PERSISTENT LOW LEVEL WAA AND RESULTING LIGHT PRECIP PRODUCTION WEST/SOUTHWEST OF THE FORECAST AREA. WEAK RADAR RETURNS OVER FAR WESTERN CWA HAVE DIMINISHED DURING THE MORNING...AND HAVE THUS REMOVED MENTIONABLE POPS FROM THOSE AREAS. FARTHER EAST...LAKE EFFECT RAIN SHOWERS CONTINUE TO DEVELOP ALONG MID-LAKE CONVERGENCE ZONE AND MOVE INLAND ACROSS NORTHWEST INDIANA COUNTIES. OF THE VARIOUS SHORT TERM/HIGH RESOLUTION GUIDANCE SETS THE RAP SEEMS TO BE HANDLING THE CURRENT LAKE PLUME THE BEST...AND WHILE IT WEAKENS THE ORGANIZATION OF THE LOW LEVEL WIND FIELD AND CONVERGENCE ZONE THIS AFTERNOON...IT MAINTAINS THE IDEA OF SOME SPOTTY LIGHT PRECIP FROM FAR ABOUT THE STATE LINE AREA EAST INTO WESTERN PORTER COUNTY THIS AFTERNOON. FORECAST SOUNDINGS INDICATE SOME GRADUAL WARMING ALOFT BY LATE AFTERNOON AND A SMALL DECREASE IN LAKE-850 MB DELTA T VALUES FROM ABOUT 17 DEG TO 15 DEG...AS WELL AS LOWERING OF EQUILIBRIUM HEIGHTS FROM ABOUT 5500-6000 FT TO LESS THAN 5000 FT BY 00Z. THUS SUSPECT LAKE EFFECT SHOWERS WILL BECOME WEAKER AND A LITTLE LESS ORGANIZED DURING THE MID/LATE AFTERNOON HOURS. OTHERWISE...ADJUSTED HOURLY SKY COVER GRIDS A BIT TO ACCOUNT FOR A LITTLE LESS CLOUD COVER NEAR THE IL/WI STATE LINE THROUGH THIS AFTERNOON. RATZER //PREV DISCUSSION... 202 AM CST A RELATIVELY QUIET PERIOD OF WEATHER TO CONTINUE FOR THE NEXT FEW DAYS...WITH THE NEXT SIGNIFICANT CHANCE FOR PCPN SETTING UP FOR ELECTION DAY TUESDAY. FOR THE REMAINDER OF THE NIGHT AND INTO SUNDAY...THE MAIN WEATHER CONCERNS WILL BE A CHANCE FOR SOME LIGHT SNOW SHOWERS OR FLURRIES IN THE ROCKFORD AREA AND LAKE EFFECT RAIN SHOWERS OVER NORTHERN PORTIONS OF LAKE AND PORTER COUNTIES IN INDIANA AND SOUTHEASTERN COOK COUNTY...ESPECIALLY NEAR THE LAKE. LATEST RADAR IMAGERY SHOWS A PERSISTENT AREA OF LAKE EFFECT SHOWERS OVER SOUTHERN LAKE MICHIGAN...FOCUSED IN A WEAK CONVERGENCE ZONE SET UP BY AN OFFSHORE LAND BREEZE FLOW PATTERN. COUPLED WITH LAKE SFC TO 850MB DELTA-T VALUES BTWN 15-18C...THE LAKE EFFECT SHOWERS SHOULD PERSIST THROUGH THE MORNING HOURS. AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO WI/IL TODAY...WEAK NORTHERLY LOW LEVEL WIND FLOW WILL PERSIST OVER THE REGION AND CONDITIONS WILL REMAIN CONDUCIVE TO SCT LAKE EFFECT RAIN SHOWERS AND ENHANCED CLOUDINESS THROUGH THE DAY TODAY AND INTO THIS EVENING. ALSO...HAVE BEEN MONITORING AN AREA PF PCPN ASSOCIATED WITH A SHORTWAVE DROPPING THROUGH NERN IA WHICH IS GENERATING SOME LIGHT PCPN. AS SFC TEMPERATURES DROP INTO THE LOWER 30S AND POSSIBLY SOME UPPER 20S...SOME VERY LIGHT SNOW OR FLURRIES ARE POSSIBLE OVER NWRN IL...INCLUDING THE ROCKFORD AREA. HOWEVER...WITH LITTLE AVAILABLE DEEP LAYER MOISTURE...LAST EVENING`S SOUNDING FROM DVN INDICATED PWAT OF ONLY 0.42 INCHES...NO MEASURABLE PCPN IS EXPECTED. AS THE SHORT WAVES QUICKLY DROPS INTO CENTRAL IL THIS AFTERNOON AND CONTINUES INTO SRN INDIANA THIS EVENING...ANY PCPN POTENTIAL OVER THE WRN PORTIONS OF THE CWA SHOULD COME TO AN END BY AROUND NOON. THE UPPER LEVEL PATTERN IS BECOMING SOMEWHAT BLOCKY AS A DEEP POLAR VORTEX DROPS SWD THROUGH QUEBEC SUNDAY NIGHT AND MONDAY WHILE UPPER RIDGING BUILDS EWD FROM THE WEST COAST INTO THE ROCKIES. THIS WILL SET UP A PERIOD OF NWLY FLOW ALOFT OVER THE UPPER MISSISSIPPI VALLEY AND INTO THE MIDWEST WITH A SERIES OF SHORTWAVES TRACKING NEAR THE LOCAL AREA. THE FIRST IN THE SERIES WILL TRACK THROUGH IOWA AND MISSOURI ON MONDAY AND INTO THE LOWER OHIO VALLEY MONDAY NIGHT. THIS SYSTEM WILL GENERATE AN AREA OF PCPN...HOWEVER...IT SHOULD REMAIN TOO FAR TO THE WEST TO BRING ANY PCPN INTO NCNRTL/NERN IL OR NWRN INDIANA. MODEL GUIDANCE IS VERY CONSISTENT ON THE TRACK OF THIS FEATURE...THOUGH THERE IS SOME DISAGREEMENT ON THE STRENGTH...WITH THE NAM A BIT WEAKER THAN THE GFS OR ECMWF. HOWEVER...REGARDLESS OF THESE DIFFERENCES...CONFIDENCE IS HIGH FOR A DRY FORECAST OVER THE CWA. THE NEXT SYSTEM IS SHAPING UP TO HAVE A MORE DIRECT IMPACT ON THE LOCAL AREA AS THE SHORTWAVE SHOULD TRACK THROUGH THE WESTERN GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY. A WEAK COLD FRONT WILL ACCOMPANY THE THE SHORTWAVE ADDING LOW LEVEL FORCING TO THE MIDLEVEL FORCING OF THE SHORTWAVE. ALSO...THIS SYSTEM IS PACIFIC-SOURCED...AND CURRENTLY OVER THE GULF OF ALASKA...SO IT IS NOT EXPECTED TO BRING ANY SIGNIFICANTLY COLDER AIR...WITH TEMPERATURES ON TUESDAY EXPECTED TO REACH INTO THE UPPER 40S TO AROUND 50F. WITH REASONABLY DECENT CONTINUITY AND CONSISTENCY AMONG THE MODELS ON THIS SYSTEM...CONFIDENCE IS RELATIVELY HIGH FOR MEASURABLE LIQUID PCPN WITH THIS SYSTEM. ALSO...AS SWLY WINDS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT...ELECTION DAY SHOULD BE BREEZY AND WET. FOR THE LONGER TERM...CONFIDENCE STARTS TO QUICKLY DETERIORATE. BY LATE TUESDAY...THE POLAR VORTEX OVER SRN QUEBEC SHOULD FINALLY KICK OUT TO THE EAST...ALLOWING FOR SOME PROGRESSION TO THE UPPER LEVEL PATTERN. THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF ON HOW FAR EAST THE UPPER RIDGE WILL PENETRATE EAST OF THE MISSISSIPPI RIVER. THE ECMWF IS MUCH MORE AMPLIFIED THAN THE GFS...WHICH WOULD HAVE A SIGNIFICANT IMPACT ON THE TRAIN OF NORTHERN STREAM SHORTWAVES. THESE MODEL DIFFERENCES COME INTO PLAY BY THE END OF THE PERIOD...ESPECIALLY FOR FRIDAY AND SATURDAY. THE MORE AMPLIFIED ECMWF SOLUTION WOULD SUGGEST BETTER CHANCES FOR PCPN THAN THE FLATTER...BROADER UPPER LEVEL PATTERN OF THE GFS. SO...WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LATTER PORTIONS OF THE LONG RANGE FORECAST...AND JUST KEEP SOME LOW POPS FOR THE NORTHERN PORTIONS OF THE CWA FOR FRIDAY NIGHT AND SATURDAY WHEN THE ECMWF BRINGS A SOUTHERN STREAM SHORTWAVE THROUGH THE AREA. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * WIND DIRECTIONS CONTINUE TO BE UNCERTAIN. RADAR AND VISIBLE SATELLITE SHOW THE APPROACH OF A LINE OF CUMULUS FROM THE EAST BEHIND WHICH THE LAKE BREEZE SHOULD MAYBE FINALLY TURN THINGS TO THE NORTHEAST AS HAS BEEN ANTICIPATED ALL AFTERNOON. * LOWERING CEILINGS TONIGHT BUT STILL LIKELY TO STAY ABOVE IFR. LENNING //DISCUSSION...UPDATED 18Z... A WEAK PRESSURE GRADIENT OVERHEAD IS ALLOWING WINDS TO FLUCTUATE IN BOTH SPEED AND DIRECTION EARLY THIS AFTERNOON. OVERALL THE TREND WOULD STILL APPEAR TO FAVOR A NORTHEASTERLY DIRECTION...ESPECIALLY IF A WEAK LAKE BREEZE CAN DEVELOP. DEVELOPING CUMULUS ALONG THE WATERFRONT SUGGESTS THIS MAY BE THE CASE...BUT ALSO RAISES THE POSSIBILITY OF SOMEWHAT LOWER CEILINGS IN THE 3500 FT RANGE THIS AFTERNOON. BOTH TRENDS WILL CONTINUE TO BE MONITORED. IF NOT THIS AFTERNOON...LOWER CIGS DO LOOK FAVORABLE THIS EVENING INTO TOMORROW MORNING IF DEVELOPING NORTHEAST FLOW OFF THE LAKE PUSHES THE CLOUDS NOW SEEN OVER INDIANA FARTHER WEST INTO DOWNTOWN CHICAGO. TO A LESSER DEGREE THE SAME TREND IS EXPECTED AT RFD BUT FOR DIFFERENT REASONS. THE AREA OUT WEST WILL BE CLOSER TO A LOW PRESSURE SYSTEM DROPPING THROUGH THE MIDWEST OVERNIGHT...BUT LIKELY NOT CLOSE ENOUGH TO BE UNDER THE PRECIPITATION SHIELD. LENNING //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM TO HIGH CONFIDENCE ON WINDS THIS AFTERNOON. * MEDIUM CONFIDENCE ON CEILING TRENDS OVERNIGHT. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...SHRA LIKELY TUESDAY AFTERNOON WITH A CHC OTHERWISE DURING THE DAY AND NIGHT. CHC OF MVFR. WEDNESDAY-THURSDAY...VFR. FRIDAY...SLIGHT CHC OF -RA DURING THE NIGHT. SATURDAY...SLIGHT CHC OF -RA DURING THE DAY. MTF && .MARINE... 102 PM CST FAIRLY BENIGN WEATHER ON THE LAKE THE NEXT 36 HOURS AS WEAK RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION. BY LATER MONDAY NIGHT INTO TUESDAY SOUTHERLY WINDS WILL INCREASE AHEAD OF A FAST MOVING CLIPPER LIKE SYSTEM DROPPING SOUTHEAST INTO THE UPPER GREAT LAKES. COULD SEE SOUTHWEST WINDS APPROACH LOW END GALES TUESDAY OVER NORTHERN PORTIONS OF THE LAKE BEFORE COLD FRONT SWEEPS ACROSS THE LAKE TUESDAY NIGHT WITH A HEALTHY SHOT OF COLD AIR ADVECTION IN THE WAKE OF THE FRONT LEADING TO A PERIOD OF FRESH NORTHWEST WINDS LATER TUESDAY NIGHT INTO EARLY WEDNESDAY BEFORE TRANSIENT HIGH PRESSURE BUILDS INTO THE AREA. MEDIUM RANGE MODELS HINT AT A FAIRLY POTENT STORM SYSTEM TRACKING INTO THE NORTHERN PLAINS LATE NEXT WEEK INTO NEXT WEEKEND WITH STRONG SOUTHERLIES A THREAT AHEAD OF THAT SYSTEM. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
102 PM CST SUN NOV 4 2012 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE MADE SOME TWEAKS TO GOING FORECAST MAINLY WITH RESPECT TO CLOUD COVER AND PRECIP TRENDS FOR TODAY. MORNING RAOB ANALYSIS AND GOES WATER VAPOR IMAGERY INDICATE MID- LEVEL SHORT WAVE PROPAGATING SOUTHEAST ACROSS THE AREA. THIS WAVE SEEMS A BIT DISJOINTED WITH BETTER LOW LEVEL WARM ADVECTION FORCING LINGERING TO THE WEST ACROSS IA...WHERE REGIONAL RADAR MOSAIC INDICATES SOME WEAK RETURNS. GUIDANCE MAINTAINS THIS THROUGH THE AFTERNOON...WITH PERSISTENT LOW LEVEL WAA AND RESULTING LIGHT PRECIP PRODUCTION WEST/SOUTHWEST OF THE FORECAST AREA. WEAK RADAR RETURNS OVER FAR WESTERN CWA HAVE DIMINISHED DURING THE MORNING...AND HAVE THUS REMOVED MENTIONABLE POPS FROM THOSE AREAS. FARTHER EAST...LAKE EFFECT RAIN SHOWERS CONTINUE TO DEVELOP ALONG MID-LAKE CONVERGENCE ZONE AND MOVE INLAND ACROSS NORTHWEST INDIANA COUNTIES. OF THE VARIOUS SHORT TERM/HIGH RESOLUTION GUIDANCE SETS THE RAP SEEMS TO BE HANDLING THE CURRENT LAKE PLUME THE BEST...AND WHILE IT WEAKENS THE ORGANIZATION OF THE LOW LEVEL WIND FIELD AND CONVERGENCE ZONE THIS AFTERNOON...IT MAINTAINS THE IDEA OF SOME SPOTTY LIGHT PRECIP FROM FAR ABOUT THE STATE LINE AREA EAST INTO WESTERN PORTER COUNTY THIS AFTERNOON. FORECAST SOUNDINGS INDICATE SOME GRADUAL WARMING ALOFT BY LATE AFTERNOON AND A SMALL DECREASE IN LAKE-850 MB DELTA T VALUES FROM ABOUT 17 DEG TO 15 DEG...AS WELL AS LOWERING OF EQUILIBRIUM HEIGHTS FROM ABOUT 5500-6000 FT TO LESS THAN 5000 FT BY 00Z. THUS SUSPECT LAKE EFFECT SHOWERS WILL BECOME WEAKER AND A LITTLE LESS ORGANIZED DURING THE MID/LATE AFTERNOON HOURS. OTHERWISE...ADJUSTED HOURLY SKY COVER GRIDS A BIT TO ACCOUNT FOR A LITTLE LESS CLOUD COVER NEAR THE IL/WI STATE LINE THROUGH THIS AFTERNOON. RATZER //PREV DISCUSSION... 202 AM CST A RELATIVELY QUIET PERIOD OF WEATHER TO CONTINUE FOR THE NEXT FEW DAYS...WITH THE NEXT SIGNIFICANT CHANCE FOR PCPN SETTING UP FOR ELECTION DAY TUESDAY. FOR THE REMAINDER OF THE NIGHT AND INTO SUNDAY...THE MAIN WEATHER CONCERNS WILL BE A CHANCE FOR SOME LIGHT SNOW SHOWERS OR FLURRIES IN THE ROCKFORD AREA AND LAKE EFFECT RAIN SHOWERS OVER NORTHERN PORTIONS OF LAKE AND PORTER COUNTIES IN INDIANA AND SOUTHEASTERN COOK COUNTY...ESPECIALLY NEAR THE LAKE. LATEST RADAR IMAGERY SHOWS A PERSISTENT AREA OF LAKE EFFECT SHOWERS OVER SOUTHERN LAKE MICHIGAN...FOCUSED IN A WEAK CONVERGENCE ZONE SET UP BY AN OFFSHORE LAND BREEZE FLOW PATTERN. COUPLED WITH LAKE SFC TO 850MB DELTA-T VALUES BTWN 15-18C...THE LAKE EFFECT SHOWERS SHOULD PERSIST THROUGH THE MORNING HOURS. AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO WI/IL TODAY...WEAK NORTHERLY LOW LEVEL WIND FLOW WILL PERSIST OVER THE REGION AND CONDITIONS WILL REMAIN CONDUCIVE TO SCT LAKE EFFECT RAIN SHOWERS AND ENHANCED CLOUDINESS THROUGH THE DAY TODAY AND INTO THIS EVENING. ALSO...HAVE BEEN MONITORING AN AREA PF PCPN ASSOCIATED WITH A SHORTWAVE DROPPING THROUGH NERN IA WHICH IS GENERATING SOME LIGHT PCPN. AS SFC TEMPERATURES DROP INTO THE LOWER 30S AND POSSIBLY SOME UPPER 20S...SOME VERY LIGHT SNOW OR FLURRIES ARE POSSIBLE OVER NWRN IL...INCLUDING THE ROCKFORD AREA. HOWEVER...WITH LITTLE AVAILABLE DEEP LAYER MOISTURE...LAST EVENING`S SOUNDING FROM DVN INDICATED PWAT OF ONLY 0.42 INCHES...NO MEASURABLE PCPN IS EXPECTED. AS THE SHORT WAVES QUICKLY DROPS INTO CENTRAL IL THIS AFTERNOON AND CONTINUES INTO SRN INDIANA THIS EVENING...ANY PCPN POTENTIAL OVER THE WRN PORTIONS OF THE CWA SHOULD COME TO AN END BY AROUND NOON. THE UPPER LEVEL PATTERN IS BECOMING SOMEWHAT BLOCKY AS A DEEP POLAR VORTEX DROPS SWD THROUGH QUEBEC SUNDAY NIGHT AND MONDAY WHILE UPPER RIDGING BUILDS EWD FROM THE WEST COAST INTO THE ROCKIES. THIS WILL SET UP A PERIOD OF NWLY FLOW ALOFT OVER THE UPPER MISSISSIPPI VALLEY AND INTO THE MIDWEST WITH A SERIES OF SHORTWAVES TRACKING NEAR THE LOCAL AREA. THE FIRST IN THE SERIES WILL TRACK THROUGH IOWA AND MISSOURI ON MONDAY AND INTO THE LOWER OHIO VALLEY MONDAY NIGHT. THIS SYSTEM WILL GENERATE AN AREA OF PCPN...HOWEVER...IT SHOULD REMAIN TOO FAR TO THE WEST TO BRING ANY PCPN INTO NCNRTL/NERN IL OR NWRN INDIANA. MODEL GUIDANCE IS VERY CONSISTENT ON THE TRACK OF THIS FEATURE...THOUGH THERE IS SOME DISAGREEMENT ON THE STRENGTH...WITH THE NAM A BIT WEAKER THAN THE GFS OR ECMWF. HOWEVER...REGARDLESS OF THESE DIFFERENCES...CONFIDENCE IS HIGH FOR A DRY FORECAST OVER THE CWA. THE NEXT SYSTEM IS SHAPING UP TO HAVE A MORE DIRECT IMPACT ON THE LOCAL AREA AS THE SHORTWAVE SHOULD TRACK THROUGH THE WESTERN GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY. A WEAK COLD FRONT WILL ACCOMPANY THE THE SHORTWAVE ADDING LOW LEVEL FORCING TO THE MIDLEVEL FORCING OF THE SHORTWAVE. ALSO...THIS SYSTEM IS PACIFIC-SOURCED...AND CURRENTLY OVER THE GULF OF ALASKA...SO IT IS NOT EXPECTED TO BRING ANY SIGNIFICANTLY COLDER AIR...WITH TEMPERATURES ON TUESDAY EXPECTED TO REACH INTO THE UPPER 40S TO AROUND 50F. WITH REASONABLY DECENT CONTINUITY AND CONSISTENCY AMONG THE MODELS ON THIS SYSTEM...CONFIDENCE IS RELATIVELY HIGH FOR MEASURABLE LIQUID PCPN WITH THIS SYSTEM. ALSO...AS SWLY WINDS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT...ELECTION DAY SHOULD BE BREEZY AND WET. FOR THE LONGER TERM...CONFIDENCE STARTS TO QUICKLY DETERIORATE. BY LATE TUESDAY...THE POLAR VORTEX OVER SRN QUEBEC SHOULD FINALLY KICK OUT TO THE EAST...ALLOWING FOR SOME PROGRESSION TO THE UPPER LEVEL PATTERN. THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF ON HOW FAR EAST THE UPPER RIDGE WILL PENETRATE EAST OF THE MISSISSIPPI RIVER. THE ECMWF IS MUCH MORE AMPLIFIED THAN THE GFS...WHICH WOULD HAVE A SIGNIFICANT IMPACT ON THE TRAIN OF NORTHERN STREAM SHORTWAVES. THESE MODEL DIFFERENCES COME INTO PLAY BY THE END OF THE PERIOD...ESPECIALLY FOR FRIDAY AND SATURDAY. THE MORE AMPLIFIED ECMWF SOLUTION WOULD SUGGEST BETTER CHANCES FOR PCPN THAN THE FLATTER...BROADER UPPER LEVEL PATTERN OF THE GFS. SO...WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LATTER PORTIONS OF THE LONG RANGE FORECAST...AND JUST KEEP SOME LOW POPS FOR THE NORTHERN PORTIONS OF THE CWA FOR FRIDAY NIGHT AND SATURDAY WHEN THE ECMWF BRINGS A SOUTHERN STREAM SHORTWAVE THROUGH THE AREA. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WINDS WILL BE RELATIVELY LIGHT TODAY BUT DIRECTION WILL BE SOMEWHAT UNCERTAIN...VARYING FROM NW TO ENE. POSSIBLE LAKE BREEZE THIS AFTERNOON WOULD FAVOR THE NE QUADRANT. * POSSIBLE LOWER CEILINGS TONIGHT INTO TOMORROW MORNING...THOUGH LIKELY STAYING ABOVE IFR. LENNING //DISCUSSION...UPDATED 18Z... A WEAK PRESSURE GRADIENT OVERHEAD IS ALLOWING WINDS TO FLUCTUATE IN BOTH SPEED AND DIRECTION EARLY THIS AFTERNOON. OVERALL THE TREND WOULD STILL APPEAR TO FAVOR A NORTHEASTERLY DIRECTION...ESPECIALLY IF A WEAK LAKE BREEZE CAN DEVELOP. DEVELOPING CUMULUS ALONG THE WATERFRONT SUGGESTS THIS MAY BE THE CASE...BUT ALSO RAISES THE POSSIBILITY OF SOMEWHAT LOWER CEILINGS IN THE 3500 FT RANGE THIS AFTERNOON. BOTH TRENDS WILL CONTINUE TO BE MONITORED. IF NOT THIS AFTERNOON...LOWER CIGS DO LOOK FAVORABLE THIS EVENING INTO TOMORROW MORNING IF DEVELOPING NORTHEAST FLOW OFF THE LAKE PUSHES THE CLOUDS NOW SEEN OVER INDIANA FARTHER WEST INTO DOWNTOWN CHICAGO. TO A LESSER DEGREE THE SAME TREND IS EXPECTED AT RFD BUT FOR DIFFERENT REASONS. THE AREA OUT WEST WILL BE CLOSER TO A LOW PRESSURE SYSTEM DROPPING THROUGH THE MIDWEST OVERNIGHT...BUT LIKELY NOT CLOSE ENOUGH TO BE UNDER THE PRECIPITATION SHIELD. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND SPEEDS GENERALLY BELOW 10 KT BUT LOW CONFIDENCE IN EXACT DIRECTION. * MEDIUM CONFIDENCE IN TREND OF LOWER CEILINGS OVERNIGHT. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...SHRA LIKELY TUESDAY AFTERNOON WITH A CHC OTHERWISE DURING THE DAY AND NIGHT. CHC OF MVFR. WEDNESDAY-THURSDAY...VFR. FRIDAY...SLIGHT CHC OF -RA DURING THE NIGHT. SATURDAY...SLIGHT CHC OF -RA DURING THE DAY. MTF && .MARINE... 102 PM CST FAIRLY BENIGN WEATHER ON THE LAKE THE NEXT 36 HOURS AS WEAK RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION. BY LATER MONDAY NIGHT INTO TUESDAY SOUTHERLY WINDS WILL INCREASE AHEAD OF A FAST MOVING CLIPPER LIKE SYSTEM DROPPING SOUTHEAST INTO THE UPPER GREAT LAKES. COULD SEE SOUTHWEST WINDS APPROACH LOW END GALES TUESDAY OVER NORTHERN PORTIONS OF THE LAKE BEFORE COLD FRONT SWEEPS ACROSS THE LAKE TUESDAY NIGHT WITH A HEALTHY SHOT OF COLD AIR ADVECTION IN THE WAKE OF THE FRONT LEADING TO A PERIOD OF FRESH NORTHWEST WINDS LATER TUESDAY NIGHT INTO EARLY WEDNESDAY BEFORE TRANSIENT HIGH PRESSURE BUILDS INTO THE AREA. MEDIUM RANGE MODELS HINT AT A FAIRLY POTENT STORM SYSTEM TRACKING INTO THE NORTHERN PLAINS LATE NEXT WEEK INTO NEXT WEEKEND WITH STRONG SOUTHERLIES A THREAT AHEAD OF THAT SYSTEM. IZZI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1217 PM CST SUN NOV 4 2012 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE MADE SOME TWEAKS TO GOING FORECAST MAINLY WITH RESPECT TO CLOUD COVER AND PRECIP TRENDS FOR TODAY. MORNING RAOB ANALYSIS AND GOES WATER VAPOR IMAGERY INDICATE MID- LEVEL SHORT WAVE PROPAGATING SOUTHEAST ACROSS THE AREA. THIS WAVE SEEMS A BIT DISJOINTED WITH BETTER LOW LEVEL WARM ADVECTION FORCING LINGERING TO THE WEST ACROSS IA...WHERE REGIONAL RADAR MOSAIC INDICATES SOME WEAK RETURNS. GUIDANCE MAINTAINS THIS THROUGH THE AFTERNOON...WITH PERSISTENT LOW LEVEL WAA AND RESULTING LIGHT PRECIP PRODUCTION WEST/SOUTHWEST OF THE FORECAST AREA. WEAK RADAR RETURNS OVER FAR WESTERN CWA HAVE DIMINISHED DURING THE MORNING...AND HAVE THUS REMOVED MENTIONABLE POPS FROM THOSE AREAS. FARTHER EAST...LAKE EFFECT RAIN SHOWERS CONTINUE TO DEVELOP ALONG MID-LAKE CONVERGENCE ZONE AND MOVE INLAND ACROSS NORTHWEST INDIANA COUNTIES. OF THE VARIOUS SHORT TERM/HIGH RESOLUTION GUIDANCE SETS THE RAP SEEMS TO BE HANDLING THE CURRENT LAKE PLUME THE BEST...AND WHILE IT WEAKENS THE ORGANIZATION OF THE LOW LEVEL WIND FIELD AND CONVERGENCE ZONE THIS AFTERNOON...IT MAINTAINS THE IDEA OF SOME SPOTTY LIGHT PRECIP FROM FAR ABOUT THE STATE LINE AREA EAST INTO WESTERN PORTER COUNTY THIS AFTERNOON. FORECAST SOUNDINGS INDICATE SOME GRADUAL WARMING ALOFT BY LATE AFTERNOON AND A SMALL DECREASE IN LAKE-850 MB DELTA T VALUES FROM ABOUT 17 DEG TO 15 DEG...AS WELL AS LOWERING OF EQUILIBRIUM HEIGHTS FROM ABOUT 5500-6000 FT TO LESS THAN 5000 FT BY 00Z. THUS SUSPECT LAKE EFFECT SHOWERS WILL BECOME WEAKER AND A LITTLE LESS ORGANIZED DURING THE MID/LATE AFTERNOON HOURS. OTHERWISE...ADJUSTED HOURLY SKY COVER GRIDS A BIT TO ACCOUNT FOR A LITTLE LESS CLOUD COVER NEAR THE IL/WI STATE LINE THROUGH THIS AFTERNOON. RATZER //PREV DISCUSSION... 202 AM CST A RELATIVELY QUIET PERIOD OF WEATHER TO CONTINUE FOR THE NEXT FEW DAYS...WITH THE NEXT SIGNIFICANT CHANCE FOR PCPN SETTING UP FOR ELECTION DAY TUESDAY. FOR THE REMAINDER OF THE NIGHT AND INTO SUNDAY...THE MAIN WEATHER CONCERNS WILL BE A CHANCE FOR SOME LIGHT SNOW SHOWERS OR FLURRIES IN THE ROCKFORD AREA AND LAKE EFFECT RAIN SHOWERS OVER NORTHERN PORTIONS OF LAKE AND PORTER COUNTIES IN INDIANA AND SOUTHEASTERN COOK COUNTY...ESPECIALLY NEAR THE LAKE. LATEST RADAR IMAGERY SHOWS A PERSISTENT AREA OF LAKE EFFECT SHOWERS OVER SOUTHERN LAKE MICHIGAN...FOCUSED IN A WEAK CONVERGENCE ZONE SET UP BY AN OFFSHORE LAND BREEZE FLOW PATTERN. COUPLED WITH LAKE SFC TO 850MB DELTA-T VALUES BTWN 15-18C...THE LAKE EFFECT SHOWERS SHOULD PERSIST THROUGH THE MORNING HOURS. AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO WI/IL TODAY...WEAK NORTHERLY LOW LEVEL WIND FLOW WILL PERSIST OVER THE REGION AND CONDITIONS WILL REMAIN CONDUCIVE TO SCT LAKE EFFECT RAIN SHOWERS AND ENHANCED CLOUDINESS THROUGH THE DAY TODAY AND INTO THIS EVENING. ALSO...HAVE BEEN MONITORING AN AREA PF PCPN ASSOCIATED WITH A SHORTWAVE DROPPING THROUGH NERN IA WHICH IS GENERATING SOME LIGHT PCPN. AS SFC TEMPERATURES DROP INTO THE LOWER 30S AND POSSIBLY SOME UPPER 20S...SOME VERY LIGHT SNOW OR FLURRIES ARE POSSIBLE OVER NWRN IL...INCLUDING THE ROCKFORD AREA. HOWEVER...WITH LITTLE AVAILABLE DEEP LAYER MOISTURE...LAST EVENING`S SOUNDING FROM DVN INDICATED PWAT OF ONLY 0.42 INCHES...NO MEASURABLE PCPN IS EXPECTED. AS THE SHORT WAVES QUICKLY DROPS INTO CENTRAL IL THIS AFTERNOON AND CONTINUES INTO SRN INDIANA THIS EVENING...ANY PCPN POTENTIAL OVER THE WRN PORTIONS OF THE CWA SHOULD COME TO AN END BY AROUND NOON. THE UPPER LEVEL PATTERN IS BECOMING SOMEWHAT BLOCKY AS A DEEP POLAR VORTEX DROPS SWD THROUGH QUEBEC SUNDAY NIGHT AND MONDAY WHILE UPPER RIDGING BUILDS EWD FROM THE WEST COAST INTO THE ROCKIES. THIS WILL SET UP A PERIOD OF NWLY FLOW ALOFT OVER THE UPPER MISSISSIPPI VALLEY AND INTO THE MIDWEST WITH A SERIES OF SHORTWAVES TRACKING NEAR THE LOCAL AREA. THE FIRST IN THE SERIES WILL TRACK THROUGH IOWA AND MISSOURI ON MONDAY AND INTO THE LOWER OHIO VALLEY MONDAY NIGHT. THIS SYSTEM WILL GENERATE AN AREA OF PCPN...HOWEVER...IT SHOULD REMAIN TOO FAR TO THE WEST TO BRING ANY PCPN INTO NCNRTL/NERN IL OR NWRN INDIANA. MODEL GUIDANCE IS VERY CONSISTENT ON THE TRACK OF THIS FEATURE...THOUGH THERE IS SOME DISAGREEMENT ON THE STRENGTH...WITH THE NAM A BIT WEAKER THAN THE GFS OR ECMWF. HOWEVER...REGARDLESS OF THESE DIFFERENCES...CONFIDENCE IS HIGH FOR A DRY FORECAST OVER THE CWA. THE NEXT SYSTEM IS SHAPING UP TO HAVE A MORE DIRECT IMPACT ON THE LOCAL AREA AS THE SHORTWAVE SHOULD TRACK THROUGH THE WESTERN GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY. A WEAK COLD FRONT WILL ACCOMPANY THE THE SHORTWAVE ADDING LOW LEVEL FORCING TO THE MIDLEVEL FORCING OF THE SHORTWAVE. ALSO...THIS SYSTEM IS PACIFIC-SOURCED...AND CURRENTLY OVER THE GULF OF ALASKA...SO IT IS NOT EXPECTED TO BRING ANY SIGNIFICANTLY COLDER AIR...WITH TEMPERATURES ON TUESDAY EXPECTED TO REACH INTO THE UPPER 40S TO AROUND 50F. WITH REASONABLY DECENT CONTINUITY AND CONSISTENCY AMONG THE MODELS ON THIS SYSTEM...CONFIDENCE IS RELATIVELY HIGH FOR MEASURABLE LIQUID PCPN WITH THIS SYSTEM. ALSO...AS SWLY WINDS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT...ELECTION DAY SHOULD BE BREEZY AND WET. FOR THE LONGER TERM...CONFIDENCE STARTS TO QUICKLY DETERIORATE. BY LATE TUESDAY...THE POLAR VORTEX OVER SRN QUEBEC SHOULD FINALLY KICK OUT TO THE EAST...ALLOWING FOR SOME PROGRESSION TO THE UPPER LEVEL PATTERN. THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF ON HOW FAR EAST THE UPPER RIDGE WILL PENETRATE EAST OF THE MISSISSIPPI RIVER. THE ECMWF IS MUCH MORE AMPLIFIED THAN THE GFS...WHICH WOULD HAVE A SIGNIFICANT IMPACT ON THE TRAIN OF NORTHERN STREAM SHORTWAVES. THESE MODEL DIFFERENCES COME INTO PLAY BY THE END OF THE PERIOD...ESPECIALLY FOR FRIDAY AND SATURDAY. THE MORE AMPLIFIED ECMWF SOLUTION WOULD SUGGEST BETTER CHANCES FOR PCPN THAN THE FLATTER...BROADER UPPER LEVEL PATTERN OF THE GFS. SO...WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LATTER PORTIONS OF THE LONG RANGE FORECAST...AND JUST KEEP SOME LOW POPS FOR THE NORTHERN PORTIONS OF THE CWA FOR FRIDAY NIGHT AND SATURDAY WHEN THE ECMWF BRINGS A SOUTHERN STREAM SHORTWAVE THROUGH THE AREA. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * WINDS WILL BE RELATIVELY LIGHT TODAY BUT DIRECTION WILL BE SOMEWHAT UNCERTAIN...VARYING FROM NW TO ENE. POSSIBLE LAKE BREEZE THIS AFTERNOON WOULD FAVOR THE NE QUADRANT. * POSSIBLE LOWER CEILINGS TONIGHT INTO TOMORROW MORNING...THOUGH LIKELY STAYING ABOVE IFR. LENNING //DISCUSSION...UPDATED 18Z... A WEAK PRESSURE GRADIENT OVERHEAD IS ALLOWING WINDS TO FLUCTUATE IN BOTH SPEED AND DIRECTION EARLY THIS AFTERNOON. OVERALL THE TREND WOULD STILL APPEAR TO FAVOR A NORTHEASTERLY DIRECTION...ESPECIALLY IF A WEAK LAKE BREEZE CAN DEVELOP. DEVELOPING CUMULUS ALONG THE WATERFRONT SUGGESTS THIS MAY BE THE CASE...BUT ALSO RAISES THE POSSIBILITY OF SOMEWHAT LOWER CEILINGS IN THE 3500 FT RANGE THIS AFTERNOON. BOTH TRENDS WILL CONTINUE TO BE MONITORED. IF NOT THIS AFTERNOON...LOWER CIGS DO LOOK FAVORABLE THIS EVENING INTO TOMORROW MORNING IF DEVELOPING NORTHEAST FLOW OFF THE LAKE PUSHES THE CLOUDS NOW SEEN OVER INDIANA FARTHER WEST INTO DOWNTOWN CHICAGO. TO A LESSER DEGREE THE SAME TREND IS EXPECTED AT RFD BUT FOR DIFFERENT REASONS. THE AREA OUT WEST WILL BE CLOSER TO A LOW PRESSURE SYSTEM DROPPING THROUGH THE MIDWEST OVERNIGHT...BUT LIKELY NOT CLOSE ENOUGH TO BE UNDER THE PRECIPITATION SHIELD. LENNING //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND SPEEDS GENERALLY BELOW 10 KT BUT LOW CONFIDENCE IN EXACT DIRECTION. * MEDIUM CONFIDENCE IN TREND OF LOWER CEILINGS OVERNIGHT. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...SHRA LIKELY TUESDAY AFTERNOON WITH A CHC OTHERWISE DURING THE DAY AND NIGHT. CHC OF MVFR. WEDNESDAY-THURSDAY...VFR. FRIDAY...SLIGHT CHC OF -RA DURING THE NIGHT. SATURDAY...SLIGHT CHC OF -RA DURING THE DAY. MTF && .MARINE... 145 AM CST AFTER A WEEK STRAIGHT OF NORTHERLY WINDS AND HIGHER WAVES...QUIET WEATHER WILL PREVAIL INTO THE START OF THIS WEEK. WINDS MAY BE VARIABLE AT TIMES OVER THE LAKE BY LATER TONIGHT THROUGH MONDAY AS A HIGH PRESSURE RIDGE SLOWLY MOVES EAST OVER THE LAKE. WINDS WILL THEN TURN SOUTHERLY LATE MONDAY NIGHT INTO TUESDAY AHEAD OF A LOW MOVING QUICKLY SOUTHEAST ACROSS THE CANADIAN PRAIRIE PROVINCES. THIS ALREADY HAS A GOOD PRESSURE AND PRESSURE TENDENCY PATTERN SIGNAL TO RESULT IN 30 KT /OR POSSIBLY JUST HIGHER/ WINDS OVER THE NORTHERN PORTION OF THE LAKE AND WAVES BRIEFLY UP TOWARD 10 FT. AN ASSOCIATED COLD FRONT IS LIKELY TO MOVE THROUGH THE LAKE ON TUESDAY NIGHT...BUT THIS FRONT SHOULD BE SLOWING AND WEAKENING AS IT CROSSES THE LAKE. HIGH PRESSURE IS EXPECTED TO PREVAIL FOR A DAY OR TWO AFTER THIS TIME...BEFORE SOUTHERLY FLOW INTO NEXT WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1040 AM CST SUN NOV 4 2012 .DISCUSSION... 1040 AM CST FOR MORNING UPDATE... HAVE MADE SOME TWEAKS TO GOING FORECAST MAINLY WITH RESPECT TO CLOUD COVER AND PRECIP TRENDS FOR TODAY. MORNING RAOB ANALYSIS AND GOES WATER VAPOR IMAGERY INDICATE MID- LEVEL SHORT WAVE PROPAGATING SOUTHEAST ACROSS THE AREA. THIS WAVE SEEMS A BIT DISJOINTED WITH BETTER LOW LEVEL WARM ADVECTION FORCING LINGERING TO THE WEST ACROSS IA...WHERE REGIONAL RADAR MOSAIC INDICATES SOME WEAK RETURNS. GUIDANCE MAINTAINS THIS THROUGH THE AFTERNOON...WITH PERSISTENT LOW LEVEL WAA AND RESULTING LIGHT PRECIP PRODUCTION WEST/SOUTHWEST OF THE FORECAST AREA. WEAK RADAR RETURNS OVER FAR WESTERN CWA HAVE DIMINISHED DURING THE MORNING...AND HAVE THUS REMOVED MENTIONABLE POPS FROM THOSE AREAS. FARTHER EAST...LAKE EFFECT RAIN SHOWERS CONTINUE TO DEVELOP ALONG MID-LAKE CONVERGENCE ZONE AND MOVE INLAND ACROSS NORTHWEST INDIANA COUNTIES. OF THE VARIOUS SHORT TERM/HIGH RESOLUTION GUIDANCE SETS THE RAP SEEMS TO BE HANDLING THE CURRENT LAKE PLUME THE BEST...AND WHILE IT WEAKENS THE ORGANIZATION OF THE LOW LEVEL WIND FIELD AND CONVERGENCE ZONE THIS AFTERNOON...IT MAINTAINS THE IDEA OF SOME SPOTTY LIGHT PRECIP FROM FAR ABOUT THE STATE LINE AREA EAST INTO WESTERN PORTER COUNTY THIS AFTERNOON. FORECAST SOUNDINGS INDICATE SOME GRADUAL WARMING ALOFT BY LATE AFTERNOON AND A SMALL DECREASE IN LAKE-850 MB DELTA T VALUES FROM ABOUT 17 DEG TO 15 DEG...AS WELL AS LOWERING OF EQUILIBRIUM HEIGHTS FROM ABOUT 5500-6000 FT TO LESS THAN 5000 FT BY 00Z. THUS SUSPECT LAKE EFFECT SHOWERS WILL BECOME WEAKER AND A LITTLE LESS ORGANIZED DURING THE MID/LATE AFTERNOON HOURS. OTHERWISE...ADJUSTED HOURLY SKY COVER GRIDS A BIT TO ACCOUNT FOR A LITTLE LESS CLOUD COVER NEAR THE IL/WI STATE LINE THROUGH THIS AFTERNOON. RATZER && .PREV DISCUSSION... 202 AM CST A RELATIVELY QUIET PERIOD OF WEATHER TO CONTINUE FOR THE NEXT FEW DAYS...WITH THE NEXT SIGNIFICANT CHANCE FOR PCPN SETTING UP FOR ELECTION DAY TUESDAY. FOR THE REMAINDER OF THE NIGHT AND INTO SUNDAY...THE MAIN WEATHER CONCERNS WILL BE A CHANCE FOR SOME LIGHT SNOW SHOWERS OR FLURRIES IN THE ROCKFORD AREA AND LAKE EFFECT RAIN SHOWERS OVER NORTHERN PORTIONS OF LAKE AND PORTER COUNTIES IN INDIANA AND SOUTHEASTERN COOK COUNTY...ESPECIALLY NEAR THE LAKE. LATEST RADAR IMAGERY SHOWS A PERSISTENT AREA OF LAKE EFFECT SHOWERS OVER SOUTHERN LAKE MICHIGAN...FOCUSED IN A WEAK CONVERGENCE ZONE SET UP BY AN OFFSHORE LAND BREEZE FLOW PATTERN. COUPLED WITH LAKE SFC TO 850MB DELTA-T VALUES BTWN 15-18C...THE LAKE EFFECT SHOWERS SHOULD PERSIST THROUGH THE MORNING HOURS. AS A WEAK RIDGE OF HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI VALLEY AND INTO WI/IL TODAY...WEAK NORTHERLY LOW LEVEL WIND FLOW WILL PERSIST OVER THE REGION AND CONDITIONS WILL REMAIN CONDUCIVE TO SCT LAKE EFFECT RAIN SHOWERS AND ENHANCED CLOUDINESS THROUGH THE DAY TODAY AND INTO THIS EVENING. ALSO...HAVE BEEN MONITORING AN AREA PF PCPN ASSOCIATED WITH A SHORTWAVE DROPPING THROUGH NERN IA WHICH IS GENERATING SOME LIGHT PCPN. AS SFC TEMPERATURES DROP INTO THE LOWER 30S AND POSSIBLY SOME UPPER 20S...SOME VERY LIGHT SNOW OR FLURRIES ARE POSSIBLE OVER NWRN IL...INCLUDING THE ROCKFORD AREA. HOWEVER...WITH LITTLE AVAILABLE DEEP LAYER MOISTURE...LAST EVENING`S SOUNDING FROM DVN INDICATED PWAT OF ONLY 0.42 INCHES...NO MEASURABLE PCPN IS EXPECTED. AS THE SHORT WAVES QUICKLY DROPS INTO CENTRAL IL THIS AFTERNOON AND CONTINUES INTO SRN INDIANA THIS EVENING...ANY PCPN POTENTIAL OVER THE WRN PORTIONS OF THE CWA SHOULD COME TO AN END BY AROUND NOON. THE UPPER LEVEL PATTERN IS BECOMING SOMEWHAT BLOCKY AS A DEEP POLAR VORTEX DROPS SWD THROUGH QUEBEC SUNDAY NIGHT AND MONDAY WHILE UPPER RIDGING BUILDS EWD FROM THE WEST COAST INTO THE ROCKIES. THIS WILL SET UP A PERIOD OF NWLY FLOW ALOFT OVER THE UPPER MISSISSIPPI VALLEY AND INTO THE MIDWEST WITH A SERIES OF SHORTWAVES TRACKING NEAR THE LOCAL AREA. THE FIRST IN THE SERIES WILL TRACK THROUGH IOWA AND MISSOURI ON MONDAY AND INTO THE LOWER OHIO VALLEY MONDAY NIGHT. THIS SYSTEM WILL GENERATE AN AREA OF PCPN...HOWEVER...IT SHOULD REMAIN TOO FAR TO THE WEST TO BRING ANY PCPN INTO NCNRTL/NERN IL OR NWRN INDIANA. MODEL GUIDANCE IS VERY CONSISTENT ON THE TRACK OF THIS FEATURE...THOUGH THERE IS SOME DISAGREEMENT ON THE STRENGTH...WITH THE NAM A BIT WEAKER THAN THE GFS OR ECMWF. HOWEVER...REGARDLESS OF THESE DIFFERENCES...CONFIDENCE IS HIGH FOR A DRY FORECAST OVER THE CWA. THE NEXT SYSTEM IS SHAPING UP TO HAVE A MORE DIRECT IMPACT ON THE LOCAL AREA AS THE SHORTWAVE SHOULD TRACK THROUGH THE WESTERN GREAT LAKES AND MIDDLE MISSISSIPPI VALLEY. A WEAK COLD FRONT WILL ACCOMPANY THE THE SHORTWAVE ADDING LOW LEVEL FORCING TO THE MIDLEVEL FORCING OF THE SHORTWAVE. ALSO...THIS SYSTEM IS PACIFIC-SOURCED...AND CURRENTLY OVER THE GULF OF ALASKA...SO IT IS NOT EXPECTED TO BRING ANY SIGNIFICANTLY COLDER AIR...WITH TEMPERATURES ON TUESDAY EXPECTED TO REACH INTO THE UPPER 40S TO AROUND 50F. WITH REASONABLY DECENT CONTINUITY AND CONSISTENCY AMONG THE MODELS ON THIS SYSTEM...CONFIDENCE IS RELATIVELY HIGH FOR MEASURABLE LIQUID PCPN WITH THIS SYSTEM. ALSO...AS SWLY WINDS INCREASE IN ADVANCE OF THE APPROACHING COLD FRONT...ELECTION DAY SHOULD BE BREEZY AND WET. FOR THE LONGER TERM...CONFIDENCE STARTS TO QUICKLY DETERIORATE. BY LATE TUESDAY...THE POLAR VORTEX OVER SRN QUEBEC SHOULD FINALLY KICK OUT TO THE EAST...ALLOWING FOR SOME PROGRESSION TO THE UPPER LEVEL PATTERN. THERE IS SOME DISAGREEMENT BETWEEN THE GFS AND ECMWF ON HOW FAR EAST THE UPPER RIDGE WILL PENETRATE EAST OF THE MISSISSIPPI RIVER. THE ECMWF IS MUCH MORE AMPLIFIED THAN THE GFS...WHICH WOULD HAVE A SIGNIFICANT IMPACT ON THE TRAIN OF NORTHERN STREAM SHORTWAVES. THESE MODEL DIFFERENCES COME INTO PLAY BY THE END OF THE PERIOD...ESPECIALLY FOR FRIDAY AND SATURDAY. THE MORE AMPLIFIED ECMWF SOLUTION WOULD SUGGEST BETTER CHANCES FOR PCPN THAN THE FLATTER...BROADER UPPER LEVEL PATTERN OF THE GFS. SO...WILL NOT MAKE ANY SIGNIFICANT CHANGES TO THE LATTER PORTIONS OF THE LONG RANGE FORECAST...AND JUST KEEP SOME LOW POPS FOR THE NORTHERN PORTIONS OF THE CWA FOR FRIDAY NIGHT AND SATURDAY WHEN THE ECMWF BRINGS A SOUTHERN STREAM SHORTWAVE THROUGH THE AREA. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * WINDS LIGHT AND SLOWING TURNING FROM NNW TO NNE BUT ORD ALREADY ON PLAN X SO NO PROBLEMS EXPECTED. * LOWER CIGS EXPECTED TO STAY OVER ON THE INDIANA SIDE OF THE LAKE TODAY. LENNING //DISCUSSION...UPDATED 12Z... A HIGH PRESSURE RIDGE REMAINS IN PLACE FROM WESTERN QUEBEC SOUTHWARD ACROSS RFD AND FROM THERE INTO CENTRAL AND SOUTHERN IL. THIS WILL CREEP SLOWLY EAST TODAY WITH CONTINUED NORTHEAST FLOW FROM LAKE MICHIGAN. SUCH A WIND COMPONENT WILL OFFER A FETCH OF MOISTURE AND INSTABILITY SUFFICIENT ENOUGH FOR CONTINUED LAKE EFFECT CLOUDS. THE CONVERGENCE AND FOCUS OF THESE CLOUDS SEEMS WELL-ESTABLISHED INTO NORTHWEST INDIANA. SOME SUBTLE SHIFTING OF THIS AXIS MAY OCCUR...BUT AT THIS POINT GIVEN ITS PLACEMENT IT APPEARS THAT EVEN ACCOUNTING FOR THAT...THE HEART OF ANY MVFR CIGS AND ISOLATED SHOWER ACTIVITY WOULD REMAIN EAST OF ORD AND MDW TODAY. IN ADDITION...AN UPPER LEVEL DISTURBANCE TRANSLATING SOUTHEAST ACROSS THE UPPER TO MID MISSISSIPPI RIVER VALLEY THIS MORNING WILL SPREAD SOME VIRGA/LIGHT SPOTTY PRECIP OVER THE AREA...NAMELY WEST AND SOUTH OF CHICAGO. THIS MAY EVEN INCLUDE SOME FLURRIES AT RFD EARLY THIS MORNING. AS FOR TONIGHT...THE LOW- LEVEL FLOW OFF OF LAKE MICHIGAN WILL VEER SOME...ALLOWING FOR THE LIKELIHOOD OF MVFR CIGS TO MOVE BACK INTO NORTHEAST IL. TIMING ON THIS COULD BE BE AS EARLY AS 02Z OR SO...BUT RIGHT NOW THINKING THE LATER ROUTE. THE CLOUD DEPTHS ARE SIMILAR TONIGHT AS TO WHAT THEY HAVE BEEN...SO AGAIN SOME SPRINKLES OR LIGHT SHOWERS THAT STRUGGLE TO MOVE VERY FAR INLAND ARE PROBABLE. THESE CLOUDS ARE LIKELY TO HANG IN THERE THROUGH THE MONDAY MORNING RUSH...THOUGH CONFIDENCE IS HIGH THEY WILL BE ABOVE 1500 FT...MORE TOWARD 2500-3500 FT. //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE FOR ALL ELEMENTS. LENNING //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...VFR. TUESDAY...SHRA LIKELY TUESDAY AFTERNOON WITH A CHC OTHERWISE DURING THE DAY AND NIGHT. CHC OF MVFR. WEDNESDAY-THURSDAY...VFR. FRIDAY...SLIGHT CHC OF -RA DURING THE NIGHT. SATURDAY...SLIGHT CHC OF -RA DURING THE DAY. MTF && .MARINE... 145 AM CST AFTER A WEEK STRAIGHT OF NORTHERLY WINDS AND HIGHER WAVES...QUIET WEATHER WILL PREVAIL INTO THE START OF THIS WEEK. WINDS MAY BE VARIABLE AT TIMES OVER THE LAKE BY LATER TONIGHT THROUGH MONDAY AS A HIGH PRESSURE RIDGE SLOWLY MOVES EAST OVER THE LAKE. WINDS WILL THEN TURN SOUTHERLY LATE MONDAY NIGHT INTO TUESDAY AHEAD OF A LOW MOVING QUICKLY SOUTHEAST ACROSS THE CANADIAN PRAIRIE PROVINCES. THIS ALREADY HAS A GOOD PRESSURE AND PRESSURE TENDENCY PATTERN SIGNAL TO RESULT IN 30 KT /OR POSSIBLY JUST HIGHER/ WINDS OVER THE NORTHERN PORTION OF THE LAKE AND WAVES BRIEFLY UP TOWARD 10 FT. AN ASSOCIATED COLD FRONT IS LIKELY TO MOVE THROUGH THE LAKE ON TUESDAY NIGHT...BUT THIS FRONT SHOULD BE SLOWING AND WEAKENING AS IT CROSSES THE LAKE. HIGH PRESSURE IS EXPECTED TO PREVAIL FOR A DAY OR TWO AFTER THIS TIME...BEFORE SOUTHERLY FLOW INTO NEXT WEEKEND. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1232 PM EST SUN NOV 4 2012 .UPDATE... ISSUED AT 1138 AM EST SUN NOV 4 2012 BASED OFF LATEST RADAR TRENDS AND HIGH RESOLUTION MODEL GUIDANCE...HAVE BUMPED UP THE ISOLATED FLURRIES TO ISOLATED SNOW SHOWERS /MIXED WITH RAIN THIS AFTERNOON NEAR THE LAKESHORE/. EXPECT A SIMILAR SITUATION TO OCCUR THIS AFTERNOON AS YESTERDAY AFTERNOON...WHERE DIURNAL AFFECTS WERE ABLE TO LIFT THE INVERSION A FEW HUNDRED FEET AND ENOUGH TO ENABLE ISOLATED SHOWERS WITH THE LAKE SUPERIOR SFC-H925 DELTA-T OF 13. HAVE CONTINUED THIS OVER THE NORTH CENTRAL AND KEWEENAW THROUGH THE NIGHT AND INTO TOMORROW MORNING...LARGELY FOLLOWING THE SLOWLY VEERING LIGHT FLOW FROM NORTH TO EAST THROUGH TOMORROW AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 443 AM EST SUN NOV 4 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A LONGWAVE PATTERN WITH A MID/UPPER LEVEL RIDGE INTO THE WRN CONUS AND A TROUGH OVER THE EAST. A SHRTWV TROUGH WAS LOCATED OVER NE IA WHILE A RIDGE EXTENDED FROM NORTH DAKOTA INTO NE MANITOBA LEAVING WEAK NRLY FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES EXTENDED FROM NRN MANITOBA AND NW ONTARIO THROUGH WRN LAKE SUPERIOR INTO WI RESULTING IN ACYC NRLY FLOW ACROSS LAKE SUPERIOR AND UPPER MI. SHALLOW MOISTURE TRAPPED BELOW A 2K-3K FT INVERSION WITH 925 MB TEMPS TO AROUND -6C HAS PROVIDED ENOUGH INSTABILITY TO SUPPORT ISOLATED LAKE EFFECT FLURRIES INTO N CNTRL UPPER MI. OTHERWISE...IR LOOP SHOWED LOW CLOUDS ACROSS NRN ONTARIO THROUGH THE CWA. SATELLITE TRENDS AND MODELS 925 RH SUGGEST THAT...SIMILAR TO YESTERDAY...THE LOW CLOUDS WILL PERSIST OVER THE AREA GIVEN LITTLE CHANGE IN THE TEMP PROFILE AND ONLY A GRADUAL WIND SHIFT. THERE MAY BE SOME AFTERNOON CLEARING AGAIN OVER THE SOUTHWEST...WHERE MIXING MAY HELP PUSH THE EDGE OF THE CLOUDS BACK TO THE NORTHEAST. EVEN THOUGH INSTABILITY AND THE WIND FIELDS REMAIN WEAK...SOME ISOLATED/INTERMITTENT FLURRIES WILL REMAIN POSSIBLE OVER N CNTRL UPPER MI INTO THIS EVENING AS WINDS GRADUALLY VEER TO THE EAST...PER HIGH RES MODELS. THE CLOUDS SHOULD ALSO KEEP TEMPS IN A NARROW RANGE WITH HIGHS TODAY ONLY INTO THE MID AND UPPER 30S NORTH TO AROUND 40 SOUTH. WITH LINGERING CLOUDS TONIGHT...EXPECT MIN READINGS TOWARD THE HIGHER END OF GUIDANCE IN THE UPPER 20S TO AROUND 30. HOWEVER... IF SOME CLEARING DEVELOPS OVER THE SW TEMPS COULD FALL OFF QUICKLY TO NEAR 20. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 443 AM EST SUN NOV 4 2012 THE 500MB WAVE CURRENTLY OVER SW CANADA WILL BE OVER THE CENTRAL PLAINS BY DAYBREAK MONDAY...WITH A REINFORCING LOW SWINGING OVER SE CANADA FROM HUDSON BAY. IN BETWEEN THESE 2 SYSTEMS UPPER MI WILL REMAIN UNDER HIGH PRESSURE AT THE SFC AND ALOFT. SW WINDS WILL BE ON THE INCREASE MONDAY NIGHT /850MB WINDS OF 20-30KTS WITH 850MB TEMPS RISING FROM -6C TO -2C/...IN ADVANCE OF THE NEARING LOW FROM THE NW. PRECIPITATION WILL BEGIN LATE MONDAY EVENING...AND BECOME LIKELY ACROSS THE ENTIRE AREA AROUND DAYBREAK TUESDAY. AROUND AN INCH OF WET SNOW WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY MORNING OVER THE HIGHER TERRAIN OF MQT...AND SE BARAGA...AND NE IRON COUNTIES...WITH THE HELP OF A POCKET OF COOLER AIR WITH SFC TEMPS EXPECTED TO REMAIN IN THE 30S THROUGH THE DAY TUESDAY. S WINDS OFF LAKE MI COULD BECOME BREEZY AT TIMES OVER THE E HALF NEAR THE GREAT LAKES SHORELINES...BUT BELOW ANY ADVISORY VALUES. THE BULK OF THE MOISTURE SHOULD EXIT TUESDAY EVENING AS THE S EXTENT OF THE ELONGATED LOW STRETCHING FROM NE MANITOBA THROUGH E LAKE SUPERIOR EXITS EASTWARD AND TEMPORARILY GETS REPLACED BY A RIDGE FROM THE SW. WHILE TIMING OF THE VARIOUS FCST MODELS IS STILL A LITTLE UNCERTAIN...THEY ARE CONSISTENT WITH THE 500MB LOW OR TROUGH DIGGING ACROSS THE UPPER GREAT LAKES TUESDAY NIGHT AND INTENSIFYING OFF THE MID ATLANTIC AS IT MERGES WITH ANOTHER WAVE ON THE S EDGE OF THE LARGER TROUGH THAT COVERS THE E HALF OF THE NATION. LAKE EFFECT/LAKE ENHANCED CLOUDS AND PRECIP SHOULD LINGER INTO WEDNESDAY...WITH THE POTENTIAL FOR BOTH RAIN AND SNOW CONTINUING. OTHERWISE FOR THE END OF THE WORK WEEK...WITH HIGH PRESSURE OVERHEAD IN BETWEEN A STRONGER SYSTEM OFF THE EASTERN SEABOARD AND ANOTHER LOW DEVELOPING OFF THE ROCKIES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1232 PM EST SUN NOV 4 2012 STRONG INVERSION AROUND 3KFT ABOVE THE SURFACE HAS CONTINUED TO TRAP CLOUDS OVER THE LAKE SUPERIOR REGION TODAY. WITH HIGH PRESSURE TO THE NORTH CONTINUING LIGHT NORTHERLY FLOW THROUGH THIS EVENING AND THEN VEERING TO THE EAST OVERNIGHT...EXPECT THE MVFR CLOUDS TO REMAIN IN PLACE AT KCMX/KSAW. ALSO EXPECT OCCASIONAL SNOW SHOWERS TO AFFECT KCMX THROUGH MUCH OF THE PERIOD...BUT ONLY THROUGH EARLY EVENING AT KSAW SINCE WINDS WILL BEGIN TO TURN UNFAVORABLE. SINCE CEILINGS ARE ALREADY AT MVFR LEVELS...DIDN/T TRY TO TIME THE BRIEF VISIBILITY REDUCTIONS WITH THE SHOWERS. AS FOR KIWD...DAYTIME MIXING IS STARTING TO BREAK UP CLOUDS AND NORTHERN WISCONSIN AND EXPECT THAT TO CONTINUE NORTH TO THIS AFTERNOON. AS HAS HAPPENED THE LAST TWO NIGHTS...EXPECT THE BREAKS TO BE SHORT LIVED...AS LIGHT NORTHEAST AND THEN EAST FLOW WILL LIKELY PUSH THE LOW CLOUDS BACK IN AFTER SUNSET. IF CLOUDS RETREAT FARTHER NORTH THAN EXPECTED...THE CLOUDS MAY STRUGGLE TO DROP BACK INTO KIWD WITH THE LIGHT WINDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST SUN NOV 4 2012 AS HIGH PRESSURE OVER NORTHWEST ONTARIO SLIDES SOUTHEAST THROUGH THE UPPER GREAT LAKES THROUGH MONDAY...EXPECT WINDS TO BE LIGHT AND LESS THAN 15KTS. A LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA ON TUESDAY WILL SWEEP A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION AND BRING INCREASING SOUTHWESTERLY WINDS TO 20-30 KTS. A WEAK HIGH PRESSURE RIDGE WILL THEN SLIDE INTO THE UPPER GREAT LAKES WEDNESDAY AFTERNOON AND REMAIN INTO FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLB LONG TERM...KF AVIATION...SRF MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1138 AM EST SUN NOV 4 2012 .UPDATE... ISSUED AT 1138 AM EST SUN NOV 4 2012 BASED OFF LATEST RADAR TRENDS AND HIGH RESOLUTION MODEL GUIDANCE...HAVE BUMPED UP THE ISOLATED FLURRIES TO ISOLATED SNOW SHOWERS /MIXED WITH RAIN THIS AFTERNOON NEAR THE LAKESHORE/. EXPECT A SIMILAR SITUATION TO OCCUR THIS AFTERNOON AS YESTERDAY AFTERNOON...WHERE DIURNAL AFFECTS WERE ABLE TO LIFT THE INVERSION A FEW HUNDRED FEET AND ENOUGH TO ENABLE ISOLATED SHOWERS WITH THE LAKE SUPERIOR SFC-H925 DELTA-T OF 13. HAVE CONTINUED THIS OVER THE NORTH CENTRAL AND KEWEENAW THROUGH THE NIGHT AND INTO TOMORROW MORNING...LARGELY FOLLOWING THE SLOWLY VEERING LIGHT FLOW FROM NORTH TO EAST THROUGH TOMORROW AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 443 AM EST SUN NOV 4 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A LONGWAVE PATTERN WITH A MID/UPPER LEVEL RIDGE INTO THE WRN CONUS AND A TROUGH OVER THE EAST. A SHRTWV TROUGH WAS LOCATED OVER NE IA WHILE A RIDGE EXTENDED FROM NORTH DAKOTA INTO NE MANITOBA LEAVING WEAK NRLY FLOW THROUGH THE NRN GREAT LAKES. AT THE SFC...HIGH PRES EXTENDED FROM NRN MANITOBA AND NW ONTARIO THROUGH WRN LAKE SUPERIOR INTO WI RESULTING IN ACYC NRLY FLOW ACROSS LAKE SUPERIOR AND UPPER MI. SHALLOW MOISTURE TRAPPED BELOW A 2K-3K FT INVERSION WITH 925 MB TEMPS TO AROUND -6C HAS PROVIDED ENOUGH INSTABILITY TO SUPPORT ISOLATED LAKE EFFECT FLURRIES INTO N CNTRL UPPER MI. OTHERWISE...IR LOOP SHOWED LOW CLOUDS ACROSS NRN ONTARIO THROUGH THE CWA. SATELLITE TRENDS AND MODELS 925 RH SUGGEST THAT...SIMILAR TO YESTERDAY...THE LOW CLOUDS WILL PERSIST OVER THE AREA GIVEN LITTLE CHANGE IN THE TEMP PROFILE AND ONLY A GRADUAL WIND SHIFT. THERE MAY BE SOME AFTERNOON CLEARING AGAIN OVER THE SOUTHWEST...WHERE MIXING MAY HELP PUSH THE EDGE OF THE CLOUDS BACK TO THE NORTHEAST. EVEN THOUGH INSTABILITY AND THE WIND FIELDS REMAIN WEAK...SOME ISOLATED/INTERMITTENT FLURRIES WILL REMAIN POSSIBLE OVER N CNTRL UPPER MI INTO THIS EVENING AS WINDS GRADUALLY VEER TO THE EAST...PER HIGH RES MODELS. THE CLOUDS SHOULD ALSO KEEP TEMPS IN A NARROW RANGE WITH HIGHS TODAY ONLY INTO THE MID AND UPPER 30S NORTH TO AROUND 40 SOUTH. WITH LINGERING CLOUDS TONIGHT...EXPECT MIN READINGS TOWARD THE HIGHER END OF GUIDANCE IN THE UPPER 20S TO AROUND 30. HOWEVER... IF SOME CLEARING DEVELOPS OVER THE SW TEMPS COULD FALL OFF QUICKLY TO NEAR 20. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 443 AM EST SUN NOV 4 2012 THE 500MB WAVE CURRENTLY OVER SW CANADA WILL BE OVER THE CENTRAL PLAINS BY DAYBREAK MONDAY...WITH A REINFORCING LOW SWINGING OVER SE CANADA FROM HUDSON BAY. IN BETWEEN THESE 2 SYSTEMS UPPER MI WILL REMAIN UNDER HIGH PRESSURE AT THE SFC AND ALOFT. SW WINDS WILL BE ON THE INCREASE MONDAY NIGHT /850MB WINDS OF 20-30KTS WITH 850MB TEMPS RISING FROM -6C TO -2C/...IN ADVANCE OF THE NEARING LOW FROM THE NW. PRECIPITATION WILL BEGIN LATE MONDAY EVENING...AND BECOME LIKELY ACROSS THE ENTIRE AREA AROUND DAYBREAK TUESDAY. AROUND AN INCH OF WET SNOW WILL BE POSSIBLE MONDAY NIGHT INTO TUESDAY MORNING OVER THE HIGHER TERRAIN OF MQT...AND SE BARAGA...AND NE IRON COUNTIES...WITH THE HELP OF A POCKET OF COOLER AIR WITH SFC TEMPS EXPECTED TO REMAIN IN THE 30S THROUGH THE DAY TUESDAY. S WINDS OFF LAKE MI COULD BECOME BREEZY AT TIMES OVER THE E HALF NEAR THE GREAT LAKES SHORELINES...BUT BELOW ANY ADVISORY VALUES. THE BULK OF THE MOISTURE SHOULD EXIT TUESDAY EVENING AS THE S EXTENT OF THE ELONGATED LOW STRETCHING FROM NE MANITOBA THROUGH E LAKE SUPERIOR EXITS EASTWARD AND TEMPORARILY GETS REPLACED BY A RIDGE FROM THE SW. WHILE TIMING OF THE VARIOUS FCST MODELS IS STILL A LITTLE UNCERTAIN...THEY ARE CONSISTENT WITH THE 500MB LOW OR TROUGH DIGGING ACROSS THE UPPER GREAT LAKES TUESDAY NIGHT AND INTENSIFYING OFF THE MID ATLANTIC AS IT MERGES WITH ANOTHER WAVE ON THE S EDGE OF THE LARGER TROUGH THAT COVERS THE E HALF OF THE NATION. LAKE EFFECT/LAKE ENHANCED CLOUDS AND PRECIP SHOULD LINGER INTO WEDNESDAY...WITH THE POTENTIAL FOR BOTH RAIN AND SNOW CONTINUING. OTHERWISE FOR THE END OF THE WORK WEEK...WITH HIGH PRESSURE OVERHEAD IN BETWEEN A STRONGER SYSTEM OFF THE EASTERN SEABOARD AND ANOTHER LOW DEVELOPING OFF THE ROCKIES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 644 AM EST SUN NOV 4 2012 WITH LIGHT NNE FLOW OFF OF LAKE SUPERIOR ON THE SOUTHERN FLANK OF HIGH PRES IN ONTARIO AND A SHARP SUBSIDENCE INVERSION...EXPECT MVFR CIGS TO PERSIST THIS FCST PERIOD. THE BEST CHANCE FOR VFR CONDITIONS WILL BE THIS AFTERNOON AT IWD...WHERE THE COMBINATION OF DIURNAL HEATING AND DOWNSLOPING NE FLOW WILL HAVE A BETTER CHANCE OF DISSIPATING THE LOW CLOUDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 443 AM EST SUN NOV 4 2012 AS HIGH PRESSURE OVER NORTHWEST ONTARIO SLIDES SOUTHEAST THROUGH THE UPPER GREAT LAKES THROUGH MONDAY...EXPECT WINDS TO BE LIGHT AND LESS THAN 15KTS. A LOW PRESSURE SYSTEM MOVING THROUGH CENTRAL CANADA ON TUESDAY WILL SWEEP A SURFACE TROUGH ACROSS THE UPPER GREAT LAKES REGION AND BRING INCREASING SOUTHWESTERLY WINDS TO 20-30 KTS. A WEAK HIGH PRESSURE RIDGE WILL THEN SLIDE INTO THE UPPER GREAT LAKES WEDNESDAY AFTERNOON AND REMAIN INTO FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
233 PM CST SUN NOV 4 2012 .SHORT TERM... ISSUED AT 233 PM CST SUN NOV 4 2012 (TONIGHT) POTENT LITTLE SHORTWAVE IS DEVELOPING OVER NORTHEAST MONTANA...AND WILL DIVE SOUTHEAST THROUGH THE GREAT PLAINS TONIGHT. THE SURFACE REFLECTION OF THIS WAVE WILL LIKEWISE DROP SOUTHEAST INTO THE PLAINS AND LINK UP WITH A BROAD/RELATIVELY WEAK AREA OF LOW PRESSURE CURRENTLY SITTING OVER KANSAS. THE COMBINED SURFACE TROF WILL STRENGTHEN SLIGHTLY AS IT MOVES INTO NORTHWEST MISSOURI LATE TONIGHT. MODELS ARE IN GOOD AGREEMENT IN SPREADING A SWATH OF RAIN OUT SOUTHEAST AHEAD OF THE SHORTWAVE. THE ONSET OF PRECIP LOOKS FASTER THAN PREVIOUSLY THOUGHT...THE HRRR IS ESPECIALLY FAST BRINGING PRECIP INTO CENTRAL MO AS EARLY AS 03Z...AND SPREADING TO NEAR THE MISSISSIPPI RIVER BY 06Z. AM STICKING CLOSER TO THE OPERATIONAL NAM AND GFS SOLUTIONS WHICH ARE 3-6HRS SLOWER...BUT WILL BRIEF THE EVENING SHIFT TO WATCH FOR A FASTER ONSET OF RAIN. CARNEY && .LONG TERM... ISSUED AT 233 PM CST SUN NOV 4 2012 (MONDAY THROUGH SUNDAY) NORTHWEST FLOW ALIVE AND WELL ACROSS THE CENTER OF THE NATION AS A DEEP LONGWAVE TROF CONTINUES TO BE CARVED OUT ACROSS THE EASTERN CONUS. SHORTWAVE OF INTEREST IN THE SHORT TERM WILL CONTINUE TO DIVE SOUTHEAST INTO THE BASE OF THIS LONGWAVE TROF AND BE RESPONSIBLE FOR THE DEVELOPMENT OF A POWERFUL STORM SYSTEM THAT WILL MOVE UP THE EAST COAST DURING THE MIDDLE PORTION OF THIS WEEK. THIS WILL CERTAINLY BE THE NATIONS WEATHER STORY...AS THE NOR`EASTER BRINGS STRONG WIND...RAIN...AND EVEN SOME WINTER WEATHER TO AREAS STILL REELING FROM SANDY. MONDAY AND MONDAY NIGHT... MODEL GUIDANCE IN VERY GOOD AGREEMENT REGARDING THE TRACK OF THE SHORTWAVE ACROSS MISSOURI. AREA OF LIGHT RAIN WILL WORK ITS WAY SOUTH ACROSS THE REGION WITH THICK CLOUD COVER AND CHILLY TEMPERATURES. HAVE WENT A DEGREE OR TWO BELOW THE LOWEST MODEL GUIDANCE. RAIN SHOULD PUSH SOUTH OF THE AREA BY MONDAY NIGHT...BUT CLOUDS WILL HANG TOUGH IN THE WAKE OF THIS SYSTEM. HAVE KEPT TEMPERATURES WARMER THAN GUIDANCE WOULD SUGGEST...WITH A LIMITED DIURNAL TEMPERATURE SWING. TUESDAY AND WEDNESDAY... A FINAL SHORTWAVE...THE CABOOSE...WILL TRACK ACROSS THE WESTERN GREAT LAKES...PUSHING A FINAL COLD FRONT ACROSS THE AREA. LIMITED MOISTURE AND AN EASTERN TRACK TO THE DISTURBANCE KEEPS POPS AT SLIGHT CHANCE AND CONFINED TO ILLINOIS COUNTIES. SURFACE RIDGE OF HIGH PRESSURE WILL THEN BUILD ACROSS THE CWA ON WEDNESDAY WITH DRY WEATHER AND SEASONAL TEMPERATURES. THURSDAY THROUGH SUNDAY... THE UPPER AIR PATTERN WILL FINALLY TRANSITION BY WEEKS END AS A MASSIVE STORM SYSTEM CARVES A LONGWAVE TROF ACROSS THE WESTERN CONUS WHICH HELPS AMPLIFY A RIDGE DOWNSTREAM ACROSS THE EASTERN CONUS. THE END RESULT WILL BE SOUTHWEST FLOW ACROSS THE MIDWEST AND ABOVE NORMAL TEMPERATURES. THIS LARGE UPPER TROF WILL BE PROGRESSIVE WITH RAIN CHANCES INCREASING SUNDAY AND SUNDAY NIGHT. CVKING && .AVIATION... ISSUED AT 1141 AM CST SUN NOV 4 2012 VFR FLIGHT CONDITIONS AND LIGHT VARIABLE WIND WILL PREVAIL THIS AFTERNOON AS HIGH PRESSURE DRIFTS ACROSS THE AREA. THERE MAY BE A SPRINKLE OR TWO OUT OF A MID CLOUD DECK STRETCHING ACROSS NORTHEAST MISSOURI...BUT EXPECT NO IMPACTS FROM THIS VERY LIGHT PRECIPITATION. A STORM WILL MOVE FROM THE NORTHERN GREAT PLAINS ACROSS THE MISSOURI VALLEY TONIGHT...BRINGING RAIN AND MVFR CIGS/VSBYS TO THE AREA BY MONDAY MORNING. WOULD NOT BE SURPRISED TO SEE AREAS OF IFR CIGS DEVELOP BEFORE 18Z MONDAY. SPECIFICS FOR KSTL... VFR FLIGHT CONDITIONS AND LIGHT VARIABLE WIND WILL PREVAIL AT LAMBERT THIS AFTERNOON AS HIGH PRESSURE DRIFTS ACROSS THE AREA. A STORM WILL MOVE FROM THE NORTHERN GREAT PLAINS ACROSS THE MISSOURI VALLEY TONIGHT...BRINGING RAIN AND MVFR CIGS/VSBYS TO THE TERMINAL BETWEEN 12Z AND 14Z MONDAY MORNING. WHILE NO IFR CONDITIONS ARE IN THE TAF AT THIS TIME...WOULD NOT BE SURPRISED TO SEE CIGS FALL TO IFR AFTER 18Z MONDAY AS THE STORM SYSTEM PASSES JUST TO THE WEST OF THE TERMINAL. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
350 PM EST SUN NOV 4 2012 .SYNOPSIS... HIGH PRESSURE ON MONDAY WILL GIVE WAY TO A DEVELOPING COASTAL STORM MONDAY NIGHT AND TUESDAY. THIS NOREASTER WILL TRACK UP THE EAST COAST IN MID WEEK AS HIGH PRESSURE PREVAILS OVER OUR REGION FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... SMALL AREA OF SHRA COINCIDENT WITH THE COLD FRONT ENTERING THE CWFA ATTM. RAP AND HRRR TAKE THIS AREA ACROSS NE GA AND THE UPSTATE AND EAST OF THE CWFA BY ABOUT 01Z. THIS LOOKS REASONABLE GIVEN CURRENT CONDITIONS. EXPECT ONLY A FEW HUNDREDTHS OF QPF AT MOST WITH THESE SHRA. SKIES SHUD CLEAR BEHIND THE PRECIP AS DRIER AIR WORKS IN BEHIND THE FRONT. A COOL AIR MASS MOVES IN AS WELL...BUT THE PRESSURE GRADIENT DOES NOT RELAX UNTIL NEARLY DAYBREAK AS HIGH PRESSURE BUILDS IN OVERNIGHT. STILL...EXPECT TEMPS A FEW DEGREES BELOW NORMAL...SO WITH CLEARING SKIES AND LIGHT WINDS...PATCHY FROST WILL DEVELOP ACROSS THE I-40 CORRIDOR. HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA FROM THE NORTH ON MONDAY. THE BULK OF THE DAY SHUD BE MOSTLY SUNNY...BUT CLOUDS WILL INCREASE ACROSS THE WRN CWFA LATE IN THE DAY AHEAD OF THE NEXT WX SYSTEM. AFTER A INCREASE IN N TO NELY WINDS WITH MIXING...WINDS BECOME LIGHT FOR THE AFTERNOON. HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 215 PM SUNDAY...MODELS ARE IN GOOD AGREEMENT WITH THE DEEP-DIGGING SHORTWAVE MONDAY NIGHT AND TUESDAY...TRENDING FURTHER SOUTH WITH THE SYSTEM AND KEEPING IT FAIRLY COMPACT AS IT ENTERS THE CAROLINA COASTAL WATERS. TAKING A BLEND...POPS WERE CUT BACK...ESP IN THE NORTHERN ZONES. TEMPS ARE TRICKY...AS MODEST SFC HIGH PRES WILL WEDGE DOWN THE EASTERN SIDE OF THE APPALACHIANS. GUIDANCE HAS TRENDED WARMER...PROBABLY DUE TO LTL IF ANY PRECIP DURING THE DAY ON TUESDAY. ONLY TWEAKED THE TEMPS FOR BOTH MONDAY NIGHT AND TUESDAY. THE 00Z ECMWF STILL HAS THE MOST QPF ALONG THE SOUTHERN FRINGE OF THE CWFA...THANKS TO A BAND OF MID LVL FRONTOGENESIS. A VERY TIGHT GRADIENT OF POPS IS LIKELY ON THE NORTH SIDE OF THIS SYSTEM...MAKING FOR A BELOW AVERAGE CONFIDENCE FCST FOR THE CHARLOTTE AREA. IN ANY CASE...IT WILL BE COOL...WITH TEMPS ABOUT 10-15 DEG BELOW NORMAL. TUESDAY NIGHT AND WEDNESDAY...A NORTHERN STREAM SHORTWAVE WILL DIVE SE INTO THE OHIO VALLEY AND CROSS THE CWFA BY MIDDAY WEDNESDAY. MODELS HAVE TRENDED A LITTLE WETTER WITH THIS FEATURE...BRINGING LLVL FLOW AROUND TO NW AND INCREASING DURING THE DAY. THE BEST UPSLOPE DOES NOT LINE UP WITH THE MID-UPR QG FORCING HOWEVER. SO WILL GO WITH A CHC POP ALONG THE TN LINE DURING THESE PERIODS. ONLY LIGHT SNOW ACCUM EXPECTED IN THE HIGHEST ELEVATIONS ALONG THE TN LINE. OTHERWISE...DOWNSLOPE AND SUBSIDENCE BEHIND THE MAIN LOW PRES SYSTEM THAT WILL BE LIFTING NE ALONG THE EASTERN SEABOARD. THICKNESSES REMAIN LOW...SUCH THAT THE MOS GUIDANCE SEEMS TOO WARM. WILL UNDERCUT MOS SLIGHTLY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 200 PM SUNDAY...THE LATEST MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT A PERIOD OF NW FLOW PRECIP OVER THE NC MOUNTAINS/VALLEYS WILL CONTINUE THROUGH WEDNESDAY EVENING AS AN ADDITIONAL UPPER ENERGY AND MOISTURE ROTATES IN BEHIND THE DEPARTING LOW PRESSURE. EXPECT MAINLY RAIN SHOWERS WITH SOME SNOW POSSIBLE IN THE HIGHER ELEVATIONS ALONG THE NC/TN BORDER AFTER SUNSET. WEDNESDAY NIGHT THROUGH SUNDAY...BOTH THE LATEST GFS AND ECMWF MODELS ARE IN GOOD AGREEMENT ON CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE EAST COAST STORM BY WED NIGHT AND LINGER INTO EARLY NEXT WEEK. THIS WILL RESULT IN CLEAR SKIES WITH TEMPERATURES GRADUALLY WARMING BACK TO NORMAL BY END OF THE WEEK. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... AT KCLT...VFR THROUGH THE PERIOD. STILL LOOKS LIKE ONLY SCT LOW VFR CLOUDS WILL MOVE IN FOR THE AFTERNOON. HOWEVER...CANNOT COMPLETELY RULE OUT A BRIEF CIG THIS AFTERNOON. OTHERWISE...STILL EXPECT ANY CONVECTION TO BE WELL SOUTH OF THE AIRFIELD THIS AFTERNOON AND EARLY EVENING WITH THE FRONT REMAINING SOUTH OF THE AIRFIELD. SYNOPTIC AND MESOSCALE GUIDANCE ALL SHOW THIS TREND AS WELL. EXPECT NLY WIND TO BECOME NNE THIS EVENING. THERE COULD BE SOME LOW END GUSTS FROM TIME TO TIME...BUT TIMING REMAINS PROBLEMATIC. EXPECT CLEARING SKIES AFTER MIDNIGHT CONTINUING THRU MON MORN. NNE WIND WILL SHOW AN UPTICK IN SPEED BY MID MORNING AS MIXING RETURNS. ELSEWHERE...VERY SIMILAR PROGRESSION AS WITH KCLT...BUT WIND WILL BE FURTHER COMPLICATED OVER THE SC SITES BY MOVEMENT OF SFC LOW ALONG THE FRONT. IN GENERAL...WINDS ACROSS NC WILL REMAIN N TO NE...WHILE WINDS AT KAND WILL GO FROM W TO NW TO N BY EVENING. KGSP/KGMU WILL BE LIGHT AND VARIABLE BECOMING NNE. N TO NE WIND WILL CONTINUE OVERNIGHT AND THRU THE MORNING MONDAY. KAVL WILL SEE GUSTS INTO EARLY EVENING. THE SC SITES COULD SEE LOW END GUSTS AS WELL. KAND HAS THE BEST CHC OF SEEING ANY CONVECTION THIS AFTERNOON...BUT EVEN THERE CHC IS TOO LOW FOR TAF MENTION. OTHERWISE...SCT LOW VFR AND BKN CIRRUS WILL CLEAR OUT AFTER MIDNIGHT AND CONTINUE MON MORNING. CANNOT RULE OUT A BRIEF LOW VFR CIG THIS AFTERNOON HOWEVER. OUTLOOK...DRY FCST CONTINUES MONDAY AFTERNOON BEFORE ANOTHER SYSTEM RETURNS FROM THE WEST MONDAY NIGHT AND TUESDAY. RESTRICTIONS LOOK POSSIBLE WITH THE TUESDAY SYSTEM...WHICH COULD STRENGTHEN RAPIDLY OFF THE SE COAST THROUGH MID WEEK. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...RWH SHORT TERM...ARK LONG TERM...JOH AVIATION...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
240 PM EST SUN NOV 4 2012 .SYNOPSIS... HIGH PRESSURE ON MONDAY WILL GIVE WAY TO A DEVELOPING COASTAL STORM MONDAY NIGHT AND TUESDAY. THIS NOREASTER WILL TRACK UP THE EAST COAST IN MID WEEK AS HIGH PRESSURE PREVAILS OVER OUR REGION FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... SMALL AREA OF SHRA COINCIDENT WITH THE COLD FRONT ENTERING THE CWFA ATTM. RAP AND HRRR TAKE THIS AREA ACROSS NE GA AND THE UPSTATE AND EAST OF THE CWFA BY ABOUT 01Z. THIS LOOKS REASONABLE GIVEN CURRENT CONDITIONS. EXPECT ONLY A FEW HUNDREDTHS OF QPF AT MOST WITH THESE SHRA. SKIES SHUD CLEAR BEHIND THE PRECIP AS DRIER AIR WORKS IN BEHIND THE FRONT. A COOL AIR MASS MOVES IN AS WELL...BUT THE PRESSURE GRADIENT DOES NOT RELAX UNTIL NEARLY DAYBREAK AS HIGH PRESSURE BUILDS IN OVERNIGHT. STILL...EXPECT TEMPS A FEW DEGREES BELOW NORMAL...SO WITH CLEARING SKIES AND LIGHT WINDS...PATCHY FROST WILL DEVELOP ACROSS THE I-40 CORRIDOR. HIGH PRESSURE CONTINUES TO BUILD INTO THE AREA FROM THE NORTH ON MONDAY. THE BULK OF THE DAY SHUD BE MOSTLY SUNNY...BUT CLOUDS WILL INCREASE ACROSS THE WRN CWFA LATE IN THE DAY AHEAD OF THE NEXT WX SYSTEM. AFTER A INCREASE IN N TO NELY WINDS WITH MIXING...WINDS BECOME LIGHT FOR THE AFTERNOON. HIGHS WILL BE 5 TO 10 DEGREES BELOW NORMAL. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... AS OF 215 PM SUNDAY...MODELS ARE IN GOOD AGREEMENT WITH THE DEEP-DIGGING SHORTWAVE MONDAY NIGHT AND TUESDAY...TRENDING FURTHER SOUTH WITH THE SYSTEM AND KEEPING IT FAIRLY COMPACT AS IT ENTERS THE CAROLINA COASTAL WATERS. TAKING A BLEND...POPS WERE CUT BACK...ESP IN THE NORTHERN ZONES. TEMPS ARE TRICKY...AS MODEST SFC HIGH PRES WILL WEDGE DOWN THE EASTERN SIDE OF THE APPALACHIANS. GUIDANCE HAS TRENDED WARMER...PROBABLY DUE TO LTL IF ANY PRECIP DURING THE DAY ON TUESDAY. ONLY TWEAKED THE TEMPS FOR BOTH MONDAY NIGHT AND TUESDAY. THE 00Z ECMWF STILL HAS THE MOST QPF ALONG THE SOUTHERN FRINGE OF THE CWFA...THANKS TO A BAND OF MID LVL FRONTOGENESIS. A VERY TIGHT GRADIENT OF POPS IS LIKELY ON THE NORTH SIDE OF THIS SYSTEM...MAKING FOR A BELOW AVERAGE CONFIDENCE FCST FOR THE CHARLOTTE AREA. IN ANY CASE...IT WILL BE COOL...WITH TEMPS ABOUT 10-15 DEG BELOW NORMAL. TUESDAY NIGHT AND WEDNESDAY...A NORTHERN STREAM SHORTWAVE WILL DIVE SE INTO THE OHIO VALLEY AND CROSS THE CWFA BY MIDDAY WEDNESDAY. MODELS HAVE TRENDED A LITTLE WETTER WITH THIS FEATURE...BRINGING LLVL FLOW AROUND TO NW AND INCREASING DURING THE DAY. THE BEST UPSLOPE DOES NOT LINE UP WITH THE MID-UPR QG FORCING HOWEVER. SO WILL GO WITH A CHC POP ALONG THE TN LINE DURING THESE PERIODS. ONLY LIGHT SNOW ACCUM EXPECTED IN THE HIGHEST ELEVATIONS ALONG THE TN LINE. OTHERWISE...DOWNSLOPE AND SUBSIDENCE BEHIND THE MAIN LOW PRES SYSTEM THAT WILL BE LIFTING NE ALONG THE EASTERN SEABOARD. THICKNESSES REMAIN LOW...SUCH THAT THE MOS GUIDANCE SEEMS TOO WARM. WILL UNDERCUT MOS SLIGHTLY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 200 PM SUNDAY...THE LATEST MEDIUM RANGE MODELS CONTINUE TO INDICATE THAT A PERIOD OF NW FLOW PRECIP ALONG THE NC/TN BORDER WILL CONTINUE THROUGH WEDNESDAY EVENING AS AN ADDITIONAL UPPER ENERGY AND MOISTURE ROTATES IN BEHIND THE DEPARTING LOW PRESSURE. THERE WILL BE NO PRECIP TYPE ISSUE AS THE TEMPS REMAIN ABOVE FREEZING LEVEL DURING THIS PERIOD. WEDNESDAY NIGHT THROUGH SUNDAY...BOTH THE LATEST GFS AND ECMWF MODELS ARE IN GOOD AGREEMENT ON CANADIAN HIGH PRESSURE BUILDING IN BEHIND THE EAST COAST STORM BY WED NIGHT AND LINGER INTO EARLY NEXT WEEK. THIS WILL RESULT IN CLEAR SKIES WITH TEMPERATURES GRADUALLY WARMING BACK TO NORMAL BY END OF THE WEEK. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... AT KCLT...VFR THROUGH THE PERIOD. STILL LOOKS LIKE ONLY SCT LOW VFR CLOUDS WILL MOVE IN FOR THE AFTERNOON. HOWEVER...CANNOT COMPLETELY RULE OUT A BRIEF CIG THIS AFTERNOON. OTHERWISE...STILL EXPECT ANY CONVECTION TO BE WELL SOUTH OF THE AIRFIELD THIS AFTERNOON AND EARLY EVENING WITH THE FRONT REMAINING SOUTH OF THE AIRFIELD. SYNOPTIC AND MESOSCALE GUIDANCE ALL SHOW THIS TREND AS WELL. EXPECT NLY WIND TO BECOME NNE THIS EVENING. THERE COULD BE SOME LOW END GUSTS FROM TIME TO TIME...BUT TIMING REMAINS PROBLEMATIC. EXPECT CLEARING SKIES AFTER MIDNIGHT CONTINUING THRU MON MORN. NNE WIND WILL SHOW AN UPTICK IN SPEED BY MID MORNING AS MIXING RETURNS. ELSEWHERE...VERY SIMILAR PROGRESSION AS WITH KCLT...BUT WIND WILL BE FURTHER COMPLICATED OVER THE SC SITES BY MOVEMENT OF SFC LOW ALONG THE FRONT. IN GENERAL...WINDS ACROSS NC WILL REMAIN N TO NE...WHILE WINDS AT KAND WILL GO FROM W TO NW TO N BY EVENING. KGSP/KGMU WILL BE LIGHT AND VARIABLE BECOMING NNE. N TO NE WIND WILL CONTINUE OVERNIGHT AND THRU THE MORNING MONDAY. KAVL WILL SEE GUSTS INTO EARLY EVENING. THE SC SITES COULD SEE LOW END GUSTS AS WELL. KAND HAS THE BEST CHC OF SEEING ANY CONVECTION THIS AFTERNOON...BUT EVEN THERE CHC IS TOO LOW FOR TAF MENTION. OTHERWISE...SCT LOW VFR AND BKN CIRRUS WILL CLEAR OUT AFTER MIDNIGHT AND CONTINUE MON MORNING. CANNOT RULE OUT A BRIEF LOW VFR CIG THIS AFTERNOON HOWEVER. OUTLOOK...DRY FCST CONTINUES MONDAY AFTERNOON BEFORE ANOTHER SYSTEM RETURNS FROM THE WEST MONDAY NIGHT AND TUESDAY. RESTRICTIONS LOOK POSSIBLE WITH THE TUESDAY SYSTEM...WHICH COULD STRENGTHEN RAPIDLY OFF THE SE COAST THROUGH MID WEEK. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...RWH SHORT TERM...ARK LONG TERM...JOH AVIATION...RWH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1155 AM CST SUN NOV 4 2012 .SHORT TERM...THROUGH TUESDAY 141 AM CST SUN NOV 4 2012 MAIN FORECAST CONCERN IS WITH THE PRECIPITATION CHANCES TONIGHT INTO MONDAY MORNING AND AGAIN MONDAY NIGHT INTO TUESDAY. SURFACE ANALYSIS THIS MORNING SHOWS A LARGE AREA OF HIGH PRESSURE REMAINS ANCHORED OVER WESTERN ONTARIO WITH THE RIDGE AXIS SOUTH INTO THE REGION. WATER VAPOR SATELLITE THIS MORNING SHOWS AN UPPER LEVEL LOW OVER SOUTHEAST MINNESOTA. LOCAL RADAR AND SURFACE OBS INDICATE A LITTLE BIT OF LIGHT PRECIPITATION IS HITTING THE GROUND ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA. THIS ACTIVITY IS MOVING TO THE SOUTHEAST AND BASED ON THE 04.03Z HRRR AND 04.00Z HI-RES ARW AND NMM...THIS ACTIVITY SHOULD BE SOUTH OF THE FORECAST AREA BY 12Z AND AT THIS POINT...DO NOT PLAN TO INCLUDE ANY MENTION OF THIS IN THE TODAY PORTION OF THE FORECAST. THE NEXT SHORT WAVE TROUGH CAN BE SEEN MOVING ACROSS SOUTHERN ALBERTA AND SASKATCHEWAN. THIS WAVE IS EXPECTED TO ADVANCE QUICKLY INTO THE REGION ON THE FAST NORTHWEST FLOW ALOFT. AS THE WAVE APPROACHES THE REGION...ANOTHER UPPER LEVEL LOW IS EXPECTED TO FORM AND PASS OVER MINNESOTA INTO IOWA WITH THE BULK OF THE SHORT WAVE TROUGH TRACKING TO THE WEST OF THE UPPER LEVEL LOW. IN FACT...THE 04.00Z GFS SHOWS ALL OF THE PV ADVECTION IN THE 500-300 MB LAYER STAYING OVER THE MISSOURI RIVER VALLEY. THE WAVE DOES GET CLOSE ENOUGH TO PRODUCE SOME WEAK QG CONVERGENCE IN THE 1000-500 MB LAYER FOR AREAS ALONG AND WEST OF THE MISSISSIPPI RIVER. THE BEST ISENTROPIC UP GLIDE WILL REMAIN WELL TO THE WEST OF THE AREA...BUT AROUND 1 TO 2 UBAR/S DOES GET INTO THE I35 CORRIDOR ON THE 285K SURFACE. NOT EXPECTING THIS WAVE TO PRODUCE A LOT OF PRECIPITATION FOR THE FORECAST AREA...BUT COULD SEE ANOTHER ROUND OF VERY LIGHT RAIN SNEAK INTO THE SOUTHWEST SECTIONS OF THE FORECAST AREA AND WILL HAVE RAIN CHANCES ALONG AND SOUTHWEST OF A ROCHESTER TO ELKADER LINE. SOME OF THIS LIGHT RAIN COULD LINGER INTO MONDAY MORNING BEFORE MOVING AWAY FROM THE AREA. WITH THE NORTHWEST FLOW ALOFT...YET ANOTHER WAVE WILL QUICKLY ADVANCE TOWARD THE REGION FOR MONDAY NIGHT AND TUESDAY. THIS WAVE LOOKS LIKE IT WILL START OUT FARTHER NORTH COMING OUT OF CENTRAL ALBERTA AND SASKATCHEWAN WHICH WILL TAKE IT FARTHER NORTHEAST THAN THE PREVIOUS TWO WAVES. THE MODELS HAVE BEEN FAIRLY CONSISTENT SHOWING THIS WAVE TRACKING RIGHT OVER THE AREA WITH THE GFS INDICATING UP TO 16 PVU/S OF VORTICITY ADVECTION COMING ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY MORNING. THE QG RESPONSE FROM THIS WAVE IS EXPECTED TO BE MODERATE IN STRENGTH BUT VERY DEEP EXTENDING FROM 1000 UP TO 300 MB. VERY LITTLE IF ANY FRONTOGENESIS IS EXPECTED WITH THIS SYSTEM AND THE ISENTROPIC RESPONSE IS ONLY AROUND 2 UBAR/S ON THE 285K SURFACE. EXPECT THAT THIS SYSTEM WILL BE ABLE TO PRODUCE SOME PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING. HAVE RAISED THE PRECIPITATION CHANCES TO 50 PERCENT ACROSS THE FAR NORTH AND EXTENDED THE 20 PERCENT CHANCES SOUTH TO COVER THE REMAINDER OF THE AREA. RAISED THE CHANCES TO 60 AND 70 PERCENT ACROSS THE EAST FOR TUESDAY MORNING WITH 30 AND 40 PERCENT CHANCES BACK ACROSS THE WEST. LOOKING AT THE FORECAST SOUNDINGS...EXPECTING MOST OF THIS PRECIPITATION TO FALL AS RAIN AS THE WARM AIR ADVECTION AHEAD OF THE WAVE SHOULD WARM THE LOW LEVEL TEMPERATURES ENOUGH TO KEEP THINGS LIQUID. HOWEVER...CAN NOT TOTALLY RULE SOME SNOW MIXING IN SO PLAN TO HAVE A LITTLE MIX FOR A WHILE. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 141 AM CST SUN NOV 4 2012 MEDIUM RANGE MODELS IN VERY GOOD AGREEMENT THIS MORNING SHOWING THE UPPER LEVEL RIDGE OVER THE ROCKIES WILL SLIDE EAST ACROSS THE MIDWEST BEHIND THE TUESDAY SYSTEM. THIS RIDGING IS EXPECTED TO SLIDE EAST PAST THE REGION THURSDAY NIGHT AND FRIDAY ALLOWING SOUTHWEST FLOW ALOFT TO DEVELOP AS AN UPPER LEVEL LOW MOVES ACROSS THE NORTHERN ROCKIES ONTO THE HIGH PLAINS BY SATURDAY. AT THE SURFACE...CYCLOGENESIS SHOULD TAKE PLACE IN THE LEE OF THE ROCKIES FRIDAY NIGHT WITH THE LOW ADVANCING NORTHEAST INTO MINNESOTA SATURDAY. STILL SIGNIFICANT DIFFERENCES ON WHERE THE WARM FRONT DEVELOPS WITH THE SURFACE LOW. THE GFS HAS THE WARM FRONT ALONG THE IOWA/MISSOURI BORDER AND SHOWS PRECIPITATION DEVELOPING NORTH OF THIS ALREADY FRIDAY WHILE THE 04.00Z ECMWF CONTINUES TO SHOW THE WARM FRONT WELL TO THE NORTH WITH ANY PRECIPITATION ACROSS SOUTHERN CANADA. THESE DIFFERENCES THEN CONTINUE THROUGH THE REMAINDER OF THE PERIOD WITH THE GFS BEING MUCH WETTER WHILE THE ECMWF KEEPS THE AREA IN THE WARM SECTOR AND DOES NOT DEVELOP ANY PRECIPITATION UNTIL FRIDAY NIGHT INTO SATURDAY AS THE SURFACE LOW AND COLD FRONT STARTS TO APPROACH. NO CHANGES PLANNED TO THE MODEL CONSENSUS GRIDS AT THIS POINT WHICH FAVOR THE DRIER ECMWF SOLUTION. && .AVIATION...THROUGH 18Z MONDAY 1155 AM CST SUN NOV 4 2012 CONDITIONS ARE EXPECTED TO DETERIORATE TO IFR AT KRST AROUND 03Z TONIGHT...LOWERING TO LIFR BY 09Z IN LIGHT RAIN AND FOG. LOOK FOR CEILINGS TO LOWER TO AROUND 900 FT BY 03Z THEN FALLING TO 200 FT BY 09Z. VISIBILITIES WILL ALSO BE REDUCED LATE TONIGHT IN FOG AT KRST WITH VISIBILITIES FALLING TO AROUND 1/2 SM. MVFR CONDITIONS ARE EXPECTED TO DEVELOP AT KLSE AROUND 02Z THIS EVENING. OTHERWISE...PLAN ON VFR TO MVFR CONDITIONS AT THE TAF SITES THIS AFTERNOON WITH BKN CUMULUS CLOUD BASES RANGING FROM 3500 FT AT KLSE TO AROUND 1700 FT AT KRST. CLOUD BASES ARE EXPECTED TO LOWER INTO THE MVFR CATEGORY AROUND 02Z TONIGHT AT KLSE WITH CEILINGS AT 2000FT...LOWERING TO AROUND 1500FT BY 08Z. LIFR CONDITIONS ARE EXPECTED TO IMPROVE TO IFR AT KRST AROUND 14Z...WITH MVFR CONDITIONS EXPECTED BY 16Z. THE LIGHT RAIN AND LOW CEILINGS ARE IN RESPONSE TO SURFACE LOW PRESSURE DEEPENING TONIGHT OVER WESTERN IOWA AS AN UPPER WAVE MOVES FROM THE DAKOTAS SOUTH ALONG THE NEBRASKA/IOWA BORDER. LOW LEVEL WARM AIR ADVECTION...PRODUCING LIGHT PRECIPITATION...AND EAST SOUTHEASTERLY UPSLOPE FLOW WILL PRODUCE FAVORABLE CONDITIONS FOR LOW CEILINGS AND FOG AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... 141 AM CST SUN NOV 4 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...WETENKAMP