Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 12/14/11


AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
945 AM EST Mon Dec 12 2011 .UPDATE...Latest RUC analysis shows most of the shortwave energy has moved east of the CWA along with the bulk of the rainfall. Other than patches of very light rain, there was only a scattering of showers over the southeast Big Bend and coastal waters. Patchy light rain or drizzle may remain possible into the afternoon but will update grids and zones shortly to trim back PoPs based on radar coverage. Abundant low level moisture will remain in place today and the low cloudiness extends through most of Mississippi and spreading to the west. The clouds will keep max temperatures today below seasonal levels for all but Dixie county where low 70s are forecast. && .MARINE (Today through Friday)... High pressure over the Mid-Atlantic states will slowly weaken over the next several days with conditions gradually improving over the coastal waters. Winds and seas have diminished to exercise caution levels this morning and the headline for today will be maintained. Winds and seas will remain elevated at caution levels, especially away from the coast through Wednesday before the gradient breaks down and winds drop below 10 knots for the end of the week. && .AVIATION...(Through 12z Tuesday)... This set of TAFs remains very similar to the previous set. In general, ceilings were either in the low end of the MVFR range, or down into IFR, at TAF issuance time. Ensemble probabilities and MOS guidance all suggest a prevailing IFR stratus ceiling for most of the day, with some periods of LIFR possible tonight. Given the rainfall over the past 12 hours adding a bit more moisture to the surface, it`s also possible we will see some light fog at the various terminals after 00z Tuesday, with the best chances being at TLH and VLD (where winds are likely to be lightest). && .HYDROLOGY...A few corridors of heavy rain overnight prompted the issuance of several Flood Advisories, the last of which is scheduled to expire at 7am EST. The Tallahassee area was directly impacted by one area of heavy rain, with widespread 3 to 5 inch totals across various parts of the city (heaviest totals generally south and west). The airport ASOS (KTLH) picked up 3.57 inches through 5:50am EST, and this is the highest 2-day rainfall total measured at Tallahassee since January 20-21, 2010. Flooding issues around the city were mainly related to some minor urban flooding and some shallow water over a few roads. Another corridor of heavy rain developed from NC Taylor County into C Madison County, FL. The KTLH radar estimated 4 to 7.5 inches of rain in a narrow band in this area, and radar rainfall estimates were pretty reliable overnight based on observed rainfall. This is also similar to the Q2 estimates (4-6 inches). && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 62 51 70 49 72 / 60 20 10 0 0 Panama City 61 50 67 50 68 / 40 10 0 0 0 Dothan 54 47 67 48 72 / 50 20 10 0 0 Albany 54 47 66 45 71 / 70 20 10 0 0 Valdosta 61 51 70 49 74 / 70 20 10 0 0 Cross City 73 53 73 50 75 / 60 20 10 0 0 Apalachicola 63 52 69 54 68 / 40 10 10 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...None. GM...None. && $$ UPDATE...Barry MARINE...Wool AVIATION...Barry/Lamers HYDROLOGY...Camp/Lamers
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
112 PM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL AT THE SURFACE THROUGH THE MIDDLE OF THE WEEK. ONSHORE LOW LEVEL FLOW AND WARM ADVECTION PROVIDE INCREASED CHANCES OF LIGHT RAIN TODAY ALONG WITH COOLER TEMPERATURES. UPPER LEVEL RIDGING WILL BRING WARMING TEMPERATURES MID WEEK WITH A FRONTAL BOUNDARY EXPECTED TO PUSH INTO THE REGION LATE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RADAR TRENDS SHOW THE BULK OF THE RAIN MOVING NORTHEAST SOUTHEAST OF A WILLISTON TO LYNCHBURG LINE. ONLY WIDELY SCATTERED SHOWERS ARE PRESENT ON RADAR ACROSS EAST CENTRAL GEORGIA AND CENTRAL SOUTH CAROLINA AS THE SHORTWAVE WORKS ITS WAY ACROSS SOUTH CAROLINA. AS A RESULT...MOVED PRECIPITATION NORTHEAST AND OUT OF THE AREA BY 00Z THIS EVENING. LOW CLOUDS WILL CONTINUE ACROSS MUCH OF THE AREA...EXCEPT FAR NORTH WHERE THERE ARE SOME BREAKS IN THE LOW CLOUDS THIS AFTERNOON. NO OTHER CHANGES WERE MADE.. UPDATED FORECAST 10 AM EST...TEMPERATURES RUNNING COOLER THAN FORECAST SO LOWERED MAXIMUM TEMPS INTO THE UPPER 40S SOUTHWEST TO CENTRAL AND LOWER 50S NORTHEAST...WHERE CHANCES OF PRECIPITATION IS LESS AND CLOUD COVER THINNER. RAIN COOLED AIR AND A DRY NORTHEAST FLOW WILL IMPEDE TEMPERATURE RISES. THE REST OF THE FORECAST WAS LEFT UNCHANGED. PRECIPITATION FORECAST IS EXCELLENT IN DEPICTING EXTEND AND MOVEMENT OF THE RAINFALL SHIELD WHICH COVERS THE SOUTHERN HALF OF THE FORECAST AREA. SHORT WAVE CAUSING THIS ACTIVITY IS NOW IN SOUTHWEST SOUTH CAROLINA AS DEPICTED BY THE WATER VAPOR SATELLITE LOOP. RUC MODEL TOO FAST...WENT WITH THE SLOWER NAM MODEL, CLOUDS SHOULD BEGIN LIFTING LATER THIS AFTERNOON AND THE RAIN WILL END FROM THE SOUTHWEST AS THE SHORT WAVE LIFTS NORTHEAST TAKING THE ISENTROPIC LIFT WITH IT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... A BUILDING UPPER RIDGE SETS UP OVER THE FORECAST AREA TUESDAY INTO WEDNESDAY IN RESPONSE TO A DEEP UPSTREAM TROUGH EJECTING FROM THE DESERT SOUTHWEST. THIS WILL BRING SOME WEAK DOWNSLOPING FLOW OFF THE MOUNTAINS AND HELP ERODE THE CLOUDS AND ALLOW FOR A WARMING TREND THROUGH MID WEEK. TEMPERATURES SHOULD CLIMB ABOVE NORMAL WITH HIGHS IN THE 60S AND LOWS IN THE UPPER 30S TO LOWER 40S WITH NO CHANCE FOR PRECIPITATION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NO LARGE CHANGES TO THE EXTENDED FORECAST. INCREASING CONFIDENCE REGARDING THE PASSAGE OF A COLD FRONT THROUGH THE FORECAST AREA LATE WEEK. LATEST GFS AND ECMWF BOTH SHOWING SHORTWAVE ENERGY LIFTING THROUGH THE GREAT LAKES REGION AND DEVELOPING WESTERLY ZONAL FLOW BEHIND THE SHORTWAVE WHICH PUSHES THE FRONT NEAR THE FORECAST AREA ON FRIDAY AND LIKELY STALLS OR SLOWLY PUSHES THROUGH THE REGION. DELAYED THE ONSET OF POPS TO THURSDAY NIGHT AND FRIDAY AND GOING WITH A DRY FORECAST ON THURSDAY AND WARMER TEMPERATURES AHEAD OF THE FRONT. TEMPERATURES FALL BACK TO NORMAL OVER THE WEEKEND WITH THE FRONT NEARBY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... HIGH PRESSURE WILL CONTINUE BUILDING IN ACROSS THE AREA OVER THE NEXT 24 HOURS. SHORT WAVE WHICH BROUGHT THE RAIN IS NOW OVER CENTRAL SOUTH CAROLINA AND MOVING EAST. MVFR CEILINGS COVER SOUTH CAROLINA AND EAST CENTRAL GEORGIA WITH IFR CONDITIONS IN SOUTHEAST GEORGIA. TRENDS INDICATE THAT THE CLOUDINESS IS ERODING FROM THE NORTH AS THE HIGH BUILDS IN. MODEL GUIDANCE SHOW ONE MORE VERY WEAK SHORT WAVE OVER THE TENNESSEE VALLEY. THIS MAY REINFORCE THE CLOUD COVER LATER THIS AFTERNOON. THE HIGH WILL CONTINUE STRENGTHENING AS RIDGE BUILDS INTO THE AREA FROM THE WEST TONIGHT. WITH LOW CLOUDINESS EXTENDING ACROSS MUCH OF THE AREA THIS AFTERNOON...KEPT MVFR CEILINGS THROUGH THE REST OF THE DAY...FAVORING THE 17Z GFS LAMP GUIDANCE. VFR CEILINGS WILL RETURN ACROSS THE ENTIRE AREA BETWEEN 23Z AND 00Z THIS EVENING. WITH CLEARING SKIES LATER TONIGHT...EXPECT SOME FOG DEVELOPMENT IN AREAS WHERE THERE WAS RAIN...AGS...OGB. EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTED EXPECTED AT THIS TIME. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1148 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL AT THE SURFACE THROUGH THE MIDDLE OF THE WEEK. ONSHORE LOW LEVEL FLOW AND WARM ADVECTION PROVIDE INCREASED CHANCES OF LIGHT RAIN TODAY ALONG WITH COOLER TEMPERATURES. UPPER LEVEL RIDGING WILL BRING WARMING TEMPERATURES MID WEEK WITH A FRONTAL BOUNDARY EXPECTED TO PUSH INTO THE REGION LATE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RADAR TRENDS SHOW THE BULK OF THE RAIN MOVING NORTHEAST SOUTHEAST OF A WILLISTON TO LYNCHBURG LINE. ONLY WIDELY SCATTERED SHOWERS ARE PRESENT ON RADAR ACROSS EAST CENTRAL GEORGIA AND CENTRAL SOUTH CAROLINA AS THE SHORTWAVE WORKS ITS WAY ACROSS SOUTH CAROLINA. AS A RESULT...MOVED PRECIPITATION NORTHEAST AND OUT OF THE AREA BY 00Z THIS EVENING. LOW CLOUDS WILL CONTINUE ACROSS MUCH OF THE AREA...EXCEPT FAR NORTH WHERE THERE ARE SOME BREAKS IN THE LOW CLOUDS THIS AFTERNOON. NO OTHER CHANGES WERE MADE.. UPDATED FORECAST 10 AM EST...TEMPERATURES RUNNING COOLER THAN FORECAST SO LOWERED MAXIMUM TEMPS INTO THE UPPER 40S SOUTHWEST TO CENTRAL AND LOWER 50S NORTHEAST...WHERE CHANCES OF PRECIPITATION IS LESS AND CLOUD COVER THINNER. RAIN COOLED AIR AND A DRY NORTHEAST FLOW WILL IMPEDE TEMPERATURE RISES. THE REST OF THE FORECAST WAS LEFT UNCHANGED. PRECIPITATION FORECAST IS EXCELLENT IN DEPICTING EXTEND AND MOVEMENT OF THE RAINFALL SHIELD WHICH COVERS THE SOUTHERN HALF OF THE FORECAST AREA. SHORT WAVE CAUSING THIS ACTIVITY IS NOW IN SOUTHWEST SOUTH CAROLINA AS DEPICTED BY THE WATER VAPOR SATELLITE LOOP. RUC MODEL TOO FAST...WENT WITH THE SLOWER NAM MODEL, CLOUDS SHOULD BEGIN LIFTING LATER THIS AFTERNOON AND THE RAIN WILL END FROM THE SOUTHWEST AS THE SHORT WAVE LIFTS NORTHEAST TAKING THE ISENTROPIC LIFT WITH IT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... A BUILDING UPPER RIDGE SETS UP OVER THE FORECAST AREA TUESDAY INTO WEDNESDAY IN RESPONSE TO A DEEP UPSTREAM TROUGH EJECTING FROM THE DESERT SOUTHWEST. THIS WILL BRING SOME WEAK DOWNSLOPING FLOW OFF THE MOUNTAINS AND HELP ERODE THE CLOUDS AND ALLOW FOR A WARMING TREND THROUGH MID WEEK. TEMPERATURES SHOULD CLIMB ABOVE NORMAL WITH HIGHS IN THE 60S AND LOWS IN THE UPPER 30S TO LOWER 40S WITH NO CHANCE FOR PRECIPITATION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NO LARGE CHANGES TO THE EXTENDED FORECAST. INCREASING CONFIDENCE REGARDING THE PASSAGE OF A COLD FRONT THROUGH THE FORECAST AREA LATE WEEK. LATEST GFS AND ECMWF BOTH SHOWING SHORTWAVE ENERGY LIFTING THROUGH THE GREAT LAKES REGION AND DEVELOPING WESTERLY ZONAL FLOW BEHIND THE SHORTWAVE WHICH PUSHES THE FRONT NEAR THE FORECAST AREA ON FRIDAY AND LIKELY STALLS OR SLOWLY PUSHES THROUGH THE REGION. DELAYED THE ONSET OF POPS TO THURSDAY NIGHT AND FRIDAY AND GOING WITH A DRY FORECAST ON THURSDAY AND WARMER TEMPERATURES AHEAD OF THE FRONT. TEMPERATURES FALL BACK TO NORMAL OVER THE WEEKEND WITH THE FRONT NEARBY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... CEILINGS LIFTING OVER THE NORTHERN TERMINALS...STAYING THE SAME OR LOWERING OVER AGS...DNL...OGB. WEAK ISENTROPIC LIFT ASSOCIATED WITH SHORTWAVE CURRENTLY OVER WESTERN SOUTH CAROLINA WILL SHIFT EAST BY THIS EVENING...12 Z NAM AND 06Z GFS ARE IN AGREEMENT IN ENDING ISENTROPIC LIFT BY TONIGHT. IMPROVED CONDITIONS TO VFR AT BOTH CAE AND CUB WITH THE BULK OF THE PRECIPITATION EXPECTED TO REMAIN SOUTH OF THESE LOCATIONS. LOWERED CEILING AT OGB WHERE WITH THE BEST CHANCE OF RAIN IS AND KEPT THE FORECAST THE SAME AT AGS AND DNL. MADE MINOR CHANGES TO THE WIND FORECAST. IN ALL LOCATIONS..HOWEVER NORTHEAST WINDS ARE EXPECTED THROUGH THE REMAINDER OF THIS AFTERNOON. REST LEFT UNCHANGED FOR NOW. LOW CEILINGS EXTEND BACK INTO WESTERN ALABAMA. WITH THE LACK OF A STRONG COLD FRONT TO SCOUR OUT THE MOISTURE...MVFR TO IFR CEILINGS MAY COME BACK ACROSS THE REGION THIS EVENING. THIS WILL BE MORE CLOSELY LOOKED AT WITH LATER MODEL RUNS. EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...07
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1013 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN CONTROL AT THE SURFACE THROUGH THE MIDDLE OF THE WEEK. ONSHORE LOW LEVEL FLOW AND WARM ADVECTION PROVIDE INCREASED CHANCES OF LIGHT RAIN TODAY ALONG WITH COOLER TEMPERATURES. UPPER LEVEL RIDGING WILL BRING WARMING TEMPERATURES MID WEEK WITH A FRONTAL BOUNDARY EXPECTED TO PUSH INTO THE REGION LATE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED FORECAST...TEMPERATURES RUNNING COOLER THAN FORECAST SO LOWERED MAXIMUM TEMPS INTO THE UPPER 40S SOUTHWEST TO CENTRAL AND LOWER 50S NORTHEAST...WHERE CHANCES OF PRECIPITATION IS LESS AND CLOUD COVER THINNER. RAIN COOLED AIR AND A DRY NORTHEAST FLOW WILL IMPEDE TEMPERATURE RISES. THE REST OF THE FORECAST WAS LEFT UNCHANGED. PRECIPITATION FORECAST IS EXCELLENT IN DEPICTING EXTEND AND MOVEMENT OF THE RAINFALL SHIELD WHICH COVERS THE SOUTHERN HALF OF THE FORECAST AREA. SHORT WAVE CAUSING THIS ACTIVITY IS NOW IN SOUTHWEST SOUTH CAROLINA AS DEPICTED BY THE WATER VAPOR SATELLITE LOOP. RUC MODEL TOO FAST...WENT WITH THE SLOWER NAM MODEL, CLOUDS SHOULD BEGIN LIFTING LATER THIS AFTERNOON AND THE RAIN WILL END FROM THE SOUTHWEST AS THE SHORT WAVE LIFTS NORTHEAST TAKING THE ISENTROPIC LIFT WITH IT. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... A BUILDING UPPER RIDGE SETS UP OVER THE FORECAST AREA TUESDAY INTO WEDNESDAY IN RESPONSE TO A DEEP UPSTREAM TROUGH EJECTING FROM THE DESERT SOUTHWEST. THIS WILL BRING SOME WEAK DOWNSLOPING FLOW OFF THE MOUNTAINS AND HELP ERODE THE CLOUDS AND ALLOW FOR A WARMING TREND THROUGH MID WEEK. TEMPERATURES SHOULD CLIMB ABOVE NORMAL WITH HIGHS IN THE 60S AND LOWS IN THE UPPER 30S TO LOWER 40S WITH NO CHANCE FOR PRECIPITATION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... NO LARGE CHANGES TO THE EXTENDED FORECAST. INCREASING CONFIDENCE REGARDING THE PASSAGE OF A COLD FRONT THROUGH THE FORECAST AREA LATE WEEK. LATEST GFS AND ECMWF BOTH SHOWING SHORTWAVE ENERGY LIFTING THROUGH THE GREAT LAKES REGION AND DEVELOPING WESTERLY ZONAL FLOW BEHIND THE SHORTWAVE WHICH PUSHES THE FRONT NEAR THE FORECAST AREA ON FRIDAY AND LIKELY STALLS OR SLOWLY PUSHES THROUGH THE REGION. DELAYED THE ONSET OF POPS TO THURSDAY NIGHT AND FRIDAY AND GOING WITH A DRY FORECAST ON THURSDAY AND WARMER TEMPERATURES AHEAD OF THE FRONT. TEMPERATURES FALL BACK TO NORMAL OVER THE WEEKEND WITH THE FRONT NEARBY. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... CEILINGS LIFTING OVER THE NORTHERN TERMINALS...STAYING THE SAME OR LOWERING OVER AGS...DNL...OGB. WEAK ISENTROPIC LIFT ASSOCIATED WITH SHORTWAVE CURRENTLY OVER WESTERN SOUTH CAROLINA WILL SHIFT EAST BY THIS EVENING...12 Z NAM AND 06Z GFS ARE IN AGREEMENT IN ENDING ISENTROPIC LIFT BY TONIGHT. IMPROVED CONDITIONS TO VFR AT BOTH CAE AND CUB WITH THE BULK OF THE PRECIPITATION EXPECTED TO REMAIN SOUTH OF THESE LOCATIONS. LOWERED CEILING AT OGB WHERE WITH THE BEST CHANCE OF RAIN IS AND KEPT THE FORECAST THE SAME AT AGS AND DNL. MADE MINOR CHANGES TO THE WIND FORECAST. IN ALL LOCATIONS..HOWEVER NORTHEAST WINDS ARE EXPECTED THROUGH THE REMAINDER OF THIS AFTERNOON. REST LEFT UNCHANGED FOR NOW. LOW CEILINGS EXTEND BACK INTO WESTERN ALABAMA. WITH THE LACK OF A STRONG COLD FRONT TO SCOUR OUT THE MOISTURE...MVFR TO IFR CEILINGS MAY COME BACK ACROSS THE REGION THIS EVENING. THIS WILL BE MORE CLOSELY LOOKED AT WITH LATER MODEL RUNS. EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1146 PM CST SUN DEC 11 2011 ...UPDATE TO AVIATION... .DISCUSSION... LATEST WATER VAPOR LOOP AT 20Z WAS SHOWING THE UPPER TROUGH MOVING SLOWLY ACROSS THE HIGH PLAINS FROM NEBRASKA INTO THE TEXAS PANHANDLE. SHOWERS HAVE DEVELOPED OUT AHEAD OF THE WAVE IN OKLAHOMA TODAY AND HAVE BEEN MOVING NORTHEAST SLOWLY THROUGH THE DAY. SOUNDING FROM 12Z AT TOP AND SGF SHOWED PLENTY OF DRY AIR OFF THE DECK THIS MORNING. SOME DRY AIR CONTINUES TO BE ENTRAINED THIS EVENING IN THE EASTERN CWA PER MODEL TIME SECTIONS. LATEST RUN OF THE RUC DOES NOT BRING ANY MEASURABLE PRECIPITATION AS FAR NORTH INTO THE SOUTHERN CWA TONIGHT. THE UPPER WAVE WILL MOVE SLOWLY MOVE ACROSS THE CENTRAL PLAINS TONIGHT WITH THE UPPER TROUGH AXIS MOVING THROUGH THE EASTERN CWA BY 09Z MONDAY. 925-850 MB WINDS BECOME SOUTH EARLY THIS EVENING THEN SOUTHWEST OVERNIGHT AND BY MORNING WILL FOCUS MOISTURE TO THE EAST. EXPECT CLOUDS TO REMAIN THROUGH THE NIGHT WITH SOME PATCHY FOG AND DRIZZLE POSSIBLE IN THE NORTHWEST WHILE SPRINKLES ARE MORE LIKELY IN THE EAST. LOWS TONIGHT WILL REMAIN ABOVE FREEZING SO NO FREEZING OR FROZEN PRECIPITATION IS EXPECTED. MONDAY SOME EARLY MORNING PATCHY DRIZZLE OR FOG IS POSSIBLE OFF THE SNOW PACK TO THE WEST IN NORTH CENTRAL KANSAS. BY MID MORNING A FRONTAL BOUNDARY WILL APPROACH FROM THE WEST BUT MAKES SLOW PROGRESS THROUGH THE DAY AND BECOMES STATIONARY FROM SOUTHEAST NEBRASKA INTO SOUTHWEST KANSAS. SOUTHERLY FLOW AHEAD OF THE FRONT WILL BRING TEMPERATURES AGAIN IN THE MID AND UPPER 40S TO THE AREA. 53 MODELS ARE SIMILAR IN TAKING UPPER TROUGH OFF THE SOUTHERN CA COAST MONDAY EVENING AND EJECTING IT NORTHEASTWARD INTO THE CENTRAL HIGH PLAINS BY MIDDAY WEDNESDAY...THEN RAPIDLY INTO THE WESTERN GREAT LAKES BY LATE WEDNESDAY NIGHT. THE MODELS ARE IN LESS AGREEMENT ON HOW FAR SOUTHEAST THE COLD FRONT WILL PUSH SOUTHEAST INTO THE NORTHWEST COUNTY WARNING AREA (CWA) MONDAY NIGHT BEFORE STALLING...WITH THE NAM/SREF THE MOST AGGRESSIVE INTO THE NORTHWEST 1/3 OF THE CWA AND THE GFS/EC NOT BRINGING IT INTO THE NORTHWEST CORNER AT ALL. WILL COMPROMISE FOR NOW WITH SOME FREEZING/SUBFREEZING TEMPS IN THE FAR NORTHWEST CORNER BEHIND THE FRONT AND WARMER ABOVE FREEZING TEMPS ELSEWHERE. WITH A CHANCE FOR DRIZZLE/LIGHT RAIN INCREASING LATER IN THE NIGHT AND NO NON DIURNAL TREND EXPECTED...CANNOT RULE OUT A WINDOW FOR SOME LIGHT FREEZING PRECIP IN THE FAR NORTHWEST CORNER OF THE CWA 06-12Z TUES...OTHERWISE EXPECT THE PRECIP WITH THIS SYSTEM TO BE A RAIN EVENT TUESDAY THROUGH WEDNESDAY BEFORE ENDING WEDNESDAY NIGHT. ELEVATED INSTABILITY AND FORCING LOOK SUFFICIENT FOR SOME THUNDER POTENTIAL AHEAD OF THE FRONT IN THE DEEPER MOISTURE AXIS ACROSS THE SOUTHEAST HALF OF THE CWA WHERE THE WARMER MORNING LOWS WEDNESDAY WILL BE IN THE LOW TO MID 40S. AFTER HIGHS IN THE LOW TO MID 40S ON TUESDAY...SHOULD SEE HIGHS RISE INTO THE LOW TO MIDDLE 50S FOR WEDNESDAY. AFTER THIS SYSTEM EXITS...MODELS DIVERGE THROUGH THE END OF THE WEEK AND INTO NEXT WEEKEND ON HOW QUICKLY THE NEXT SHORTWAVE TO DIG INTO THE SOUTHWEST CONUS WILL EJECT OUT INTO THE PLAINS. THE ECMWF MODEL IS ABOUT 2 DAYS SLOWER WITH ITS ARRIVAL AND ASSOCIATED PRECIP THAN THE GFS. WITH SUCH LOW CONFIDENCE ON ITS ARRIVAL TIME AND CURRENT DRY FCST THROUGH SATURDAY...OPTED TO KEEP FCST DRY UNTIL SATURDAY NIGHT/SUNDAY WITH LOW CHANCES FOR RAIN/FREEZING RAIN OR A SNOW POTENTIAL. AFTER LOWS IN THE 20S AND HIGHS IN THE 30S BOTH FRIDAY AND SATURDAY...HIGHS TEMPS SHOULD SLOWLY MODERATE AHEAD OF THE NEXT UPPER TROUGH INTO THE 40S FOR HIGHS ON SUNDAY. 63 && .AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH MOST OF THE OVERNIGHT HOURS WITH BKN/OVC CEILINGS OF 4-6KFT. EXPECT CEILINGS TO LOWER BY THE MORNING HOURS AND BECOME MVFR/NEAR MVFR FOR THE REMAINDER OF THE PERIOD. BLAIR && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1121 PM CST SUN DEC 11 2011 .AVIATION... FOR THE 06Z TAF ISSUANCE... STATUS CONTINUES TO SPREAD NORTH ACROSS ALL OF THE TAF SITES AS OF 05Z WITH THE 00Z NAM BUFR SOUNDINGS ALSO SUPPORTING A THICKENING AND LOWERING TREND OF THESE LOW CLOUDS THROUGH THE EARLY MORNING HOURS. AS THIS STATUS THICKENS AND LOWERS SOME HIGH LEVEL CLOUD COVER WILL BEGIN TO SPREAD INTO SOUTHWEST KANSAS AS AN UPPER LEVEL SHORT WAVE TROUGH APPROACHES THE AREA FROM THE SOUTHWEST. AS A RESULT THIS STATUS WILL BE SLOW TO ERODE SO HAVE DECIDED TO FOLLOW THE LATEST NAM GUIDANCE, HRRR AND BUFR SOUNDINGS IN KEEPING THESE LOW CIGS IN PLACE THROUGH AT LEAST LATE MORNING. WINDS WILL CONTINUE AROUND 20KTS THROUGH MUCH OF THE NIGHT BUT WILL BEGIN TO SUBSIDE AT OR SHORTLY AFTER 12Z AS A TROUGH OF LOW PRESSURE AT THE SURFACE STARTS TO MOVE INTO WESTERN KANSAS. GIVEN THESE WINDS SOME LIGHT FOG WILL BE POSSIBLE BUT AREAS OF DENSE FOG IS NOT ANTICIPATED. THE POSSIBLE EXCEPTION WILL BE NEAR THE GCK WHERE WIND SPEEDS ARE EXPECTED BE LIGHTER GIVEN THE CLOSER PROXIMITY TO THE SURFACE LEE TROUGH EARLY MONDAY MORNING. WILL THEREFORE BE A LITTLE MORE PESSIMISTIC IN THE VSBYS BETWEEN BETWEEN 12 AND 15Z AT GCK THAN AT DDC OR HYS. -RB && PREV DISCUSSION... /ISSUED 326 PM CST SUN DEC 11 2011/ DISCUSSION... DAYS 1-2... BREEZY SOUTH TO SOUTHWEST WINDS THIS EVENING WILL DECREASE TO AROUND 10 TO 15 MPH BY MORNING. DEWPOINTS ARE ANTICIPATED TO INCREASE A FEW DEGREES ACROSS EASTERN PORTIONS OF THE CWA AND STRATUS IS EXPECTED TO REDEVELOP OR CONTINUE, MAINLY ACROSS AREAS EAST OF WAKEENEY TO LIBERAL. A FEW PLACES MAY EXPERIENCE REDUCED VISIBILITIES DUE TO FOG AFTER MIDNIGHT, HOWEVER, IT SHOULD NOT BE WIDESPREAD LIKE YESTERDAY. SOME CIRROSTRATUS IS POSSIBLE ACROSS WESTERN KANSAS AS UPPER LEVEL MOISTURE MOVES INTO THE PLAINS AHEAD OF THE UPPER LEVEL TROUGH OVER CALIFORNIA. A COLD FRONT IS EXPECTED TO MOVE SOUTH ACROSS NEBRASKA INTO NORTHERN KANSAS TOMORROW. MODELS THEN HAVE THIS FRONT STALLING OUT AND BISECTING OUR CWA IN THE AFTERNOON. LOWER TO MID LEVEL MOISTURE WILL CONTINUE TO INCREASE ACROSS OUR AREA ALLOWING FOR MOSTLY CLOUDY SKIES TO PREVAIL. THE FRONTAL BOUNDARY THEN MOVES NORTH AS A WARM FRONT TOMORROW NIGHT. SOME LIGHT DRIZZLE OR LIGHT RAIN WILL BE POSSIBLE ACROSS THE EASTERN THIRD OF THE CWA WITH FREEZING FOG OR FREEZING DRIZZLE POSSIBLE ACROSS THE NORTHWESTERN PORTION OF THE CWA. MODELS CONTINUE TO INDICATE AN UPPER LEVEL SHORTWAVE MOVING ACROSS NEW MEXICO AND INTO THE HIGH PLAINS ON TUESDAY. A STRONG 250MB JET WILL BE FOUND ACROSS OUR AREA AT THIS TIME ENHANCING LIFT ACROSS THE AREA. THESE FEATURES ARE ANTICIPATED TO BRING A CHANCE OF RAIN ACROSS MUCH OF THE FORECAST AREA. OTHERWISE EXPECT MOSTLY CLOUDY SKIES. LOWS TONIGHT ARE ANTICIPATED TO RANGE FROM THE MID TO UPPER 20S IN THE WEST TO MID 30S ACROSS EASTERN PORTIONS OF THE CWA. LOWS TOMORROW NIGHT ARE EXPECTED TO RANGE FROM THE LOWER 30S NORTHWEST TO UPPER 30S SOUTHEAST. HIGHS MONDAY AND TUESDAY ARE ANTICIPATED TO RANGE FROM THE UPPER 30S NORTHWEST TO UPPER 40S SOUTHEAST. DAYS 3-7... THE MEDIUM RANGE FORECAST WILL START WITH A WARM FRONT STRADDLING THE CWA ON WEDNESDAY, WITH A SHORT WAVE ALOFT PASSING FROM WEST TO EAST. RAIN WILL MOSTLY LIKELY FALL WEDNESDAY OVER MOST OF THE CWA. A FEW THUNDERSTORMS WILL BE POSSIBLE ACROSS THE EXTREME SOUTHEAST CWA WEDNESDAY AFTERNOON, WITH EITHER FREEZING DRIZZLE OR LIGHT SNOW MORE POSSIBLE IN OUR EXTREME NORTHWESTERN COUNTIES. THIS SHORT WAVE IN THE 500MB LEVEL IS SMALL BUT POTENT, AND IT SHOULD KEEP SOME PRECIP ACROSS OUR EAST UNTIL EARLY WEDNESDAY NIGHT. THURSDAY AND FRIDAY WILL BE BETWEEN UPPER SYSTEMS AND SHOULD BE DRY. IT WILL COOL DOWN THURSDAY AND FRIDAY FROM THE HIGHS ON WEDNESDAY IN THE UPPER 40S NORTHWEST TO THE UPPER 50S IN THE SOUTHEAST. HIGHS BY FRIDAY WILL ONLY RANGE FROM THE UPPER 30S IN OUR NORTH TO THE MIDDLE 40S ACROSS OUR SOUTH. SATURDAY WILL COOL DOWN DUE TO INCREASING CLOUDS AND A SLIGHT FOR SNOW MOVING IN FROM THE SOUTH. THE TRACK OF THE ASSOCIATED UPPER LOW WILL PLAY HEAVILY ON IF AND WHERE WE GET ANY SNOW. BUT, IT DOES LOOK LIKE THE GEM AND GFS BOTH TRACK THE UPPER 500 MB LOW DOWN INTO SOUTHWESTERN NEW MEXICO BY SATURDAY, AND THEN BRING THE LOW NORTHEASTWARD INTO NORTH CENTRAL OKLAHOMA BY SUNDAY NIGHT. THE EC MODEL IS SLOWER AND A BIT FARTHER SOUTH WITH THE SYSTEM. ANYWAY, THE CREXTENDED MODEL INITIALLY PLACED 60 POPS IN MY SOUTHEAST SUNDAY, GRADUATING DOWNWARD TO 30 POPS ACROSS OUR WEST. I DID LOWER THE POPS TO 40 PERCENT IN OUR SOUTHEAST AND 30 PERCENT IN OUR WEST SUNDAY. THESE POPS CAN BE ADJUSTED UPWARDS OR DOWNWARDS LATER, AS MODEL TRENDS BECOME MORE RELIABLE. FOR NOW, IF THE GFS MODEL IS RIGHT, 2 TO 4 INCHES COULD FALL ACROSS A PORTION OF OUR CWA SATURDAY NIGHT INTO SUNDAY. IF THE EC MODEL IS MORE CORRECT, THEN JUST OUR SOUTHERN CWA WILL SEE SOME SNOW AND IT WILL BE LATER THAN SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 35 44 35 46 / 10 20 50 50 GCK 32 42 32 45 / 0 10 40 50 EHA 27 43 37 48 / 10 10 40 40 LBL 34 45 37 49 / 10 10 40 40 HYS 34 41 32 43 / 10 10 40 50 P28 35 47 39 48 / 10 20 50 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1247 PM CST MON DEC 12 2011 .DISCUSSION... 18Z TAF PACKAGE. && .AVIATION... CHALLENGING AVIATION FORECAST THIS CYCLE...WITH NEAR TERM CONCERN THE LOW STRATUS DECK OVER THE ACADIANA TERMINALS. VISIBLE SATELLITE IMAGERY SHOWING STEADY EROSION OF THIS CLOUD DECK...SO A TEMPO GROUP WAS USED AT KLFT AND KARA FOR THE NEXT 1 TO 2 HOURS RESPECTIVELY. VFR WILL PREVAIL HERE THE REST OF THE AFTERNOON INTO THE EARLY EVENING...BUT MODEL GUIDANCE IS INDICATING A RETURN OF LOW CLOUDS/VISIBILITY RESTRICTIONS LATER TONIGHT. WILL BRING PREVAILING LIFR HERE AND ALSO KAEX WHERE ADVECTI0N OF THE LOWER CLOUD DECK IS EXPECTED. MORE UNCERTAINTY EXISTS FARTHER WEST AS MID LEVEL CLOUDS AND HIGHER BOUNDARY LAYER WINDS COME INTO PLAY. WILL LOWER TO MVFR FOR NOW...BUT THIS MAY PROVE OPTIMISTIC IN LIGHT OF VISIBLE SATELLITE LOOP SHOWING WESTWARD PROGRESSION OF MARINE STRATUS ALONG THE LA COAST. 13 && .PREV DISCUSSION... /ISSUED 1116 AM CST MON DEC 12 2011/ UPDATE...STRATUS NOW OVER ACADIANA/EAST CENTRAL LOUISIANA HAS STALLED ITS WESTWARD MIGRATION AND IS IN THE PROCESS OF ERODING. RAPID WARMUP THEN EXPECTED OVER ACADIANA. BULK OF WIDESPREAD ALTOCUMULUS OVER EAST TEXAS/NORTH LOUISIANA SHOULD REMAIN PRIMARILY OVER THIS AREA PER LATEST RUC 850-700 MB RH. WILL MAINTAIN CURRENT FORECAST. NO UPDATE COMING. MARCOTTE PREV DISCUSSION... /ISSUED 520 AM CST MON DEC 12 2011/ DISCUSSION... 12Z TAF ISSUANCE. AVIATION... MID LEVEL BKN/OVC DECK ~9000FT MOVING ACROSS SE TX...EXPECTED TO GRADUALLY MOVE EAST ACROSS C AND SC LA TODAY...OTHERWISE VFR EXPECTED THROUGH THE PERIOD. NE WINDS EXPECTED TO GRADUALLY BECOME MORE E BY LATE AFTERNOON AND EVENING. DML PREV DISCUSSION... /ISSUED 438 AM CST MON DEC 12 2011/ DISCUSSION... SFC ANALYSIS SHOWS HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST CONTINUING TO RIDGE OVER THE FORECAST AREA WITH LIGHT NERLY LOW-LEVEL LOW PREVAILING AGAIN THIS MORNING. WATER VAPOR IMAGERY SHOWS A DECENT SHORTWAVE CROSSING THE SRN PLAINS/WRN GULF COAST STATES WHICH HAS HELPED PRODUCED A FEW SPRINKLES OR VERY LIGHT SHOWERS MAINLY OVER THE WRN 1/2 OF THE FORECAST AREA SO FAR OVERNIGHT. MEANWHILE WRLY FLOW ALOFT FROM THE PACIFIC CONTINUING TO SPREAD PLENTY OF MID/UPPER-LEVEL MOISTURE AND ASSOCIATED CLOUDINESS OVER THE REGION. TEMPS HAVE DIPPED JUST BELOW FREEZING ACROSS THE NERN EXTREME OF THE FORECAST AREA WHERE CLOUDS HAVE YET TO ENCROACH AND CUT OFF THE GOOD RADIATIVE COOLING...OTHERWISE TEMPS GENERALLY IN THE MID/UPPER 30S ALONG/EAST OF THE SABINE AND LOWER/MID 40S OVER SERN TX. NO SIGNIFICANT CHANGES TO THE EARLY PART OF THIS FORECAST PACKAGE. ANOTHER DAY OF LIGHT ERLY/NERLY FLOW EXPECTED TODAY AS THE SFC HIGH LINGERS NEAR THE ERN SEA BOARD. MEANWHILE SRLY FLOW WILL BEGIN TO DEVELOP ALOFT AS STRONG STORM SYSTEM CRASHES ASHORE ALONG THE SRN CALIFORNIA COAST. RISING HEIGHTS/WARMING ALOFT WILL LEAD TO THE BEGINNINGS OF A WARMING TREND WITH MAX TEMPS TODAY GENERALLY 10 DEGREES WARMER THAN YESTERDAY. MEANWHILE MINS TONIGHT FORECAST TO JUMP ALL THE WAY TO THE MID/UPPER 40S...WITH LOWER 50S COASTAL LA AND GOLDEN TRIANGLE REGION. MOISTURE WILL CONTINUE TO INCREASE THROUGH THE EARLY PART OF THE WEEK AS LOW-LEVEL FLOW VEERS AROUND TO THE SOUTHEAST. DEWPOINTS WILL CLIMB TO THE 50S/LOWER 60S THROUGH TUESDAY WHICH WILL ALLOW FOR SOME FOG DEVELOPMENT...ESPECIALLY NEAR THE COAST WITH SST CURRENTLY RUNNING IN THE LOWER/MID 50S. THE SYSTEM MOVING ASHORE OVER SRN CA TODAY WILL EJECT NEWD THROUGH MID-WEEK SPAWNING SFC LOW DEVELOPMENT OVER THE LEE OF THE ROCKIES ON WEDNESDAY. THE LOW WILL PUSH NEWD...GRADUALLY PULLING A SFC FRONTAL BOUNDARY TOWARD THE REGION. MODELS THIS MORNING ARE IN BETTER AGREEMENT WITH OOZING THE FRONT ACROSS THE FORECAST AREA LATE THURSDAY/EARLY FRIDAY TIME FRAME. NOT MUCH LIFT EXPECTED ALOFT WITH BEST ENERGY PULLING WELL NE OF THE AREA BY FROPA... INSTABILITY FAIRLY NEGLIGIBLE AS WELL SO ATTM EXPECTING MAINLY JUST SCATTERED SHOWERS WITH THE FRONT WITH MAYBE SOME ISOLATED THUNDER OVER THE FAR NERN ZONES. DUE TO THE SLOW-MOVING NATURE OF THE FRONT AND FAIRLY NON-PROGRESSIVE PATTERN ALOFT WE COULD SEE A FEW DAYS OF LINGERING SHOWERS AND THUS HAVE KEPT SMALL POPS IN THE FORECAST THROUGH THE WEEKEND. MARINE... MAINLY LIGHT FLOW EXPECTED TODAY AND TONIGHT WITH HIGH PRESSURE REMAINING IN CONTROL. WINDS WILL BEGIN TO INCREASE GRADUALLY STARTING TOMORROW WITH LOW PRESSURE DEVELOPING OFF THE ROCKIES ALTHOUGH SPEEDS SHOULD REMAIN BELOW ANY FLAGS. WINDS WILL STEADILY VEER TO A SERLY DIRECTION THROUGH MID-WEEK...BECOMING MORE SRLY ON THURSDAY AS THE FRONT APPROACHES...THEN FINALLY SHIFT TO AN OFFSHORE FLOW POST-FROPA FRIDAY. SPLIT THE DIFFERENCE ON SPEEDS BEHIND THE FRONT AS THE GFS GOES SCA WITH ITS NRLY WINDS...WHILE THE EC IS A BIT MORE SLUGGISH WITH WINDS TOPPING OUT AROUND 10 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... KLCH 48 69 59 73 / 0 10 10 10 KBPT 52 69 61 73 / 0 10 10 20 KAEX 44 69 54 74 / 0 10 10 20 KLFT 48 69 57 74 / 0 10 10 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1116 AM CST MON DEC 12 2011 .UPDATE...STRATUS NOW OVER ACADIANA/EAST CENTRAL LOUISIANA HAS STALLED ITS WESTWARD MIGRATION AND IS IN THE PROCESS OF ERODING. RAPID WARMUP THEN EXPECTED OVER ACADIANA. BULK OF WIDESPREAD ALTOCUMULUS OVER EAST TEXAS/NORTH LOUISIANA SHOULD REMAIN PRIMARILY OVER THIS AREA PER LATEST RUC 850-700 MB RH. WILL MAINTAIN CURRENT FORECAST. NO UPDATE COMING. && MARCOTTE && .PREV DISCUSSION... /ISSUED 520 AM CST MON DEC 12 2011/ DISCUSSION... 12Z TAF ISSUANCE. AVIATION... MID LEVEL BKN/OVC DECK ~9000FT MOVING ACROSS SE TX...EXPECTED TO GRADUALLY MOVE EAST ACROSS C AND SC LA TODAY...OTHERWISE VFR EXPECTED THROUGH THE PERIOD. NE WINDS EXPECTED TO GRADUALLY BECOME MORE E BY LATE AFTERNOON AND EVENING. DML PREV DISCUSSION... /ISSUED 438 AM CST MON DEC 12 2011/ DISCUSSION... SFC ANALYSIS SHOWS HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST CONTINUING TO RIDGE OVER THE FORECAST AREA WITH LIGHT NERLY LOW-LEVEL LOW PREVAILING AGAIN THIS MORNING. WATER VAPOR IMAGERY SHOWS A DECENT SHORTWAVE CROSSING THE SRN PLAINS/WRN GULF COAST STATES WHICH HAS HELPED PRODUCED A FEW SPRINKLES OR VERY LIGHT SHOWERS MAINLY OVER THE WRN 1/2 OF THE FORECAST AREA SO FAR OVERNIGHT. MEANWHILE WRLY FLOW ALOFT FROM THE PACIFIC CONTINUING TO SPREAD PLENTY OF MID/UPPER-LEVEL MOISTURE AND ASSOCIATED CLOUDINESS OVER THE REGION. TEMPS HAVE DIPPED JUST BELOW FREEZING ACROSS THE NERN EXTREME OF THE FORECAST AREA WHERE CLOUDS HAVE YET TO ENCROACH AND CUT OFF THE GOOD RADIATIVE COOLING...OTHERWISE TEMPS GENERALLY IN THE MID/UPPER 30S ALONG/EAST OF THE SABINE AND LOWER/MID 40S OVER SERN TX. NO SIGNIFICANT CHANGES TO THE EARLY PART OF THIS FORECAST PACKAGE. ANOTHER DAY OF LIGHT ERLY/NERLY FLOW EXPECTED TODAY AS THE SFC HIGH LINGERS NEAR THE ERN SEA BOARD. MEANWHILE SRLY FLOW WILL BEGIN TO DEVELOP ALOFT AS STRONG STORM SYSTEM CRASHES ASHORE ALONG THE SRN CALIFORNIA COAST. RISING HEIGHTS/WARMING ALOFT WILL LEAD TO THE BEGINNINGS OF A WARMING TREND WITH MAX TEMPS TODAY GENERALLY 10 DEGREES WARMER THAN YESTERDAY. MEANWHILE MINS TONIGHT FORECAST TO JUMP ALL THE WAY TO THE MID/UPPER 40S...WITH LOWER 50S COASTAL LA AND GOLDEN TRIANGLE REGION. MOISTURE WILL CONTINUE TO INCREASE THROUGH THE EARLY PART OF THE WEEK AS LOW-LEVEL FLOW VEERS AROUND TO THE SOUTHEAST. DEWPOINTS WILL CLIMB TO THE 50S/LOWER 60S THROUGH TUESDAY WHICH WILL ALLOW FOR SOME FOG DEVELOPMENT...ESPECIALLY NEAR THE COAST WITH SST CURRENTLY RUNNING IN THE LOWER/MID 50S. THE SYSTEM MOVING ASHORE OVER SRN CA TODAY WILL EJECT NEWD THROUGH MID-WEEK SPAWNING SFC LOW DEVELOPMENT OVER THE LEE OF THE ROCKIES ON WEDNESDAY. THE LOW WILL PUSH NEWD...GRADUALLY PULLING A SFC FRONTAL BOUNDARY TOWARD THE REGION. MODELS THIS MORNING ARE IN BETTER AGREEMENT WITH OOZING THE FRONT ACROSS THE FORECAST AREA LATE THURSDAY/EARLY FRIDAY TIME FRAME. NOT MUCH LIFT EXPECTED ALOFT WITH BEST ENERGY PULLING WELL NE OF THE AREA BY FROPA... INSTABILITY FAIRLY NEGLIGIBLE AS WELL SO ATTM EXPECTING MAINLY JUST SCATTERED SHOWERS WITH THE FRONT WITH MAYBE SOME ISOLATED THUNDER OVER THE FAR NERN ZONES. DUE TO THE SLOW-MOVING NATURE OF THE FRONT AND FAIRLY NON-PROGRESSIVE PATTERN ALOFT WE COULD SEE A FEW DAYS OF LINGERING SHOWERS AND THUS HAVE KEPT SMALL POPS IN THE FORECAST THROUGH THE WEEKEND. MARINE... MAINLY LIGHT FLOW EXPECTED TODAY AND TONIGHT WITH HIGH PRESSURE REMAINING IN CONTROL. WINDS WILL BEGIN TO INCREASE GRADUALLY STARTING TOMORROW WITH LOW PRESSURE DEVELOPING OFF THE ROCKIES ALTHOUGH SPEEDS SHOULD REMAIN BELOW ANY FLAGS. WINDS WILL STEADILY VEER TO A SERLY DIRECTION THROUGH MID-WEEK...BECOMING MORE SRLY ON THURSDAY AS THE FRONT APPROACHES...THEN FINALLY SHIFT TO AN OFFSHORE FLOW POST-FROPA FRIDAY. SPLIT THE DIFFERENCE ON SPEEDS BEHIND THE FRONT AS THE GFS GOES SCA WITH ITS NRLY WINDS...WHILE THE EC IS A BIT MORE SLUGGISH WITH WINDS TOPPING OUT AROUND 10 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... KLCH 62 48 69 59 73 / 0 0 10 10 10 KBPT 62 52 69 61 73 / 0 0 10 10 20 KAEX 61 44 69 54 74 / 0 0 10 10 20 KLFT 65 48 69 57 74 / 0 0 10 10 10 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
819 PM EST TUE DEC 13 2011 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS AND A RIDGE OVER THE SE WITH MAINLY ZONAL FLOW FROM THE NRN PLAINS TO NEW ENGLAND. A VIGOROUS SHORTWAVE TROUGH WAS MOVING THROUGH AZ WHILE A WEAKER UPSTREAM SHRTWV WAS MOVING INTO SRN SD. AT THE SFC...A RIDGE EXTENDED FROM NORTHERN QUEBEC TO LAKE SUPERIOR RESULTING IN WEAK ACYC FLOW OVER THE CWA WITH NO PCPN INDICATED BY RADAR. WITH THE MILD/MOIST AIRMASS IN PLACE...PATCHY FOG LINGERED OVER LOCATIONS NEAR THE WI BORDER. && .SHORT TERM...TONIGHT AND WEDNESDAY TONIGHT...AS THE HIGH SLIDES OFF TO THE SE...SRLY LOW LEVEL FLOW WILL INCREASE WEAK UPSLOPE FLOW INTO PORTIONS OF WEST AND CENTRAL UPPER MI MAY BE ENOUGH TO SUPPORT SOME PATCHY -DZ/-FZDZ AFT 06Z EVEN THOUGH OVERALL LOW LEVEL (925-850 MB) LIFT IS VERY WEAK...PER NAM/RUC...280K ISENTROPIC PROGS. OTHERWISE...WITH LITTLE DIURNAL TEMP CHANGE IS EXPECTED OVER THE AREA. AREAS OF FOG...SOME LCLY DENSE...MAY ALSO THICKEN WITH SLIGHT INCREASE IN MOISTURE ADVECTION. WEDNESDAY...AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND MOVES TOWARD THE UPPER MS VALLEY...LOW/MID LEVEL WAA AND MOISTURE ADVECTION WILL INCREASE. THIS SHOULD BRING AN AREA OF LIGHT PCPN OVER THE ENTIRE CWA BY AFTERNOON...PER NAM/GFS 290K-295K ISENTROPIC PROGS. NAM WET-BULB ZERO HEIGHTS SUGGEST THAT THE PCPN SHOULD BE MAINLY RAIN. HOWEVER...GIVEN LOW LEVEL TEMP PROFILES NEAR 0C OVER THE INTERIOR WEST...CANNOT RULE OUT SOME SNOW. ANY ACCUMULATIONS WOULD BE MINIMAL. EVEN THOUGH TEMPS WILL BE ABOVE FREEZING WHEN THE RAIN ARRIVES...SOME UNTREATED ROADS MAY STILL BE COLD ENOUGH TO CREATE PATCHY ICY SPOTS. .LONG TERM /WED NIGHT THROUGH NEXT TUESDAY/... SHORTWAVE CURRENTLY ROUNDING THE UPPER TROUGH OFF THE COAST OF SRN CA WILL MOVE TOWARDS THE AREA LATE WED AFTN AND MOVE ACROSS THE AREA WED EVENING. MODELS FAIRLY CONSISTENT ON THE MAIN ENERGY FROM THE SHORTWAVE MOVING ACROSS CNTRL/ERN UPPER MI...WHICH WILL GRADUALLY INTENSIFY THE LOW MOVING FROM IOWA AT 00Z THURS TO SE ONTARIO AT 12Z THURS. OTHER THAN THE FAST AND NW OUTLIER 12Z NAM...MAIN DIFFERENCES BETWEEN THE MODELS IS IN THE INTENSITY OF THE LOW. 06-12Z GFS RUNS ON THE STRONG SIDE AND 00Z ECMWF ON WEAKER SIDE. WILL FOLLOW A BLEND OF THE TWO SINCE TRACKS ARE SIMILAR AND ONLY MINOR DIFF IN THE THERMAL PROFILES. DURING THE EVENING...06 AND 12Z GFS SHOWING STRONG FGEN FROM H800-400 ACROSS THE CWA. THINK THE BEST FORCING WILL BE ALONG THE H800-600 FGEN AREA...WHERE THERE IS ABUNDANT MOISTURE AND STRONG AGEOSTROPHIC UPWARD CIRCULATION. FARTHER NW...APPEARS TO BE A DECENT H700-500 DRY AIR LAYER...AND DOWNWARD CIRCULATION MAY LIMIT PCPN FARTHER NW TOWARDS A KIWD TO KCMX LINE. OVER THE E...EXPECT A STRONG AREA OF H850-700 WAA AND 285-300K SFC ISENTROPIC ASCENT DURING THE EVENING. THINK THE EXISTING 100 POPS LOOK GOOD AND WILL LEAVE THEM AS IS. THEN HAVE A GRADUAL LOWERING HEADING OVER THE WEST TOWARDS HIGH END LIKELY. COULD BE A SHARP CUTOFF TO THE WEST EXTENT OF THE PCPN OVER THE WRN HALF OF LK SUPERIOR WITH THE FGEN CIRCULATION...SO TRIED TO SHOW THAT POTENTIAL. P-TYPE FOR THE WED NIGHT PERIOD IS WHERE THINGS GET TRICKY. BUFKIT SOUNDINGS FROM THE GFS SHOW AN ISOTHERMAL PROFILE FROM SFC TO 5-6KFT. WITH THAT TYPE OF SITUATION...IT WILL LIKELY BE SNOW WHERE LAYER IS NEAR 0C AND THEN RA/SN AROUND 1C AND ALL RA AROUND 2-3C. KCMX MAY BE FAR ENOUGH N AND AWAY FROM THE WARM SURGE TO KEEP PCPN A RA/SN MIX OR POSSIBLY EVEN ALL SNOW. THEN HEADING S AND E ACROSS THE CWA...EXPECT A TRANSITION TO ALL RAIN. BIGGEST CONCERN IS GETTING THAT RA/SN AREA PINNED DOWN AND STILL DON/T HAVE A GREAT FEEL...BUT IT SHOULD BE OVER THE NW THIRD. FORTUNATELY...THE HEAVIEST QPF WILL LIKELY BE TO THE SE OF THE UNCERTAIN AREA FOR RA/SN...SO IT SHOULD LIMIT THE IMPACT IF IT DOES END UP ALL SNOW. LAST COUPLE OF RUNS OF THE GFS HAVE REALLY BUMPED UP THE QPF IN THE FGEN LOCATION MOVING ACROSS CNTRL UPPER MI...WITH LIQUID AMOUNTS EXCEEDING 0.75IN...BUT IT IS LIKELY DUE TO THE MORE WRAPPED UP LOW SOLN. WILL NOT GO THAT HIGH...BUT WILL NEED TO BE MONITORED IF STRONGER LOW SOLN PANS OUT. OTHERWISE...EXPECT 0.25 TO 0.4 OF LIQUID ACROSS THE SE HALF OF THE CWA...MAINLY DURING THE EVENING. MAIN ENERGY AND DEEPER H700-500 MOISTURE PULLS OUT OVERNIGHT WED AND HAVE DIMINISHING POPS TO ACCOUNT FOR THAT. P-TYPE IS AGAIN A CONCERN HEADING INTO THE OVERNIGHT...SINCE THE DEEPER MOISTURE PULLS OUT BEFORE THE COLDER AIR ARRIVES LATE WED NIGHT INTO THURS. THIS WILL CUT THE POTENTIAL FOR ICE CRYSTALS IN THE CLOUD WAY DOWN AND LIMIT THE POTENTIAL FOR SNOW. WITH TEMPERATURES DROPPING TOWARDS FREEZING OVER THE WEST TOWARDS 12Z THURS...DID KEEP A MENTION OF -FZRA IN THE FORECAST LATE...BUT POTENTIAL SEEMS LIMITED DURING THE OVERNIGHT HOURS WITH THE SHORT PERIOD OF AT OR BELOW FREEZING TIME. OTHERWISE...WILL ONLY MENTION A LOW CHANCE FOR SNOW OVER THE WEST OVERNIGHT DUE TO LIMITED ICE CRYSTAL PRESENCE AND RAIN OVER THE CENTRAL AND EAST. THINK THE BIGGEST HAZARD IS MORE LIKELY TO BE THE WET ROADS ICING UP ON THURS...AS TEMPS FALL BELOW FREEZING THROUGH THE DAY. NRN STREAM UPPER TROUGH WILL SWEEP THROUGH THE CWA ON THURS. STILL DIFFERENCES IN THE SPEED/INTENSITY IN THE MODELS WITH THIS WAVE...BUT ALL HAVE THE GENERAL IDEA OF IT MOVING THROUGH THE UPPER GREAT LKS ON THURS. THIS WAVE WILL DROP H850 TEMPS THROUGH THE DAY TO -12C OVER THE W BY 00Z FRI. THESE COLDER TEMPS WILL STAY OVER THE AREA THROUGH THE DAY FRI...ANOTHER WEAKER SHORTWAVE DROPS ACROSS THE AREA. WITH TEMPS ALOFT PUTTING THE CLOUD LAYER BACK INTO THE ICE CRYSTAL AREA ON THURS...EXPECT TO CHANCES FOR SNOW AS THE P-TYPE TO BE ON THE INCREASE FROM WEST TO EAST. SHORTWAVE ENERGY WILL HELP ENHANCE THE DEVELOPING LES THROUGH THE DAY. WILL CONTINUE TREND OF HIGHER POPS OVER THE WEST IN THE MORNING WITH LES DEVELOPING AND SHORTWAVE ARRIVING...THEN INCREASE LES POPS OVER THE E UNDER NW WINDS IN THE AFTN INTO THURS NIGHT. IN ADDITION...WITH THE LOW INTENSIFYING TO THE NE OF THE AREA...EXPECT A BREEZY DAY ON THURS ACROSS THE AREA. THE HIGHEST WINDS SHOULD BE OVER THE E NEAR LK SUPERIOR...WHERE WINDS COULD GUST TO 40-45MPH LATE IN THE AFTERNOON. SFC RIDGE QUICKLY MOVES FROM W TO E OVER THE CWA ON THURS NIGHT INTO FRI. MODELS SHOWING VERY PRONOUNCED H925-700 DRYING WITH THE ARRIVAL OF THE RIDGE...SO HAVE TRENDED BACK LES POPS...ESPECIALLY OVER THE WEST WHERE BUFKIT SOUNDINGS SHOWING INVERSION HEIGHTS FALLING TOWARDS 3KFT. DID KEEP LIKELY/S OVER THE NW WIND FAVORED E LOCATIONS THURS NIGHT INTO FRI MORNING...BUT DROPPED TO CHANCES IN THE AFTN AS THE DRY AIR LIMITS POTENTIAL. DAYS 4 THROUGH 7 /FRI NIGHT THROUGH NEXT TUESDAY/... WEAK SHORTWAVE MOVING ACROSS THE AREA FRI NIGHT WILL BRING A LITTLE MORE MOISTURE TO THE AREA AND KEEP COLDER AIR IN PLACE. EXPECT ONGOING LES TO CONTINUE OVER THE E...WITH WINDS GRADUALLY SHIFTING MORE WRLY. LES MAY TRY TO REDEVELOP OVER THE W WITH THE ARRIVAL OF THE SHORTWAVE AND ADDITIONAL LLVL MOISTURE. WILL GO WITH LOW CHANCES OVER THE KEWEENAW WITH THE MORE WRLY WINDS AND THEN LOW END LIKELY/S OVER THE EAST. UPPER TROUGH SHIFTS E ON SAT AND DRAGS A SFC TROUGH OVER NRN LK SUPERIOR AND SRN ONTARIO THROUGH THE DAY AND INTO SAT NIGHT. THERE HAS BEEN A STRONGER TREND WITH THE SFC FEATURES AND UPPER FORCING OVER THE LAST DAY FOR THE SAT AND SAT NIGHT PERIOD...SO HAVE BUMPED POPS UP TO SLIGHTS OVER THE NRN U.P. AND CHANCES OVER THE LAKE. SOME DIFFERENCES APPEAR IN THE EXTENDED MODELS ON SUN INTO MON WITH THE HANDLING OF A POTENTIAL RIDGE IN THE NRN STREAM AND A CLOSED LOW OVER THE SW CONUS. LATEST 12Z RUN OF THE GFS HAS TRENDED SLOWER WITH THE EXIT OF THE UPPER LOW OVER THE SW CONUS SUN INTO MON...AND MORE IN LINE WITH THE 00Z ECMWF...SO HAVE FOLLOWED THAT FOR THE REST OF THE EXTENDED. SFC RIDGE WILL MOVE ACROSS THE CWA ON SUN INTO SUN NIGHT. NRN STREAM SHORTWAVE WILL APPROACH THE AREA MON INTO TUES...BRINGING ANOTHER LOW CHANCE OF PCPN. HAS BEEN A GOOD AMOUNT OF FLUCTUATION IN H850 TEMPS AFTER SUN...SO HAVE LIMITED CONFIDENCE IN VALUES...BUT APPEARS THAT TEMPS WILL SLIGHTLY ABOVE NORMAL. && .AVIATION /FOR THE 00Z TAF ISSUANCE/... LOW-LEVELS WILL REMAIN MOIST THROUGH THE TAF PERIOD AS A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS LIFTS NORTH INTO THE UPPER GREAT LAKES ON WEDNESDAY. LIMITED MIXING TONIGHT AND MOIST LOW-LVLS WILL CONTRIBUTE TO LOWER IFR CONDITIONS WITH CONDITIONS POSSIBLY FALLING TO AROUND AIRPORT MINIMUMS WHEN WINDS PROVIDE ADDITIONAL UPSLOPE LIFT. SOME DRYING MAY WORK INTO THE AREA TONIGHT AS WINDS BECOME MORE SOUTHERLY. BEST CHANCE OF IMPROVEMENT WILL BE AT KIWD WITH DOWNSLOPE WINDS...WHILE KSAW WILL REMAIN IFR AS SRLY WINDS ADD ADDITIONAL MOISTURE OFF OF LK MICHIGAN AND ALSO PROVIDE SOME UPSLOPE. CONFIDENCE IN DETAILS THROUGH ENTIRE TAF PERIOD IS ON THE LOW SIDE. IN GENERAL...SIGNIFICANT IMPROVEMENT IS NOT ANTICIPATED THROUGH WEDNESDAY MORNING. RAIN IS EXPECTED WED AFTERNOON AS SYSTEM APPROACHES FROM THE CENTRAL PLAINS. THIS ADDITIONAL MOISTURE WILL LIKELY KEEP CIGS IN THE LIFR CATEGORY WITH VBSYS RANGING FROM IFR TO MVFR DURING THE DAY. && .MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/... LIGHT SOUTHERLY WINDS WILL INCREASE INTO THE 15 TO 25 KT RANGE OVER THE CENTRAL AND EAST PORTIONS OF THE LAKE WED AHEAD OF LOW PRESSURE DEVELOPING IN THE PLAINS. THE LOW IS FCST TO DEEPEN AS IT LIFTS ACROSS THE UPPER LAKES BY THURSDAY MORNING. STRONGEST WINDS THIS WEEK WILL OCCUR JUST IN THE WAKE OF THE LOW THURSDAY MORNING THROUGH MIDNIGHT THURSDAY NIGHT. CONFIDENCE THAT 35-40 KT GALES WILL OCCUR IS HIGH SO THE WATCH CONTINUES FOR MUCH OF LK SUPERIOR. STRONG WINDS WILL DIMINISH ON FRI WITH THE SLOW APPROACH OF A HIGH PRESSURE RIDGE. A STRONGER SW FLOW WILL REDEVELOP ON SAT AFTER THIS HIGH SHIFTS TO THE SE WITH WINDS TO AROUND 30 KT OVER WEST AND CENTRAL PORTIONS OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...SRF AVIATION...JV MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 PM EST MON DEC 12 2011 .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS NAMERICA WITH SRN BRANCH SW FLOW ALF OVER THE GRT LKS BTWN RDG OVER THE ERN CONUS AND A WRN TROF. A SHRTWV EMBEDDED IN THIS SW FLOW IS OVER MN AND CAUSING AN AREA OF -RA OVER WI INTO SE UPR MI...WHERE DEEPER MSTR IS PRESENT. SOME SN IS MIXING IN WITH THIS PCPN IN THE PRESENCE OF DYNAMIC COOLING ACCOMPANYING THE SHRTWV EVEN THOUGH SFC TEMPS ARE ABV 32. ISSUED SPS THIS AFTN TO ACCOUNT FOR PERIODS OF HEAVY SN/SLUSHY ACCUMS IN A SWATH OVER THE CNTRL WHERE DYNAMIC COOLING RELATED TO AREA OF H85-7 FGEN IS MOST PRONOUNCED. OTRW... TEMPS OVER THE ENTIRE CWA ARE WELL ABV NORMAL AND IN THE 30S. ABUNDANT LLVL MSTR WITH DWPTS ALSO IN THE 30S IN LGT SW SFC FLOW HAS CAUSED QUITE A BIT OF LO CLD/FOG OVER THE CWA...BUT A COLD FNT TO THE N ASSOCIATED WITH A DISTURBANCE IN THE ARCTIC BRANCH OVER CAN IS PRESSING SLOWLY SWD INTO LK SUP. THE COLD AIR BEHIND THIS FNT IS QUITE SHALLOW PER THE 12Z INL RAOB...BUT SFC TEMPS AT NOON FALL QUITE SHARPLY FM ARND 35 OVER THE KEWEENAW AND AHEAD OF THE FNT TO 19 AT THUNDER BAY ONTARIO. && .SHORT TERM DISCUSSION /TNGT AND TUE/... MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN CHCS/PTYPE ASSOCIATED WITH SHRTWV LIFTING INTO WI. FOCUS FOR LATER TNGT AND TUE SHIFTS TO INFLUX OF COLDER/DRIER AIR FM THE N AND IMPACT ON THE WX. TNGT...SHRTWV OVER WI AND ACCOMPANYING DYNAMICS/DEEPER MSTR ARE PROGGED TO LIFT OUT AND EXIT THE ERN ZNS BY LATE EVNG...SO GOING MORE WDSPRD MIXED PCPN OVER MAINLY THE SE HALF WL DIMINISH WITH MID LVL SUBSIDENCE/DRYING OVERSPREADING THE FA. HOWEVER...INFLUX OF SHALLOW COLD AIR FOLLOWING NW-SE PASSAGE OF SFC COLD FNT WL MAINTAIN A SHARP LLVL INVRN AND PRESENT OVC ST/SC DECK. IN PLACES WITH UPSLOPE WIND FLOW...OPTED TO MAINTAIN MENTION OF -DZ/-FZDZ WITH SHALLOW MSTR WELL BLO THE DGZ AND UNDER SUBSIDENCE ALF. CONSIDERING THE LLVL CHILL OBSVD UPSTREAM...TENDED TO GO TOWARD THE LO SIDE OF GUIDANCE FOR TEMPS FOLLOWING THE COLD FROPA. EVEN SO...AIRMASS WL NOT BE SUFFICIENTLY COLD TO SUPPORT LES WITH SHARP INVRN. TUE...SHALLOW COLD WEDGE WL REMAIN IN PLACE WITH SLOWING VEERING FLOW TO MORE ESE IN THE AFTN AS CENTER OF HI PRES IN ONTARIO DRIFTS TO THE E. WITH COLD WEDGE GETTING A BIT MORE SHALLOW...SUSPECT LINGERING -DZ/-FZDZ WL BE MORE TIED TO UPSLOPE FLOW OVER THE NCNTRL WHERE THERE WL BE ADDITIONAL MOISTENING OFF LK SUP. EXPECT LTL DIURNAL TEMP RISE WITH LINGERING LO CLD OVC. .LONG TERM /TUES NIGHT THROUGH NEXT MONDAY/... ACTIVE MID TERM PORTION OF THE FORECAST...WITH A LOW PRESSURE SYSTEM MOVING THROUGH THE AREA AROUND MID WEEK AND PROVIDING A WINTRY MIX OF PCPN. TUES NIGHT...UPPER RIDGE AXIS WILL BE SHIFTING E OF THE CWA THROUGH THE NIGHT. SHOULD KEEP MUCH OF THE AREA DRY...ALTHOUGH PERSISTANT LOW CLOUDS WILL BE COVERING MUCH OF THE AREA. WITH INCREASING ISENTROPIC ASCENT AROUND THE 280 SFC AND DRY AIR ABOVE 5KFT...WOULDN/T BE SURPRISED IF THE SWRN HALF OF THE CWA EXPERIENCES SOME DZ/FZDZ...SO HAVE PUT THE MENTION IN FOR MUCH OF THE NIGHT. TRANSITIONED TO A RA/SN MIX ALONG THE WI BORDER OVERNIGHT...AS THE 280-300K ISENTROPIC ASCENT BEGINS TO MOVE INTO THE AREA. WITH THE MOISTURE EATING AWAY AT THE DRY AIR...EXPECT THE DZ/RA TO QUICKLY TRANSITION TO MAINLY SNOW ALONG THE BORDER AS ICE BECOMES PRESENT AND THERE IS A NEARLY ISOTHERMAL LAYER AT/BELOW 0C FROM THE SFC TO 6KFT. WITH THE MAIN TROUGH STILL WELL TO THE SW IN THE FOUR CORNERS REGION...WEAK SHORTWAVE ENERGY WILL BE EJECTING NE TOWARDS THE AREA ON WED. THIS WILL PUSH A WEAK LOW PRESSURE TROUGH ACROSS THE CWA THROUGH THE DAY. BEST CHANCES OF PCPN ARE S AND E...CLOSER TO THE MAIN PUSH OF THE SHORTWAVE...ALONG WITH H850-700 WAA AND ISENTROPIC ASCENT. THIS AREA OF PCPN SHOULD QUICKLY MOVE NE THROUGH THE CWA DURING THE MORNING AND EARLY AFTN AND LEAD TO A SLIGHTLY DRIER PERIOD OVER THE W IN THE LATE AFTN BEFORE THE NEXT WAVE AFFECTS THE AREA. DIFFICULTY IN THE FCST COMES FROM PCPN TYPE...AS THERE COULD BE A MIXED BAG WITH THE PASSAGE OF THE SYSTEM. SOUNDINGS CONTINUE TO SHOW A NEARLY ISOTHERMAL 0C LAYER FROM SFC TO 7KFT FOR THE CENTRAL/WRN PORTIONS OF THE AREA...WHICH WOULD SUPPORT SNOW IN THE MORNING. THEN AS SRLY WINDS INCREASE THROUGH THE DAY...LLVL TEMPS LOOK TO RISE AND LEAVE THE LOWEST 2-4KFT ABOVE FREEZING /TOWARDS 2-3C/. AT THAT SAME TIME...THE DEEP MOISTURE EXITS THE AREA AND THERE WILL LIKELY BE LITTLE/NO ICE POTENTIAL IN THE CLOUDS...SO HAVE WENT MAINLY RAIN...WITH JUST A MENTION OF SNOW OVER THE N. MAY END UP BEING JUST A -RA/DZ SITUATION IN THE LATE AFTN BEFORE NEXT WAVE ARRIVES. MAIN SHORTWAVE FROM THE SW FLOW ARRIVES ON WED NIGHT OVER THE ERN CWA...WHICH MODELS RESPOND TO BY INTENSIFYING THE LOW OVER THE UPPER GREAT LAKES. AT THE SAME TIME...NRN STREAM SHORTWAVE BEGINS TO ENTER THE NRN PLAINS AND PHASES WITH THE SRN STREAM. MODELS HAVE A NOTORIOUSLY TOUGH TIME WITH THESE EVENTS AND IT APPEARS THAT IT CONTINUES WITH THIS SITUATION. ISSUES APPEAR WITH THE TIMING/STRENGTH OF THE NRN STREAM WAVE...WHICH AFFECTS INTENSITY/TRACK OF LOW. TRENDS IN THE GFS/ECMWF OVER THE LAST DAY OR TWO HAVE BEEN FOR A WEAKER LOW TO TRACK ACROSS THE FAR ERN CWA WITH A WEAKER NRN STREAM WAVE. WILL FOLLOW THAT TREND FOR THE WED NIGHT AND THURS FORECAST...WITH AN EMPHASIS ON THE HPC PREFERRED GFS. THEREFORE...HAVE THE HIGHEST POPS /80 PLUS/ OVER THE ERN HALF OF THE CWA WITH THE BEST FORCING/MOISTURE. EXPECT THIS TO BE MAINLY RAIN OVER THE EAST HALF...BUT IF THE ECMWF ENDS UP BEING CORRECT THERE COULD BE SOME MIXING LATE. FCST IS A LITTLE MORE TRICKY OVER THE W...SINCE IT IS ON THE FRINGE OF THE BEST DEEP MOISTURE AND FORCING. IF PCPN OCCURS...HAVE A FEELING THAT POTENTIAL FOR ICE IN THE CLOUDS IS LIMITED. HAVE TRENDED TOWARDS MORE OF A RA SITUATION UNTIL THE COLDER AIR ARRIVES TOWARDS DAYBREAK THURSDAY. DEPENDING ON HOW QUICKLY TEMPS FALL DURING THE NIGHT AND INTO THURS MORNING...COULD SEE A PERIOD OF FZDZ BEFORE TURNING TO ALL SNOW DURING THE MORNING. THE LOW SHOULD THEN INTENSIFY OVER QUEBEC ON THURS...AS THE SHORTWAVES PHASE. WITH SFC HIGH OVER THE NRN PLAINS AND JUST E OF THE CANADIAN ROCKIES...EXPECT NW WINDS AND H850 TEMPS NEAR -12C TO LEAD TO AT LEAST SOME LES DEVELOPING. INVERSION HEIGHTS AROUND 6-8KFT GIVES A DECENT CLOUD DEPTH...BUT WITH BEST FORCING BELOW THE DGZ WILL LIMIT SNOW GROWTH. OPTED TO BUMP POPS UP HEADING INTO THE AFTN...AS MORE FAVORABLE CONDITIONS FOR LES ARRIVE...ESPECIALLY SINCE THE NRN CWA SHOULD BE SEEING WRAP AROUND MID-LVL MOISTURE FROM THE LOW. FINALLY...SHOULD BE A BREEZY DAY ON THURS...WITH GUSTS ALONG THE ERN LK SUPERIOR SHORELINE APPROACHING 40MPH. DAYS 4 THROUGH 7 /THURS NIGHT THROUGH NEXT MONDAY/... OVERALL...GOOD AGREEMENT IN THE EXTENDED MODELS ON THE OVERALL PATTERN FOR THE EXTENDED PERIOD. ON THURS NIGHT...UPPER TROUGH WILL BE PUSHING THROUGH THE AREA AND DROPPING H850 TEMPS TOWARDS -14C. SHOULD STILL BE SOME MID-LVL MOISTURE OVER THE E BEFORE THE MOISTURE EXITS THE AREA ON FRI AS THE INVERSION HEIGHTS FALL TOWARDS 5KFT WITH HIGH PRESSURE RIDGE MOVING OVER THE WRN CWA. THUS...LES INTENSITY SHOULD HIT IT/S PEAK THURS NIGHT...AS SHOWN IN LES PARAMETER...BEFORE DIMINISHING IN INTENSITY THROUGH FRI. ONLY MADE MINOR TWEAKS UP TO THE POPS OVER THE EAST AND THEN BUMPED UP TO HIGH END CHANCE AND LOW LIKELY/S OVER THE NW WIND SNOW BELTS OVER THE WEST FOR THURS NIGHT INTO FRI...ALTHOUGH THE CHANCES WILL DIMINISH OVER THE W IN THE AFTN. IN ADDITION...WEAK SHORTWAVE ON FRI COULD BRING SOME MID CLOUDS. SFC HIGH PRESSURE RIDGE WILL QUICKLY MOVE EAST OF THE AREA ON FRI NIGHT...WITH MODELS CONSISTENT ON A SHORTWAVE MOVING THROUGH THE UPPER MISS VALLEY ON SAT. THIS WAVE WILL LIKELY DIVE S OF THE CWA...AND CARRY THE BEST MOISTURE AND H850-500 Q-VECTOR CONV WITH IT. OTHER THAN LINGERING LES OVER THE NW FAVORED LOCATIONS OVER THE E IN THE MORNING BEFORE WIND SHIFT TO THE SW...WILL KEEP THE REST OF THE CWA DRY. UPPER RIDGE MOVING THROUGH SUNDAY...WITH H850 TEMPS RISING TOWARDS 1-4C. SHOULD LEAD TO ANOTHER WARM SUNDAY ACROSS THE AREA...BUT MAY NOT BE QUITE AS WARM AS YESTERDAY/S HIGHS. DID BUMP UP TEMPS FROM THE CONSENSUS OVER THE DOWNSLOPE AREAS NEAR LK SUPERIOR INTO THE UPPER 30S. NEXT TROUGH WILL AFFECT THE AREA SUN NIGHT INTO MON...BRINGING ANOTHER CHANCE OF PCPN TO THE AREA. DIFFERENCES IN HOW AMPLIFIED THE TROUGH IS...ALONG WITH MOISTURE RETURN FROM THE GULF...SO WILL LEAVE POPS AT SLIGHT/CHANCES. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... EXPECT PREDOMINANT IFR/LIFR CONDITIONS AT ALL 3 SITES THIS FCST PERIOD WITH MOIST SW FLOW AHEAD OF A SLOW MOVING COLD FNT APRCHG FM THE N. ALTHOUGH THE FNT WILL SINK SLOWLY S OVER THE FA LATER TDAY/ TNGT...SHALLOW INFLUX OF COLD AIR FM THE N THAT SHARPENS LLVL INVRN WL MAINTAIN THE LO CLDS. THE BEST CHC FOR IMPROVEMENT TO MVFR WL BE AT CMX...AS SOME LLVL DRYING BEHIND THE FNT MIGHT IMPACT THE KEWEENAW WITH LESS OF AN UPSLOPE WIND COMPONENT AT TIMES TNGT. SOME -FZDZ MAY IMPACT ALL 3 SITES AT TIMES WHEN THE LLVL WINDS ARE UPSLOPE. && .MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/... RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO EARLY WED AS A LOW PRESSURE TROUGH SLOWLY SLIDES ACROSS LK SUPERIOR. WINDS BECOME MORE SOUTHERLY AS ANOTHER LO PRES SYSTEM DEVELOPING IN THE PLAINS BEGINS TO LIFT TOWARD THE UPPER GREAT LAKES. SE WINDS AHEAD OF THIS LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF ON WED. THE MAIN HAZARD WILL BE AFTER THE LOW MOVES TOWARD QUEBEC ON THU...WHEN NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE SLOW APPROACH OF HI PRES. A STRONGER WSW FLOW WILL REDEVELOP ON SAT AFTER THIS HI SHIFTS TO THE SE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...KC SHORT TERM...KC LONG TERM...SRF AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 AM EST MON DEC 12 2011 UPDATED AVIATION DISCUSSION FOR 06Z TAFS .SYNOPSIS... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW ACRS NAMERICA WITH NRN BRANCH RDGING BLDG INTO THE UPR GRT LKS. THESE RISING HGTS...WITH 00Z-12Z H3 RISES UP TO 150M AT APX...ARE BEING FORCED BY VIGOROUS WAD IN THE STRONG WSW FLOW /12Z H85 WIND SPEED AT INL WAS 50KT/ BTWN SFC-H85 HI PRES IN THE MID ATLANTIC STATES AND LO PRES JUST N OF THE BORDER MOVING E INTO NW ONTARIO THAT IS ASSOCIATED WITH A SHRTWV NEAR LK WINNIPEG. THIS STRONG WAD HAS PUSHED H85 TEMPS IN THE UPR MS VALLEY/GREAT LKS TO UNSEASONABLY HI LVLS...WITH 12Z H85 TEMPS AT INL/MPX UP TO 7C VS 0C AT APX AND 3C AT GRB TOWARD THE RETREATING COLD AIR. LO CLDS OVER THE E HALF OF THE CWA THAT FORMED AS THIS WARMER AIR PUSHED OVER MORE RESILIENT NEAR SFC COLD AIR IN THE PRESENCE OF RADIATIONAL COOLING LAST NGT ARE ONLY GRDLY DISSIPATING EARLY THIS AFTN. OTRW...THE OVERALL DRYNESS OF THE LOCAL 12Z RAOBS IS ALLOWING A MOSUNNY DAY. BUT MORE LO CLDS ARE PUSHING NEWD THRU IOWA TOWARD THE UPR MIDWEST IN THE SW LLVL FLOW ARND THE HI IN THE MID ATLANTIC. A DISTURBANCE IN THE SRN BRANCH FLOW IS NOW IN KANSAS AND MOVING NEWD AS WELL. && .SHORT TERM DISCUSSION /TNGT AND MON/... MAIN FCST CONCERNS THIS PACKAGE ARE LO CLD TRENDS AND THE POTENTIAL FOR MIXED PCPN ON MON AS DISTURBANCE NOW IN KANSAS RIDES TO THE NE. TNGT...EXPECT THE LINGERING LO CLDS OVER THE E TO BE GONE BY FCST ISSUANCE...WITH MOCLR SKIES/WELL ABV NORMAL TEMPS DOMINATING. ALTHOUGH THE LO CLDS HEADING NE FM IOWA ARE LIKELY TO MIX OUT WITH DAYTIME TEMPS RISING INTO THE 30S/40S THIS AFTN...EXPECT THE ST/SC TO REDVLP WITH LOSS OF DAYTIME HEATING AFT SUNSET. 12Z MODEL GUIDANCE SHOWS THE HIER LLVL RH ARRIVING NEAR THE WI BORDER W OF IMT THIS EVNG...SO EXPECT EXPANDING LO CLDS SW-NE. THE COMBINATION OF THE LO CLDS/STEADY SW FLOW OF MILD AIR WL GREATLY REDUCE DIURNAL FALL OF TEMPS...BUT MIN TEMPS WL STILL FALL BLO 32 EVERYWHERE. LOCATIONS NEAR LK SUP WHERE THE SW FLOW DOWNSLOPES WL BE WARMEST. OPTED TO RETAIN MENTION OF SOME -FZDZ OVER THE INTERIOR W LATE AWAY FM THE DOWNSLOPING NEAR LK SUP AS SHALLOW MSTR INFLUX GROWS A BIT DEEPER WITH SOME DPVA/OMEGA/DEEPER MSTR ADVCTN AHEAD OF APRCHG KANSAS SHRTWV. BUT SINCE THE HIER RH WL REMAIN WELL BLO THE DGZ AND STILL BE RELATIVELY SHALLOW /BLO ABOUT H85/...ANY PCPN SHOULD REMAIN IN THE FORM OF SMALL WATER DROPLETS. MON...COMBINATION OF ARRIVAL OF LO PRES TROF ATTENDANT TO SHRTWV/SFC LO NOW IN NW ONTARIO...DEEPER MSTR FM THE SW...AND SHRTWV NOW IN KANSAS/ACCOMPANYING DYNAMICS WL RESULT IN EXPANDING PCPN CHCS. THE 12Z NAM/GFS/LOCAL WRF-ARW RUNS ALL EXHIBIT THE HIEST QPF UP TO ARND 0.20 INCH OVER THE SE CWA...WHERE GFS SHOWS AN AXIS OF SHARPER H85-7 FGEN AND THE ALL MODELS INDICATE DEEPER MSTR/OMEGA EXTENDING THRU THE DGZ. SO OPTED TO RETAIN GOING LIKELY POPS IN THIS AREA. PTYPE WL BE A SGNFT CONCERN. SUSPECT ONLY -FZDZ/FLURRIES WL BE ARND EARLY WITH RELATIVELY SHALLOW MSTR YET...BUT EITHER RA...SN...OR A MIX IS MORE LIKELY BY THE AFTN AT LEAST OVER OVER THE SE HALF WITH DEEPER MSTR/LARGER PCPN PARTICLES. FOR THE PAST SEVERAL RUNS...THE NAM HAS BEEN WARMEST WITH LLVL TEMPS AND THUS INDICATES RA WL BE THE PREDOMINANT PTYPE AT LEAST OVER THE SE. THE 12Z CNDN MODEL SUPPORTS THIS WARMER RUN AS WELL. ALTHOUGH THE UNSEASONABLE WARMTH TDAY WOULD SUG THESE MODELS ARE ON THE RIGHT TRACK...RELATIVELY DRY NATURE OF THE AIRMASS/POTENTIAL FOR EVAP COOLING HINTS THE COOLER GFS/WRF-ARW/ 09Z SREF ARE ON THE RIGHT TRACK. BLENDED IN THAT DIRECTION FOR LLVL TEMPS FIELDS FOR NOW TO DETERMINE PTYES. .LONG TERM /00Z TUESDAY THROUGH NEXT SUNDAY/... MAIN FOCUS FOR THE EXTENDED IS WITH PTYPES AND CHANCES FOR FREEZING PRECIP FROM MON NIGHT THROUGH WED MORNING...THEN WITH A SYSTEM MOVING THROUGH WED NIGHT/THU. A SFC TROUGH/FRONT WILL BE STALLED OVER UPPER MI FROM THE CENTRAL PLAINS FROM THE START OF THE PERIOD MON NIGHT...THROUGH TUE. A WEAK UPPER WAVE WILL BE MOVING THROUGH THE ERN CWA PRIOR TO 06Z TUE...PRODUCING SOME RAIN EAST. THE HARDEST PART OF THIS FORECAST PERIOD IS THAT SHALLOW MOISTURE WILL EXIST ALONG AND SOUTH OF THE FRONT...WITH DRY MID LEVELS KEEPING ICE CRYSTALS FROM FORMING. THE TEMP PROFILE WILL BE SUB-FREEZING THROUGH WEDNESDAY MORNING /EXCEPT NEAR SFC TEMPS DURING THE DAY TUE/...WHICH WILL KEEP PRECIP WITH THE DEEPER MOISTURE AND LIFT OVER THE EAST MON NIGHT AS SNOW...AND DRIZZLE/FREEZING DRIZZLE DIFFERENTIATION ELSEWHERE WILL BE DEPENDENT ON SFC TEMPS. AT THIS POINT...IT LOOKS LIKE THERE IS POTENTIAL FOR UP TO A TENTH OF AN INCH OF ICE ACCUMULATION FROM 00Z TUE INTO TUE MORNING...MAINLY OVER THE WEST HALF OF UPPER MI. SOME UNCERTAINTY STILL EXISTS WITH HOW MUCH FREEZING DRIZZLE WILL FALL...AND WHERE THE HEAVIEST AMOUNTS WILL BE. ATTENTION THEN TURNS TO THE NEXT SYSTEM MOVING IN AS AN UPPER TROUGH FROM CENTRAL CANADA EXTENDS OVER THE PLAINS AT 00Z THU...MOVES ACROSS UPPER MI THU...THEN INTO QUEBEC FRI NIGHT. MODELS SEEM TO BE COMING INTO BETTER AGREEMENT WITH THIS SYSTEM BUT THERE ARE STILL SOME BIG DIFFERENCES BETWEEN THEM...AND THOSE DIFFERENCES PLAY A HUGE ROLE IN THE FORECAST. THE GEM AND NAM LOOK ANOMALOUS WITH THE SYSTEM...SO THEY WERE NOT USED. THE 11/00Z ECMWF...WHICH HAS SHOWN BETTER RUN TO RUN CONTINUITY THAN THE GFS...HAS A DEEPER UPPER WAVE CO-LOCATED WITH THE CLOSED SFC LOW THAN THE GFS. THE MAIN DIFFERENCE BETWEEN THE MODEL STEMS FROM THE STRENGTH OF THE UPPER TROUGH MOVING IN...WHICH LEADS TO /AMONG OTHER THINGS/ TIMING DIFFERENCES IN THE LOW LEVELS. THE 11/12Z GFS BRINGS THE SFC LOW INTO THE CWA AROUND 06Z THU...WHILE THE 11/00Z ECMWF LAGS UNTIL AROUND 15Z THU. BOTH MODELS BRING IN MID LEVEL TEMPS THAT WOULD LEAD TO LIQUID PRECIP UNTIL THE LOW PASSES AND COLDER AIR COMES IN. SFC TEMPS WED NIGHT WILL FALL TO AROUND 30F OVER THE WEST HALF OF UPPER MI...BUT SHOULD STAY NEAR OR ABOVE FREEZING OVER THE EAST HALF. TEMPS OVER THE W LOOK TO STAY NEAR OR ABOVE FREEZING THROUGH AROUND 03Z THU...AND STAY THERE UNTIL MID TO LATE MORNING THU. THE GFS BRING THE BULK OF THE SYNOPTIC QPF /EASILY GREATER THAN 0.25 INCHES IN SOME SPOTS FROM BOTH THE ECMWF AND GFS/ BETWEEN 00Z AND 12Z THU...WHILE THE ECMWF IS BETWEEN 12Z AND 18Z THU...SO REGARDLESS OF MODEL THERE IS POTENTIAL FOR SIGNIFICANT FREEZING RAIN IF ALL THE INGREDIENTS COME TOGETHER. IT NEEDS TO BE STRESSED AGAIN THAT THERE IS STILL A CONSIDERABLE AMOUNT OF UNCERTAINTY WITH THIS SYSTEM...ESPECIALLY WITH THE SMALL SCALE DETAILS NEEDED FOR FREEZING RAIN. DUE TO THE POTENTIAL FOR SIGNIFICANT FREEZING RAIN ACCUMULATIONS...PAY EXTRA ATTENTION AND KEEP UP TO DATE WITH LATER FORECASTS ON THIS SYSTEM. MODELS ARE IN DECENT GENERAL AGREEMENT FROM FRI THROUGH SUN. NW WINDS AND 850MB TEMPS FALLING TO AOB -12C BY AT LEAST 12Z FRI WILL MAKE FOR POTENTIAL FOR LES...BUT DRY AIR IS ALSO MOVING IN. A SFC RIDGE WILL MOVE THROUGH SAT AFTERNOON AND EAST BY LATE SAT...BRINGING SWLY WINDS. SW FLOW BEHIND THE DEPARTING HIGH E AND LOW PRESSURE W...ALONG WITH AN UPPER RIDGE BUILDING IN FROM THE W...WILL LEAD TO 850MB TEMPS INCREASING TO AOA 0C BY LATE SUNDAY. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... LOW MVFR CIGS CONTINUE TO SPREAD ACROSS THE REGION THIS MORNING AND WILL GRADUALLY LOWER TO IFR AT ALL THREE TAF SITES BY 10Z. CLOUD PRODUCING LAYER IS QUITE SHALLOW SO DEVELOPMENT OF -DZ/FZDZ WILL BE DELAYED UNTIL SOME DEEPER MOISTURE ARRIVES CLOSER TO 12Z. NOT CONFIDENT ON THE DEVELOPMENT OF -FZDZ AS SFC TEMPERATURE TRENDS WARMER THAN BUFKIT SOUNDINGS BY A FEW DEGREES. ONCE TROUGH SWINGS THOUGH THE AREA EXPECT BETTER LIFT/FORCING TO PRODUCE LIGHT SNOW DURING THE DAYTIME HOURS. KSAW TO HAVE A LITTLE WARMER TEMPERATURE PROFILE AND SHOULD SEE -RASN IN THE AFTERNOON. AREAS OF SNOW EXPECTED OVER ALL THREE SITES BY 0Z TUESDAY AS COLDER AIR FILTERS IN. && .MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/... EXPECT SW WINDS UP TO 30 KTS LATE THIS AFTN TO DIMINISH TONIGHT WITH THE APPROACH OF A LO PRES TROF AND WEAKER PRES GRADIENT. ALTHOUGH THERE WILL BE A WSHFT TO THE N FOLLOWING THE PASSAGE OF THIS TROF ON MON...RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PERSIST INTO WED BUT SLOWLY VEER TO THE S AS A LO PRES SYSTEM DEVELOPING IN THE PLAINS BEGINS TO MOVE NE TOWARD THE UPPER GREAT LKS. SE WINDS AHEAD OF THIS LO MAY INCREASE TO 25 KTS ESPECIALLY OVER THE E HALF. THE MAIN HAZARD WILL BE AFTER THE LO MOVES TO THE NE ON THU...WHEN NW GALES IN ITS WAKE ENHANCED BY THE ARRIVAL OF VERY COLD AIR/MIXING WILL PREVAIL. EXPECT THESE STRONG WINDS TO DIMINISH ON FRI WITH THE SLOW APPROACH OF HI PRES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...KC SHORT TERM...KC LONG TERM...TITUS AVIATION...RJT MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1144 AM CST MON DEC 12 2011 .AVIATION... /18Z TAF ISSUANCE/ FRONTAL BOUNDARY MEANDERS FROM NEAR A KDLH-KSTC-KFSD LINE AT TAF ISSUANCE. THE FRONT WILL DRIFT SLOWLY SE TO KMSP-KRNH THIS AFTERNOON AND THEN TURN STATIONARY. CEILINGS ALONG THE FRONT ARE MAINLY IFR AND THIS SHOULD PERSIST THROUGH THE TAF PERIOD. THE OUTER FRINGES...KAXN AND KEAU...ARE A CHALLENGE WITH MVFR FORECAST TO BECOME IFR TONIGHT. THE LIGHT WINDS AND MOIST LOW LEVEL CONDITIONS SHOULD ALLOW FOR VISIBILITIES NEAR 1 MILE ALONG WITH CEILINGS IN THE 200-400 FOOT RANGE TUESDAY MORNING. THE FLOW WILL SLOWLY BECOME SOUTHEAST ON TUESDAY WITH RAIN ARRIVING LATE IN THE DAY FOR KRWF AND KMSP. THE RAIN WILL SPREAD INTO KSTC...KRNH AND KEAU TUESDAY EVENING. TEMPERATURES LOOK WARM ENOUGH THROUGH THE NIGHT FOR RAIN AT THESE LOCATION. KAXN MAY BE A PROBLEM EARLY TUESDAY EVENING WITH SOME POTENTIAL FOR FREEZING RAIN. KMSP...CEILINGS BETWEEN 010-015 EARLY THIS AFTERNOON THEN DROPPING BELOW 010 LATE IN THE AFTERNOON AS A FRONTAL BOUNDARY SETTLES OVERHEAD. NOT CONFIDENT THE IFR CEILINGS WILL LIFT IN THE 24-30 HOUR PORTION OF THE TAF AND KEPT THEM IN. HOWEVER...DID ALLOW FOR MVFR VISIBILITY TO DEVELOP LATE TUESDAY MORNING ONWARD. && .DISCUSSION... /ISSUED 449 AM CST MON DEC 12 2011/ SUMMARY...STILL A CONCERN FOR SOME SLICK ROADS IN WESTERN WISCONSIN...BUT OVERALL FREEZING DRIZZLE WILL NOT BE MUCH OF A FACTOR THIS MORNING. MIXED PRECIPITATION IS EXPECTED TUESDAY NIGHT THROUGH WEDNESDAY...BUT WE SHOULD SEE MOSTLY RAIN IN THE TWIN CITIES METRO. ALL THE AIRPORT OBSERVATIONS THIS MORNING RANGING BETWEEN 34-39 DEGREES IN MN AND WI. TEMPERATURES HAVE BEEN STEADY ALL NIGHT...SO DON`T EXPECT MUCH OF A CHANGE THROUGHOUT THE MORNING HOURS. MADE SOME CALLS TO COUNTIES IN WESTERN WI THIS MORNING. THERE HAVE BEEN SOME SLICK SPOTS ON ROADS IN RUSK...PRICE...AND TAYLOR COUNTIES THIS MORNING. EVEN WITH THE AIR TEMPERATURE ABOVE FREEZING...ROAD PAVEMENT TEMPERATURES ARE RANGING BETWEEN 30-33 DEGREES GIVEN THE FROST IN THE GROUND. UNTREATED ROADS ARE SLICK WHERE PRECIP IS FALLING IN WESTERN WI. SO FAR EASTERN MN HAS REMAINED MAINLY DRIZZLE FREE AND TEMPERATURES IN MN ARE A COUPLE DEGREES WARMER...SO THE SKIN TEMP ON THE ROADS MAY ALSO BE JUST ABOVE FREEZING. WE`LL LET THE CURRENT FREEZING RAIN ADVISORY IN WI RIDE FOR NOW AND THE 15Z EXPIRATION IS STILL REASONABLE AT THIS TIME. 06-09Z RUNS OF THE HRRR HAVE BEEN HANDLING THE CURRENT LIGHT PRECIP QUITE WELL...EVEN HIGHLIGHTING THE MORE CELLULAR NATURE TO THE LIGHT RAIN ECHOES IN ARX`S AREA OF SOUTHWEST WI. THE HRRR DOES SPREAD A MORE UNIFORM AREA OF LIGHT RETURNS FURTHER NORTHWEST INTO EASTERN MN AND WESTERN WI BETWEEN 11-14Z AND LINGERS IT UNTIL THE EARLY THIS AFTERNOON. AS A RESULT...HAVE KEPT REASONABLY HIGH POPS AND MENTION OF DRIZZLE GOING FOR MOST OF THE DAY. THIS ALSO AGREES WELL WITH THE SATURATION ON THE 280-295K ISENTROPIC SURFACES FROM THE RUC AND NAM THIS MORNING. REALLY DIDN`T CHANGE A WHOLE LOT FROM THE PREVIOUS FORECAST WITH RESPECT TO THE MID WEEK SYSTEM. YESTERDAY`S FORECAST ALREADY INTRODUCED 70-80% IN MANY LOCATIONS...AND HARD TO GO MUCH HIGHER WITH THE 12.00Z ECMWF SHOWING A SLIGHTLY SLOWER TREND AND THE LEADING WAVE OF PRECIP BRACKETING THE 12Z TIME FRAME WEDNESDAY MORNING. IT`S BECOMING LESS LIKELY THAT WE`LL HAVE MUCH RAIN ON THE FRONT SIDE OF THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING. 925-850MB TEMPS JUST SEEM TO WARM TOO FAST WHEN THE ISENTROPIC LIFT KICKS IN. 2M TEMPS ARE STILL NEAR FREEZING DURING THIS TIME...WITH MOST OF THE GUIDANCE SHOWING 31-35 DEGREES BY WEDNESDAY MORNING. MUCH LIKE TODAY...WITH AIR TEMPERATURES NEAR FREEZING AND FROST IN THE GROUND...A LIGHT ICE ACCUMULATION IS POSSIBLE ON UNTREATED SURFACES. HAVE INCLUDED A MIXTURE OF RAIN/FREEZING RAIN IN THE FORECAST...AND EVENTUALLY TREND TOWARD ALL RAIN BY WEDNESDAY AFTERNOON. THE ACTUALLY PV ANOMALY DOESN`T SWING THROUGH AT THE BASE OF THE 500MB TROF UNTIL 06-12Z THURSDAY. THE 12.00Z GFS AND ECMWF HAVE SOME SLIGHT TIMING DIFFERENCES WITH STRENGTHENING AND PROPAGATION OF THE SURFACE REFLECTION BUT THE OVERALL TRACK IS IN REASONABLE AGREEMENT...ALTHOUGH THE 12.06Z GFS I SEE IS NOW COMING IN MUCH MORE AGGRESSIVE IN TERMS OF QPF. THE 06-12Z THURSDAY WINDOW IS LIKELY OUR BEST WINDOW FOR ACCUMULATING SNOWFALL. IT ALL DEPENDS ON HOW FAST THE TEMPERATURE PROFILE COLLAPSES AND WHERE THE DEFORMATION PRECIP SETS UP ACROSS SOUTHEAST MN AND WESTERN WI. OVERALL...THE MID WEEK SYSTEM AT LEAST HAS THE POTENTIAL TO BRING THE MOST PRECIP WE`VE SEEN IN A COUPLE MONTHS...WHICH REALLY ISN`T SAYING MUCH GIVEN HOW DRY IT`S BEEN. AFTER A FEW MORE MILD MID DECEMBER TEMPERATURE DAYS...WE`LL GET A COOL DOWN FOR THURSDAY AND FRIDAY...BUT HEIGHTS BUILD AGAIN FOR THE WEEKEND. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
709 AM CST MON DEC 12 2011 .UPDATE... UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW. && .DISCUSSION... SUMMARY...STILL A CONCERN FOR SOME SLICK ROADS IN WESTERN WISCONSIN...BUT OVERALL FREEZING DRIZZLE WILL NOT BE MUCH OF A FACTOR THIS MORNING. MIXED PRECIPITATION IS EXPECTED TUESDAY NIGHT THROUGH WEDNESDAY...BUT WE SHOULD SEE MOSTLY RAIN IN THE TWIN CITIES METRO. ALL THE AIRPORT OBSERVATIONS THIS MORNING RANGING BETWEEN 34-39 DEGREES IN MN AND WI. TEMPERATURES HAVE BEEN STEADY ALL NIGHT...SO DON`T EXPECT MUCH OF A CHANGE THROUGHOUT THE MORNING HOURS. MADE SOME CALLS TO COUNTIES IN WESTERN WI THIS MORNING. THERE HAVE BEEN SOME SLICK SPOTS ON ROADS IN RUSK...PRICE...AND TAYLOR COUNTIES THIS MORNING. EVEN WITH THE AIR TEMPERATURE ABOVE FREEZING...ROAD PAVEMENT TEMPERATURES ARE RANGING BETWEEN 30-33 DEGREES GIVEN THE FROST IN THE GROUND. UNTREATED ROADS ARE SLICK WHERE PRECIP IS FALLING IN WESTERN WI. SO FAR EASTERN MN HAS REMAINED MAINLY DRIZZLE FREE AND TEMPERATURES IN MN ARE A COUPLE DEGREES WARMER...SO THE SKIN TEMP ON THE ROADS MAY ALSO BE JUST ABOVE FREEZING. WE`LL LET THE CURRENT FREEZING RAIN ADVISORY IN WI RIDE FOR NOW AND THE 15Z EXPIRATION IS STILL REASONABLE AT THIS TIME. 06-09Z RUNS OF THE HRRR HAVE BEEN HANDLING THE CURRENT LIGHT PRECIP QUITE WELL...EVEN HIGHLIGHTING THE MORE CELLULAR NATURE TO THE LIGHT RAIN ECHOES IN ARX`S AREA OF SOUTHWEST WI. THE HRRR DOES SPREAD A MORE UNIFORM AREA OF LIGHT RETURNS FURTHER NORTHWEST INTO EASTERN MN AND WESTERN WI BETWEEN 11-14Z AND LINGERS IT UNTIL THE EARLY THIS AFTERNOON. AS A RESULT...HAVE KEPT REASONABLY HIGH POPS AND MENTION OF DRIZZLE GOING FOR MOST OF THE DAY. THIS ALSO AGREES WELL WITH THE SATURATION ON THE 280-295K ISENTROPIC SURFACES FROM THE RUC AND NAM THIS MORNING. REALLY DIDN`T CHANGE A WHOLE LOT FROM THE PREVIOUS FORECAST WITH RESPECT TO THE MID WEEK SYSTEM. YESTERDAY`S FORECAST ALREADY INTRODUCED 70-80% IN MANY LOCATIONS...AND HARD TO GO MUCH HIGHER WITH THE 12.00Z ECMWF SHOWING A SLIGHTLY SLOWER TREND AND THE LEADING WAVE OF PRECIP BRACKETING THE 12Z TIME FRAME WEDNESDAY MORNING. IT`S BECOMING LESS LIKELY THAT WE`LL HAVE MUCH RAIN ON THE FRONT SIDE OF THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING. 925-850MB TEMPS JUST SEEM TO WARM TOO FAST WHEN THE ISENTROPIC LIFT KICKS IN. 2M TEMPS ARE STILL NEAR FREEZING DURING THIS TIME...WITH MOST OF THE GUIDANCE SHOWING 31-35 DEGREES BY WEDNESDAY MORNING. MUCH LIKE TODAY...WITH AIR TEMPERATURES NEAR FREEZING AND FROST IN THE GROUND...A LIGHT ICE ACCUMULATION IS POSSIBLE ON UNTREATED SURFACES. HAVE INCLUDED A MIXTURE OF RAIN/FREEZING RAIN IN THE FORECAST...AND EVENTUALLY TREND TOWARD ALL RAIN BY WEDNESDAY AFTERNOON. THE ACTUALLY PV ANOMALY DOESN`T SWING THROUGH AT THE BASE OF THE 500MB TROF UNTIL 06-12Z THURSDAY. THE 12.00Z GFS AND ECMWF HAVE SOME SLIGHT TIMING DIFFERENCES WITH STRENGTHENING AND PROPAGATION OF THE SURFACE REFLECTION BUT THE OVERALL TRACK IS IN REASONABLE AGREEMENT...ALTHOUGH THE 12.06Z GFS I SEE IS NOW COMING IN MUCH MORE AGGRESSIVE IN TERMS OF QPF. THE 06-12Z THURSDAY WINDOW IS LIKELY OUR BEST WINDOW FOR ACCUMULATING SNOWFALL. IT ALL DEPENDS ON HOW FAST THE TEMPERATURE PROFILE COLLAPSES AND WHERE THE DEFORMATION PRECIP SETS UP ACROSS SOUTHEAST MN AND WESTERN WI. OVERALL...THE MID WEEK SYSTEM AT LEAST HAS THE POTENTIAL TO BRING THE MOST PRECIP WE`VE SEEN IN A COUPLE MONTHS...WHICH REALLY ISN`T SAYING MUCH GIVEN HOW DRY IT`S BEEN. AFTER A FEW MORE MILD MID DECEMBER TEMPERATURE DAYS...WE`LL GET A COOL DOWN FOR THURSDAY AND FRIDAY...BUT HEIGHTS BUILD AGAIN FOR THE WEEKEND. && .AVIATION.../12Z TAF ISSUANCE/ PLENTY OF LOW LEVEL MOISTURE BEING ADVECTED IN FROM THE SOUTH AHEAD OF A SLUGGISH COLD FRONT DRAPED OVER NRN MN INTO ERN SD MAKING FOR WIDESPREAD LOW CLOUDS AND PATCHY REDUCED CIGS. WEAK PRECIP ECHOES ARE BECOMING MORE PREVALENT ON KMPX RADAR THIS MORNING...PRIMARILY SOUTH AND EAST OF KMSP WHERE PRECIP IS EXPECTED TO REMAIN THROUGH THE DAY. NOT EXPECTING -FZDZ AS AIR TEMPS ARE EXPECTED TO REMAIN ABOVE FREEZING...BUT WILL LOOK FOR PERIODS OF -DZ THROUGH EARLY AFTN. EVEN IF PRECIP DOES NOT REACH ANY OF THE TERMINALS...MVFR/IFR CIGS WILL BE A PRIMARY CONCERN WITH MVFR VSBYS SECONDARY. LOW CLOUDS WILL REMAIN IN PLACE THROUGH THE DAY. WINDS BETWEEN 5-10 KT WILL MAINLY MAKE FOR LOW STRATUS WITH DECKS THROUGH EARLY AFTN IN THE LOWER RANGE OF MVFR ALTHOUGH PERIODS OF IFR ARE POSSIBLE. BY THIS EVENING...IFR CIGS WILL BE PREVALENT WITH MVFR VSBYS. AT TIMES...CIGS MAY DROP TO LIFR BUT CONFIDENCE IS NOT HIGH ENOUGH ATTM TO GO THAT LOW WHEREAS CONFIDENCE IS RATHER HIGH OF SEEING IFR...IF NOT LOWER...CIGS. DEGRADED CONDITIONS WILL REMAIN THROUGH DAYBREAK TUESDAY MORNING. MSP...MVFR CIGS WILL PREVAIL THROUGH LATE AFTN BUT THE 1700 FT THRESHOLD WILL BE A TRICKY PROPOSITION TODAY. AM EXPECTING CIGS TO WOBBLE BETWEEN 1500-1900 FT WHICH MAY CAUSE ISSUES WITH TRAFFIC MANAGEMENT. AS FOR PRECIP THROUGH THE DAY...-FZDZ IS NOT EXPECTED WITH A SHALLOW ENOUGH LOW LEVEL LAYER AND SFC TEMPS WELL ABOVE FREEZING. THEREFORE...ANY PRECIP IS EXPECTED TO BE LIQUID AND NOT A LOT AT THAT /ONLY UP TO A TENTH OF AN INCH ACCUMULATION/. MVFR CIGS WILL PREVAIL THROUGH LATE AFTN THEN WILL LOOK FOR CIGS TO DROP TO IFR WHICH WILL THEN PREVAIL TONIGHT THROUGH TUE MORNING. LIFR CIGS ARE POSSIBLE DURING THE EARLY MORNING HOURS...BUT CONFIDENCE NOT THAT HIGH ATTM FOR ITS INCLUSION. OUTLOOK...MVFR CIGS MAY LINGER THROUGH TUESDAY AS THE FRONT SETTLES NEAR THE IA/MN BORDER. COMPLEX SYSTEM MOVING SOUTHWEST TO NORTHEAST ALONG THE FRONT TUE NIGHT THROUGH WED NIGHT WILL BRING A VARIETY OF FROZEN AND/OR LIQUID PRECIPITATION WITH A HIGH PROBABILITY OF DEGRADED FLIGHT CATEGORIES. VFR CONDITIONS RETURN THU AND FRI AS HIGH PRESSURE RETURNS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...FREEZING RAIN ADVISORY UNTIL 9 AM CST THIS MORNING FOR BARRON- CHIPPEWA-EAU CLAIRE-RUSK. && $$ JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
449 AM CST MON DEC 12 2011 .DISCUSSION... SUMMARY...STILL A CONCERN FOR SOME SLICK ROADS IN WESTERN WISCONSIN...BUT OVERALL FREEZING DRIZZLE WILL NOT BE MUCH OF A FACTOR THIS MORNING. MIXED PRECIPITATION IS EXPECTED TUESDAY NIGHT THROUGH WEDNESDAY...BUT WE SHOULD SEE MOSTLY RAIN IN THE TWIN CITIES METRO. ALL THE AIRPORT OBSERVATIONS THIS MORNING RANGING BETWEEN 34-39 DEGREES IN MN AND WI. TEMPERATURES HAVE BEEN STEADY ALL NIGHT...SO DON`T EXPECT MUCH OF A CHANGE THROUGHOUT THE MORNING HOURS. MADE SOME CALLS TO COUNTIES IN WESTERN WI THIS MORNING. THERE HAVE BEEN SOME SLICK SPOTS ON ROADS IN RUSK...PRICE...AND TAYLOR COUNTIES THIS MORNING. EVEN WITH THE AIR TEMPERATURE ABOVE FREEZING...ROAD PAVEMENT TEMPERATURES ARE RANGING BETWEEN 30-33 DEGREES GIVEN THE FROST IN THE GROUND. UNTREATED ROADS ARE SLICK WHERE PRECIP IS FALLING IN WESTERN WI. SO FAR EASTERN MN HAS REMAINED MAINLY DRIZZLE FREE AND TEMPERATURES IN MN ARE A COUPLE DEGREES WARMER...SO THE SKIN TEMP ON THE ROADS MAY ALSO BE JUST ABOVE FREEZING. WE`LL LET THE CURRENT FREEZING RAIN ADVISORY IN WI RIDE FOR NOW AND THE 15Z EXPIRATION IS STILL REASONABLE AT THIS TIME. 06-09Z RUNS OF THE HRRR HAVE BEEN HANDLING THE CURRENT LIGHT PRECIP QUITE WELL...EVEN HIGHLIGHTING THE MORE CELLULAR NATURE TO THE LIGHT RAIN ECHOES IN ARX`S AREA OF SOUTHWEST WI. THE HRRR DOES SPREAD A MORE UNIFORM AREA OF LIGHT RETURNS FURTHER NORTHWEST INTO EASTERN MN AND WESTERN WI BETWEEN 11-14Z AND LINGERS IT UNTIL THE EARLY THIS AFTERNOON. AS A RESULT...HAVE KEPT REASONABLY HIGH POPS AND MENTION OF DRIZZLE GOING FOR MOST OF THE DAY. THIS ALSO AGREES WELL WITH THE SATURATION ON THE 280-295K ISENTROPIC SURFACES FROM THE RUC AND NAM THIS MORNING. REALLY DIDN`T CHANGE A WHOLE LOT FROM THE PREVIOUS FORECAST WITH RESPECT TO THE MID WEEK SYSTEM. YESTERDAY`S FORECAST ALREADY INTRODUCED 70-80% IN MANY LOCATIONS...AND HARD TO GO MUCH HIGHER WITH THE 12.00Z ECMWF SHOWING A SLIGHTLY SLOWER TREND AND THE LEADING WAVE OF PRECIP BRACKETING THE 12Z TIME FRAME WEDNESDAY MORNING. IT`S BECOMING LESS LIKELY THAT WE`LL HAVE MUCH RAIN ON THE FRONT SIDE OF THIS SYSTEM TUESDAY NIGHT INTO WEDNESDAY MORNING. 925-850MB TEMPS JUST SEEM TO WARM TOO FAST WHEN THE ISENTROPIC LIFT KICKS IN. 2M TEMPS ARE STILL NEAR FREEZING DURING THIS TIME...WITH MOST OF THE GUIDANCE SHOWING 31-35 DEGREES BY WEDNESDAY MORNING. MUCH LIKE TODAY...WITH AIR TEMPERATURES NEAR FREEZING AND FROST IN THE GROUND...A LIGHT ICE ACCUMULATION IS POSSIBLE ON UNTREATED SURFACES. HAVE INCLUDED A MIXTURE OF RAIN/FREEZING RAIN IN THE FORECAST...AND EVENTUALLY TREND TOWARD ALL RAIN BY WEDNESDAY AFTERNOON. THE ACTUALLY PV ANOMALY DOESN`T SWING THROUGH AT THE BASE OF THE 500MB TROF UNTIL 06-12Z THURSDAY. THE 12.00Z GFS AND ECMWF HAVE SOME SLIGHT TIMING DIFFERENCES WITH STRENGTHENING AND PROPAGATION OF THE SURFACE REFLECTION BUT THE OVERALL TRACK IS IN REASONABLE AGREEMENT...ALTHOUGH THE 12.06Z GFS I SEE IS NOW COMING IN MUCH MORE AGGRESSIVE IN TERMS OF QPF. THE 06-12Z THURSDAY WINDOW IS LIKELY OUR BEST WINDOW FOR ACCUMULATING SNOWFALL. IT ALL DEPENDS ON HOW FAST THE TEMPERATURE PROFILE COLLAPSES AND WHERE THE DEFORMATION PRECIP SETS UP ACROSS SOUTHEAST MN AND WESTERN WI. OVERALL...THE MID WEEK SYSTEM AT LEAST HAS THE POTENTIAL TO BRING THE MOST PRECIP WE`VE SEEN IN A COUPLE MONTHS...WHICH REALLY ISN`T SAYING MUCH GIVEN HOW DRY IT`S BEEN. AFTER A FEW MORE MILD MID DECEMBER TEMPERATURE DAYS...WE`LL GET A COOL DOWN FOR THURSDAY AND FRIDAY...BUT HEIGHTS BUILD AGAIN FOR THE WEEKEND. && .AVIATION.../06Z TAF ISSUANCE/ WIDESPREAD MVFR CIGS WERE PREVALENT ALONG WITH FEW POCKETS OF IFR CONDITIONS OVER SOUTH CENTRAL MN AT THIS TIME. SURFACE WINDS HAVE STAYED UP FOR THE MOST PART ACROSS THE TAF SITES...KEEPING THE BOUNDARY LAYER WELL MIXED. WATER VAPOR FROM THE SNOW MELT ACROSS THE PARTS OF NORTHERN IOWA AND SOUTHERN MN...WAS ALSO KEEPING SURFACE TEMPERATURES FROM LOWERING BELOW THE FREEZING MARK SO FAR. EXPECT SOME PATCHY LIGHT DRIZZLE TO DEVELOP OVERNIGHT. LIGHT FREEZING DRIZZLE APPARENTLY MORE LIKELY OVER PARTS OF WEST CENTRAL WISCONSIN THAN OVER MN...BUT STILL SOMEWHAT OF CONCERN FOR AVIATION INTEREST WITH NO DEICING EQUIPMENT THE REST OF TONIGHT AND MONDAY MORNING. STRONG INVERSION ALOFT OVER THE TAF SITES...PRECIP SHOULD BE MAINLY LIQUID THE REST OF THE DAY(MONDAY). AS THE COLD FRONT THAT IS DRAPED OVER NORTHERN HALF OF MN...SLOWLY SAGS SOUTH DURING THE PERIOD...EXPECT MORE WIDESPREAD IFR OR LIFR FLYING CONDITIONS DEVELOPING OVER THE UPPER MIDWEST LATE IN THE DAY AND OVERNIGHT MONDAY. KMSP...MVFR CONDITIONS WILL PERSIST OVERNIGHT WITH CEILINGS OR VISIBILITIES LOWERING BELOW 1000 FEET AGL AND 3 MILES IN PATCHY MIST AND FOG. WEATHER CONDITIONS ARE EXPECTED TO LOWER AS A COLD FRONT DIPS SOUTH LATE IN THE DAY MONDAY/MONDAY NIGHT WITH CEILING LOWERING BELOW 1000 FEET AND VISIBILITIES 3 MILES IN FOG. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...FREEZING RAIN ADVISORY UNTIL 9 AM CST THIS MORNING FOR BARRON- CHIPPEWA-EAU CLAIRE-RUSK. && $$ CLF/JVM
AREA FORECAST DISCUSSION...UPDATED
NWS HASTINGS NE
1128 AM CST MON DEC 12 2011 .UPDATE...SHORT UPDATE EARLIER THIS MORNING FOR AFTERNOON WEATHER AND LESS FOG ACROSS THE AREA. CHALLENGE THIS AFTERNOON IS THE NORTHWEST/WEST FRINGES OF THE NEBRASKA COUNTIES WHERE SKIES CLEARED AND TEMPERATURES TANKED...AND LOCALLY DENSE FOG HAD SET IN. HARD TO GAGE JUST HOW MUCH WARMING THEY MAY GET WITH SNOW STILL ON THE GROUND BUT ALSO SOME PERIODS OF SUNSHINE. ELSEWHERE...CLOUDS SKIES WILL HOLD FORM AND TEMPERATURES IN THE 30S TO LOWER 40S. NORTHWEST WINDS BEHIND WEAK SURFACE BOUNDARY MAY ALLOW FOR TEMPERATURES TO SLIP A FEW DEGREES LATER THIS AFTERNOON ACROSS THE NORTHERN SECTIONS OF THE FORECAST AREA. THERE IS INCREASING CONTINUITY AMONGST MORNING MODEL RUNS THAT THE PERIOD OF MAIN CONCERN FOR ICING WILL BE AFTER 08Z TONIGHT WITH INITIAL FREEZING DRIZZLE...AND THEN FROM ABOUT 12Z TO 18Z TUESDAY ACROSS THE NORTHWEST PART OF THE CWFA IN TERMS OF FREEZING RAIN. THIS WILL BE THE FOCUS THIS AFTERNOON IN THE SHORT TERM. && .AVIATION...MVFR TO IFR CONDITIONS WILL PREVAIL THROUGHOUT THIS FORECAST PERIOD FOR KGRI. THE MAIN ISSUE WILL BE LATER TONIGHT WHEN NEAR LIFR CEILINGS/VISIBILITIES WILL START TO SET UP ALONG WITH SOME LIGHT FREEZING DRIZZLE AFTER ABOUT 08Z. EVENTUALLY THIS WILL TURN TO MORE OF A LIGHT FREEZING RAIN SHORTLY AFTER SUNRISE TUESDAY...BUT TEMPERATURES WILL WARM BY NOON TO HAVE RAIN START TO BE MORE PROMINENT. WINDS WILL BE LIGHT...BUT SHIFTING TO THE NORTH AND EVENTUALLY EAST. && .PREV DISCUSSION... /ISSUED 726 AM CST MON DEC 12 2011/ AVIATION...12Z KGRI TAF. GENERALLY POOR AVIATION CONDITIONS ARE EXPECTED AT KGRI FOR MUCH OF THE NEXT 24 HOURS. THE WIDESPREAD LOW LEVEL STRATUS ACROSS THE REGION THIS MORNING IS EXPECTED TO THICKEN OVER THE NEXT FEW HOURS...WITH LOW MVFR CIGS AND VSBY LIKELY TO RETURN AND PERSIST AT KGRI THROUGH ABOUT 12/18Z. CEILINGS AND VSBYS WILL EVENTUALLY IMPROVE TO MORE ELEVATED MVFR LEVELS BY EARLY AFTERNOON...HOWEVER THIS MINOR IMPROVEMENT IS EXPECTED TO BE VERY SHORT LIVED...WITH LOW MVFR...OR EVEN IFR...VISIBILITIES AND CEILINGS EXPECTED TO DEVELOP AFTER THE SUN SETS. IN ADDITION...AN APPROACHING SYSTEM WILL BRING THE CHANCE FOR SOME LIGHT FREEZING DRIZZLE OR LIGHT FREEZING RAIN LATE IN THE TAF PERIOD...BUT KEPT AS -DZ FOR CURRENT TAF ISSUANCE AS ONSET IS VERY NEAR THE END OF CURRENT VALID PERIOD. LIGHT SOUTHERLY WINDS NEAR 10 KTS THIS MORNING WILL SHIFT MORE WESTERLY THROUGH THE PERIOD...EVENTUALLY TRANSITIONING FULL CIRCLE OVERNIGHT...BECOMING NORTHEASTERLY OVERNIGHT TONIGHT. PREV DISCUSSION... /ISSUED 556 AM CST MON DEC 12 2011/ SHORT TERM...THROUGH WEDNESDAY NIGHT. PLENTY OF ISSUES TRYING TO NAIL DOWN PRECIP TYPES/AMOUNTS ETC. DURING THE NEXT FEW DAYS HAS LED TO A CHALLENGING NIGHT ON THE FORECAST DESK. MAIN CONCERNS DURING THE NEXT FEW DAYS INVOLVE WHETHER THE CWA WILL SEE ANY APPRECIABLE RISK OF GENERALLY LIGHT ICING...ALTHOUGH GENERAL WARMING TREND OF SURFACE TEMPERATURES DURING LAST SEVERAL MODEL RUNS SEEMS TO BE CONFINING THE MAIN RISK ZONE TO A SMALLER AND SMALLER AREA OF THE NORTHWEST CWA. STARTING OFF EARLY THIS MORNING...BEEN AN INTERESTING NIGHT FROM A TEMP PERSPECTIVE...AS WIDESPREAD STRATUS AND SOUTHERLY BREEZES HAVE KEPT READINGS SEVERAL DEGREES ABOVE FREEZING ACROSS THE VAST MAJORITY OF THE CWA...RESULTING IN A SOMEWHAT RARE MODEST OVERNIGHT SNOW MELT FOR THIS TIME OF YEAR. MAIN CONCERNS OVERNIGHT...AND THROUGH THE NEXT FEW/SEVERAL HOURS ARE ACROSS THE FAR WESTERN PORTIONS OF THE CWA...WHERE WEB CAMS AND AUTOMATED OBS HAVE SUGGESTED THAT THERE IS A NARROW CORRIDOR OF LOCALLY DENSE FOG LIKELY LURKING NEAR/WITHIN WESTERN PORTIONS OF DAWSON...GOSPER AND FURNAS COUNTIES. THIS FOG IS GENERALLY TIED TO THE EDGE OF THE EXPANSIVE LOW CLOUD DECK COVERING MUCH OF THE REGION...ALONG WHICH THERE IS QUITE A TEMP GRADIENT INCLUDING A STRIKING 26 DEGREE DIFFERENCE BETWEEN HOLDREGE AND MCCOOK AT 11Z. WITH ANY DENSE FOG SEEMINGLY AFFECTING SUCH A SMALL PORTION OF THE AREA...HAVE OPTED AGAINST AN ADVISORY...BUT HAVE IT MENTIONED IN THE GRIDS AND ALSO IN THE HWO. AS FOR ANY LIGHT FREEZING DRIZZLE CONCERNS FROM 12-24 HOURS AGO...THESE HAVE APPARENTLY BEEN AVOIDED FOR NOW GIVEN THE SEASONABLY MILD OVERNIGHT TEMPS...AND EVEN PLAIN LIGHT DRIZZLE HAS APPARENTLY BEEN QUITE SCANT OVERNIGHT ACROSS THE AREA. A QUICK LOOK AT 11Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK TROUGH AXIS NEAR THE EDGE OF THE STRATUS/NEAR THE WESTERN EDGE OF THE CWA...WITH STEADY SOUTH BREEZES 5-15 MPH AFFECTING NEARLY ALL OF THE CWA TO THE EAST OF THIS AXIS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM THE PRESENCE OF A FAIRLY WEAK MID LEVEL SHORTWAVE STARTING TO DEPART EASTERN NEB TO THE EAST- NORTHEAST...WITH LOW STRATUS CEILINGS ACTUALLY RISING QUITE A BIT IN MUCH OF THE CWA IN ITS WAKE. UPSTREAM...THE MAIN LARGE-SCALE TROUGH OF CONCERN IS STILL CENTERED NEAR THE PACIFIC COAST. FOR TODAY...THE MAIN CONCERN THIS MORNING IS WHETHER ANY DENSE FOG ALONG THE STRATUS EDGE CAN WORK A BIT FARTHER EASTWARD INTO THE AREA. FOR NOW HAVE DENSE FOG MENTION CONFINED SOLELY TO PARTS OF DAWSON...GOSPER...FURNAS. AS FOR SKY COVER...LATEST SUGGESTIONS FROM HRRR MODEL IS THAT STRATUS SHOULD HOLD FIRM ACROSS MOST OF THE CWA THROUGH THE DAY...ALTHOUGH ROUGHLY THE WESTERN 1/4 OF THE AREA COULD SEE SOME PARTIAL CLEARING ALONG/WEST OF THE WEAK LOW LEVEL TROUGH AXIS. DEFINITELY SOMETHING TO WATCH. TEMP WISE...GIVEN THE WARM START RAISED HIGHS ROUGHLY 3-4 DEGREES OVER PREVIOUS FORECAST MOST AREAS...AND POSSIBLY NOT ENOUGH. WILL AIM FOR A GRADIENT FROM MID 30S NORTHWEST TO LOW 40S SOUTHEAST...AND MAYBE EVEN UPPER 40S IN THE MITCHELL COUNTY KS AREA. LIMITED LIFT SHOULD KEEP ANY POTENTIAL DRIZZLE AT BAY TODAY. TONIGHT...MAIN CHANGE WAS TO RAISE LOW TEMPS A NOTABLE 4-8 DEGREES OVER PREVIOUS FORECAST MOST AREAS...ALTHOUGH THIS IS VERY DEPENDENT ON WIDESPREAD CLOUD COVER HOLDING FIRM. ASSUMING THIS OCCURS...AM NOW TALKING A GRADIENT FROM LOW-MID 20S NORTHWEST TO LOW-MID 30S SOUTHEAST. WITH LIGHT WINDS...CANNOT RULE OUT PATCHY TO AREAS OF FOG OVERNIGHT...BUT NOTHING THAT CAN REALLY BE PINNED DOWN FOR POSSIBLE DENSE DEVELOPMENT. KEPT THEME FROM PREVIOUS FORECAST INTACT...WITH SLIGHT CHANCE OF DRIZZLE IN THE SOUTH BEFORE MIDNIGHT...AND THEN BETTER CHANCES FOR LIGHT MEASURABLE PRECIP AFTER MIDNIGHT MAINLY ACROSS THE SOUTHERN HALF OF THE CWA AS FIRST LEAD SHORTWAVE MOVES INTO THE REGION. COULD SEE LIGHT ICING MAINLY ACROSS NEB ZONES...BUT NOT ANTICIPATING MAJOR ISSUES AND DAY SHIFT SHOULD BE ABLE TO BETTER PIN DOWN THE SURFACE TEMP TREND. TUESDAY...RAISED POPS 10-20 PERCENT OVER PREVIOUS FORECAST MAINLY FOR THE AFTERNOON...WITH 60-80 POPS NOW OVER MUCH OF THE CENTRAL/SOUTHEAST CWA. ALSO RAISED HIGHS 2-4 DEGREES MOST AREAS...WITH ANY RISK FOR FREEZING RAIN DURING THE DAY LARGELY CONFINED TO LOCATIONS NORTHWEST OF A GREELEY-ELWOOD LINE...AND EVEN THIS AREA MAY BE OVERDONE IF THE ECMWF/GFS HAVE A DECENT HANDLE ON SURFACE TEMPS. HAVE HIGHS RANGING FROM THE MID 30S NORTHWEST TO LOW-MID 40S IN KS ZONES AND AROUND HEBRON. TUESDAY NIGHT...FORCING FROM INCOMING MID LEVEL WAVE AND UPPER LEVEL JET INCREASE...AND HAVE AT LEAST 50 POPS CWA-WIDE...AND LIKELIES MAINLY ACROSS THE EASTERN 1/3. COULD EASILY SEE SLIGHTLY RISING/AT LEAST STEADY TEMPS THROUGH THE NIGHT...WITH ANY MENTION OF FREEZING RAIN NOW CONFINED MAINLY TO VALLEY...SHERMAN...DAWSON COUNTIES. WITH BOTH THE NAM/GFS PULLING AT LEAST 100-300 J/KG OF MUCAPE INTO THE CWA...AND THE SREF PROBABILITIES INCREASING FOR GENERAL THUNDER...EVEN INTRODUCED AN ISOLATED THUNDER MENTION TO ROUGHLY THE SOUTHEAST 1/2 OF THE CWA OVERNIGHT...WHICH MAY OR MAY NOT EXTEND INTO WED AS WELL BUT DON/T HAVE IT IN THERE YET. WED INTO WED NIGHT...THE MAIN MID LEVEL WAVE MOVES DIRECTLY THROUGH THE REGION...WITH ALL PRECIP LIKELY OVER BY MIDNIGHT. HAVE LIKELY POPS ALREADY IN PLACE ACROSS ROUGHLY THE EASTERN 1/2 OF THE CWA ALREADY...WHICH MAY NEED EXTENDED WESTWARD IN LATER UPDATES. UNLESS MODELS SUDDENLY START TRENDING COLDER...THIS SHOULD BE A FAIRLY WIDESPREAD LIGHT-MODERATE RAIN EVENT...WITH ONLY THE SMALLEST CHANCE OF FREEZING RAIN IN FAR NORTHWEST ZONES WED MORNING. AS THE SYSTEM DEPARTS WED EVENING...CAN`T RULE OUT A VERY BRIEF PERIOD OF SNOW OR RAIN/SNOW MIX IN THE NORTHEAST. RAISED WED HIGHS 2-3 DEGREES ON AVERAGE...NOW RANGING FROM UPPER 30S NORTHWEST TO LOW 50S FAR SOUTHEAST. IN SUMMARY...MAIN CONCERN OVER NEXT FEW DAYS IS WHETHER OR NOT FREEZING RAIN WILL AMOUNT TO ANYTHING. DESPITE RECENT WARMING TRENDS IN MODELS...CURRENTLY HAVE 1-2 HUNDREDTHS OF ICE POTENTIAL IN MANY AREAS...AND LOCATIONS GENERALLY NORTHWEST OF A GREELEY TO ELWOOD LINE UP TO AROUND 5 HUNDREDTHS TOTAL. ALTHOUGH THIS WOULD BE ENOUGH TO CAUSE AT LEAST MINOR ISSUES...CONFIDENCE IN WHETHER IT WILL OCCUR AT ALL IS STILL LOW ENOUGH TO PRECLUDE ANYTHING BEYOND AN HWO MENTION. BESIDES...WOULD GENERALLY PREFER TO SEE TEMPS INTO THE 20S VERSUS LOW 30S/AROUND 30 FOR ICING TO REALLY TAKE HOLD...AND FOR MOST OF THE NEXT FEW DAYS THIS IS NOT THE CASE DURING ANTICIPATED TIMES OF PRECIPITATION. LONG TERM...12Z THURSDAY THROUGH SUNDAY...A RELATIVELY QUIET WEATHER PATTERN APPEARS TO BE IN STORE FOR THE END OF THE WORK WEEK AS A SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING DISTURBANCE. UNDER THIS PATTERN...NORTHWESTERLY FLOW ALOFT WILL CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE EXTENDED WHEN THE AFOREMENTIONED LOW EJECTS INTO THE PLAINS...AS THE EC AND GFS HAVE DISTINCTLY DIFFERENT SOLUTIONS FOR EARLY NEXT WEEK...WITH THE GFS TAKING A MUCH MORE NORTHERLY AND WETTER TRACK LOCALLY WITH THIS LOW AND THE EC KEEPING THE SYSTEM FURTHER SOUTH. DUE TO THE UNCERTAINTY IN TRACK AND TIMING OF THIS NEXT SYSTEM AS WELL AS PER COORDINATION WITH SURROUNDING OFFICES...MENTIONED MAINLY SLIGHT CHANCES FOR PRECIP LATE IN THE UPCOMING WEEKEND AS MOISTURE ADVECTS NORTHWARD AHEAD OF THE MAIN AREA OF LOW PRESSURE...MOST LIKELY IN THE FORM OF RAIN OR A RAIN SNOW MIX. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
726 AM CST MON DEC 12 2011 .AVIATION...12Z KGRI TAF. GENERALLY POOR AVIATION CONDITIONS ARE EXPECTED AT KGRI FOR MUCH OF THE NEXT 24 HOURS. THE WIDESPREAD LOW LEVEL STRATUS ACROSS THE REGION THIS MORNING IS EXPECTED TO THICKEN OVER THE NEXT FEW HOURS...WITH LOW MVFR CIGS AND VSBY LIKELY TO RETURN AND PERSIST AT KGRI THROUGH ABOUT 12/18Z. CEILINGS AND VSBYS WILL EVENTUALLY IMPROVE TO MORE ELEVATED MVFR LEVELS BY EARLY AFTERNOON...HOWEVER THIS MINOR IMPROVEMENT IS EXPECTED TO BE VERY SHORT LIVED...WITH LOW MVFR...OR EVEN IFR...VISIBILITIES AND CEILINGS EXPECTED TO DEVELOP AFTER THE SUN SETS. IN ADDITION...AN APPROACHING SYSTEM WILL BRING THE CHANCE FOR SOME LIGHT FREEZING DRIZZLE OR LIGHT FREEZING RAIN LATE IN THE TAF PERIOD...BUT KEPT AS -DZ FOR CURRENT TAF ISSUANCE AS ONSET IS VERY NEAR THE END OF CURRENT VALID PERIOD. LIGHT SOUTHERLY WINDS NEAR 10 KTS THIS MORNING WILL SHIFT MORE WESTERLY THROUGH THE PERIOD...EVENTUALLY TRANSITIONING FULL CIRCLE OVERNIGHT...BECOMING NORTHEASTERLY OVERNIGHT TONIGHT. && .PREV DISCUSSION... /ISSUED 556 AM CST MON DEC 12 2011/ SHORT TERM...THROUGH WEDNESDAY NIGHT. PLENTY OF ISSUES TRYING TO NAIL DOWN PRECIP TYPES/AMOUNTS ETC. DURING THE NEXT FEW DAYS HAS LED TO A CHALLENGING NIGHT ON THE FORECAST DESK. MAIN CONCERNS DURING THE NEXT FEW DAYS INVOLVE WHETHER THE CWA WILL SEE ANY APPRECIABLE RISK OF GENERALLY LIGHT ICING...ALTHOUGH GENERAL WARMING TREND OF SURFACE TEMPERATURES DURING LAST SEVERAL MODEL RUNS SEEMS TO BE CONFINING THE MAIN RISK ZONE TO A SMALLER AND SMALLER AREA OF THE NORTHWEST CWA. STARTING OFF EARLY THIS MORNING...BEEN AN INTERESTING NIGHT FROM A TEMP PERSPECTIVE...AS WIDESPREAD STRATUS AND SOUTHERLY BREEZES HAVE KEPT READINGS SEVERAL DEGREES ABOVE FREEZING ACROSS THE VAST MAJORITY OF THE CWA...RESULTING IN A SOMEWHAT RARE MODEST OVERNIGHT SNOW MELT FOR THIS TIME OF YEAR. MAIN CONCERNS OVERNIGHT...AND THROUGH THE NEXT FEW/SEVERAL HOURS ARE ACROSS THE FAR WESTERN PORTIONS OF THE CWA...WHERE WEB CAMS AND AUTOMATED OBS HAVE SUGGESTED THAT THERE IS A NARROW CORRIDOR OF LOCALLY DENSE FOG LIKELY LURKING NEAR/WITHIN WESTERN PORTIONS OF DAWSON...GOSPER AND FURNAS COUNTIES. THIS FOG IS GENERALLY TIED TO THE EDGE OF THE EXPANSIVE LOW CLOUD DECK COVERING MUCH OF THE REGION...ALONG WHICH THERE IS QUITE A TEMP GRADIENT INCLUDING A STRIKING 26 DEGREE DIFFERENCE BETWEEN HOLDREGE AND MCCOOK AT 11Z. WITH ANY DENSE FOG SEEMINGLY AFFECTING SUCH A SMALL PORTION OF THE AREA...HAVE OPTED AGAINST AN ADVISORY...BUT HAVE IT MENTIONED IN THE GRIDS AND ALSO IN THE HWO. AS FOR ANY LIGHT FREEZING DRIZZLE CONCERNS FROM 12-24 HOURS AGO...THESE HAVE APPARENTLY BEEN AVOIDED FOR NOW GIVEN THE SEASONABLY MILD OVERNIGHT TEMPS...AND EVEN PLAIN LIGHT DRIZZLE HAS APPARENTLY BEEN QUITE SCANT OVERNIGHT ACROSS THE AREA. A QUICK LOOK AT 11Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK TROUGH AXIS NEAR THE EDGE OF THE STRATUS/NEAR THE WESTERN EDGE OF THE CWA...WITH STEADY SOUTH BREEZES 5-15 MPH AFFECTING NEARLY ALL OF THE CWA TO THE EAST OF THIS AXIS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM THE PRESENCE OF A FAIRLY WEAK MID LEVEL SHORTWAVE STARTING TO DEPART EASTERN NEB TO THE EAST- NORTHEAST...WITH LOW STRATUS CEILINGS ACTUALLY RISING QUITE A BIT IN MUCH OF THE CWA IN ITS WAKE. UPSTREAM...THE MAIN LARGE-SCALE TROUGH OF CONCERN IS STILL CENTERED NEAR THE PACIFIC COAST. FOR TODAY...THE MAIN CONCERN THIS MORNING IS WHETHER ANY DENSE FOG ALONG THE STRATUS EDGE CAN WORK A BIT FARTHER EASTWARD INTO THE AREA. FOR NOW HAVE DENSE FOG MENTION CONFINED SOLELY TO PARTS OF DAWSON...GOSPER...FURNAS. AS FOR SKY COVER...LATEST SUGGESTIONS FROM HRRR MODEL IS THAT STRATUS SHOULD HOLD FIRM ACROSS MOST OF THE CWA THROUGH THE DAY...ALTHOUGH ROUGHLY THE WESTERN 1/4 OF THE AREA COULD SEE SOME PARTIAL CLEARING ALONG/WEST OF THE WEAK LOW LEVEL TROUGH AXIS. DEFINITELY SOMETHING TO WATCH. TEMP WISE...GIVEN THE WARM START RAISED HIGHS ROUGHLY 3-4 DEGREES OVER PREVIOUS FORECAST MOST AREAS...AND POSSIBLY NOT ENOUGH. WILL AIM FOR A GRADIENT FROM MID 30S NORTHWEST TO LOW 40S SOUTHEAST...AND MAYBE EVEN UPPER 40S IN THE MITCHELL COUNTY KS AREA. LIMITED LIFT SHOULD KEEP ANY POTENTIAL DRIZZLE AT BAY TODAY. TONIGHT...MAIN CHANGE WAS TO RAISE LOW TEMPS A NOTABLE 4-8 DEGREES OVER PREVIOUS FORECAST MOST AREAS...ALTHOUGH THIS IS VERY DEPENDENT ON WIDESPREAD CLOUD COVER HOLDING FIRM. ASSUMING THIS OCCURS...AM NOW TALKING A GRADIENT FROM LOW-MID 20S NORTHWEST TO LOW-MID 30S SOUTHEAST. WITH LIGHT WINDS...CANNOT RULE OUT PATCHY TO AREAS OF FOG OVERNIGHT...BUT NOTHING THAT CAN REALLY BE PINNED DOWN FOR POSSIBLE DENSE DEVELOPMENT. KEPT THEME FROM PREVIOUS FORECAST INTACT...WITH SLIGHT CHANCE OF DRIZZLE IN THE SOUTH BEFORE MIDNIGHT...AND THEN BETTER CHANCES FOR LIGHT MEASURABLE PRECIP AFTER MIDNIGHT MAINLY ACROSS THE SOUTHERN HALF OF THE CWA AS FIRST LEAD SHORTWAVE MOVES INTO THE REGION. COULD SEE LIGHT ICING MAINLY ACROSS NEB ZONES...BUT NOT ANTICIPATING MAJOR ISSUES AND DAY SHIFT SHOULD BE ABLE TO BETTER PIN DOWN THE SURFACE TEMP TREND. TUESDAY...RAISED POPS 10-20 PERCENT OVER PREVIOUS FORECAST MAINLY FOR THE AFTERNOON...WITH 60-80 POPS NOW OVER MUCH OF THE CENTRAL/SOUTHEAST CWA. ALSO RAISED HIGHS 2-4 DEGREES MOST AREAS...WITH ANY RISK FOR FREEZING RAIN DURING THE DAY LARGELY CONFINED TO LOCATIONS NORTHWEST OF A GREELEY-ELWOOD LINE...AND EVEN THIS AREA MAY BE OVERDONE IF THE ECMWF/GFS HAVE A DECENT HANDLE ON SURFACE TEMPS. HAVE HIGHS RANGING FROM THE MID 30S NORTHWEST TO LOW-MID 40S IN KS ZONES AND AROUND HEBRON. TUESDAY NIGHT...FORCING FROM INCOMING MID LEVEL WAVE AND UPPER LEVEL JET INCREASE...AND HAVE AT LEAST 50 POPS CWA-WIDE...AND LIKELIES MAINLY ACROSS THE EASTERN 1/3. COULD EASILY SEE SLIGHTLY RISING/AT LEAST STEADY TEMPS THROUGH THE NIGHT...WITH ANY MENTION OF FREEZING RAIN NOW CONFINED MAINLY TO VALLEY...SHERMAN...DAWSON COUNTIES. WITH BOTH THE NAM/GFS PULLING AT LEAST 100-300 J/KG OF MUCAPE INTO THE CWA...AND THE SREF PROBABILITIES INCREASING FOR GENERAL THUNDER...EVEN INTRODUCED AN ISOLATED THUNDER MENTION TO ROUGHLY THE SOUTHEAST 1/2 OF THE CWA OVERNIGHT...WHICH MAY OR MAY NOT EXTEND INTO WED AS WELL BUT DON/T HAVE IT IN THERE YET. WED INTO WED NIGHT...THE MAIN MID LEVEL WAVE MOVES DIRECTLY THROUGH THE REGION...WITH ALL PRECIP LIKELY OVER BY MIDNIGHT. HAVE LIKELY POPS ALREADY IN PLACE ACROSS ROUGHLY THE EASTERN 1/2 OF THE CWA ALREADY...WHICH MAY NEED EXTENDED WESTWARD IN LATER UPDATES. UNLESS MODELS SUDDENLY START TRENDING COLDER...THIS SHOULD BE A FAIRLY WIDESPREAD LIGHT-MODERATE RAIN EVENT...WITH ONLY THE SMALLEST CHANCE OF FREEZING RAIN IN FAR NORTHWEST ZONES WED MORNING. AS THE SYSTEM DEPARTS WED EVENING...CAN`T RULE OUT A VERY BRIEF PERIOD OF SNOW OR RAIN/SNOW MIX IN THE NORTHEAST. RAISED WED HIGHS 2-3 DEGREES ON AVERAGE...NOW RANGING FROM UPPER 30S NORTHWEST TO LOW 50S FAR SOUTHEAST. IN SUMMARY...MAIN CONCERN OVER NEXT FEW DAYS IS WHETHER OR NOT FREEZING RAIN WILL AMOUNT TO ANYTHING. DESPITE RECENT WARMING TRENDS IN MODELS...CURRENTLY HAVE 1-2 HUNDREDTHS OF ICE POTENTIAL IN MANY AREAS...AND LOCATIONS GENERALLY NORTHWEST OF A GREELEY TO ELWOOD LINE UP TO AROUND 5 HUNDREDTHS TOTAL. ALTHOUGH THIS WOULD BE ENOUGH TO CAUSE AT LEAST MINOR ISSUES...CONFIDENCE IN WHETHER IT WILL OCCUR AT ALL IS STILL LOW ENOUGH TO PRECLUDE ANYTHING BEYOND AN HWO MENTION. BESIDES...WOULD GENERALLY PREFER TO SEE TEMPS INTO THE 20S VERSUS LOW 30S/AROUND 30 FOR ICING TO REALLY TAKE HOLD...AND FOR MOST OF THE NEXT FEW DAYS THIS IS NOT THE CASE DURING ANTICIPATED TIMES OF PRECIPITATION. LONG TERM...12Z THURSDAY THROUGH SUNDAY...A RELATIVELY QUIET WEATHER PATTERN APPEARS TO BE IN STORE FOR THE END OF THE WORK WEEK AS A SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING DISTURBANCE. UNDER THIS PATTERN...NORTHWESTERLY FLOW ALOFT WILL CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE EXTENDED WHEN THE AFOREMENTIONED LOW EJECTS INTO THE PLAINS...AS THE EC AND GFS HAVE DISTINCTLY DIFFERENT SOLUTIONS FOR EARLY NEXT WEEK...WITH THE GFS TAKING A MUCH MORE NORTHERLY AND WETTER TRACK LOCALLY WITH THIS LOW AND THE EC KEEPING THE SYSTEM FURTHER SOUTH. DUE TO THE UNCERTAINTY IN TRACK AND TIMING OF THIS NEXT SYSTEM AS WELL AS PER COORDINATION WITH SURROUNDING OFFICES...MENTIONED MAINLY SLIGHT CHANCES FOR PRECIP LATE IN THE UPCOMING WEEKEND AS MOISTURE ADVECTS NORTHWARD AHEAD OF THE MAIN AREA OF LOW PRESSURE...MOST LIKELY IN THE FORM OF RAIN OR A RAIN SNOW MIX. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CST MON DEC 12 2011 .SHORT TERM...THROUGH WEDNESDAY NIGHT. PLENTY OF ISSUES TRYING TO NAIL DOWN PRECIP TYPES/AMOUNTS ETC. DURING THE NEXT FEW DAYS HAS LED TO A CHALLENGING NIGHT ON THE FORECAST DESK. MAIN CONCERNS DURING THE NEXT FEW DAYS INVOLVE WHETHER THE CWA WILL SEE ANY APPRECIABLE RISK OF GENERALLY LIGHT ICING...ALTHOUGH GENERAL WARMING TREND OF SURFACE TEMPERATURES DURING LAST SEVERAL MODEL RUNS SEEMS TO BE CONFINING THE MAIN RISK ZONE TO A SMALLER AND SMALLER AREA OF THE NORTHWEST CWA. STARTING OFF EARLY THIS MORNING...BEEN AN INTERESTING NIGHT FROM A TEMP PERSPECTIVE...AS WIDESPREAD STRATUS AND SOUTHERLY BREEZES HAVE KEPT READINGS SEVERAL DEGREES ABOVE FREEZING ACROSS THE VAST MAJORITY OF THE CWA...RESULTING IN A SOMEWHAT RARE MODEST OVERNIGHT SNOW MELT FOR THIS TIME OF YEAR. MAIN CONCERNS OVERNIGHT...AND THROUGH THE NEXT FEW/SEVERAL HOURS ARE ACROSS THE FAR WESTERN PORTIONS OF THE CWA...WHERE WEB CAMS AND AUTOMATED OBS HAVE SUGGESTED THAT THERE IS A NARROW CORRIDOR OF LOCALLY DENSE FOG LIKELY LURKING NEAR/WITHIN WESTERN PORTIONS OF DAWSON...GOSPER AND FURNAS COUNTIES. THIS FOG IS GENERALLY TIED TO THE EDGE OF THE EXPANSIVE LOW CLOUD DECK COVERING MUCH OF THE REGION...ALONG WHICH THERE IS QUITE A TEMP GRADIENT INCLUDING A STRIKING 26 DEGREE DIFFERENCE BETWEEN HOLDREGE AND MCCOOK AT 11Z. WITH ANY DENSE FOG SEEMINGLY AFFECTING SUCH A SMALL PORTION OF THE AREA...HAVE OPTED AGAINST AN ADVISORY...BUT HAVE IT MENTIONED IN THE GRIDS AND ALSO IN THE HWO. AS FOR ANY LIGHT FREEZING DRIZZLE CONCERNS FROM 12-24 HOURS AGO...THESE HAVE APPARENTLY BEEN AVOIDED FOR NOW GIVEN THE SEASONABLY MILD OVERNIGHT TEMPS...AND EVEN PLAIN LIGHT DRIZZLE HAS APPARENTLY BEEN QUITE SCANT OVERNIGHT ACROSS THE AREA. A QUICK LOOK AT 11Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK TROUGH AXIS NEAR THE EDGE OF THE STRATUS/NEAR THE WESTERN EDGE OF THE CWA...WITH STEADY SOUTH BREEZES 5-15 MPH AFFECTING NEARLY ALL OF THE CWA TO THE EAST OF THIS AXIS. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM THE PRESENCE OF A FAIRLY WEAK MID LEVEL SHORTWAVE STARTING TO DEPART EASTERN NEB TO THE EAST- NORTHEAST...WITH LOW STRATUS CEILINGS ACTUALLY RISING QUITE A BIT IN MUCH OF THE CWA IN ITS WAKE. UPSTREAM...THE MAIN LARGE-SCALE TROUGH OF CONCERN IS STILL CENTERED NEAR THE PACIFIC COAST. FOR TODAY...THE MAIN CONCERN THIS MORNING IS WHETHER ANY DENSE FOG ALONG THE STRATUS EDGE CAN WORK A BIT FARTHER EASTWARD INTO THE AREA. FOR NOW HAVE DENSE FOG MENTION CONFINED SOLELY TO PARTS OF DAWSON...GOSPER...FURNAS. AS FOR SKY COVER...LATEST SUGGESTIONS FROM HRRR MODEL IS THAT STRATUS SHOULD HOLD FIRM ACROSS MOST OF THE CWA THROUGH THE DAY...ALTHOUGH ROUGHLY THE WESTERN 1/4 OF THE AREA COULD SEE SOME PARTIAL CLEARING ALONG/WEST OF THE WEAK LOW LEVEL TROUGH AXIS. DEFINITELY SOMETHING TO WATCH. TEMP WISE...GIVEN THE WARM START RAISED HIGHS ROUGHLY 3-4 DEGREES OVER PREVIOUS FORECAST MOST AREAS...AND POSSIBLY NOT ENOUGH. WILL AIM FOR A GRADIENT FROM MID 30S NORTHWEST TO LOW 40S SOUTHEAST...AND MAYBE EVEN UPPER 40S IN THE MITCHELL COUNTY KS AREA. LIMITED LIFT SHOULD KEEP ANY POTENTIAL DRIZZLE AT BAY TODAY. TONIGHT...MAIN CHANGE WAS TO RAISE LOW TEMPS A NOTABLE 4-8 DEGREES OVER PREVIOUS FORECAST MOST AREAS...ALTHOUGH THIS IS VERY DEPENDENT ON WIDESPREAD CLOUD COVER HOLDING FIRM. ASSUMING THIS OCCURS...AM NOW TALKING A GRADIENT FROM LOW-MID 20S NORTHWEST TO LOW-MID 30S SOUTHEAST. WITH LIGHT WINDS...CANNOT RULE OUT PATCHY TO AREAS OF FOG OVERNIGHT...BUT NOTHING THAT CAN REALLY BE PINNED DOWN FOR POSSIBLE DENSE DEVELOPMENT. KEPT THEME FROM PREVIOUS FORECAST INTACT...WITH SLIGHT CHANCE OF DRIZZLE IN THE SOUTH BEFORE MIDNIGHT...AND THEN BETTER CHANCES FOR LIGHT MEASURABLE PRECIP AFTER MIDNIGHT MAINLY ACROSS THE SOUTHERN HALF OF THE CWA AS FIRST LEAD SHORTWAVE MOVES INTO THE REGION. COULD SEE LIGHT ICING MAINLY ACROSS NEB ZONES...BUT NOT ANTICIPATING MAJOR ISSUES AND DAY SHIFT SHOULD BE ABLE TO BETTER PIN DOWN THE SURFACE TEMP TREND. TUESDAY...RAISED POPS 10-20 PERCENT OVER PREVIOUS FORECAST MAINLY FOR THE AFTERNOON...WITH 60-80 POPS NOW OVER MUCH OF THE CENTRAL/SOUTHEAST CWA. ALSO RAISED HIGHS 2-4 DEGREES MOST AREAS...WITH ANY RISK FOR FREEZING RAIN DURING THE DAY LARGELY CONFINED TO LOCATIONS NORTHWEST OF A GREELEY-ELWOOD LINE...AND EVEN THIS AREA MAY BE OVERDONE IF THE ECMWF/GFS HAVE A DECENT HANDLE ON SURFACE TEMPS. HAVE HIGHS RANGING FROM THE MID 30S NORTHWEST TO LOW-MID 40S IN KS ZONES AND AROUND HEBRON. TUESDAY NIGHT...FORCING FROM INCOMING MID LEVEL WAVE AND UPPER LEVEL JET INCREASE...AND HAVE AT LEAST 50 POPS CWA-WIDE...AND LIKELIES MAINLY ACROSS THE EASTERN 1/3. COULD EASILY SEE SLIGHTLY RISING/AT LEAST STEADY TEMPS THROUGH THE NIGHT...WITH ANY MENTION OF FREEZING RAIN NOW CONFINED MAINLY TO VALLEY...SHERMAN...DAWSON COUNTIES. WITH BOTH THE NAM/GFS PULLING AT LEAST 100-300 J/KG OF MUCAPE INTO THE CWA...AND THE SREF PROBABILITIES INCREASING FOR GENERAL THUNDER...EVEN INTRODUCED AN ISOLATED THUNDER MENTION TO ROUGHLY THE SOUTHEAST 1/2 OF THE CWA OVERNIGHT...WHICH MAY OR MAY NOT EXTEND INTO WED AS WELL BUT DON/T HAVE IT IN THERE YET. WED INTO WED NIGHT...THE MAIN MID LEVEL WAVE MOVES DIRECTLY THROUGH THE REGION...WITH ALL PRECIP LIKELY OVER BY MIDNIGHT. HAVE LIKELY POPS ALREADY IN PLACE ACROSS ROUGHLY THE EASTERN 1/2 OF THE CWA ALREADY...WHICH MAY NEED EXTENDED WESTWARD IN LATER UPDATES. UNLESS MODELS SUDDENLY START TRENDING COLDER...THIS SHOULD BE A FAIRLY WIDESPREAD LIGHT-MODERATE RAIN EVENT...WITH ONLY THE SMALLEST CHANCE OF FREEZING RAIN IN FAR NORTHWEST ZONES WED MORNING. AS THE SYSTEM DEPARTS WED EVENING...CAN`T RULE OUT A VERY BRIEF PERIOD OF SNOW OR RAIN/SNOW MIX IN THE NORTHEAST. RAISED WED HIGHS 2-3 DEGREES ON AVERAGE...NOW RANGING FROM UPPER 30S NORTHWEST TO LOW 50S FAR SOUTHEAST. IN SUMMARY...MAIN CONCERN OVER NEXT FEW DAYS IS WHETHER OR NOT FREEZING RAIN WILL AMOUNT TO ANYTHING. DESPITE RECENT WARMING TRENDS IN MODELS...CURRENTLY HAVE 1-2 HUNDREDTHS OF ICE POTENTIAL IN MANY AREAS...AND LOCATIONS GENERALLY NORTHWEST OF A GREELEY TO ELWOOD LINE UP TO AROUND 5 HUNDREDTHS TOTAL. ALTHOUGH THIS WOULD BE ENOUGH TO CAUSE AT LEAST MINOR ISSUES...CONFIDENCE IN WHETHER IT WILL OCCUR AT ALL IS STILL LOW ENOUGH TO PRECLUDE ANYTHING BEYOND AN HWO MENTION. BESIDES...WOULD GENERALLY PREFER TO SEE TEMPS INTO THE 20S VERSUS LOW 30S/AROUND 30 FOR ICING TO REALLY TAKE HOLD...AND FOR MOST OF THE NEXT FEW DAYS THIS IS NOT THE CASE DURING ANTICIPATED TIMES OF PRECIPITATION. .LONG TERM...12Z THURSDAY THROUGH SUNDAY...A RELATIVELY QUIET WEATHER PATTERN APPEARS TO BE IN STORE FOR THE END OF THE WORK WEEK AS A SPLIT UPPER LEVEL FLOW PATTERN WILL RESULT IN SHORT WAVE RIDGING ACROSS THE CENTRAL PLAINS BEHIND WEDNESDAYS DEPARTING DISTURBANCE. UNDER THIS PATTERN...NORTHWESTERLY FLOW ALOFT WILL CARRY MULTIPLE UPPER LEVEL DISTURBANCES ACROSS THE NORTHERN PLAINS AS A CUT OFF LOW MEANDERS ACROSS THE DESERT SOUTHWEST...RESULTING IN DRY AND SEASONABLE CONDITIONS LOCALLY. QUESTION WILL BE LATE IN THE EXTENDED WHEN THE AFOREMENTIONED LOW EJECTS INTO THE PLAINS...AS THE EC AND GFS HAVE DISTINCTLY DIFFERENT SOLUTIONS FOR EARLY NEXT WEEK...WITH THE GFS TAKING A MUCH MORE NORTHERLY AND WETTER TRACK LOCALLY WITH THIS LOW AND THE EC KEEPING THE SYSTEM FURTHER SOUTH. DUE TO THE UNCERTAINTY IN TRACK AND TIMING OF THIS NEXT SYSTEM AS WELL AS PER COORDINATION WITH SURROUNDING OFFICES...MENTIONED MAINLY SLIGHT CHANCES FOR PRECIP LATE IN THE UPCOMING WEEKEND AS MOISTURE ADVECTS NORTHWARD AHEAD OF THE MAIN AREA OF LOW PRESSURE...MOST LIKELY IN THE FORM OF RAIN OR A RAIN SNOW MIX. && .PREV DISCUSSION... /ISSUED 945 PM CST SUN DEC 11 2011/ AVIATION...12Z KGRI TAF. GENERALLY POOR AVIATION CONDITIONS ARE EXPECTED AT KGRI FOR MUCH OF THE NEXT 24 HOURS. THE WIDESPREAD LOW LEVEL STRATUS ACROSS THE REGION THIS MORNING IS EXPECTED TO THICKEN OVER THE NEXT FEW HOURS...WITH LOW MVFR CIGS AND VSBY LIKELY TO RETURN AND PERSIST AT KGRI THROUGH ABOUT 12/18Z. CEILINGS AND VSBYS WILL EVENTUALLY IMPROVE TO MORE ELEVATED MVFR LEVELS BY EARLY AFTERNOON...HOWEVER THIS MINOR IMPROVEMENT IS EXPECTED TO BE VERY SHORT LIVED...WITH LOW MVFR...OR EVEN IFR...VISIBILITIES AND CEILINGS EXPECTED TO DEVELOP AFTER THE SUN SETS. IN ADDITION...AN APPROACHING SYSTEM WILL BRING THE CHANCE FOR SOME LIGHT FREEZING DRIZZLE OR LIGHT FREEZING RAIN LATE IN THE TAF PERIOD...BUT KEPT AS -DZ FOR CURRENT TAF ISSUANCE AS ONSET IS VERY NEAR THE END OF CURRENT VALID PERIOD. LIGHT SOUTHERLY WINDS NEAR 10 KTS THIS MORNING WILL SHIFT MORE WESTERLY THROUGH THE PERIOD...EVENTUALLY TRANSITIONING FULL CIRCLE OVERNIGHT...BECOMING NORTHEASTERLY OVERNIGHT TONIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1015 AM CST MON DEC 12 2011 .DISCUSSION...CLOUDS AND RESULTANT TEMPERATURES CONTINUE TO BE THE MAIN CHALLENGE TODAY. 925MB WINDS ARE NORTHEAST WHILE SFC WINDS ARE DUE NORTH...AND THESE WINDS SHOULD REMAIN CONSISTENT THROUGH THE DAY. THUS...CURRENT CLOUD LOCATIONS EXPECTED TO CHANGE LITTLE (CLEARING AREA SOMEWHERE IN THE MIDDLE OF THE FA). NOT SURE IF THE CLEAR AREA WILL FILL IN...BUT MODEL CONVECTIVE TEMPS INTO THE 70S SUGGEST IT WILL NOT. BASED ON EXPECTED CLOUD COVER...ADJUSTED TEMPS FOR LITTLE RISE UNDER CLOUDS AND 5-7F RISE IN CLEAR AREA. && .AVIATION...THERE STILL REMAINS A HIGH DEGREE OF UNCERTAINTY CONCERNING CEILING FORECAST TODAY. KDVL...KBJI...KFAR ARE IFR/MVFR WHILE KGFK AND KTVF ARE VFR. IFR/MVFR CEILINGS LIKELY TO REMAIN IN ABOUT THE SAME LOCATION THROUGH THE AFTERNOON HOURS. DUE TO DRY NORTHEAST LOW-LEVEL FLOW...DIFFICULT TO KNOW THE EXTENT TO WHICH CLOUDS MAY IMPACT TAF SITES. KGFK AND KTVF SHOULD STAY VFR THROUGH AT LEAST 18 UTC...WITH LOW CLOUDS POSSIBLY IMPACTING THESE AIRFIELDS THIS AFTERNOON. WILL UPDATE TAFS AS GREATER CERTAINTY IS REALIZED. && .PREV DISCUSSION... /ISSUED 402 AM CST MON DEC 12 2011/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT PRIMARY FORECAST CHALLENGE WILL BE CLOUD COVER AND CORRESPONDING TEMPERATURES. GFS/NAM/ECMWF/GEM MASS/THERMAL FIELDS ARE IN GOOD AGREEMENT...BUT ONLY THE RUC AND HRRR BEST RESEMBLE CURRENT CLOUD TRENDS. WILL FOLLOW HIGH RESOLUTION MODELS FOR THE NEAR TERM... TRANSITIONING TO A MODEL BLEND THEREAFTER. 09 UTC SURFACE ANALYSIS SHOWS A WEAK TROUGH EXTENDING FROM SOUTH CENTRAL SD INTO THE MN ARROWHEAD WITH LOW STRATUS ALONG AND SOUTHEAST OF THE TROUGH AXIS. A SECOND AREA OF LOW CLOUDS IS TRAPPED BENEATH CANADIAN HIGH PRESSURE AND EXTENDS ALONG AND NORTHWEST OF A LINE FROM HALLOCK TO DEVILS LAKE TO BISMARCK. BETWEEN THESE CLOUDS SKIES ARE CLEAR...BUT THE TWO CLOUD DECKS ARE CRAWLING TOWARD EACH OTHER. RUC/HRRR SUGGEST DRY LOW-LEVEL NORTHEAST FLOW WILL KEEP SOUTHEAST ND INTO NORTH CENTRAL MN CLOUD FREE THROUGH AT LEAST EARLY MORNING...BUT MAY BEGIN TO FILL IN THEREAFTER. AS A RESULT...AREAS NOT IN THE NORTHWEST OR SOUTHEAST FORECAST AREA WILL START THE DAY SUNNY WITH A GRADUAL INCREASE IN CLOUDS...POSSIBLY BECOMING MOSTLY CLOUDY BY LATE THIS AFTERNOON. WILL KEEP FORECAST DRY TODAY...BUT SOME LIGHT DRIZZLE IS POSSIBLE GIVEN VERY DRY AIR ATOP NEAR SURFACE SATURATED LAYER. AS CLOUD COVER EXPANDS...DO NOT EXPECT MUCH MOVEMENT IN TEMPERATURES WITH A GENERAL GRADIENT FROM THE UPPER TEENS ACROSS PORTIONS OF THE DEVILS LAKE BASIN TO THE UPPER 20S TO NEAR 30 DEGREES ACROSS WEST CENTRAL MN. LIGHT NORTHEAST WIND WILL BE THE RULE THROUGH THE DAY. TUESDAY WILL BE DRY AND SLIGHTLY WARMER AS SURFACE HIGH PRESSURE AXIS DRIFTS ACROSS THE FORECAST AREA AND LIGHT RETURN FLOW DEVELOPS. HIGHS WILL RANGE FROM THE MID 20S TO LOWER 30S. DID NOT CHANGE POPS MUCH WEDNESDAY AND WEDNESDAY NIGHT...KEEPING CHANCES FOR SNOW ALONG AND EAST OF A LINE FROM LISBON TO FARGO TO BAUDETTE. MODELS ARE NOW IN GOOD AGREEMENT SHOWING A NORTHERN STREAM SHORT-WAVE KICK MORE POTENT ENERGY FROM SOUTHWEST CONUS CUT-OFF LOW FARTHER SOUTH AND EAST ACROSS IA AND WI. ACCUMULATIONS...IF ANY...SHOULD BE MINIMAL. TEMPERATURES WEDNESDAY WILL RISE INTO THE UPPER 20S TO LOWER 30S BEFORE COOLING OFF THE LATTER HALF OF THE WEEK. LONG TERM...THURSDAY THROUGH SUNDAY NIGHT THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH NO STORMS IN SIGHT. A COLD FRONT WILL USHER IN MUCH COLDER AIR ON THURSDAY ALONG WITH BRISK/BREEZY CONDITIONS. TEMPS WILL MODERATE ABOVE NORMAL BY NEXT WEEKEND WITH UPPER RIDGE BUILDING AND 850MB TEMPS CLIMBING OVER 0C ONCE AGAIN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
402 AM CST MON DEC 12 2011 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT PRIMARY FORECAST CHALLENGE WILL BE CLOUD COVER AND CORRESPONDING TEMPERATURES. GFS/NAM/ECMWF/GEM MASS/THERMAL FIELDS ARE IN GOOD AGREEMENT...BUT ONLY THE RUC AND HRRR BEST RESEMBLE CURRENT CLOUD TRENDS. WILL FOLLOW HIGH RESOLUTION MODELS FOR THE NEAR TERM... TRANSITIONING TO A MODEL BLEND THEREAFTER. 09 UTC SURFACE ANALYSIS SHOWS A WEAK TROUGH EXTENDING FROM SOUTH CENTRAL SD INTO THE MN ARROWHEAD WITH LOW STRATUS ALONG AND SOUTHEAST OF THE TROUGH AXIS. A SECOND AREA OF LOW CLOUDS IS TRAPPED BENEATH CANADIAN HIGH PRESSURE AND EXTENDS ALONG AND NORTHWEST OF A LINE FROM HALLOCK TO DEVILS LAKE TO BISMARCK. BETWEEN THESE CLOUDS SKIES ARE CLEAR...BUT THE TWO CLOUD DECKS ARE CRAWLING TOWARD EACH OTHER. RUC/HRRR SUGGEST DRY LOW-LEVEL NORTHEAST FLOW WILL KEEP SOUTHEAST ND INTO NORTH CENTRAL MN CLOUD FREE THROUGH AT LEAST EARLY MORNING...BUT MAY BEGIN TO FILL IN THEREAFTER. AS A RESULT...AREAS NOT IN THE NORTHWEST OR SOUTHEAST FORECAST AREA WILL START THE DAY SUNNY WITH A GRADUAL INCREASE IN CLOUDS...POSSIBLY BECOMING MOSTLY CLOUDY BY LATE THIS AFTERNOON. WILL KEEP FORECAST DRY TODAY...BUT SOME LIGHT DRIZZLE IS POSSIBLE GIVEN VERY DRY AIR ATOP NEAR SURFACE SATURATED LAYER. AS CLOUD COVER EXPANDS...DO NOT EXPECT MUCH MOVEMENT IN TEMPERATURES WITH A GENERAL GRADIENT FROM THE UPPER TEENS ACROSS PORTIONS OF THE DEVILS LAKE BASIN TO THE UPPER 20S TO NEAR 30 DEGREES ACROSS WEST CENTRAL MN. LIGHT NORTHEAST WIND WILL BE THE RULE THROUGH THE DAY. TUESDAY WILL BE DRY AND SLIGHTLY WARMER AS SURFACE HIGH PRESSURE AXIS DRIFTS ACROSS THE FORECAST AREA AND LIGHT RETURN FLOW DEVELOPS. HIGHS WILL RANGE FROM THE MID 20S TO LOWER 30S. DID NOT CHANGE POPS MUCH WEDNESDAY AND WEDNESDAY NIGHT...KEEPING CHANCES FOR SNOW ALONG AND EAST OF A LINE FROM LISBON TO FARGO TO BAUDETTE. MODELS ARE NOW IN GOOD AGREEMENT SHOWING A NORTHERN STREAM SHORT-WAVE KICK MORE POTENT ENERGY FROM SOUTHWEST CONUS CUT-OFF LOW FARTHER SOUTH AND EAST ACROSS IA AND WI. ACCUMULATIONS...IF ANY...SHOULD BE MINIMAL. TEMPERATURES WEDNESDAY WILL RISE INTO THE UPPER 20S TO LOWER 30S BEFORE COOLING OFF THE LATTER HALF OF THE WEEK. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT THE MAIN CHALLENGE WILL CONTINUE TO BE TEMPS WITH NO STORMS IN SIGHT. A COLD FRONT WILL USHER IN MUCH COLDER AIR ON THURSDAY ALONG WITH BRISK/BREEZY CONDITIONS. TEMPS WILL MODERATE ABOVE NORMAL BY NEXT WEEKEND WITH UPPER RIDGE BUILDING AND 850MB TEMPS CLIMBING OVER 0C ONCE AGAIN. && .AVIATION... HIGH DEGREE OF UNCERTAINTY CONCERNING CEILING FORECAST TODAY AS THE REGION IS SANDWICHED BY IFR/LOW MVFR CLOUDS TO THE NORTHWEST AND SOUTHEAST. KDVL AND KBJI ARE CLOUDY WITH CLEARING JUST TO THEIR SOUTHEAST AND NORTHWEST RESPECTIVELY. IFR/MVFR CEILINGS LIKELY TO IMPACT THESE TWO AIRFIELDS FOR MUCH OF THE DAY. DUE TO DRY NORTHEAST LOW-LEVEL FLOW...DIFFICULT TO KNOW THE EXTENT TO WHICH CLOUDS MAY IMPACT VALLEY TAF SITES. KGFK...KFAR AND KTVF SHOULD STAY CLOUD-FREE THROUGH AT LEAST 12 UTC...WITH LOW CLOUDS POSSIBLY IMPACTING AIRFIELDS LATER THIS MORNING OR EARLY AFTERNOON. WILL UPDATE TAFS AS GREATER CERTAINTY IS REALIZED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ ROGERS/DK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1239 PM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THE REGIONS WEATHER INTO TUESDAY. THE HIGH WILL MOVE EAST TUESDAY NIGHT AS A WARM FRONT APPROACHES THE AREA FROM THE SOUTHWEST. THE WARM FRONT WILL PUSH ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT INTO THURSDAY. TEMPERATURES WILL WARM TO ABOVE NORMAL READINGS THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURFACE HIGH PRESSURE EXTENDED FROM THE NEW ENGLAND COAST TO THE THE OHIO AND TENNESSEE VALLEYS THIS MORNING. THE HIGH IS EXPECTED TO MOVE LITTLE TODAY. AFTER A COLD START...TEMPERATURES WILL MODERATE UNDER ABUNDANT SUNSHINE. CIRRUS WILL INCREASE IN COVERAGE BUT IT WILL REMAIN MOSTLY SUNNY. HIGHS WILL RANGE FROM THE LOWER 40S NORTH TO THE UPPER 40S SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... SURFACE HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE OHIO VALLEY TONIGHT INTO TUESDAY. MEANWHILE...WEAK UPR LVL ENERGY WILL TRACK ACROSS THE GREAT LAKES. RETURN LOW LEVEL FLOW MAY BRING SOME LOWER CLOUDS TO OUR SE CWFA THIS EVENING/OVERNIGHT WHILE MID LVL MOISTURE STREAMS IN FROM THE WEST. CLOUD COVER WILL PREVENT TEMPERATURES FROM COOLING OFF TOO MUCH AND SHOULD RANGE FROM THE MID 20S TO THE LOWER 30S. SKIES ON TUESDAY WILL RANGE FROM PARTLY TO MOSTLY CLOUDY AS MID LVL MOISTURE CONTINUES TO ADVECT ACROSS THE REGION FROM THE WEST. HIGHS WILL VARY FROM THE MID 40S NORTH TO NEAR 50 SOUTH. MODELS ARE IN GOOD AGREEMENT FOR TUESDAY NIGHT INTO WEDNESDAY. SURFACE HIGH WILL MOVE EAST AS A WARM FRONT DEVELOPS TO OUR SOUTHWEST. THE WARM FRONT WILL MOVE ACROSS THE AREA ON WEDNESDAY. DEEP MOISTURE WILL INCREASE OVER THE REGION THROUGH THE PERIOD. THIS MOISTURE WILL COINCIDE WITH A STRONG LOW LEVEL JET AND UPR LVL DIVERGENCE FROM THE RR QUAD OF AN UPR LVL JET. THIS WILL RESULT IN SHOWERS WITH THE HIGHEST THREAT POISED FOR THE NRN ZONES. HAVE RAISED POPS TO CATEGORICAL ACRS NRN AREAS TUESDAY NIGHT INTO WEDNESDAY. PCPN CHANCES WILL DIMINISH TO LOW CHANCE SOUTH OF THE OHIO RIVER. THE WARM FRONT WILL LIFT NORTH OF THE AREA WEDNESDAY NIGHT. THE WARM FRONT WILL BE FOLLOWED BY A COLD FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION ON THURSDAY. DEEP MOISTURE COUPLED WITH DECENT LOW LEVEL FORCING AHEAD OF THE FRONT WILL BRING ANOTHER ROUND OF SHOWERS. HAVE GONE WITH CATEGORICAL POPS. THE FRONT WILL PUSH SOUTHEAST THURSDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. THIS WILL BRING AN END TO THE PCPN. TEMPERATURES TUESDAY NIGHT INTO THURSDAY NIGHT WILL EXHIBIT NON DIURNAL TRENDS AND HAVE RELIED ON A BLEND OF RAW 2 M GFS AND ECMWF FOR THE MOST PART. && .LONG TERM /FRIDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND. A WEAK SHORT WAVE MAY DROP DOWN ACROSS THE GREAT LAKES ON SATURDAY...BUT IT LOOKS LIKE BETTER FORCING WITH THIS WILL REMAIN OFF TO OUR NORTH SO WILL THEREFORE MAINTAIN A DRY FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. COOLER AIR WILL FILTER IN BEHIND THE FRONT LATE IN THE WEEK...LEADING TO A RETURN TO MORE SEASONABLE TEMPERATURES THROUGH THE WEEKEND. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... WITH HIGH PRESSURE REMAINING OVER THE REGION...VFR IS EXPECTED TO PERSIST. BR FORMATION IS NOT LIKELY IN THIS DRY AIRMASS. MODELS SHOW INCREASING CLOUDS...FIRST IN HIGH LEVELS TODAY...THEN IN THE MID LEVELS TONIGHT...FOLLOWED BY A LAYER AT AROUND 5000 FT ON TUESDAY. WINDS WILL STAY LIGHT OUT OF THE SOUTH. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...CONIGLIO/HICKMAN SHORT TERM...HICKMAN LONG TERM...HICKMAN/JGL AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
933 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THE REGIONS WEATHER INTO TUESDAY. THE HIGH WILL MOVE EAST TUESDAY NIGHT AS A WARM FRONT APPROACHES THE AREA FROM THE SOUTHWEST. THE WARM FRONT WILL PUSH ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT INTO THURSDAY. TEMPERATURES WILL WARM TO ABOVE NORMAL READINGS THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURFACE HIGH PRESSURE EXTENDED FROM THE NEW ENGLAND COAST TO THE THE OHIO AND TENNESSEE VALLEYS THIS MORNING. THE HIGH IS EXPECTED TO MOVE LITTLE TODAY. AFTER A COLD START...TEMPERATURES WILL MODERATE UNDER ABUNDANT SUNSHINE. CIRRUS WILL INCREASE IN COVERAGE BUT IT WILL REMAIN MOSTLY SUNNY. HIGHS WILL RANGE FROM THE LOWER 40S NORTH TO THE UPPER 40S SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... SURFACE HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE OHIO VALLEY TONIGHT INTO TUESDAY. MEANWHILE...WEAK UPR LVL ENERGY WILL TRACK ACROSS THE GREAT LAKES. RETURN LOW LEVEL FLOW MAY BRING SOME LOWER CLOUDS TO OUR SE CWFA THIS EVENING/OVERNIGHT WHILE MID LVL MOISTURE STREAMS IN FROM THE WEST. CLOUD COVER WILL PREVENT TEMPERATURES FROM COOLING OFF TOO MUCH AND SHOULD RANGE FROM THE MID 20S TO THE LOWER 30S. SKIES ON TUESDAY WILL RANGE FROM PARTLY TO MOSTLY CLOUDY AS MID LVL MOISTURE CONTINUES TO ADVECT ACROSS THE REGION FROM THE WEST. HIGHS WILL VARY FROM THE MID 40S NORTH TO NEAR 50 SOUTH. MODELS ARE IN GOOD AGREEMENT FOR TUESDAY NIGHT INTO WEDNESDAY. SURFACE HIGH WILL MOVE EAST AS A WARM FRONT DEVELOPS TO OUR SOUTHWEST. THE WARM FRONT WILL MOVE ACROSS THE AREA ON WEDNESDAY. DEEP MOISTURE WILL INCREASE OVER THE REGION THROUGH THE PERIOD. THIS MOISTURE WILL COINCIDE WITH A STRONG LOW LEVEL JET AND UPR LVL DIVERGENCE FROM THE RR QUAD OF AN UPR LVL JET. THIS WILL RESULT IN SHOWERS WITH THE HIGHEST THREAT POISED FOR THE NRN ZONES. HAVE RAISED POPS TO CATEGORICAL ACRS NRN AREAS TUESDAY NIGHT INTO WEDNESDAY. PCPN CHANCES WILL DIMINISH TO LOW CHANCE SOUTH OF THE OHIO RIVER. THE WARM FRONT WILL LIFT NORTH OF THE AREA WEDNESDAY NIGHT. THE WARM FRONT WILL BE FOLLOWED BY A COLD FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION ON THURSDAY. DEEP MOISTURE COUPLED WITH DECENT LOW LEVEL FORCING AHEAD OF THE FRONT WILL BRING ANOTHER ROUND OF SHOWERS. HAVE GONE WITH CATEGORICAL POPS. THE FRONT WILL PUSH SOUTHEAST THURSDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. THIS WILL BRING AN END TO THE PCPN. TEMPERATURES TUESDAY NIGHT INTO THURSDAY NIGHT WILL EXHIBIT NON DIURNAL TRENDS AND HAVE RELIED ON A BLEND OF RAW 2 M GFS AND ECMWF FOR THE MOST PART. && .LONG TERM /FRIDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND. A WEAK SHORT WAVE MAY DROP DOWN ACROSS THE GREAT LAKES ON SATURDAY...BUT IT LOOKS LIKE BETTER FORCING WITH THIS WILL REMAIN OFF TO OUR NORTH SO WILL THEREFORE MAINTAIN A DRY FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. COOLER AIR WILL FILTER IN BEHIND THE FRONT LATE IN THE WEEK...LEADING TO A RETURN TO MORE SEASONABLE TEMPERATURES THROUGH THE WEEKEND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL MEANDER OVER THE UPPER OHIO VALLEY REGION THROUGH THE NEXT DAY OR SO. THIS WILL BRING LIGHT TO CALM WINDS (OCCASIONALLY UP TO AROUND 5 KNOTS OUT OF THE SOUTH). SOME CIRRUS WILL SPILL INTO THE REGION TODAY...WITH MID CLOUDS POSSIBLE OVERNIGHT AND EARLY TUESDAY. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...CONIGLIO/HICKMAN SHORT TERM...HICKMAN LONG TERM...HICKMAN/JGL AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
627 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THE REGIONS WEATHER INTO TUESDAY. THE HIGH WILL MOVE EAST TUESDAY NIGHT AS A WARM FRONT APPROACHES THE AREA FROM THE SOUTHWEST. THE WARM FRONT WILL PUSH ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT INTO THURSDAY. TEMPERATURES WILL WARM TO ABOVE NORMAL READINGS THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURFACE HIGH PRESSURE EXTENDED FROM THE NEW ENGLAND COAST TO THE THE OHIO AND TENNESSEE VALLEYS THIS MORNING. THE HIGH IS EXPECTED TO MOVE LITTLE TODAY. AFTER A COLD START...TEMPERATURES ARE EXPECTED TO MODERATE UNDER ABUNDANT SUNSHINE. HIGHS WILL RANGE FROM THE LOWER 40S NORTH TO THE UPPER 40S SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... SURFACE HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE OHIO VALLEY TONIGHT INTO TUESDAY. MEANWHILE...WEAK UPR LVL ENERGY WILL TRACK ACROSS THE GREAT LAKES. RETURN LOW LEVEL FLOW MAY BRING SOME LOWER CLOUDS TO OUR SE CWFA THIS EVENING/OVERNIGHT WHILE MID LVL MOISTURE STREAMS IN FROM THE WEST. CLOUD COVER WILL PREVENT TEMPERATURES FROM COOLING OFF TOO MUCH AND SHOULD RANGE FROM THE MID 20S TO THE LOWER 30S. SKIES ON TUESDAY WILL RANGE FROM PARTLY TO MOSTLY CLOUDY AS MID LVL MOISTURE CONTINUES TO ADVECT ACROSS THE REGION FROM THE WEST. HIGHS WILL VARY FROM THE MID 40S NORTH TO NEAR 50 SOUTH. MODELS ARE IN GOOD AGREEMENT FOR TUESDAY NIGHT INTO WEDNESDAY. SURFACE HIGH WILL MOVE EAST AS A WARM FRONT DEVELOPS TO OUR SOUTHWEST. THE WARM FRONT WILL MOVE ACROSS THE AREA ON WEDNESDAY. DEEP MOISTURE WILL INCREASE OVER THE REGION THROUGH THE PERIOD. THIS MOISTURE WILL COINCIDE WITH A STRONG LOW LEVEL JET AND UPR LVL DIVERGENCE FROM THE RR QUAD OF AN UPR LVL JET. THIS WILL RESULT IN SHOWERS WITH THE HIGHEST THREAT POISED FOR THE NRN ZONES. HAVE RAISED POPS TO CATEGORICAL ACRS NRN AREAS TUESDAY NIGHT INTO WEDNESDAY. PCPN CHANCES WILL DIMINISH TO LOW CHANCE SOUTH OF THE OHIO RIVER. THE WARM FRONT WILL LIFT NORTH OF THE AREA WEDNESDAY NIGHT. THE WARM FRONT WILL BE FOLLOWED BY A COLD FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION ON THURSDAY. DEEP MOISTURE COUPLED WITH DECENT LOW LEVEL FORCING AHEAD OF THE FRONT WILL BRING ANOTHER ROUND OF SHOWERS. HAVE GONE WITH CATEGORICAL POPS. THE FRONT WILL PUSH SOUTHEAST THURSDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. THIS WILL BRING AN END TO THE PCPN. TEMPERATURES TUESDAY NIGHT INTO THURSDAY NIGHT WILL EXHIBIT NON DIURNAL TRENDS AND HAVE RELIED ON A BLEND OF RAW 2 M GFS AND ECMWF FOR THE MOST PART. && .LONG TERM /FRIDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND. A WEAK SHORT WAVE MAY DROP DOWN ACROSS THE GREAT LAKES ON SATURDAY...BUT IT LOOKS LIKE BETTER FORCING WITH THIS WILL REMAIN OFF TO OUR NORTH SO WILL THEREFORE MAINTAIN A DRY FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. COOLER AIR WILL FILTER IN BEHIND THE FRONT LATE IN THE WEEK...LEADING TO A RETURN TO MORE SEASONABLE TEMPERATURES THROUGH THE WEEKEND. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL MEANDER OVER THE UPPER OHIO VALLEY REGION THROUGH THE NEXT DAY OR SO. THIS WILL BRING LIGHT TO CALM WINDS (OCCASIONALLY UP TO AROUND 5 KNOTS OUT OF THE SOUTH). SOME CIRRUS WILL SPILL INTO THE REGION TODAY...WITH MID CLOUDS POSSIBLE OVERNIGHT AND EARLY TUESDAY. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...HICKMAN SHORT TERM...HICKMAN LONG TERM...HICKMAN/JGL AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
356 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THE REGIONS WEATHER INTO TUESDAY. THE HIGH WILL MOVE EAST TUESDAY NIGHT AS A WARM FRONT APPROACHES THE AREA FROM THE SOUTHWEST. THE WARM FRONT WILL PUSH ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A COLD FRONT WEDNESDAY NIGHT INTO THURSDAY. TEMPERATURES WILL WARM TO ABOVE NORMAL READINGS THROUGH THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURFACE HIGH PRESSURE EXTENDED FROM THE NEW ENGLAND COAST TO THE THE OHIO AND TENNESSEE VALLEYS THIS MORNING. THE HIGH IS EXPECTED TO MOVE LITTLE TODAY. AFTER A COLD START...TEMPERATURES ARE EXPECTED TO MODERATE UNDER ABUNDANT SUNSHINE. HIGHS WILL RANGE FROM THE LOWER 40S NORTH TO THE UPPER 40S SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... SURFACE HIGH PRESSURE WILL REESTABLISH ITSELF OVER THE OHIO VALLEY TONIGHT INTO TUESDAY. MEANWHILE...WEAK UPR LVL ENERGY WILL TRACK ACROSS THE GREAT LAKES. RETURN LOW LEVEL FLOW MAY BRING SOME LOWER CLOUDS TO OUR SE CWFA THIS EVENING/OVERNIGHT WHILE MID LVL MOISTURE STREAMS IN FROM THE WEST. CLOUD COVER WILL PREVENT TEMPERATURES FROM COOLING OFF TOO MUCH AND SHOULD RANGE FROM THE MID 20S TO THE LOWER 30S. SKIES ON TUESDAY WILL RANGE FROM PARTLY TO MOSTLY CLOUDY AS MID LVL MOISTURE CONTINUES TO ADVECT ACROSS THE REGION FROM THE WEST. HIGHS WILL VARY FROM THE MID 40S NORTH TO NEAR 50 SOUTH. MODELS ARE IN GOOD AGREEMENT FOR TUESDAY NIGHT INTO WEDNESDAY. SURFACE HIGH WILL MOVE EAST AS A WARM FRONT DEVELOPS TO OUR SOUTHWEST. THE WARM FRONT WILL MOVE ACROSS THE AREA ON WEDNESDAY. DEEP MOISTURE WILL INCREASE OVER THE REGION THROUGH THE PERIOD. THIS MOISTURE WILL COINCIDE WITH A STRONG LOW LEVEL JET AND UPR LVL DIVERGENCE FROM THE RR QUAD OF AN UPR LVL JET. THIS WILL RESULT IN SHOWERS WITH THE HIGHEST THREAT POISED FOR THE NRN ZONES. HAVE RAISED POPS TO CATEGORICAL ACRS NRN AREAS TUESDAY NIGHT INTO WEDNESDAY. PCPN CHANCES WILL DIMINISH TO LOW CHANCE SOUTH OF THE OHIO RIVER. THE WARM FRONT WILL LIFT NORTH OF THE AREA WEDNESDAY NIGHT. THE WARM FRONT WILL BE FOLLOWED BY A COLD FRONT WHICH WILL PUSH SOUTHEAST ACROSS THE REGION ON THURSDAY. DEEP MOISTURE COUPLED WITH DECENT LOW LEVEL FORCING AHEAD OF THE FRONT WILL BRING ANOTHER ROUND OF SHOWERS. HAVE GONE WITH CATEGORICAL POPS. THE FRONT WILL PUSH SOUTHEAST THURSDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. THIS WILL BRING AN END TO THE PCPN. TEMPERATURES TUESDAY NIGHT INTO THURSDAY NIGHT WILL EXHIBIT NON DIURNAL TRENDS AND HAVE RELIED ON A BLEND OF RAW 2 M GFS AND ECMWF FOR THE MOST PART. && .LONG TERM /FRIDAY THROUGH SUNDAY/... HIGH PRESSURE WILL BUILD INTO THE AREA FOR THE WEEKEND. A WEAK SHORT WAVE MAY DROP DOWN ACROSS THE GREAT LAKES ON SATURDAY...BUT IT LOOKS LIKE BETTER FORCING WITH THIS WILL REMAIN OFF TO OUR NORTH SO WILL THEREFORE MAINTAIN A DRY FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD. COOLER AIR WILL FILTER IN BEHIND THE FRONT LATE IN THE WEEK...LEADING TO A RETURN TO MORE SEASONABLE TEMPERATURES THROUGH THE WEEKEND. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL MEANDER OVER THE UPPER OHIO VALLEY REGION THROUGH THE NEXT DAY OR SO. THIS WILL BRING LIGHT TO CALM WINDS (OCCASIONALLY UP TO AROUND 5 KNOTS OUT OF THE SOUTH). SOME CIRRUS WILL SPILL INTO THE REGION TODAY...BUT NO LOW CLOUDS ARE EXPECTED AT THIS TIME. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HICKMAN NEAR TERM...HICKMAN SHORT TERM...HICKMAN LONG TERM...HICKMAN/JGL AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
947 AM EST MON DEC 12 2011 .SYNOPSIS... HIGH PRESSURE WILL BE CENTERED OVER THE MID ATLANTIC THROUGH MUCH OF THE FIRST HALF OF THE WEEK. A MOIST FLOW OFF THE ATLANTIC AND NORTH ACROSS FLORIDA AND GEORGIA WILL RESULT IN CLOUDY SKIES AND SOME RAIN TODAY AND THEN DRIER WEATHER WILL RETURN INTO MID WEEK. A COLD FRONT WILL APPROACH TOWARD THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM...WATER VAPOR IMAGERY AND RUC 500 MB HEIGHT FIELDS SHOW A SHORTWAVE LIFTING NE THROUGH THE THE CENTRAL CAROLINAS MID MORNING. THIS FEATURE SHOULD LIFT ANY LINGERING LIGHT PIEDMONT PRECIPITATION EAST OF THE AREA BY NOON. LOW LEVEL WARM AND MOIST ADVECTION WILL CONTINUE FROM THE SW...HOWEVER...SO THE CLOUDS SHOULD BE HERE TO STAY OVER THE NOSE OF SFC HIGH PRES...WITH SLIGHT CHC TO CHC POPS STILL WARRANTED FOR THE SW PART OF THE AREA THROUGH THE AFTN. WILL MAINTAIN A DECENT GRADIENT ON MAX T FROM MID TO UPPER 40S IN NE GA/WRN UPSTATE TO LOWER 50S INTERSTATE 77 AREA THIS AFTN. THE SFC HIGH WILL RETROGRADE WWD TONIGHT AS HEIGHTS RISE ALOFT. 850 MB FLOW WILL STEADILY VEER W THEN NW THROUGH THE OVERNIGHT HOURS. ANY SPRINKLES SHOULD BE CONFINED MAINLY TO MTN AREAS...WITH DOWNSLOPING POSSIBLY ALLOWING SOME SCATTERING IN THE FOOTHILLS/PIEDMONT CLOUDS. LINGERING CLOUDS AND LIGHT MIXING SHOULD ALLOW MIN TEMPS TO RUN 5 TO 10 DEGREES ABOVE NORMAL MOST AREAS. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 200 AM MONDAY...UPPER LEVEL HEIGHTS ATOP THE SE CONUS WILL BE RISING ON TUESDAY. THE COOLISH NORTHERLY LLVL FLOW IS PROGGED TO WEAKEN...AND AN ACCOMPANYING RISE IN 100-85H THICKNESS SHOULD BOOST MAX TEMPS TO ABT 8 DEG F ABOVE CLIMO...AS PER THE LATEST MOS BLEND. UPPER LEVEL RIDGE AXIS WILL CONTINUE TO BUILD EAST THRU WEDNESDAY... ALIGNING ITSELF ATOP THE CWFA AND AIDING IN THE CONTINUATION OF FAIR WX CONDITIONS. MILD LLVL RETURN FLOW INCREASES AND SHOULD SUPPORT MAX TEMPS A FEW DEG F WARMER THAN PERSISTENCE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 230 AM MONDAY...THE MEDIUM RANGE MODELS AGREE ON THE UPPER RIDGE BREAKING DOWN OVER THE SOUTHEAST WITH THE AXIS FROM FLORIDA TO EASTERN VIRGINIA EARLY THURSDAY. BY 00Z FRIDAY...THE RIDGE WILL HAVE SIGNIFICANTLY FLATTENED OUT WITH THE STRONG SHORTWAVE CROSSING THE GREAT LAKES. THE SLOW MOVING COLD FRONT WILL DRAPE SW TO NE ACROSS THE SOUTHERN APPALACHIANS. FROM THURSDAY INTO THURSDAY NIGHT WAVES OF LOW PRESSURE WILL ENHANCE PRECIP ALONG THE FRONT. THE SUPPORTING ENERGY WILL MOVE OUT FRIDAY WITH VERY LITTLE RAIN OVER THE AREA. THE NEW ECMWF BRINGS ANOTHER SHORTWAVE RAPIDLY ACROSS THE PLAINS AND MISS VALLEY SATURDAY INDUCING THE SURFACE RESPONSE ACROSS THE SOUTHEAST ALONG THE FRONT. THIS LAST BATCH OF RAIN WILL MOVE EAST OF OUR AREA SATURDAY NIGHT. HIGH PRESSURE WILL BE IN CONTROL SUNDAY AND SUNDAY NIGHT WITH DRY WEATHER. TEMPERATURES WILL BE ABOVE NORMAL IN THE MEDIUM RANGE...MUCH ABOVE THURS AND FRI...THEN ONLY A FEW DEGREES ABOVE NORMAL OVER THE WEEKEND FOR HIGH TEMPS. WITH CLOUDINESS...LOWS WILL BE MUCH ABOVE NORMAL. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... AT KCLT AND ELSEWHERE...A SURFACE RIDGE STRETCHING FROM THE DELMARVA TO THE WESTERN CAROLINAS WILL MAINTAIN NE WINDS IN THE 5 TO 10 KT RANGE THROUGHOUT TODAY...EXCEPT SOUTHEAST AT KAVL. THE SFC RIDGING WILL ACTUALLY BUILD WWD TOWARD THE MTN CHAIN TONIGHT AS HEIGHTS RISE FROM THE WEST ALOFT. WINDS WILL DIMINISH THIS EVENING. LOW VFR TO MVFR STRATOCUMULUS WILL PERSIST ACROSS THE REGION IN MOIST...WARM ADVECTION FLOW THROUGH THE DAY...BUT ANY LIGHT LINGERING PRECIP SHOULD MOVE EAST OF THE AREA WITH AN UPPER LEVEL SHORTWAVE BY 18Z. SOME LIGHT PRECIP COULD RETURN THIS EVENING FROM THE SW...BUT THIS APPEARS UNLIKELY TO IMPACT ANY OF THE TAF SITES. WILL KEEP CONDITIONS VFR THROUGH THE EVENING...WITH SCATTERING OVERNIGHT AS 850 MB FLOW TURNS A WESTERLY DOWNSLOPE. OUTLOOK...GENERALLY DRY CONDITIONS SHOULD PERSIST UNTIL AT LEAST THURSDAY...WHEN A COLD FRONT WILL APPROACH FROM THE WEST. 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...HG SHORT TERM...CSH LONG TERM...DEO AVIATION...HG
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1225 PM CST MON DEC 12 2011 .UPDATE... AREAS OF FOG HAVE FOR THE MOST PART LIFTED ACROSS THE TEXAS AND OKLAHOMA PANHANDLES THIS MORNING. POSSIBLE FOR PATCHY AREAS OF LIGHT FOG TO CONTINUE EARLY THIS AFTERNOON BUT NOT EXPECTING FOG TO BECOME MORE WIDE SPREAD GIVEN WIND SPEEDS AROUND 10 TO 20 MPH. THUS HAVE OPTED TO LEAVE THIS OUT OF THE FORECAST FOR THIS AFTERNOON. OTHERWISE EXPECT ANOTHER CLOUDY AND COOL DAY WITH HIGH TEMPS MAINLY IN THE 40S TO NEAR 50 IN THE EASTERN TEXAS AND OKLAHOMA PANHANDLES. HAVE MADE MINOR ADJUSTMENTS TO WIND AND SKY GRIDS TO ACCOUNT FOR CURRENT TRENDS...BUT FOR THE MOST PART THE INHERITED FORECAST LOOKS TO BE ON TRACK WITH NO OTHER AMENDMENTS NEEDED. UPDATED FORECAST PRODUCTS HAVE BEEN SENT. CLK && .PREV DISCUSSION... /ISSUED 1156 AM CST MON DEC 12 2011/ AVIATION... /18 UTC TAFS/ FOG AND LOW CLOUDS REMAIN THE MAIN AVIATION FORECAST CONCERN FOR THIS FORECAST CYCLE. AT KAMA...HAVE SEEN VISBYS IMPROVE AS THE FOG HAS SLOWLY LIFTED. EXPECT VISBYS TO IMPROVE TO VFR BY 19 UTC...HOWEVER WILL CONTINUE TO SEE LIFR CIGS THROUGH THE AFTERNOON. GUSTY SOUTHWEST WINDS THIS MORNING WILL DIMINISH BUT STILL REMAIN BETWEEN 10-15 KTS THIS AFTERNOON. LIGHT FOG WILL DEVELOP AT THE TERMINAL /AROUND 23Z/ BUT NOT EXPECTING VISBYS TO REALLY DETEIORATE UNTIL CLOSER TO 06Z IN AREAS OF FOG AND DRIZZLE. SHOULD SEE VISBYS IMPROVE BY 16 UTC TUESDAY HOWEVER STILL EXPECT IFR CONDITIONS. WINDS WILL BACK MORE TO THE SOUTHEAST WITH SPEEDS AGAIN BETWEEN 10-15 KTS. AT KDHT/KGUY...CONDITIONS HAVE IMPROVED TO VFR BUT EXPECT THIS TO BE FLEETING AS AREAS OF LIGHT FOG WITH CIGS AND VISBYS DETEIORATING TO MVFR. SIMILAR TO KAMA...EXPECT AREAS OF DRIZZLE AND FOG TO DEVELOP AROUND 03 UTC WHICH WILL CAUSE CONDITIONS TO LOWER TO LIFR. SHOULD SEE VISBYS AND CIGS IMPROVE TO IFR AT THE END OFF THE FORECAST PERIOD. WINDS WILL BE LIGHTER AT KDHT/KGUY AS THE EFFECTS A 45-50 KT LOW LEVEL JET WILL BE MORE PRONOUNCED ACROSS THE SOUTHERN TEXAS PANHANDLE. CLK PREV DISCUSSION... /ISSUED 556 AM CST MON DEC 12 2011/ AVIATION... FOR THE 12Z TAFS...GENERALLY HAVE LOW TO MODERATE CONFIDENCE AT ALL SITES. AT KAMA...BELIEVE IFR OR LOWER CONDITIONS WILL PREVAIL FOR AT LEAST THE NEXT 24 HOURS AND WENT WITH A MORE PESSIMISTIC FORECAST IN REGARDS TO CEILINGS/VISIBILITIES. CONFIDENCE IS MODERATE THAT VLIFR CONDITIONS WILL OCCUR THROUGH 16Z...THEN SOME IMPROVEMENT 16-24Z... BEFORE CONDITIONS DETERIORATE AFTER 00Z. HAVE MODERATE CONFIDENCE THAT LIFR CONDITIONS OR LOWER WILL OCCUR AFTER 00Z. -DZ WILL LIKELY OCCUR AFTER 02Z. AT KDHT...THINK IFR CONDITIONS WILL IMPROVE TO AT LEAST MVFR IF NOT BETTER 17-20Z. DETERIORATING CONDITIONS WILL LIKELY OCCUR AFTER 00Z. HAVE LOW CONFIDENCE FOR LIFR CONDITIONS AFTER 04Z. AT KGUY...HAVE MODERATE CONFIDENCE THAT CONDITIONS WILL IMPROVE TO VFR 16-20Z...BEFORE DETERIORATING AFTER 22Z...ESPECIALLY AFTER 06Z. HAVE VERY LOW CONFIDENCE FOR LIFR CONDITIONS AFTER 11Z. MBS PREV DISCUSSION... /ISSUED 443 AM CST MON DEC 12 2011/ DISCUSSION... TODAY-TONIGHT: HAVE SEEN SOME PATCHY AREAS OF FOG ACROSS THE PANHANDLES THIS MORNING...BUT STRONGER SURFACE WINDS HAVE PRECLUDED ANY DENSE FOG CONCERNS. EXPECT PATCHY FOG TO CONTINUE THROUGH MOST OF THE MORNING HOURS SOUTH AND EAST OF A LINE FROM DALHART TO GUYMON. MUCH LOWER VISIBILITIES HAVE BEEN NOTED ACROSS THE SOUTH PLAINS WHERE SURFACE/LOW-LEVEL WINDS HAVE WEAKENED...PER KLBB VAD DATA. RUC DATA INDICATES WINDS ACROSS THE PANHANDLES MAY ALSO WEAKEN...AND IF THIS OCCURS...VISIBILITIES WILL LIKELY DETERIORATE. STILL NOT EXPECTING ANY DENSE FOG ISSUES AS SURFACE WINDS SHOULD REMAIN ABOVE 10 MPH...BUT WILL MONITOR CLOSELY. WOULDN/T BE SURPRISED TO SEE SOME DRIZZLE ACROSS THE FAR SOUTHEAST TEXAS PANHANDLE THROUGH 9 AM WHERE FORECAST SOUNDINGS INDICATE THE LOW-LEVEL MOISTURE WILL REMAIN AROUND 2000 FT DEEP...BUT SINCE THIS IS ON THE MARGINAL END FOR DRIZZLE...LEFT OUT OF THE FORECAST FOR NOW. OTHERWISE...EXPECT MOST OF THE AREA TO REMAIN GRUNGED IN WITH LOW CLOUDS FOR MOST OF THE DAY. AS A RESULT...HIGH TEMPERATURES WILL CONTINUE TO REMAIN BELOW SEASONAL NORMS. IT IS INTERESTING TO NOTE THAT THE AVERAGE DAILY TEMPERATURE AT AMARILLO...BORGER...DALHART...AND GUYMON HAS NOT BEEN ABOVE NORMAL SINCE NOVEMBER 30. AS ISENTROPIC ASCENT INCREASES THIS EVENING AND OVERNIGHT...PRECIPITATION CHANCES WILL ALSO INCREASE. QPF AMOUNTS WILL BE LIGHT WITH MOST LOCATIONS SEEING LESS THAN 0.10" THROUGH SUNRISE ON TUESDAY. EXPECTING THE PRECIPITATION TYPE TO BE ALL LIQUID AS WARM AIR ADVECTION...MOISTURE ADVECTION...AND LOW CLOUDS SHOULD KEEP TEMPERATURES ABOVE FREEZING. ONCE AGAIN...ANOTHER ROUND OF PATCHY FOG IS EXPECTED DEVELOP AREAWIDE...BUT THE RAIN SHOULD KEEP THE NEAR GROUND AIR MIXED ENOUGH TO LIMIT ANY DENSE FOG CONCERNS. TUESDAY-TUESDAY NIGHT: PATCHY FOG MAY LINGER INTO THE LATE MORNING HOURS ON TUESDAY. OTHERWISE...ANOTHER DREARY DAY IS EXPECTED WITH LOW CLOUDS AND INCREASING PRECIPITATION CHANCES...ESPECIALLY AFTER NOON. MAX TEMPS WILL ONCE AGAIN BE ON THE COOL SIDE. MET AND MAV GUIDANCE APPEAR TOO HIGH...SO FOLLOWED RAW NAM TEMPERATURES CLOSELY. BY TUESDAY AFTERNOON...FORECAST SOUNDINGS INDICATE SOME WEAK ELEVATED INSTABILITY DEVELOPING ACROSS MOST OF THE PANHANDLES AS LOW-LEVEL MOISTURE INCREASES AND MID-LEVEL LAPSE RATES STEEPEN. KEPT THUNDERSTORMS IN THE FORECAST AND SHIFTED THEM SLIGHTLY WESTWARD. STRONGER MOISTURE ADVECTION IS EXPECTED ACROSS MOST OF THE AREA ON TUESDAY NIGHT....AND IN FACT...THE ECMWF...GGEM...AND GFS ALL SHOW SURFACE DEW POINTS IN THE MID TO UPPER 50S ACROSS THE SOUTHEAST TEXAS PANHANDLE! IT/S AMAZING TO REALIZE THAT WE STRUGGLED TO SEE DEW POINTS THAT HIGH DURING THE SPRING AND SUMMER...BUT IT/S POSSIBLE THEY MAY REACH THAT HIGH IN DECEMBER. REGARDLESS...AS FORCING FOR ASCENT IMPINGES ON THE MOIST AND WEAKLY UNSTABLE AIR MASS...PRECIPITATION AND THUNDERSTORM CHANCES WILL REALLY RAMP UP TUESDAY EVENING AND NIGHT. WITHIN THE LAST COUPLE OF WEEKS...HAVE NOTICED THAT THE SUBTROPICAL JET HAS HAD A CONNECTION TO THE TROPICS...AND THIS LOOKS TO BE THE CASE AGAIN WITH THIS SYSTEM. AS A RESULT...WON/T BE SURPRISED TO SEE RAINFALL AMOUNTS OVERACHIEVE IN SOME LOCATIONS. REGARDING THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS ARE SHOWING UP TO 300 J/KG OF MUCAPE ALONG WITH DEEP LAYER SHEAR AROUND 70 KT. AS A RESULT...MAY SEE A FEW STRONG STORMS PRODUCE SMALL HAIL TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. NOT EXPECTING ANY WINTRY PRECIPITATION AS SURFACE AND LOW-LEVEL TEMPERATURES WILL REMAIN ABOVE FREEZING. WEDNESDAY-WEDNESDAY NIGHT: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE FORECAST AREA DURING THE DAY. THERE MAY BE ENOUGH LINGERING LOW- LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING FOR A CHANCE OF PRECIPITATION. KEPT THUNDERSTORMS IN THE FORECAST...BUT FORECAST SOUNDINGS INDICATING LESS THAN 50 J/KG OF MUCAPE. THANKS TO THE DRY SLOT...THE SUN WILL MAKE AN APPEARANCE ACROSS THE REGION. HIGH TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY 60S AS STRONG DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS. FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW AND WILL NOT BE ABLE TO TAP INTO THE HIGH MOMENTUM MID-LEVEL AIR. NONETHELESS...FORECAST SOUNDINGS ARE SHOWING 30-35 KT FLOW AT THE TOP OF THE BOUNDARY LAYER. CONTINUED TO KEEP WINDS BELOW ADVISORY CRITERIA...ESPECIALLY SINCE MET WINDS ARE TRENDING LOWER. HOWEVER...IF THE GFS IS CORRECT...COULD SEE ADVISORY LEVEL WINDS...ESPECIALLY ON THE CAPROCK. AS THE UPPER TROUGH AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE UNDER 10 MPH BY SUNRISE THURSDAY. THURSDAY-THURSDAY NIGHT: DRY AND SUB-SEASONAL TEMPERATURES ARE EXPECTED AS NNE UPSLOPE WINDS PREVAIL THROUGH THE DAY. DUE TO THE UPSLOPE WINDS...LOWERED HIGHS IN ALL AREAS. A CHILLY NIGHT IS EXPECTED WITH LOWS IN THE 20S AND LOWER 30S. FRIDAY-MONDAY: STILL A LOT OF UNCERTAINTIES DURING THIS TIME PERIOD. THE DGEX AND GFS CONTINUE TO REMAIN FASTER WITH THE CUTOFF LOW THAN THE ECMWF AND GGEM. JUST NOTICED THE NEW 06 UTC GFS HAS NOW TRENDED SLOWER WITH THE CLOSED LOW AND IS MORE SIMILAR TO THE ECMWF AND GGEM. EXPECT PRECIPITATION TO DEVELOP ACROSS THE SOUTHWEST TEXAS PANHANDLE SATURDAY EVENING BEFORE SPREADING ACROSS ALL OF THE FORECAST AREA SATURDAY NIGHT. RAIN IS LIKELY SATURDAY EVENING AND THEN POSSIBLY MIXING WITH OR CHANGING TO SNOW SATURDAY NIGHT. SOME INDICATIONS THAT LOW-LEVEL THERMAL PROFILES MAY BE A LITTLE WARM FOR SNOW...BUT DUE TO THE UNCERTAINTY...KEPT A RAIN/SNOW MIX IN THE FORECAST. BEYOND SUNDAY...CONSIDERABLE UNCERTAINTY EXISTS...BUT FOLLOWED MORE CLOSELY TO THE ECMWF FOR NOW. IF IT DOES VERIFY...WE COULD BE LOOKING AT MORE WINTER MISCHIEF BY EARLY NEXT WEEK. STILL PLENTY OF TIME TO WATCH THIS SYSTEM SO STAY TUNED. JACKSON FIRE WEATHER... RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 05/03
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1158 AM CST MON DEC 12 2011 .DISCUSSION...SEE AVIATION AND SHORT TERM SECTIONS FOR UPDATES. && .SHORT TERM UPDATE /THIS AFTERNOON/...NOTHING TOO EARTH-SHAKING BUT DID TWEAK TEMPERATURES DOWN SEVERAL DEGREES ACROSS THE BOARD BASED ON CURRENT TRENDS...AS WELL AS RUC AND NAM DATA. SOUTHEAST FLOW JUST OFF THE DECK IS TRYING HARD TO ERODE THE CLOUD MASS NEAR THE COAST AND HAVING MODEST SUCCESS...BUT TEMPERATURES WILL STRUGGLE TO THE 75/76 RANGE AS PREVIOUSLY FORECAST AND HAVE DIPPED TO THE LOWER 70S. FARTHER WEST AND NORTH...MAINLY WEST OF HIGHWAY 281...THE COLD AIR IS STILL TRAPPED AND MAY BARELY ERODE BEFORE SUNSET. MCALLEN THROUGH WESTERN BROOKS LOOKS LIKE THE EDGE...WITH AREAS TO THE WEST TOTALLY SOCKED IN ANOTHER DAY. THIS WILL KEEP TEMPERATURES FROM REACHING MUCH ABOVE 60 AND HAVE LOWERED HIGHS 3 TO 5 DEGREES HERE AS WELL. THE OTHER BIG STORY WILL BE EXPECTATION FOR DENSE FOG OVERNIGHT. MORE IN THE AFTERNOON DISCUSSION AT AROUND 2 PM. SEE PRELIMINARY NUMBERS BELOW FOR ADJUSTMENTS./52-BSG/ .AVIATION...SOUTHEAST FLOW TRYING TO REACH THE SURFACE HAS HELPED PUSH BREAKS INTO THE LOWER VALLEY (KHRL/KBRO)...AND CEILINGS HAVE RESPONDED BY LIFTING INTO VFR RANGE. WINDS DEAD CALM AT 18Z BUT SHOULD INCREASE A HAIR FROM THE EAST OR EAST/SOUTHEAST FOR A FEW HOURS BEFORE SETTLING BACK TO LIGHT...BUT IMPORTANT...SPEEDS OVERNIGHT. EXPECT CEILINGS TO TUMBLE BACK TO IFR TOWARD MIDNIGHT AND VISIBILITY TO FOLLOW AFTER MIDNIGHT...CONTINUING THROUGH MID MORNING BEFORE RAIPDLY BREAKING WITH SOUTHEAST WINDS PICKING UP TO NEAR 10 KNOTS...AND JUMPING MUCH HIGHER RIGHT AROUND 18Z. LIFE IS DIFFERENT 40 TO 50 MILES TO THE WEST. KMFE REMAINS IN IFR BUT SHOULD HESITANTLY BREAK TO THE EDGE OF MVFR BEFORE 20Z...WITH VISIBILITY NO ISSUE THIS AFTERNOON. OVERNIGHT WILL BE ANOTHER ISSUE. CURRENT DATA FROM THE NAM 3 HOUR FORECAST SOUNDINGS...ALONG WITH IDEA THAT TEMPERATURE AND DEWPOINT WILL REMAIN STEADY OR SLOWLY RISE A DEGREE OR TWO WILL SET UP HIGH POTENTIAL FOR DENSE FOG AND LOW CEILINGS...LIFR/LIFR WITH CALM WINDS. LOWEST CONDITIONS WILL COINCIDE WITH EARLY MORNING PREP AND FLIGHTS...AND DELAYS ARE A GOOD BET INTO AND OUT OF MCALLEN. HAVE ISSUED A RARE PREVAILING LIFR CEILING/VISIBILITY FORECAST...WITH A GRADUAL LIFT THROUGH LATE MORNING AND A MORE RAPID RISE TOWARD NOON. FINALLY...AT ALL TERMINALS...LOW LEVEL WIND SHEAR WILL BE NOTABLE BUT NOT ENOUGH TO ADD WITH SPEEDS HOLDING AT OR BELOW 25 KNOTS THROUGH 12Z WITHIN THE 500 TO 2000 FOOT LAYER./52-BSG/ && .PREV DISCUSSION... /ISSUED 526 AM CST MON DEC 12 2011/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...CIGS HAVE FALLEN BELOW 500 FEET AT ALL LOCATIONS THIS MORNING...WITH FOG BEGINNING TO LOWER BELOW 3 MILES. CONDITIONS SHOULD IMPROVE AFTER SUNRISE...WITH CIGS REACHING 300 FEET BY NOON. SOME BINOVC STILL EXPECTED LATE AFTERNOON...BUT CIGS THICKEN BACK UP AFTER SUNSET. STILL LOOKING AT MORE FOG TONIGHT...AND HAS GOOD CHANCE OF BEING DENSER AND STARTING EARLIER IN THE EVENING. LIGHT WINDS WILL SHIFT SOUTHEAST AND INCREASE TO 10 TO 15 KNOTS DURING THE AFTERNOON. WINDS WILL RETURN TO L/V AFTER SUNSET. PREV DISCUSSION... /ISSUED 406 AM CST MON DEC 12 2011/ SHORT TERM .SHORT TERM /MONDAY THROUGH TUESDAY/...OVERCAST SKIES CONTINUE WITH OCCASIONAL DRIZZLE AND LIGHT RAIN AS THE COASTAL TROUGH CONTINUES TO INDUCE OVERRUNNING AREAWIDE. WEAK RIDGING ALOFT WILL BEGIN TO HELP BREAK DOWN THE SFC TROUGH THIS AFTERNOON...BRINGING OVERRUNNING PRECIP TO AN END. CLOUD COVER WILL REMAIN MOSTLY OVERCAST TODAY...WITH BREAKS FINALLY STARTING TO SHOW UP LATE AFTERNOON. LIGHT WINDS AND ABUNDANT MOISTURE WILL SET THE STAGE FOR FOG FORMATION OVERNIGHT TONIGHT. LLVL MOISTURE AND INSTABILITY FROM A WEAK SHORTWAVE ROTATING AROUND THE GULF RIDGE WILL BRING ANOTHER CHANCE FOR MORE SHOWERY PRECIPITATION DURING THE DAY TUESDAY. HAVE NUDGED POP CHANCES UP ACCORDINGLY...BUT RAINS WILL NOT BE WIDESPREAD AS IN PREVIOUS DAYS. TEMPERATURES WILL HAVE A BETTER CHANCE TO REACH INTO THE 60S TODAY...WITH HIGHEST READINGS WHERE ANY BREAKS IN CLOUD COVER OCCUR. LOWS TONIGHT WILL ONLY REACH THE LOW TO MID 60S DUE TO FURTHER INCREASES OF LLVL MOISTURE ACROSS THE REGION. TEMPS TUESDAY REACH FURTHER INTO THE 70S...POSSIBLY REACHING 80...WITH BETTER AMOUNTS OF SUNSHINE. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...PROGRESSIVE SPLIT FLOW PATTERN ACROSS NORTH AMERICA TO MAINTAIN AN UNSETTLED WET AND MILD FORECAST FOR ALL OF DEEP SOUTH TEXAS AND RIO GRANDE RIVER. THIS UN LA NINA LIKE SET UP WILL BE DIFFICULT TO TIME THE SEVERAL SHORTWAVE TROUGHS TRACKING STEADILY FROM THE WEST COAST THROUGH THE DESERT SOUTHWEST AND INTO THE PLAINS. BOTH GFS AND ECMWF ARE UNCANNY SIMILAR SO FORECAST CONFIDENCE IS ABOVE AVERAGE. AS MENTIONED BIG QUESTIONS ARISE WITH TIMING OF SHORTWAVE AND STRENGTH OF SHORTWAVES AND THE MAIN UPPER TROUGH. DO NOT SEE ANY SIGNIFICANT COLD AIR SURGES MAKING THIS FAR SOUTH WITH THE NORTHERN JET REMAINING ALONG THE CANADIAN BORDER DIPPING INTO THE MIDWEST STATES. A MORE MILD MARITIME AIRMASS WILL KEEP OUR TEMPERATURES ABOVE NORMAL MUCH OF THE LONG TERM. MOISTURE FIELDS LOOK MODEST THROUGH THE MIDDLE HALF OF THE WEEK WITH DEEPER MOISTURE SEEN FOR NEXT FRIDAY AND SATURDAY SIMILAR TO WHAT WAS EXPERIENCED THIS PASS WEEKEND. WILL START OUT WITH A BREEZY TO WINDY WEDNESDAY AS A STORM SYSTEM LIFTS OUT OF THE 4 CORNERS REGION. GFS SUGGEST A STRONG LOW LEVEL JET DEVELOPING AND WITH THE FINALLY PEAKING OUT MODEST MIXING OF THE STRONGER WINDS ARE ANTICIPATED. THIS WILL PUSH TEMPERATURES INTO THE LOWER 80S MOST LOCATIONS. RAIN CHANCES ARE NEAR NIL. SHOWERS RETURN TO THE FORECAST THURSDAY AS ANOTHER COASTAL TROUGH IS PROGGED TO DEVELOP. THIS TROUGH BECOMES ENHANCED FRIDAY AND SATURDAY AS A LARGE UPPER TROUGH DIGS INTO THE SW DESERTS. A COLD FRONT BEGINS TO ADVANCE TOWARDS THE CWA DURING THE LATER HALF OF THE WEEK POSSIBLE DRAPING ITSELF ACROSS THE REGION ON SATURDAY. GRIDDS SHOW CHANCE POPS AT THIS TIME AS DOES THE MODEL GUIDANCE THIS WILL LIKELY BECOME MORE DEFINED AS WE APPROACH NEXT WEEKEND. TEMPERATURES TO FALL DUE TO THE INCREASE IN CLOUDS...RAIN AND POSSIBLE COLD FRONT PASSAGE. MARINE... NOW THROUGH TUESDAY...BREEZY CONDITIONS IN THE VICINITY OF THE SFC COASTAL TROUGH CONTINUE TO PRODUCE WINDS AROUND 20 KNOTS AND SEAS 6 TO 7 FEET OFFSHORE. WINDS HAVE BEGUN TO DECREASE SLOWLY AS THE TROUGH BEGINS TO WEAKEN OFFSHORE. SMALL CRAFT ADVISORIES REMAIN FOR THE GULF WATERS THROUGH 6AM...AND WITH SLOWLY IMPROVING CONDITIONS EXPECTED...WILL NOT BE ANTICIPATING EXTENDING ADVISORIES FURTHER. BREEZY CONDITIONS WILL STILL BE ABLE TO KEEP SEAS ELEVATED AT 6 TO 7 FEET TODAY...FALLING TO 4 TO 5 FEET TUESDAY AFTERNOON. TUESDAY NIGHT THROUGH FRIDAY...AN INCREASE IN WINDS AND SEAS ARE ANTICIPATED TUESDAY NIGHT INTO WEDNESDAY AS STORM SYSTEM TRACKS INTO INTO THE CENTRAL PLAINS. PRESSURE GRADIENT TO TIGHTEN AS PRESSURES LOWER COMBINING WITH BROAD HIGH PRESSURE OVER THE GULF. SMALL CRAFT ADVISORIES ARE LIKELY. WINDS TO RELAX THURSDAY AND FRIDAY BUT SEAS WILL BE SLOW TO SUBSIDE WITH A PERSISTENT EAST FLOW ACROSS THE GULF PRODUCING A MODERATE LONG PERIOD SWELL. UNCERTAIN HOW HIGH THE SWELL GETS OR HOW LOW IT MIGHT FALL BUT AT LEAST EXERCISE CAUTION WORDING IS ANTICIPATED. RAIN CHANCES INCREASE THURSDAY WITH EVEN HIGHER CHANCES FRIDAY AND SATURDAY. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 71 67 76 66 / 20 10 20 10 BROWNSVILLE 70 65 78 65 / 20 10 20 10 HARLINGEN 72 64 79 64 / 30 10 20 10 MCALLEN 66 64 82 65 / 30 10 20 10 RIO GRANDE CITY 60 59 80 62 / 40 10 20 10 SOUTH PADRE ISLAND 69 68 73 67 / 20 10 20 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR GMZ150- 155-170-175. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WWW.WEATHER.GOV/BROWNSVILLE
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1156 AM CST MON DEC 12 2011 .AVIATION... /18 UTC TAFS/ FOG AND LOW CLOUDS REMAIN THE MAIN AVIATION FORECAST CONCERN FOR THIS FORECAST CYCLE. AT KAMA...HAVE SEEN VISBYS IMPROVE AS THE FOG HAS SLOWLY LIFTED. EXPECT VISBYS TO IMPROVE TO VFR BY 19 UTC...HOWEVER WILL CONTINUE TO SEE LIFR CIGS THROUGH THE AFTERNOON. GUSTY SOUTHWEST WINDS THIS MORNING WILL DIMINISH BUT STILL REMAIN BETWEEN 10-15 KTS THIS AFTERNOON. LIGHT FOG WILL DEVELOP AT THE TERMINAL /AROUND 23Z/ BUT NOT EXPECTING VISBYS TO REALLY DETEIORATE UNTIL CLOSER TO 06Z IN AREAS OF FOG AND DRIZZLE. SHOULD SEE VISBYS IMPROVE BY 16 UTC TUESDAY HOWEVER STILL EXPECT IFR CONDITIONS. WINDS WILL BACK MORE TO THE SOUTHEAST WITH SPEEDS AGAIN BETWEEN 10-15 KTS. AT KDHT/KGUY...CONDITIONS HAVE IMPROVED TO VFR BUT EXPECT THIS TO BE FLEETING AS AREAS OF LIGHT FOG WITH CIGS AND VISBYS DETEIORATING TO MVFR. SIMILAR TO KAMA...EXPECT AREAS OF DRIZZLE AND FOG TO DEVELOP AROUND 03 UTC WHICH WILL CAUSE CONDITIONS TO LOWER TO LIFR. SHOULD SEE VISBYS AND CIGS IMPROVE TO IFR AT THE END OFF THE FORECAST PERIOD. WINDS WILL BE LIGHTER AT KDHT/KGUY AS THE EFFECTS A 45-50 KT LOW LEVEL JET WILL BE MORE PRONOUNCED ACROSS THE SOUTHERN TEXAS PANHANDLE. CLK && .PREV DISCUSSION... /ISSUED 556 AM CST MON DEC 12 2011/ AVIATION... FOR THE 12Z TAFS...GENERALLY HAVE LOW TO MODERATE CONFIDENCE AT ALL SITES. AT KAMA...BELIEVE IFR OR LOWER CONDITIONS WILL PREVAIL FOR AT LEAST THE NEXT 24 HOURS AND WENT WITH A MORE PESSIMISTIC FORECAST IN REGARDS TO CEILINGS/VISIBILITIES. CONFIDENCE IS MODERATE THAT VLIFR CONDITIONS WILL OCCUR THROUGH 16Z...THEN SOME IMPROVEMENT 16-24Z... BEFORE CONDITIONS DETERIORATE AFTER 00Z. HAVE MODERATE CONFIDENCE THAT LIFR CONDITIONS OR LOWER WILL OCCUR AFTER 00Z. -DZ WILL LIKELY OCCUR AFTER 02Z. AT KDHT...THINK IFR CONDITIONS WILL IMPROVE TO AT LEAST MVFR IF NOT BETTER 17-20Z. DETERIORATING CONDITIONS WILL LIKELY OCCUR AFTER 00Z. HAVE LOW CONFIDENCE FOR LIFR CONDITIONS AFTER 04Z. AT KGUY...HAVE MODERATE CONFIDENCE THAT CONDITIONS WILL IMPROVE TO VFR 16-20Z...BEFORE DETERIORATING AFTER 22Z...ESPECIALLY AFTER 06Z. HAVE VERY LOW CONFIDENCE FOR LIFR CONDITIONS AFTER 11Z. MBS PREV DISCUSSION... /ISSUED 443 AM CST MON DEC 12 2011/ DISCUSSION... TODAY-TONIGHT: HAVE SEEN SOME PATCHY AREAS OF FOG ACROSS THE PANHANDLES THIS MORNING...BUT STRONGER SURFACE WINDS HAVE PRECLUDED ANY DENSE FOG CONCERNS. EXPECT PATCHY FOG TO CONTINUE THROUGH MOST OF THE MORNING HOURS SOUTH AND EAST OF A LINE FROM DALHART TO GUYMON. MUCH LOWER VISIBILITIES HAVE BEEN NOTED ACROSS THE SOUTH PLAINS WHERE SURFACE/LOW-LEVEL WINDS HAVE WEAKENED...PER KLBB VAD DATA. RUC DATA INDICATES WINDS ACROSS THE PANHANDLES MAY ALSO WEAKEN...AND IF THIS OCCURS...VISIBILITIES WILL LIKELY DETERIORATE. STILL NOT EXPECTING ANY DENSE FOG ISSUES AS SURFACE WINDS SHOULD REMAIN ABOVE 10 MPH...BUT WILL MONITOR CLOSELY. WOULDN/T BE SURPRISED TO SEE SOME DRIZZLE ACROSS THE FAR SOUTHEAST TEXAS PANHANDLE THROUGH 9 AM WHERE FORECAST SOUNDINGS INDICATE THE LOW-LEVEL MOISTURE WILL REMAIN AROUND 2000 FT DEEP...BUT SINCE THIS IS ON THE MARGINAL END FOR DRIZZLE...LEFT OUT OF THE FORECAST FOR NOW. OTHERWISE...EXPECT MOST OF THE AREA TO REMAIN GRUNGED IN WITH LOW CLOUDS FOR MOST OF THE DAY. AS A RESULT...HIGH TEMPERATURES WILL CONTINUE TO REMAIN BELOW SEASONAL NORMS. IT IS INTERESTING TO NOTE THAT THE AVERAGE DAILY TEMPERATURE AT AMARILLO...BORGER...DALHART...AND GUYMON HAS NOT BEEN ABOVE NORMAL SINCE NOVEMBER 30. AS ISENTROPIC ASCENT INCREASES THIS EVENING AND OVERNIGHT...PRECIPITATION CHANCES WILL ALSO INCREASE. QPF AMOUNTS WILL BE LIGHT WITH MOST LOCATIONS SEEING LESS THAN 0.10" THROUGH SUNRISE ON TUESDAY. EXPECTING THE PRECIPITATION TYPE TO BE ALL LIQUID AS WARM AIR ADVECTION...MOISTURE ADVECTION...AND LOW CLOUDS SHOULD KEEP TEMPERATURES ABOVE FREEZING. ONCE AGAIN...ANOTHER ROUND OF PATCHY FOG IS EXPECTED DEVELOP AREAWIDE...BUT THE RAIN SHOULD KEEP THE NEAR GROUND AIR MIXED ENOUGH TO LIMIT ANY DENSE FOG CONCERNS. TUESDAY-TUESDAY NIGHT: PATCHY FOG MAY LINGER INTO THE LATE MORNING HOURS ON TUESDAY. OTHERWISE...ANOTHER DREARY DAY IS EXPECTED WITH LOW CLOUDS AND INCREASING PRECIPITATION CHANCES...ESPECIALLY AFTER NOON. MAX TEMPS WILL ONCE AGAIN BE ON THE COOL SIDE. MET AND MAV GUIDANCE APPEAR TOO HIGH...SO FOLLOWED RAW NAM TEMPERATURES CLOSELY. BY TUESDAY AFTERNOON...FORECAST SOUNDINGS INDICATE SOME WEAK ELEVATED INSTABILITY DEVELOPING ACROSS MOST OF THE PANHANDLES AS LOW-LEVEL MOISTURE INCREASES AND MID-LEVEL LAPSE RATES STEEPEN. KEPT THUNDERSTORMS IN THE FORECAST AND SHIFTED THEM SLIGHTLY WESTWARD. STRONGER MOISTURE ADVECTION IS EXPECTED ACROSS MOST OF THE AREA ON TUESDAY NIGHT....AND IN FACT...THE ECMWF...GGEM...AND GFS ALL SHOW SURFACE DEW POINTS IN THE MID TO UPPER 50S ACROSS THE SOUTHEAST TEXAS PANHANDLE! IT/S AMAZING TO REALIZE THAT WE STRUGGLED TO SEE DEW POINTS THAT HIGH DURING THE SPRING AND SUMMER...BUT IT/S POSSIBLE THEY MAY REACH THAT HIGH IN DECEMBER. REGARDLESS...AS FORCING FOR ASCENT IMPINGES ON THE MOIST AND WEAKLY UNSTABLE AIR MASS...PRECIPITATION AND THUNDERSTORM CHANCES WILL REALLY RAMP UP TUESDAY EVENING AND NIGHT. WITHIN THE LAST COUPLE OF WEEKS...HAVE NOTICED THAT THE SUBTROPICAL JET HAS HAD A CONNECTION TO THE TROPICS...AND THIS LOOKS TO BE THE CASE AGAIN WITH THIS SYSTEM. AS A RESULT...WON/T BE SURPRISED TO SEE RAINFALL AMOUNTS OVERACHIEVE IN SOME LOCATIONS. REGARDING THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS ARE SHOWING UP TO 300 J/KG OF MUCAPE ALONG WITH DEEP LAYER SHEAR AROUND 70 KT. AS A RESULT...MAY SEE A FEW STRONG STORMS PRODUCE SMALL HAIL TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. NOT EXPECTING ANY WINTRY PRECIPITATION AS SURFACE AND LOW-LEVEL TEMPERATURES WILL REMAIN ABOVE FREEZING. WEDNESDAY-WEDNESDAY NIGHT: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE FORECAST AREA DURING THE DAY. THERE MAY BE ENOUGH LINGERING LOW- LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING FOR A CHANCE OF PRECIPITATION. KEPT THUNDERSTORMS IN THE FORECAST...BUT FORECAST SOUNDINGS INDICATING LESS THAN 50 J/KG OF MUCAPE. THANKS TO THE DRY SLOT...THE SUN WILL MAKE AN APPEARANCE ACROSS THE REGION. HIGH TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY 60S AS STRONG DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS. FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW AND WILL NOT BE ABLE TO TAP INTO THE HIGH MOMENTUM MID-LEVEL AIR. NONETHELESS...FORECAST SOUNDINGS ARE SHOWING 30-35 KT FLOW AT THE TOP OF THE BOUNDARY LAYER. CONTINUED TO KEEP WINDS BELOW ADVISORY CRITERIA...ESPECIALLY SINCE MET WINDS ARE TRENDING LOWER. HOWEVER...IF THE GFS IS CORRECT...COULD SEE ADVISORY LEVEL WINDS...ESPECIALLY ON THE CAPROCK. AS THE UPPER TROUGH AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE UNDER 10 MPH BY SUNRISE THURSDAY. THURSDAY-THURSDAY NIGHT: DRY AND SUB-SEASONAL TEMPERATURES ARE EXPECTED AS NNE UPSLOPE WINDS PREVAIL THROUGH THE DAY. DUE TO THE UPSLOPE WINDS...LOWERED HIGHS IN ALL AREAS. A CHILLY NIGHT IS EXPECTED WITH LOWS IN THE 20S AND LOWER 30S. FRIDAY-MONDAY: STILL A LOT OF UNCERTAINTIES DURING THIS TIME PERIOD. THE DGEX AND GFS CONTINUE TO REMAIN FASTER WITH THE CUTOFF LOW THAN THE ECMWF AND GGEM. JUST NOTICED THE NEW 06 UTC GFS HAS NOW TRENDED SLOWER WITH THE CLOSED LOW AND IS MORE SIMILAR TO THE ECMWF AND GGEM. EXPECT PRECIPITATION TO DEVELOP ACROSS THE SOUTHWEST TEXAS PANHANDLE SATURDAY EVENING BEFORE SPREADING ACROSS ALL OF THE FORECAST AREA SATURDAY NIGHT. RAIN IS LIKELY SATURDAY EVENING AND THEN POSSIBLY MIXING WITH OR CHANGING TO SNOW SATURDAY NIGHT. SOME INDICATIONS THAT LOW-LEVEL THERMAL PROFILES MAY BE A LITTLE WARM FOR SNOW...BUT DUE TO THE UNCERTAINTY...KEPT A RAIN/SNOW MIX IN THE FORECAST. BEYOND SUNDAY...CONSIDERABLE UNCERTAINTY EXISTS...BUT FOLLOWED MORE CLOSELY TO THE ECMWF FOR NOW. IF IT DOES VERIFY...WE COULD BE LOOKING AT MORE WINTER MISCHIEF BY EARLY NEXT WEEK. STILL PLENTY OF TIME TO WATCH THIS SYSTEM SO STAY TUNED. JACKSON FIRE WEATHER... RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 05/03
AREA FORECAST DISCUSSION
NWS AMARILLO TX
443 AM CST MON DEC 12 2011 .DISCUSSION... TODAY-TONIGHT: HAVE SEEN SOME PATCHY AREAS OF FOG ACROSS THE PANHANDLES THIS MORNING...BUT STRONGER SURFACE WINDS HAVE PRECLUDED ANY DENSE FOG CONCERNS. EXPECT PATCHY FOG TO CONTINUE THROUGH MOST OF THE MORNING HOURS SOUTH AND EAST OF A LINE FROM DALHART TO GUYMON. MUCH LOWER VISIBILITIES HAVE BEEN NOTED ACROSS THE SOUTH PLAINS WHERE SURFACE/LOW-LEVEL WINDS HAVE WEAKENED...PER KLBB VAD DATA. RUC DATA INDICATES WINDS ACROSS THE PANHANDLES MAY ALSO WEAKEN...AND IF THIS OCCURS...VISIBILITIES WILL LIKELY DETERIORATE. STILL NOT EXPECTING ANY DENSE FOG ISSUES AS SURFACE WINDS SHOULD REMAIN ABOVE 10 MPH...BUT WILL MONITOR CLOSELY. WOULDN/T BE SURPRISED TO SEE SOME DRIZZLE ACROSS THE FAR SOUTHEAST TEXAS PANHANDLE THROUGH 9 AM WHERE FORECAST SOUNDINGS INDICATE THE LOW-LEVEL MOISTURE WILL REMAIN AROUND 2000 FT DEEP...BUT SINCE THIS IS ON THE MARGINAL END FOR DRIZZLE...LEFT OUT OF THE FORECAST FOR NOW. OTHERWISE...EXPECT MOST OF THE AREA TO REMAIN GRUNGED IN WITH LOW CLOUDS FOR MOST OF THE DAY. AS A RESULT...HIGH TEMPERATURES WILL CONTINUE TO REMAIN BELOW SEASONAL NORMS. IT IS INTERESTING TO NOTE THAT THE AVERAGE DAILY TEMPERATURE AT AMARILLO...BORGER...DALHART...AND GUYMON HAS NOT BEEN ABOVE NORMAL SINCE NOVEMBER 30. AS ISENTROPIC ASCENT INCREASES THIS EVENING AND OVERNIGHT...PRECIPITATION CHANCES WILL ALSO INCREASE. QPF AMOUNTS WILL BE LIGHT WITH MOST LOCATIONS SEEING LESS THAN 0.10" THROUGH SUNRISE ON TUESDAY. EXPECTING THE PRECIPITATION TYPE TO BE ALL LIQUID AS WARM AIR ADVECTION...MOISTURE ADVECTION...AND LOW CLOUDS SHOULD KEEP TEMPERATURES ABOVE FREEZING. ONCE AGAIN...ANOTHER ROUND OF PATCHY FOG IS EXPECTED DEVELOP AREAWIDE...BUT THE RAIN SHOULD KEEP THE NEAR GROUND AIR MIXED ENOUGH TO LIMIT ANY DENSE FOG CONCERNS. TUESDAY-TUESDAY NIGHT: PATCHY FOG MAY LINGER INTO THE LATE MORNING HOURS ON TUESDAY. OTHERWISE...ANOTHER DREARY DAY IS EXPECTED WITH LOW CLOUDS AND INCREASING PRECIPITATION CHANCES...ESPECIALLY AFTER NOON. MAX TEMPS WILL ONCE AGAIN BE ON THE COOL SIDE. MET AND MAV GUIDANCE APPEAR TOO HIGH...SO FOLLOWED RAW NAM TEMPERATURES CLOSELY. BY TUESDAY AFTERNOON...FORECAST SOUNDINGS INDICATE SOME WEAK ELEVATED INSTABILITY DEVELOPING ACROSS MOST OF THE PANHANDLES AS LOW-LEVEL MOISTURE INCREASES AND MID-LEVEL LAPSE RATES STEEPEN. KEPT THUNDERSTORMS IN THE FORECAST AND SHIFTED THEM SLIGHTLY WESTWARD. STRONGER MOISTURE ADVECTION IS EXPECTED ACROSS MOST OF THE AREA ON TUESDAY NIGHT....AND IN FACT...THE ECMWF...GGEM...AND GFS ALL SHOW SURFACE DEW POINTS IN THE MID TO UPPER 50S ACROSS THE SOUTHEAST TEXAS PANHANDLE! IT/S AMAZING TO REALIZE THAT WE STRUGGLED TO SEE DEW POINTS THAT HIGH DURING THE SPRING AND SUMMER...BUT IT/S POSSIBLE THEY MAY REACH THAT HIGH IN DECEMBER. REGARDLESS...AS FORCING FOR ASCENT IMPINGES ON THE MOIST AND WEAKLY UNSTABLE AIR MASS...PRECIPITATION AND THUNDERSTORM CHANCES WILL REALLY RAMP UP TUESDAY EVENING AND NIGHT. WITHIN THE LAST COUPLE OF WEEKS...HAVE NOTICED THAT THE SUBTROPICAL JET HAS HAD A CONNECTION TO THE TROPICS...AND THIS LOOKS TO BE THE CASE AGAIN WITH THIS SYSTEM. AS A RESULT...WON/T BE SURPRISED TO SEE RAINFALL AMOUNTS OVERACHIEVE IN SOME LOCATIONS. REGARDING THUNDERSTORM POTENTIAL...FORECAST SOUNDINGS ARE SHOWING UP TO 300 J/KG OF MUCAPE ALONG WITH DEEP LAYER SHEAR AROUND 70 KT. AS A RESULT...MAY SEE A FEW STRONG STORMS PRODUCE SMALL HAIL TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. NOT EXPECTING ANY WINTRY PRECIPITATION AS SURFACE AND LOW-LEVEL TEMPERATURES WILL REMAIN ABOVE FREEZING. WEDNESDAY-WEDNESDAY NIGHT: THE DRY SLOT WILL QUICKLY SWEEP ACROSS THE FORECAST AREA DURING THE DAY. THERE MAY BE ENOUGH LINGERING LOW- LEVEL MOISTURE ACROSS THE FAR EASTERN PANHANDLES DURING THE MORNING FOR A CHANCE OF PRECIPITATION. KEPT THUNDERSTORMS IN THE FORECAST...BUT FORECAST SOUNDINGS INDICATING LESS THAN 50 J/KG OF MUCAPE. THANKS TO THE DRY SLOT...THE SUN WILL MAKE AN APPEARANCE ACROSS THE REGION. HIGH TEMPERATURES SHOULD BE ABLE TO RISE INTO THE 50S AND POSSIBLY 60S AS STRONG DOWNSLOPING WINDS DEVELOP. SPEAKING OF THE WINDS...EXPECT THEM TO STRENGTHEN BY LATE WEDNESDAY MORNING INTO THE MID-AFTERNOON HOURS. FORECAST SOUNDINGS INDICATE MIXING HEIGHTS WILL BE RELATIVELY SHALLOW AND WILL NOT BE ABLE TO TAP INTO THE HIGH MOMENTUM MID-LEVEL AIR. NONETHELESS...FORECAST SOUNDINGS ARE SHOWING 30-35 KT FLOW AT THE TOP OF THE BOUNDARY LAYER. CONTINUED TO KEEP WINDS BELOW ADVISORY CRITERIA...ESPECIALLY SINCE MET WINDS ARE TRENDING LOWER. HOWEVER...IF THE GFS IS CORRECT...COULD SEE ADVISORY LEVEL WINDS...ESPECIALLY ON THE CAPROCK. AS THE UPPER TROUGH AND ATTENDANT SURFACE LOW MOVE INTO THE UPPER MISSISSIPPI VALLEY...A COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PANHANDLES WITH MUCH COOLER AND DRIER AIR FILTERING INTO THE AREA. AS THE AFOREMENTIONED SYNOPTIC FEATURES PULL AWAY FROM THE AREA...THE PRESSURE GRADIENT WILL ALSO RELAX...ALLOWING WINDS TO QUICKLY SUBSIDE UNDER 10 MPH BY SUNRISE THURSDAY. THURSDAY-THURSDAY NIGHT: DRY AND SUB-SEASONAL TEMPERATURES ARE EXPECTED AS NNE UPSLOPE WINDS PREVAIL THROUGH THE DAY. DUE TO THE UPSLOPE WINDS...LOWERED HIGHS IN ALL AREAS. A CHILLY NIGHT IS EXPECTED WITH LOWS IN THE 20S AND LOWER 30S. FRIDAY-MONDAY: STILL A LOT OF UNCERTAINTIES DURING THIS TIME PERIOD. THE DGEX AND GFS CONTINUE TO REMAIN FASTER WITH THE CUTOFF LOW THAN THE ECMWF AND GGEM. JUST NOTICED THE NEW 06 UTC GFS HAS NOW TRENDED SLOWER WITH THE CLOSED LOW AND IS MORE SIMILAR TO THE ECMWF AND GGEM. EXPECT PRECIPITATION TO DEVELOP ACROSS THE SOUTHWEST TEXAS PANHANDLE SATURDAY EVENING BEFORE SPREADING ACROSS ALL OF THE FORECAST AREA SATURDAY NIGHT. RAIN IS LIKELY SATURDAY EVENING AND THEN POSSIBLY MIXING WITH OR CHANGING TO SNOW SATURDAY NIGHT. SOME INDICATIONS THAT LOW-LEVEL THERMAL PROFILES MAY BE A LITTLE WARM FOR SNOW...BUT DUE TO THE UNCERTAINTY...KEPT A RAIN/SNOW MIX IN THE FORECAST. BEYOND SUNDAY...CONSIDERABLE UNCERTAINTY EXISTS...BUT FOLLOWED MORE CLOSELY TO THE ECMWF FOR NOW. IF IT DOES VERIFY...WE COULD BE LOOKING AT MORE WINTER MISCHIEF BY EARLY NEXT WEEK. STILL PLENTY OF TIME TO WATCH THIS SYSTEM SO STAY TUNED. JACKSON && .FIRE WEATHER... RELATIVE HUMIDITY VALUES ARE EXPECTED TO REMAIN ABOVE 30 PERCENT ACROSS ALL OF THE PANHANDLES FOR THE NEXT SEVEN DAYS. AS A RESULT...NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED. && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 48 40 49 43 58 / 5 30 50 50 5 BEAVER OK 50 39 49 45 55 / 5 30 50 60 20 BOISE CITY OK 44 36 45 36 51 / 5 20 50 50 10 BORGER TX 50 42 48 45 58 / 5 30 50 60 10 BOYS RANCH TX 50 40 49 43 57 / 5 30 50 50 5 CANYON TX 48 41 49 43 60 / 5 30 50 50 5 CLARENDON TX 50 41 50 48 61 / 10 30 50 60 20 DALHART TX 49 36 49 35 54 / 5 30 50 50 5 GUYMON OK 48 36 48 41 55 / 5 20 50 60 10 HEREFORD TX 48 42 49 43 58 / 5 30 50 50 5 LIPSCOMB TX 50 41 49 47 57 / 5 30 50 60 20 PAMPA TX 48 41 48 45 57 / 5 30 50 60 20 SHAMROCK TX 51 40 50 49 63 / 10 30 50 60 20 WELLINGTON TX 51 41 52 49 65 / 10 30 50 60 20 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 17/13
AREA FORECAST DISCUSSION
NWS SPOKANE WA
230 PM PST Mon Dec 12 2011 .SYNOPSIS...High pressure will be over the Inland Northwest for through Wednesday. Expect more fog/stratus formation tonight. A stronger and more organized Pacific storm system will arrive Wednesday evening and Thursday with the possibility of more substantial snow accumulations over a large area. Dry and benign conditions will return for the beginning of the weekend. && .DISCUSSION... Tonight through Wednesday: More fog and stratus to deal with. With the departure of the low pressure trough, high pressure has been sinking into the region from the north and funneling down the north/south valleys especially the Okanogan valley. This process has helped erode and keep back the stratus that has been banked up across the southern section of the forecast area. This area has a well defined line - stretching from Othello to Harrington to just south of Spokane and Coeur d`Alene to the Silver Valley. This evening the northerly pressure gradient will weaken as high pressure settles over the region. This will shut off the winds and allow the area of stratus and fog to expand northward. This is seen well by the NAM, RUC and the HRR encompassing the Spokane/ Coeur d`Alene area and the Moses Lake/Ephrata area and heading to the northern valleys overnight and into Tuesday morning. Mixing and winds will be weak on Tuesday giving way to little break up the low level cloud deck. This will make temperatures tricky depending on how clear some areas will be and for how long. Anticipate diurnal temperature change from Lewiston to Pullman and Ritzville. The coolest spots will be in the sheltered northern valleys like the Methow and near Priest Lake. For Tuesday and Tuesday night, a weak weather disturbance will ride over the upper level ridge and spread mid and high level clouds across the Inland Northwest. Dynamics look weak with a dry air above the boundary layer, giving way to a slight chance of snow for the higher elevations into the north and the Idaho Panhandle. This may disrupt the stratus deck temporarily, but high pressure will return again on Wednesday for more stable and dry conditions. The air stagnation advisory will remain in effect for the region. /rfox. Wednesday night and Thursday...A dramatic change to the stagnant and benign weather conditions of late will occur on Wednesday night and Thursday. Just about all of the available model guidance brings a noticeably stronger system through the region than the recent feeble impulses. The ECMWF model has been most consistent with the character of this incoming storm over the past few days...although the GFS/Canadian/UKMET and SREF guidance have also tenuously climbed aboard in the last 24 hours. At this time it appears a rather vigorous and fast moving short wave will drop through the region from northwest to southeast. the cyclonic diffluent base dynamic region will sweep through the northern zones and sustain a steady strength or slightly weakening surface low pressure tracking just north of the Canadian border and dropping into Montana by late Thursday. The close approach of this low will drag a warm front/cold front couplet through the northern and eastern zones late Wednesday night and Thursday morning. For a six to 9 hour period or so a moderate Pacific moisture feed will fuel precipitation along this frontal couplet. Air mass characteristics will support snow in just about all locations overnight and Thursday morning...but snow-water ratios will likely be rather low in the lowest elevations at Lewiston and Wenatchee. Thus...confidence is increasing for a widespread snow event Wednesday night and Thursday. The northerly track of the offending surface low and the relatively fast transit of the heaviest lift region argues strongly that this will be a significant...but generally sub-warning criteria event...perhaps 2-4 inches in the higher plateaus of the Columbia Basin and valleys north and west of the basin. The best chance of truly heavy snow will probably be near the Canadian border over Northeast Washington and North Idaho closer to the actual surface low track...and in the Panhandle Mountains where post frontal orographic ascent will augment synoptic accumulation potential. It is too early to pin down this potential as of yet. In any event...Thursday morning`s commute will probably be dicey over much of Eastern Washington and North Idaho. This system will likely provide some relief to the recent run of stagnant air quality...and the next conference call with air quality officials will occur Thursday morning and the disposition of the current Air Stagnation Advisory will be further evaluated based on how this system manifest itself. By late Thursday this storm is moving out of the region with lingering snow showers in the Panhandle Mountains and probably the Camas Prairie...While a new shot of dry continental air will push down the Okanogan Valley and begin a new low level air mass exchange in the Columbia Basin. Thursday night through Saturday...Reasonable model agreement continues this period featuring a new upper level ridge forming over the northwest. This will lead to generally dry and quiet conditions with a possible return to increasingly stagnant inversion conditions once again. Where models do differ...it is with the strength of this ridge and the potential for weak impulses to trigger a few mountain snow showers across the north and maybe a stray flurry in some valley locations. Otherwise it looks like an essentially dry and cool period...but with a better potential for overnight and early morning fog since fresh snow cover will provide a better moisture source and enhance overnight radiational cooling potential better than the recent stretch of quiet weather. /Fugazzi For Saturday night through Monday...The EC brings a quick hitting system across the Inland Northwest Saturday night in deep northwesterly flow. This would likely only result in light mountain snow before the model develops the ridge of high pressure back over the Pacific Northwest. The GFS meanwhile brings a weak stretching system across the Inland Northwest Sunday dampening the ridge, which allows the jet stream to shift overhead, and subsequently allow a series of storm systems to move into the region early next week...more typical of December. However, given the pattern of late, I trended pops below climo and more in line with the EC. /Neuman && .AVIATION... 18Z TAFs...High pressure will continue to build into the region. Northerly flow resulted in an erosion of fog and low clouds from KEAT and KGEG/KSFF. But IFR/MVFR cigs and vsbys will plague KCOE, KPUW, KLWS and KMWH through 21z with slight improvements through 00z. Surface pressure gradients and winds will become very light and combined with high pressure, and clearing of mid and high level clouds will lead to more widespread fog and stratus formation especially after 6z and persisting through 18z Tuesday at most of the TAF locations. /rfox. && .PRELIMINARY POINT TEMPS/POPS... Spokane 18 29 21 32 25 33 / 0 10 10 0 60 60 Coeur d`Alene 18 30 22 33 26 33 / 0 10 10 10 70 60 Pullman 23 33 23 36 27 35 / 0 10 10 10 50 60 Lewiston 22 35 25 38 29 40 / 0 10 10 10 30 50 Colville 20 30 20 32 22 34 / 0 10 10 10 70 60 Sandpoint 18 28 22 31 24 33 / 0 10 20 10 70 70 Kellogg 20 29 22 32 25 31 / 0 10 20 20 60 70 Moses Lake 16 30 15 33 21 36 / 0 10 0 10 40 20 Wenatchee 19 29 23 32 26 36 / 0 10 0 10 60 20 Omak 13 30 18 32 21 36 / 0 10 0 10 70 30 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Air Stagnation Advisory until Noon PST Thursday for Central Panhandle Mountains-Coeur d`Alene Area-Idaho Palouse- Lewiston Area-Northern Panhandle. WA...Air Stagnation Advisory until Noon PST Thursday for East Slopes Northern Cascades-Lower Garfield and Asotin Counties-Moses Lake Area-Northeast Mountains-Okanogan Highlands-Okanogan Valley-Spokane Area-Upper Columbia Basin-Washington Palouse- Waterville Plateau-Wenatchee Area. && $$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
943 PM CST TUE DEC 13 2011 .UPDATE... MAIN PROBLEM IS SMALL POSSIBILITY OF RAIN/SNOW MIX ACROSS MAINLY PORTIONS OF MARQUETTE COUNTY. FORECAST SOUNDINGS INDICATE THAT BY THE TIME THE PRECIPITATION ARRIVES IT SHOULD BE MAINLY RAIN. PRECIPITATION BEGAN AS RAIN OVER THE DELLS. EVAPORATIVE COOLING WILL MAKE IT A CLOSE CALL. && .AVIATION/06Z TAFS/... EXPECT PRECIPITATION TO SPREAD NORTH AND EAST DURING THE EARLY MORNING HOURS WITH CIGS/VSBYS EVENTUALLY LOWERING TO IFR/LIFR. MAIN SURFACE LOW RILL MOVE ACROSS SOUTHWEST TO NORTHEAST WISCONSIN WEDNESDAY NIGHT...WITH FAR SOUTH CENTRAL AND PORTIONS OF SOUTHEAST WISCONSIN GETTING INTO THE MILDER AIR BRIEFLY. THIS SHOULD CAUSE CIGS/VSBYS TO IMPROVE. MINIMAL ELEVATED CAPE COULD BRING SOME EMBEDDED THUNDERSTORMS MAINLY WEDNESDAY EVENING. && .PREV DISCUSSION... /ISSUED 327 PM CST TUE DEC 13 2011/ VERY SHORT TERM... TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOWED A DEEP TROUGH OVER THE WESTERN U.S...WITH A LARGE PLUME OF MOISTURE STRETCHING FROM TEXAS THROUGH NORTHERN MISSOURI. SHORTWAVE EJECTING OUT OF THE SW UPPER LOW WILL BRING A SFC LOW FROM THE PLAINS THROUGH IOWA ON WED. FIRST ROUND OF PRECIPITATION WILL BEGIN ALREADY TONIGHT ON THE NOSE OF THE LOW LEVEL JET AND AN INITIAL WEAK SHORTWAVE OUT AHEAD OF THE MAIN TROUGH. STRONG ISENTROPIC LIFT ALONG THIS SURGE OF WARM AND MOIST AIR WILL ALLOW FOR MODERATE RAIN OVERNIGHT THROUGH EARLY WED MORNING. MODELS SLOWED DOWN THE ONSET OF THE PRECIP...SO BACKED OFF POPS A BIT IN THE 03Z-06Z TIME RANGE. PRECIP FOR THE FIRST ROUND COULD APPROACH A QUARTER INCH. A LULL IN THE STEADY PRECIP IS EXPECTED DURING THE MORNING HOURS ON WED. THE INITIAL WAA AND ISENTROPIC LIFT WILL BE TO THE NORTH OF THE FORECAST AREA...AND THE WARM FRONTAL PRECIP WILL STILL BE SOUTH OF THE WI/IL BORDER. DURING THIS LULL...THERE MAY BE SOME AREAS OF FOG AND MUCH LOWER CLOUDS. THEN THE SECOND ROUND OF PRECIP WILL COME IN EITHER LATE MORNING OR EARLY AFTERNOON ON WED...TIMING STILL UNCERTAIN. STRONG DYNAMICS WITH THIS SURGE OF MOISTURE...SINCE THE 500MB TROUGH AND SFC LOW WILL BE APPROACHING...ALONG WITH THE SFC AND 850MB WARM FRONT. WITH THE STRONG FORCING...ISOLATED THUNDER NOT OUT OF THE QUESTION. KEPT THE SCHC THUNDER MENTION IN THE AFTERNOON. UP TO A HALF INCH OF RAIN POSSIBLE WITH THIS SECOND ROUND. TEMPS EXPECTED TO RISE INTO THE MID/UPPER 40S WITH THE FRONT LATE WED AFTERNOON. SHORT TERM...WEDNESDAY NIGHT THROUGH FRIDAY. WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. SOUTHERLY FLOW AHEAD OF THE SURFACE LOW BRINGS THERMAL RIDGE INTO THE SOUTHEAST THAT WILL ALLOW TEMPERATURES TO CLIMB TO THE LOW 50S. MAIN AREA OF PRECIPITATION WILL END FROM WEST TO EAST AFTER 06Z THURSDAY WITH SUBSIDENCE BEHIND 500 MB AND SURFACE TROUGHS. OMEGA AHEAD OF SECOND NORTHERN STREAM SHORT WAVE MAINLY FOCUSED TO THE NORTH WITH THE STRONGEST 700-500MB FRONTOGENETIC RESPONSE DURING THE DAY THURSDAY. COLDER AIR HOLDS OFF UNTIL PASSAGE OF THIS SECOND WAVE...SO EXPECT ANY LINGERING PRECIPITATION THURSDAY TO BE VERY LIGHT RAIN OR DRIZZLE...WITH DRYING IN THE DENDRITE GROWTH ZONE PREVENTING CRYSTAL FORMATION AND SNOW. EARLY DAYTIME HIGH TEMPERATURES AROUND 12-13Z THURSDAY THEN COOLING THROUGH THE DAY. ANY LIGHT PRECIPITATION SHOULD END BY 18Z. THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. SURFACE HIGH PRESSURE BUILDS OVER FOR THURSDAY NIGHT AND FRIDAY. CLEARING SKIES THURSDAY NIGHT...BUT WINDS WILL TAKE A BIT LONGER TO LIGHTEN/DECOUPLE OVERNIGHT. LOWS AROUND 20 NORTHWEST...TO MID 20S ALONG THE LAKE. -5C TO -6C 925 MB TEMPERATURES SUPPORT LOW TO MID 30 HIGHS FRIDAY. LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. FORECAST CONFIDENCE LOW TO MEDIUM. NORTHWEST TO SOUTHEAST MOVING SHORT WAVE CROSSES REGION FRIDAY NIGHT/SATURDAY...BUT DRY LOWER LAYERS WILL PREVENT MEASURABLE...THOUGH A FEW FLURRIES ARE POSSIBLE. WILL LEAVE ANY PRECIPITATION MENTION OUT FOR NOW. DRY NORTHWEST FLOW WITH NORMAL TEMPERATURES SATURDAY...BEGINS TO BACK WEST SUNDAY AND THEN SOUTHWEST MONDAY AS NEXT SYSTEM EJECTS OUT OF THE SOUTHWEST U.S. INTO THE CENTRAL PLAINS. WHILE MODELS DIFFER ON EXACTING DETAILS...EARLY TREND IS TO TAKE SURFACE LOW ACROSS ILLINOIS AND INDIANA MONDAY NIGHT/TUESDAY...WITH SOUTHERN WISCONSIN ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. WARMTH PUSHING BACK NORTH AHEAD OF LOW WILL BRING A MAINLY RAIN/SNOW MIX...CHANGING TO ALL SNOW AFTER LOW PASSAGE. WILL HAVE TO WATCH FOR ACCUMULATING SNOW POTENTIAL IF PROFILE TEMPERATURES COO MORE THAN CURRENTLY INDICATED. AVIATION/00Z TAFS/...VFR CIGS WILL SLOWLY LOWER AS SOUTH WINDS SLOWLY INCREASE LOW LEVEL MOISTURE THIS EVENING. SLOWED THE TIMING OF THIS LOWERING TO EARLY EVENING. MVFR CIGS WILL DEVELOP FROM WEST TO EAST ACROSS THE CWA DURING THE AFTERNOON INTO THE EARLY EVENING. RAIN VIA WARM...MOIST ADVECTION WILL THEN ARRIVE AT THE TAF SITES BY AROUND MIDNIGHT AND CONTINUE INTO WED. CIGS WILL FALL TO LIFR WITH THE RAIN AND SATURATION OF THE LOW LEVEL ATMOSPHERE WHILE VSBYS WILL FALL TO IFR. THERE SHOULD BE A PERIOD OF TIME WED MORNING WHERE THERE IS A LULL IN THE STEADY RAIN...WHICH WOULD ACTUALLY DIMINISH VISIBILITY AND LOWER THE CEILING HEIGHTS. NOT SURE OF EXACT TIMING OF THIS LULL...THEN RAIN WILL INCREASE ONCE AGAIN EARLY WED AFTERNOON AS THE MAIN UPPER AND SFC LOW APPROACH SOUTHERN WI. THE SECOND ROUND OF RAIN IS EXPECTED TO BE HEAVIER THAN THE FIRST...AND THE STRONG FORCING SHOULD ALLOW FOR SOME ISOLATED THUNDER. MARINE...INCREASING SOUTHERLY WINDS WILL ALLOW FOR BUILDING WAVES TO NEAR-SMALL CRAFT ADVISORY CRITERIA WED AFTERNOON. WAVE MODEL FCST WAVE HEIGHTS UP TO 3 TO 4 FEET...SO HELD OFF ON ISSUING A SMALL CRAFT ADVY. WEST WINDS BEHIND THE DEPARTING LOW ON THU WILL INCREASE...AND WIND GUSTS TO 25 KNOTS ARE POSSIBLY/LIKELY WITH THE COLD AIR ADVECTION. SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/WEDNESDAY AND AVIATION/MARINE...MRC WEDNESDAY NIGHT THROUGH TUESDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
610 PM CST TUE DEC 13 2011 .SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT 233 PM CST TUE DEC 13 2011 ACTIVE WEATHER NEXT 48 HOURS LOOKS TO HAVE MINIMAL IMPACT. FOCUS REMAINS CENTERED ON DETAILS OF PRECIPITATION LATER TONIGHT AND INTO WEDNESDAY NIGHT. SHORT WAVE ENERGY ROTATING OUT OF LARGE SOUTHWEST U.S. PV-ANOMALY WILL DRAMATICALLY INCREASE DYNAMICS STARTING THIS EVENING WITH STRONG LIFT...LARGE LOW LEVEL MOISTURE PUSH AND EXPECTED INCREASE IN PRECIPITATION COVERAGE. LAYER PRECIPITABLE WATER VALUES EXCEED 300 PERCENT AHEAD OF THIS WAVE WITH PROGGED 850 MB DEW POINT TEMPERATURES CLOSE TO 10 C MOVING NORTHWARD. SURFACE TEMPERATURES STARTING OFF RELATIVELY MILD /ALL ABOVE FREEZING/ AS LOW LEVEL WARM AIR ADVECTION EXPECTED TO INCREASE THIS EVENING. THIS SHOULD KEEP BULK OF PRECIPITATION AT ONSET TONIGHT AS JUST RAIN BUT STILL SOME CONCERN ALONG AND NORTHEAST OF INTERSTATE 94 WHERE SOME COOLING COULD ALLOW MIX BEFORE EVERYONE CHANGES TO RAIN EARLY TOMORROW MORNING. MODEL SOUNDINGS SUGGEST VERY CLOSE CALL ON RAIN/SNOW MIX BUT EVEN SHORT RANGE ENSEMBLE PLUMES POINTING TOWARDS MAINLY RAIN. AS BULK OF SHORT WAVE ENERGY EJECTS ON WEDNESDAY SHOULD BE RAIN AROUND FOR MOST OF WEDNESDAY. BEST LOW LEVEL WARM AIR AND MOISTURE ADVECTION APPEARS TO REMAIN JUST SOUTH AND EAST OF FORECAST AREA BUT COULD NOT RULE OUT SOME THUNDER WITH ISOLATED CONVECTION PER PREVIOUS FORECAST AND STORM PREDICTION CENTER DAY 2 OUTLOOK. HIGHEST RISK FOR ANY THUNDER FROM EASTERN IOWA INTO SOUTHERN WISCONSIN. LEADING SHORT WAVE ENERGY SHOULD MOVE EAST FAIRLY QUICKLY WEDNESDAY NIGHT SO UNSURE HOW EXTENSIVE PRECIPITATION WILL BE BEHIND THIS. AS COOLER AIR BEGINS TO WRAP IN SO DOES SOME DRYING. EVEN THOUGH COLUMN TEMPERATURES COOL ENOUGH FOR TRANSITION OVER TO SNOW...ICE VANISHES FROM CLOUD LAYER JUST ABOUT AS FAST. HAD INITIALLY THOUGHT ABOUT CHANCE FOR SOME FREEZING DRIZZLE AS COLDER AIR SETTLES IN BUT LACK OF LIFT SHOULD PREVENT THAT. MOST LIKELY SCENARIO IS ABRUPT END TO RAIN AND FALLING TEMPERATURES...ESPECIALLY AFTER A MILD WEDNESDAY EVENING AHEAD OF FRONT. SHORT WAVE TROUGH PROGGED BY MOST GUIDANCE IN NORTHWEST BRANCH OF SPLIT UPPER FLOW TO FOLLOW ON THE HEELS OF THIS SYSTEM BRINGING STRONG COLD AIR ADVECTION FOR THURSDAY. PRESSURE GRADIENT SUGGESTS LOW END WIND EVENT BUT NOT SURE SPEEDS WILL HIT ADVISORY CRITERIA. ONE CHANGE IN FORECASTS INCLUDES INCREASE IN CLOUDS AS WRAP AROUND STRATUS FIELD COULD FORM IN COLD AIR ADVECTION AND LAST INTO FRIDAY. AT THIS POINT WILL REMAIN OPTIMISTIC THAT CLOUDS WILL CLEAR WITH DRYING THURSDAY NIGHT BUT THIS WILL HAVE TO BE MONITORED ALONG WITH WIND SPEEDS. FALLING TEMPERATURES THURSDAY EXPECTED IN WHAT APPEARS TO BE A RAW...WINDY LATE FALL DAY BEFORE THINGS RELAX ON FRIDAY. .LONG TERM...SATURDAY THROUGH TUESDAY 233 PM CST TUE DEC 13 2011 SPLIT FLOW REGIME CONTINUES IN MEDIUM RANGE WITH WEEKEND STARTING OFF ON COOLER SIDE. SOME HINTS OF WEAK SHORT WAVE ENERGY OR UPPER SHEAR AXIS IN NORTHWEST FLOW STRETCHING FROM SOUTHERN CANADA INTO THE GREAT LAKES BUT FAIRLY DRY REGIME SHOULD KEEP THINGS QUIET. MAIN FOCUS IN THIS RANGE IS SIGNAL OF SOUTHWEST SYSTEM EJECTING INTO THE CENTRAL U.S. EARLY NEXT WEEK. ECMWF HAS BEEN MORE CONSISTENT KEEPING THIS SYSTEM JUST SOUTH OF THE AREA WHILE GFS RUNS HAVE BEEN BACK AND FORTH. 13.12Z GFS MORE IN LINE WITH ECMWF WITH FURTHER SOUTH SOLUTION BUT WILL KEEP SMALL POPS GOING FOR DAY 6 /MON/ FOR CONSISTENCY AND COLLABORATION PURPOSES. STILL TOO EARLY FOR DETAILS WITH ANY POTENTIAL IMPACT. WITH BARE GROUND ANTICIPATED WILL INTRODUCE MIX OF RAIN AND SNOW WITH HIGHS IN THE 30S KEEPING CHANCES OF A BROWN CHRISTMAS HIGHER THAN NORMAL THIS YEAR. && .AVIATION...TONIGHT AND WEDNESDAY 609 PM CST TUE DEC 13 2011 FORECAST CONCERNS THIS TAF PERIOD ARE PRECIPITATION TIMING AND CEILINGS/VISIBILITIES AT BOTH KRST AND KLSE. DEVELOPING SURFACE LOW ACROSS CENTRAL PLAINS WILL CONTINUE TO LIFT NORTHEAST TOWARDS THE AREA. AS OF 00Z...VFR CONDITIONS WERE ACROSS SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN. MVFR CONDITIONS WITH LIGHT RAIN / DRIZZLE ACROSS NORTHWEST IOWA AND SOUTHWEST MINNESOTA WILL SPREAD EAST LATER THIS EVENING. COMPARED TO OBSERVATIONS...BOTH RUC AND NAM MODEL FORECASTS ARE SEVERAL HOURS DELAYED IN PRECIPITATION TIMING...SO BROUGHT IN RAIN EARLIER...03Z AT KRST AND 05Z AT KLSE. INCREASING MOISTURE AND SATURATION OVERNIGHT WILL ALLOW CEILINGS AND VISIBILITIES DROP TO IFR...TO AROUND 600 FT AT KRST AND 900 FT AT KLSE. LIGHTER WINDS ON WEDNESDAY MAY ALLOW LIFR CONDITIONS TO DEVELOP...ESPECIALLY AT KRST...WHERE CEILINGS AS LOW AS 300 FT ARE POSSIBLE. AT KLSE...KEPT A 500 FT DECK THROUGH THE DAY. PRECIPITATION FOR MUCH OF THE DAY WILL LEAD TO IFR CONDITIONS THROUGH WEDNESDAY EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... 233 PM CST TUE DEC 13 2011 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...SHEA LONG TERM....SHEA AVIATION...ZT/HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
534 AM CST MON DEC 12 2011 .SHORT TERM...TODAY THROUGH WEDNESDAY 331 AM CST MON DEC 12 2011 FORECAST CONCERNS ARE ON DRIZZLE/FREEZING DRIZZLE THIS MORNING AND AGAIN TONIGHT AND THE POTENTIAL FOR AREAS OF FOG LATE TONIGHT INTO TUESDAY MORNING. FOCUS THEN TURNS TO STORM SYSTEM EXPECTED TO IMPACT THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH PRECIPITATION TYPE CONCERNS. CURRENT RADAR AND SURFACE OBSERVATIONS SHOWED DRIZZLE FALLING ACROSS MUCH OF THE FORECAST AREA. AREAS OF FREEZING DRIZZLE HAVE BEEN REPORTED ACROSS NORTH CENTRAL WISCONSIN THROUGH SOUTHWEST WISCONSIN...WITH SOME SECONDARY ROADWAYS VERY SLICK. DRIZZLE WILL CONTINUE ACROSS THE AREA THIS MORNING AS LOW LEVEL MOISTURE CONTINUES TO STREAM INTO THE REGION FROM THE SOUTHERN PLAINS. ISENTROPIC LIFT ON THE 280-300K SURFACE ALONG WITH A WEAK SHORTWAVE TROUGH MOVING ACROSS THE REGION...WILL ACT TO PRODUCE DRIZZLE ACROSS MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON. SURFACE TEMPERATURES HAVE WARMED ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA EARLY THIS MORNING. HOWEVER...SOME SECONDARY ROADWAYS AND SHADED LOCATIONS WILL LIKELY HAVE SURFACE TEMPERATURES AROUND FREEZING AND SHOULD EXPERIENCE SOME LIGHT ICING. WILL CONTINUE THE FREEZING DRIZZLE ADVISORY THROUGH 9 AM FOR THIS LIGHT ICING POTENTIAL. DRIZZLE AND CLOUDY SKIES CAN BE EXPECTED INTO THIS EVENING...WITH THE DRIZZLE GRADUALLY TAPERING OFF DURING THE LATE EVENING INTO THE OVERNIGHT HOURS. SOME PATCHY FREEZING DRIZZLE CAN BE EXPECTED ACROSS WESTERN AND CENTRAL WISCONSIN...WHERE A FEW LOCATIONS WILL DROP TO FREEZING. AT THIS TIME IT APPEARS ICING WILL BE MINIMAL BUT WILL HAVE TO CLOSELY MONITOR TEMPERATURES THROUGH THE DAY TODAY. IF TEMPERATURES COOL FURTHER THAN WHAT IS CURRENTLY ANTICIPATED...A FREEZING RAIN ADVISORY MAY BE NEEDED THIS EVENING INTO TONIGHT...ESPECIALLY ALONG AND NORTH OF THE I-94 CORRIDOR. LOOK FOR LOW TEMPERATURES TO FALL INTO THE LOWER 30S TONIGHT UNDER CLOUDY SKIES. LOW LEVEL MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA ON TUESDAY WITH WEAK RIDGING ALOFT MOVING OVERHEAD. WITH LIGHT AND VARIABLE WINDS ACROSS THE REGION AND ANY REMAINING SNOW MELTING...AREAS OF FOG MAY DEVELOP AND COULD POTENTIALLY BE DENSE EARLY TUESDAY MORNING. HAVE ADDED AREAS OF FOG TO THE FORECAST LATE MONDAY NIGHT THROUGH MID MORNING TUESDAY. STRATUS LOOKS TO PERSIST ACROSS MUCH OF THE FORECAST AREA WITH MOSTLY CLOUDY SKIES EXPECTED. ANY VERTICAL MOTION MOVING ACROSS THE REGION COULD TRIGGER SOME LIGHT DRIZZLE. TEMPERATURES SHOULD BE ABOVE FREEZING ON TUESDAY...WITH HIGHS IN THE MID 30S TO AROUND 40 SO ICING SHOULD NOT BE A CONCERN. AN UPPER LEVEL TROUGH IS EXPECTED TO MOVE FROM THE SOUTHWEST CONUS INTO THE CENTRAL PLAINS LATE TUESDAY NIGHT. WARM AIR ADVECTION ALOFT WILL SPREAD ACROSS THE REGION...WITH RAIN AND SNOW DEVELOPING ACROSS MUCH OF THE FORECAST AREA. AT THIS TIME FORECAST SOUNDINGS APPEAR WARM ENOUGH FOR THE PRECIPITATION TO FALL AS RAIN. TEMPERATURES LOOK TO FALL INTO THE 33 TO 36 DEGREE RANGE LATE TUESDAY EVENING THEN GRADUALLY WARM AFTER MIDNIGHT. WILL HAVE TO CLOSELY MONITOR THE NEXT FEW MODEL RUNS...IF TEMPERATURES DO NOT WARM AS ANTICIPATED A BRIEF PERIOD OF FREEZING RAIN MAY DEVELOP LATE TUESDAY NIGHT. HAVE KEPT PRECIPITATION TYPES AS RAIN/SNOW TUESDAY NIGHT GIVEN THE EXPECTED TEMPERATURES. FORECAST SOUNDINGS ARE SHOWING SOME ELEVATED CAPE ACROSS MUCH OF THE FORECAST AREA...WITH AROUND 150 J/KG LIFTING FROM 730 MB. IF THE ELEVATED CAPE CONTINUES IN THE NEXT SET OF MODEL RUNS...ISOLATED THUNDER MAY NEED TO BE ADDED TO THE FORECAST LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. 12.00 GFS AND ECMWF ARE IN REASONABLE AGREEMENT ON WEDNESDAY SHOWING RAIN PERSISTING THROUGH THE DAY ACROSS THE FORECAST AREA AS THE UPPER LEVEL TROUGH MOVES FROM THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE NAM KEEPS THE BULK OF THE PRECIPITATION ACROSS SOUTHEAST IOWA THROUGH NORTHERN ILLINOIS. HAVE LEANED MORE TOWARD THE GFS AND ECMWF SOLUTION. FELT THE GFS WAS A BIT OVERDONE ACROSS SOUTHEAST MINNESOTA INTO NORTHWEST WISCONSIN...PAINTING MUCH HEAVIER PRECIPITATION ACROSS THE AREA WITH A DEEPER SURFACE LOW OVER THE OTHER MODELS. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE FORECAST AREA LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING WITH TEMPERATURES FALLING. RAIN SHOULD GRADUALLY CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST AS COOLER AIR FILTERS INTO THE AREA. LIGHT SNOW ACCUMULATION IS POSSIBLE...BUT EXACTLY HOW MUCH WILL FALL WILL DEPEND ON THE TRACK OF THE LOW AND WHEN THE COOLER AIR WRAPS INTO THE REGION. LOOK FOR LOW TEMPERATURES TO OCCUR LATE IN THE NIGHT...WITH TEMPS FALLING INTO THE UPPER 20S ACROSS SOUTHEAST MINNESOTA THOUGH NORTH CENTRAL WISCONSIN TO THE MID 30S ACROSS FAR SOUTHWEST WISCONSIN. .LONG TERM...THURSDAY THROUGH SUNDAY 331 AM CST MON DEC 12 2011 MUCH COLDER AIR WILL PUSH INTO THE AREA ON THURSDAY IN THE WAKE OF A COLD FRONT...WITH 850 MB TEMPERATURES FALLING FROM 1 C EARLY THURSDAY MORNING...TO -8 C BY EARLY THURSDAY EVENING. LOOK FOR TEMPERATURES TO FALL THROUGH THE DAY...WITH READINGS IN THE MID 20S BY LATE THURSDAY AFTERNOON. SOME LIGHT SNOW MAY LINGER ACROSS THE AREA ON THURSDAY BUT SHOULD QUICKLY TAPER OFF INTO THE AFTERNOON AS COLD HIGH PRESSURE STARTS TO BUILD IN. LOOK FOR LOWS TO FALL INTO THE TEENS THURSDAY NIGHT. THE HIGH IS EXPECTED TO REMAIN OVER THE AREA INTO THE WEEKEND WITH COOL AND QUIET WEATHER ANTICIPATED. HIGHS WILL BE MAINLY IN THE 20S WITH LOWS IN THE TEENS. MODELS ARE SHOWING A WARM UP FOR SUNDAY WITH HIGHS CLIMBING BACK INTO THE MID TO UPPER 30S. && .AVIATION...TODAY AND TONIGHT 534 AM CST MON DEC 12 2011 ABUNDANT LOW LEVEL MOISTURE ALONG WITH A SHORTWAVE TROUGH MOVING THROUGH MINNESOTA HAS RESULTED IN WIDESPREAD DRIZZLE ACROSS THE AREA. MOST OF THE PRECIPITATION THUS FAR HAS BEEN AFFECTING THE KLSE TAF SITE...BUT EXPECT DRIZZLE AT KRST AT TIMES THROUGH MUCH OF THE DAY ALSO. CEILINGS HAVE REMAINED IN THE UPPER MVFR TO LOWER VFR CATEGORIES. HOWEVER....BOTH THE 12.07Z RUC AND 13.06Z NAM BUFKIT SOUNDING CONTINUE TO INDICATE LOWERING CEILINGS THIS MORNING BETWEEN 12Z-15Z. DID LOWER CEILINGS INTO THE LOWER MVFR CATEGORY...BUT WILL HAVE WATCH CLOSELY FOR ANY IFR CONDITIONS. PRECIPITATION WILL COME TO AN END THIS EVENING...WITH A FEW POCKET OF FREEZING DRIZZLE STILL POSSIBLE. HOWEVER...FELL BETTER CHANCES WILL BE TO THE EAST OF THE TAF SITES. PRESSURE GRADIENT DOES RELAX TONIGHT AND WITH THE CONTINUATION OF LOW LEVEL MOISTURE...EXPECT CEILINGS TO ONCE AGAIN LOWER INTO THE IFR CATEGORY. WITH AN ADDITIONAL INFLUX OF MOISTURE FROM MELTING SNOW WOULD EXPECT FOG FORMATION TO OCCUR. DID LOWER VISIBILITIES INTO THE IFR CATEGORY AFTER 05Z AT BOTH SITES...BUT CANNOT RULE OUT DENSE FOG WITH VISIBILITIES UNDER ONE QUARTER OF A MILE. && .ARX WATCHES/WARNINGS/ADVISORIES... 331 AM CST MON DEC 12 2011 WI...FREEZING RAIN ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017- 029-034-042>044-053>055-061. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
331 AM CST MON DEC 12 2011 .SHORT TERM...TODAY THROUGH WEDNESDAY 331 AM CST MON DEC 12 2011 FORECAST CONCERNS ARE ON DRIZZLE/FREEZING DRIZZLE THIS MORNING AND AGAIN TONIGHT AND THE POTENTIAL FOR AREAS OF FOG LATE TONIGHT INTO TUESDAY MORNING. FOCUS THEN TURNS TO STORM SYSTEM EXPECTED TO IMPACT THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH PRECIPITATION TYPE CONCERNS. CURRENT RADAR AND SURFACE OBSERVATIONS SHOWED DRIZZLE FALLING ACROSS MUCH OF THE FORECAST AREA. AREAS OF FREEZING DRIZZLE HAVE BEEN REPORTED ACROSS NORTH CENTRAL WISCONSIN THROUGH SOUTHWEST WISCONSIN...WITH SOME SECONDARY ROADWAYS VERY SLICK. DRIZZLE WILL CONTINUE ACROSS THE AREA THIS MORNING AS LOW LEVEL MOISTURE CONTINUES TO STREAM INTO THE REGION FROM THE SOUTHERN PLAINS. ISENTROPIC LIFT ON THE 280-300K SURFACE ALONG WITH A WEAK SHORTWAVE TROUGH MOVING ACROSS THE REGION...WILL ACT TO PRODUCE DRIZZLE ACROSS MUCH OF THE FORECAST AREA THROUGH THIS AFTERNOON. SURFACE TEMPERATURES HAVE WARMED ABOVE FREEZING ACROSS MUCH OF THE FORECAST AREA EARLY THIS MORNING. HOWEVER...SOME SECONDARY ROADWAYS AND SHADED LOCATIONS WILL LIKELY HAVE SURFACE TEMPERATURES AROUND FREEZING AND SHOULD EXPERIENCE SOME LIGHT ICING. WILL CONTINUE THE FREEZING DRIZZLE ADVISORY THROUGH 9 AM FOR THIS LIGHT ICING POTENTIAL. DRIZZLE AND CLOUDY SKIES CAN BE EXPECTED INTO THIS EVENING...WITH THE DRIZZLE GRADUALLY TAPERING OFF DURING THE LATE EVENING INTO THE OVERNIGHT HOURS. SOME PATCHY FREEZING DRIZZLE CAN BE EXPECTED ACROSS WESTERN AND CENTRAL WISCONSIN...WHERE A FEW LOCATIONS WILL DROP TO FREEZING. AT THIS TIME IT APPEARS ICING WILL BE MINIMAL BUT WILL HAVE TO CLOSELY MONITOR TEMPERATURES THROUGH THE DAY TODAY. IF TEMPERATURES COOL FURTHER THAN WHAT IS CURRENTLY ANTICIPATED...A FREEZING RAIN ADVISORY MAY BE NEEDED THIS EVENING INTO TONIGHT...ESPECIALLY ALONG AND NORTH OF THE I-94 CORRIDOR. LOOK FOR LOW TEMPERATURES TO FALL INTO THE LOWER 30S TONIGHT UNDER CLOUDY SKIES. LOW LEVEL MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA ON TUESDAY WITH WEAK RIDGING ALOFT MOVING OVERHEAD. WITH LIGHT AND VARIABLE WINDS ACROSS THE REGION AND ANY REMAINING SNOW MELTING...AREAS OF FOG MAY DEVELOP AND COULD POTENTIALLY BE DENSE EARLY TUESDAY MORNING. HAVE ADDED AREAS OF FOG TO THE FORECAST LATE MONDAY NIGHT THROUGH MID MORNING TUESDAY. STRATUS LOOKS TO PERSIST ACROSS MUCH OF THE FORECAST AREA WITH MOSTLY CLOUDY SKIES EXPECTED. ANY VERTICAL MOTION MOVING ACROSS THE REGION COULD TRIGGER SOME LIGHT DRIZZLE. TEMPERATURES SHOULD BE ABOVE FREEZING ON TUESDAY...WITH HIGHS IN THE MID 30S TO AROUND 40 SO ICING SHOULD NOT BE A CONCERN. AN UPPER LEVEL TROUGH IS EXPECTED TO MOVE FROM THE SOUTHWEST CONUS INTO THE CENTRAL PLAINS LATE TUESDAY NIGHT. WARM AIR ADVECTION ALOFT WILL SPREAD ACROSS THE REGION...WITH RAIN AND SNOW DEVELOPING ACROSS MUCH OF THE FORECAST AREA. AT THIS TIME FORECAST SOUNDINGS APPEAR WARM ENOUGH FOR THE PRECIPITATION TO FALL AS RAIN. TEMPERATURES LOOK TO FALL INTO THE 33 TO 36 DEGREE RANGE LATE TUESDAY EVENING THEN GRADUALLY WARM AFTER MIDNIGHT. WILL HAVE TO CLOSELY MONITOR THE NEXT FEW MODEL RUNS...IF TEMPERATURES DO NOT WARM AS ANTICIPATED A BRIEF PERIOD OF FREEZING RAIN MAY DEVELOP LATE TUESDAY NIGHT. HAVE KEPT PRECIPITATION TYPES AS RAIN/SNOW TUESDAY NIGHT GIVEN THE EXPECTED TEMPERATURES. FORECAST SOUNDINGS ARE SHOWING SOME ELEVATED CAPE ACROSS MUCH OF THE FORECAST AREA...WITH AROUND 150 J/KG LIFTING FROM 730 MB. IF THE ELEVATED CAPE CONTINUES IN THE NEXT SET OF MODEL RUNS...ISOLATED THUNDER MAY NEED TO BE ADDED TO THE FORECAST LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. 12.00 GFS AND ECMWF ARE IN REASONABLE AGREEMENT ON WEDNESDAY SHOWING RAIN PERSISTING THROUGH THE DAY ACROSS THE FORECAST AREA AS THE UPPER LEVEL TROUGH MOVES FROM THE CENTRAL PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE NAM KEEPS THE BULK OF THE PRECIPITATION ACROSS SOUTHEAST IOWA THROUGH NORTHERN ILLINOIS. HAVE LEANED MORE TOWARD THE GFS AND ECMWF SOLUTION. FELT THE GFS WAS A BIT OVERDONE ACROSS SOUTHEAST MINNESOTA INTO NORTHWEST WISCONSIN...PAINTING MUCH HEAVIER PRECIPITATION ACROSS THE AREA WITH A DEEPER SURFACE LOW OVER THE OTHER MODELS. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE FORECAST AREA LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING WITH TEMPERATURES FALLING. RAIN SHOULD GRADUALLY CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST AS COOLER AIR FILTERS INTO THE AREA. LIGHT SNOW ACCUMULATION IS POSSIBLE...BUT EXACTLY HOW MUCH WILL FALL WILL DEPEND ON THE TRACK OF THE LOW AND WHEN THE COOLER AIR WRAPS INTO THE REGION. LOOK FOR LOW TEMPERATURES TO OCCUR LATE IN THE NIGHT...WITH TEMPS FALLING INTO THE UPPER 20S ACROSS SOUTHEAST MINNESOTA THOUGH NORTH CENTRAL WISCONSIN TO THE MID 30S ACROSS FAR SOUTHWEST WISCONSIN. .LONG TERM...THURSDAY THROUGH SUNDAY 331 AM CST MON DEC 12 2011 MUCH COLDER AIR WILL PUSH INTO THE AREA ON THURSDAY IN THE WAKE OF A COLD FRONT...WITH 850 MB TEMPERATURES FALLING FROM 1 C EARLY THURSDAY MORNING...TO -8 C BY EARLY THURSDAY EVENING. LOOK FOR TEMPERATURES TO FALL THROUGH THE DAY...WITH READINGS IN THE MID 20S BY LATE THURSDAY AFTERNOON. SOME LIGHT SNOW MAY LINGER ACROSS THE AREA ON THURSDAY BUT SHOULD QUICKLY TAPER OFF INTO THE AFTERNOON AS COLD HIGH PRESSURE STARTS TO BUILD IN. LOOK FOR LOWS TO FALL INTO THE TEENS THURSDAY NIGHT. THE HIGH IS EXPECTED TO REMAIN OVER THE AREA INTO THE WEEKEND WITH COOL AND QUIET WEATHER ANTICIPATED. HIGHS WILL BE MAINLY IN THE 20S WITH LOWS IN THE TEENS. MODELS ARE SHOWING A WARM UP FOR SUNDAY WITH HIGHS CLIMBING BACK INTO THE MID TO UPPER 30S. && .AVIATION...THROUGH 06Z TUESDAY 1135 PM CST SUN DEC 11 2011 CEILINGS HAVE ACTUALLY LIFTED ACROSS THE AREA THIS EVENING AND WILL START THE TAFS OUT WITH EITHER MVFR OR VFR CEILINGS BUT WITH MVFR VISIBILITIES FROM SOME LIGHT FOG. STILL EXPECTING CONDITIONS TO DETERIORATE LATER TONIGHT AS THE SHORT WAVE TROUGH APPROACHES AND INCREASES THE LIFT. THE 12.03Z RUC AND 12.00Z NAM NOW SUGGESTS THE LOWER CEILINGS...VISIBILITY AND DRIZZLE WILL BE SLOWER TO ARRIVE AND PUSHED THIS BACK TO AROUND 10Z BUT THERE ARE SOME INDICATIONS IT COULD EVEN HOLD OFF LONGER. TEMPERATURES STILL TO BE WARM ENOUGH TO KEEP THE PRECIPITATION AS DRIZZLE WITH LITTLE THREAT FOR ANY FREEZING DRIZZLE AT THE TAF SITES. THE DRIZZLE SHOULD BEGIN TO TAPER OFF DURING THE AFTERNOON AND HAVE PUSHED BOTH THE VISIBILITY AND CEILING UP A LITTLE AS THIS OCCURS. THE LOW LEVEL MOISTURE DOES NOT GET CLEANED OUT OF THE AREA WITH THE FLOW REMAINING OUT OF THE SOUTH OR SOUTHWEST THROUGH 06Z MONDAY SO VERY POSSIBLE THAT THE CEILINGS WILL START TO GO DOWN AGAIN MONDAY EVENING WITH SOME COOLING. && .ARX WATCHES/WARNINGS/ADVISORIES... 331 AM CST MON DEC 12 2011 WI...FREEZING RAIN ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ017- 029-034-042>044-053>055-061. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CST SUN DEC 11 2011 .SHORT TERM...TONIGHT THROUGH WEDNESDAY 250 PM CST SUN DEC 11 2011 AMPLE CHALLENGES TO THE FORECAST FOR THE NEXT FEW DAYS...WITH THE FOCUS ON THE PCPN TYPE. TONIGHT AND MONDAY NOT LOOKING AS CLEAR-CUT AS THE PAST FEW DAYS SUGGESTED IT WOULD BE...WITH FREEZING DRIZZLE TO DRIZZLE AND BACK OVER TO FREEZING DRIZZLE. PCPN WILL OCCUR FOR THE REGION...BUT WHAT FALLS IS MORE HAZY NOW. LATEST FOG/STRATUS SATELLITE IMAGERY INDICATES AN EXPANSIVE AREA OF STRATUS MOVING NORTHEAST ACROSS THE PLAINS...SURGING ACROSS THE LOCAL AREA. THIS WAS IN RESPONSE TO A WARM/MOIST PUSH OF LOW LEVEL AIR RIDING ACROSS A SNOW PACK. DESPITE WINDS OF 10 KTS OR GREATER...VSBYS WITH THE STRATUS ARE 2-4 MILES...BRINGING AN ASPECT OF ADVECTION FOG TO THE FORECAST. THE FAVORABLE LOW LEVEL MOISTURE TRANSPORT/WARM AIR ADVECTION NOSES ACROSS THE FORECAST AREA TONIGHT...PERSISTING THROUGH MUCH OF MONDAY. THIS IS ASSOCIATED WITH AN UPPER LEVEL SHORTWAVE THAT WILL SPIN FROM THE CENTRAL PLAINS TO ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY 18Z MON. THE SATURATION IS ALL IN THE LOW LEVELS THOUGH...AS EVIDENCED BY TIME/HEIGHT X-SECTIONS AND BUFKIT SOUNDINGS. AS SUCH...THE DEPTH OF THE SATURATION AND TEMPS AT THE TOP OF THE ANTICIPATED CLOUD LAYER WILL HAVE AN IMPACT ON THE PCPN TYPE. PREVIOUS MODEL RUNS POINTED TO NO ICE IN THE CLOUD...THUS LIQUID AND LIKELY DRIZZLE. HOWEVER...INDICATIONS NOW ARE THAT -10 TO -12 C COULD BE REALIZED IN CLOUD TOPS...MAKING ICE MORE LIKELY AND POTENTIALLY SNOW IF THE REST OF THE THERMAL PROFILE WOULD SUPPORT IT. IN ADDITION...THE SATURATION COULD BECOME DEEP ENOUGH FOR A PERIOD ON SAT WHERE RAIN WOULD BE MORE LIKELY RATHER THAN DRIZZLE. ACCUMULATION WOULD STILL BE MINOR...AND BELIEVE DRIZZLE WILL BE THE MORE PREDOMINANT LIQUID TYPE...SO WILL STAY WITH DRIZZLE FOR NOW. ANOTHER QUESTION THAT HAS BECOME PROBLEMATIC ARE SFC TEMPS. PREVIOUSLY FREEZING TEMPERATURES OVERNIGHT/MONDAY MORNING LOOKED LIKE A SURE THING FOR THE ENTIRE FORECAST AREA. LATEST MODELS RUNS BRING THIS INTO QUESTION. THE LOW LEVEL WARM AIR ADVECTION WILL NOT ONLY GO INTO CLOUD/PCPN PRODUCTION LATE TONIGHT...BUT IT SHOULD ALSO SERVE TO HELP STEADY...OR EVEN RISE...TEMPERATURES OVERNIGHT. IF THIS OCCURS...WESTERN PARTS OF THE FORECAST AREA HAVE A PRETTY GOOD CHANCE OF STAYING ABOVE FREEZING. LATEST RUC13 TEMPS AND LAMP GUIDANCE SUPPORTS THIS...AND HAVE TAILORED TEMPS TONIGHT THIS WAY. AS A RESULT...THE WESTERN 1/2 OF THE FORECAST AREA WILL LIKELY MISS OUT ON ANY FREEZING DRIZZLE. FARTHER EAST THOUGH TEMPS HAVE A MUCH BETTER CHANCE TO COOL TO FREEZING...AND THUS AN ICING THREAT WHEN THE DRIZZLE MOVES IN. WILL GO WITH A FREEZING RAIN ADV FOR THE COUNTIES IN THE EAST...ESPECIALLY IN THE I-94 CORRIDOR...FROM 09-15Z MON. THIS SCENARIO WILL HAVE TO BE MONITORED VERY CLOSELY TONIGHT...AS THE AMOUNT OF WARMING AND ONSET OF THE DRIZZLE WILL OBVIOUSLY PLAY KEY ROLES IN WHERE THE FREEZING DRIZZLE THREAT WILL BE HIGHEST. AN UPPER LEVEL TROUGH WILL LIFT OUT OF THE DESERT SOUTHWEST...BRINGING THE TROUGH AXIS ACROSS THE REGION ON WED. THIS SYSTEM LOOKS LIKE IT COULD PACK A PRETTY GOOD PUNCH WITH GOOD QG CONVERGENCE...SLOPING FRONTOGENETIC LIFT...AND THE ENERGY FROM THE UPPER LEVEL SHORTWAVE. TIMING AND POSITIONING WILL PLAY AN IMPORTANT ROLE AS WARM AIR WILL BE A FACTOR FOR PCPN TYPE. UNFORTUNATELY...EACH MODEL HAS A DIFFERENT IDEA ON WHAT WILL OCCUR...AND BRINGS THE FORECAST CONFIDENCE DOWN AS A RESULT. NAM IS THE QUICKEST OF ALL...TAKING THE SFC LOW TO LAKE SUPERIOR BY 00Z THU. THE GFS IS OVER SOUTHWEST IA...THE EC THE CENTRAL PLAINS...AND THE GEM EASTERN IA. A LOT OF INCONSISTENCY WITHIN THE MODELS TOO...EXCEPT FOR THE EC WHICH SHOWS A BIT BETTER RUN TO RUN AGREEMENT. WILL LEAN ON THE EC AS A RESULT...BLENDING IT WITH THE CONSENSUS SOLUTION. BEFORE THE HEART OF THE SYSTEM MOVES IN WED AFTERNOON/NIGHT...ANOTHER GOOD SURGE OF LOW LEVEL MOISTURE TRANSPORT/WARM AIR ADVECTION TUE NIGHT/WED MORNING WILL LIKELY LEAD TO A BROAD AREA OF PRECIPITATION SPREADING ACROSS PORTIONS OF THE REGION. SATURATION LOOKS DEEP ENOUGH TO SUPPORT ICE IN THE CLOUD...BUT WARMING IN THE NEAR SFC LAYER SUGGESTS MELTING AND THE POTENTIAL FOR RAIN OR FREEZING RAIN. THE WARMING CONTINUES FOR THE REST OF WED AS THE MAIN PART OF THE STORM MOVES IN...WITH RAIN THE LIKELY PCPN TYPE AS A RESULT. LOOKS LIKE ANY SNOW BAND WITH THIS STORM WILL HANG WELL WEST/NORTH. OVERALL...CONFIDENCE IS HIGH THAT PRECIPITATION WILL OCCUR. WHEN ITS MOST LIKELY IS NOT. CONFIDENCE IS ALSO RISING THAT IT WILL LIKELY BE RAIN FOR THE MAJORITY OF THE EVENT. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 250 PM CST SUN DEC 11 2011 MODEL DIFFERENCES CONTINUE...LOWERING CONFIDENCE IN SOME OF THE DETAILS. WHILE THE GFS HAS MOVED TO A NORTHWEST STORM TRACK ALA THE ECMWF AND GEM...STILL LOTS OF TIMING VARIANCE ON HOW QUICKLY THE SYSTEM WILL KICK NORTHEAST. THE GFS IS THE FAST SOLUTION...WITH THE EC SLOWER AND THE GEM IN BETWEEN. THE EC WOULD LINGER PCPN LONGER OVER THE FORECAST AREA...CONTINUING INTO THU. ALSO...WITH THE EC STAYING THE FARTHEST WEST...ITS ALSO MUCH WARMER MAKING RAIN A MORE LIKELY PCPN TYPE FOR A LONGER STRETCH OF TIME. PCPN TYPE WILL BE A DIFFICULTY WITH THIS STORM. WILL CONTINUE TO LEAN ON THE EC/CONSENSUS SOLUTION FOR NOW. HIGH PRESSURE STARTS TO BUILD IN FROM THE WEST THU NIGHT...MOVING OVERHEAD FOR SAT WHILE THE UPPER LEVEL FLOW TAKES ON A MORE ZONAL SHAPE FOR THE WEEKEND. FRI/SAT SHOULD BE DRY WITH SEASONAL TEMPS. && .AVIATION...THROUGH 06Z TUESDAY 1135 PM CST SUN DEC 11 2011 CEILINGS HAVE ACTUALLY LIFTED ACROSS THE AREA THIS EVENING AND WILL START THE TAFS OUT WITH EITHER MVFR OR VFR CEILINGS BUT WITH MVFR VISIBILITIES FROM SOME LIGHT FOG. STILL EXPECTING CONDITIONS TO DETERIORATE LATER TONIGHT AS THE SHORT WAVE TROUGH APPROACHES AND INCREASES THE LIFT. THE 12.03Z RUC AND 12.00Z NAM NOW SUGGESTS THE LOWER CEILINGS...VISIBILITY AND DRIZZLE WILL BE SLOWER TO ARRIVE AND PUSHED THIS BACK TO AROUND 10Z BUT THERE ARE SOME INDICATIONS IT COULD EVEN HOLD OFF LONGER. TEMPERATURES STILL TO BE WARM ENOUGH TO KEEP THE PRECIPITATION AS DRIZZLE WITH LITTLE THREAT FOR ANY FREEZING DRIZZLE AT THE TAF SITES. THE DRIZZLE SHOULD BEGIN TO TAPER OFF DURING THE AFTERNOON AND HAVE PUSHED BOTH THE VISIBILITY AND CEILING UP A LITTLE AS THIS OCCURS. THE LOW LEVEL MOISTURE DOES NOT GET CLEANED OUT OF THE AREA WITH THE FLOW REMAINING OUT OF THE SOUTH OR SOUTHWEST THROUGH 06Z MONDAY SO VERY POSSIBLE THAT THE CEILINGS WILL START TO GO DOWN AGAIN MONDAY EVENING WITH SOME COOLING. && .ARX WATCHES/WARNINGS/ADVISORIES... 250 PM CST SUN DEC 11 2011 WI...FREEZING RAIN ADVISORY FROM 3 AM TO 9 AM CST MONDAY FOR WIZ017- 029-034-042>044-053>055-061. MN...NONE. IA...NONE. && $$ SHORT TERM... RIECK LONG TERM.... RIECK AVIATION...04
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EST WED DEC 14 2011 UPDATED AVIATION DISCUSSION FOR 06Z TAFS .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A TROUGH OVER THE WRN CONUS AND A RIDGE OVER THE SE WITH MAINLY ZONAL FLOW FROM THE NRN PLAINS TO NEW ENGLAND. A VIGOROUS SHORTWAVE TROUGH WAS MOVING THROUGH AZ WHILE A WEAKER UPSTREAM SHRTWV WAS MOVING INTO SRN SD. AT THE SFC...A RIDGE EXTENDED FROM NORTHERN QUEBEC TO LAKE SUPERIOR RESULTING IN WEAK ACYC FLOW OVER THE CWA WITH NO PCPN INDICATED BY RADAR. WITH THE MILD/MOIST AIRMASS IN PLACE...PATCHY FOG LINGERED OVER LOCATIONS NEAR THE WI BORDER. && .SHORT TERM...TONIGHT AND WEDNESDAY TONIGHT...AS THE HIGH SLIDES OFF TO THE SE...SRLY LOW LEVEL FLOW WILL INCREASE WEAK UPSLOPE FLOW INTO PORTIONS OF WEST AND CENTRAL UPPER MI MAY BE ENOUGH TO SUPPORT SOME PATCHY -DZ/-FZDZ AFT 06Z EVEN THOUGH OVERALL LOW LEVEL (925-850 MB) LIFT IS VERY WEAK...PER NAM/RUC...280K ISENTROPIC PROGS. OTHERWISE...WITH LITTLE DIURNAL TEMP CHANGE IS EXPECTED OVER THE AREA. AREAS OF FOG...SOME LCLY DENSE...MAY ALSO THICKEN WITH SLIGHT INCREASE IN MOISTURE ADVECTION. WEDNESDAY...AS LOW PRESSURE DEVELOPS IN THE CENTRAL PLAINS AND MOVES TOWARD THE UPPER MS VALLEY...LOW/MID LEVEL WAA AND MOISTURE ADVECTION WILL INCREASE. THIS SHOULD BRING AN AREA OF LIGHT PCPN OVER THE ENTIRE CWA BY AFTERNOON...PER NAM/GFS 290K-295K ISENTROPIC PROGS. NAM WET-BULB ZERO HEIGHTS SUGGEST THAT THE PCPN SHOULD BE MAINLY RAIN. HOWEVER...GIVEN LOW LEVEL TEMP PROFILES NEAR 0C OVER THE INTERIOR WEST...CANNOT RULE OUT SOME SNOW. ANY ACCUMULATIONS WOULD BE MINIMAL. EVEN THOUGH TEMPS WILL BE ABOVE FREEZING WHEN THE RAIN ARRIVES...SOME UNTREATED ROADS MAY STILL BE COLD ENOUGH TO CREATE PATCHY ICY SPOTS. .LONG TERM /WED NIGHT THROUGH NEXT TUESDAY/... SHORTWAVE CURRENTLY ROUNDING THE UPPER TROUGH OFF THE COAST OF SRN CA WILL MOVE TOWARDS THE AREA LATE WED AFTN AND MOVE ACROSS THE AREA WED EVENING. MODELS FAIRLY CONSISTENT ON THE MAIN ENERGY FROM THE SHORTWAVE MOVING ACROSS CNTRL/ERN UPPER MI...WHICH WILL GRADUALLY INTENSIFY THE LOW MOVING FROM IOWA AT 00Z THURS TO SE ONTARIO AT 12Z THURS. OTHER THAN THE FAST AND NW OUTLIER 12Z NAM...MAIN DIFFERENCES BETWEEN THE MODELS IS IN THE INTENSITY OF THE LOW. 06-12Z GFS RUNS ON THE STRONG SIDE AND 00Z ECMWF ON WEAKER SIDE. WILL FOLLOW A BLEND OF THE TWO SINCE TRACKS ARE SIMILAR AND ONLY MINOR DIFF IN THE THERMAL PROFILES. DURING THE EVENING...06 AND 12Z GFS SHOWING STRONG FGEN FROM H800-400 ACROSS THE CWA. THINK THE BEST FORCING WILL BE ALONG THE H800-600 FGEN AREA...WHERE THERE IS ABUNDANT MOISTURE AND STRONG AGEOSTROPHIC UPWARD CIRCULATION. FARTHER NW...APPEARS TO BE A DECENT H700-500 DRY AIR LAYER...AND DOWNWARD CIRCULATION MAY LIMIT PCPN FARTHER NW TOWARDS A KIWD TO KCMX LINE. OVER THE E...EXPECT A STRONG AREA OF H850-700 WAA AND 285-300K SFC ISENTROPIC ASCENT DURING THE EVENING. THINK THE EXISTING 100 POPS LOOK GOOD AND WILL LEAVE THEM AS IS. THEN HAVE A GRADUAL LOWERING HEADING OVER THE WEST TOWARDS HIGH END LIKELY. COULD BE A SHARP CUTOFF TO THE WEST EXTENT OF THE PCPN OVER THE WRN HALF OF LK SUPERIOR WITH THE FGEN CIRCULATION...SO TRIED TO SHOW THAT POTENTIAL. P-TYPE FOR THE WED NIGHT PERIOD IS WHERE THINGS GET TRICKY. BUFKIT SOUNDINGS FROM THE GFS SHOW AN ISOTHERMAL PROFILE FROM SFC TO 5-6KFT. WITH THAT TYPE OF SITUATION...IT WILL LIKELY BE SNOW WHERE LAYER IS NEAR 0C AND THEN RA/SN AROUND 1C AND ALL RA AROUND 2-3C. KCMX MAY BE FAR ENOUGH N AND AWAY FROM THE WARM SURGE TO KEEP PCPN A RA/SN MIX OR POSSIBLY EVEN ALL SNOW. THEN HEADING S AND E ACROSS THE CWA...EXPECT A TRANSITION TO ALL RAIN. BIGGEST CONCERN IS GETTING THAT RA/SN AREA PINNED DOWN AND STILL DON/T HAVE A GREAT FEEL...BUT IT SHOULD BE OVER THE NW THIRD. FORTUNATELY...THE HEAVIEST QPF WILL LIKELY BE TO THE SE OF THE UNCERTAIN AREA FOR RA/SN...SO IT SHOULD LIMIT THE IMPACT IF IT DOES END UP ALL SNOW. LAST COUPLE OF RUNS OF THE GFS HAVE REALLY BUMPED UP THE QPF IN THE FGEN LOCATION MOVING ACROSS CNTRL UPPER MI...WITH LIQUID AMOUNTS EXCEEDING 0.75IN...BUT IT IS LIKELY DUE TO THE MORE WRAPPED UP LOW SOLN. WILL NOT GO THAT HIGH...BUT WILL NEED TO BE MONITORED IF STRONGER LOW SOLN PANS OUT. OTHERWISE...EXPECT 0.25 TO 0.4 OF LIQUID ACROSS THE SE HALF OF THE CWA...MAINLY DURING THE EVENING. MAIN ENERGY AND DEEPER H700-500 MOISTURE PULLS OUT OVERNIGHT WED AND HAVE DIMINISHING POPS TO ACCOUNT FOR THAT. P-TYPE IS AGAIN A CONCERN HEADING INTO THE OVERNIGHT...SINCE THE DEEPER MOISTURE PULLS OUT BEFORE THE COLDER AIR ARRIVES LATE WED NIGHT INTO THURS. THIS WILL CUT THE POTENTIAL FOR ICE CRYSTALS IN THE CLOUD WAY DOWN AND LIMIT THE POTENTIAL FOR SNOW. WITH TEMPERATURES DROPPING TOWARDS FREEZING OVER THE WEST TOWARDS 12Z THURS...DID KEEP A MENTION OF -FZRA IN THE FORECAST LATE...BUT POTENTIAL SEEMS LIMITED DURING THE OVERNIGHT HOURS WITH THE SHORT PERIOD OF AT OR BELOW FREEZING TIME. OTHERWISE...WILL ONLY MENTION A LOW CHANCE FOR SNOW OVER THE WEST OVERNIGHT DUE TO LIMITED ICE CRYSTAL PRESENCE AND RAIN OVER THE CENTRAL AND EAST. THINK THE BIGGEST HAZARD IS MORE LIKELY TO BE THE WET ROADS ICING UP ON THURS...AS TEMPS FALL BELOW FREEZING THROUGH THE DAY. NRN STREAM UPPER TROUGH WILL SWEEP THROUGH THE CWA ON THURS. STILL DIFFERENCES IN THE SPEED/INTENSITY IN THE MODELS WITH THIS WAVE...BUT ALL HAVE THE GENERAL IDEA OF IT MOVING THROUGH THE UPPER GREAT LKS ON THURS. THIS WAVE WILL DROP H850 TEMPS THROUGH THE DAY TO -12C OVER THE W BY 00Z FRI. THESE COLDER TEMPS WILL STAY OVER THE AREA THROUGH THE DAY FRI...ANOTHER WEAKER SHORTWAVE DROPS ACROSS THE AREA. WITH TEMPS ALOFT PUTTING THE CLOUD LAYER BACK INTO THE ICE CRYSTAL AREA ON THURS...EXPECT TO CHANCES FOR SNOW AS THE P-TYPE TO BE ON THE INCREASE FROM WEST TO EAST. SHORTWAVE ENERGY WILL HELP ENHANCE THE DEVELOPING LES THROUGH THE DAY. WILL CONTINUE TREND OF HIGHER POPS OVER THE WEST IN THE MORNING WITH LES DEVELOPING AND SHORTWAVE ARRIVING...THEN INCREASE LES POPS OVER THE E UNDER NW WINDS IN THE AFTN INTO THURS NIGHT. IN ADDITION...WITH THE LOW INTENSIFYING TO THE NE OF THE AREA...EXPECT A BREEZY DAY ON THURS ACROSS THE AREA. THE HIGHEST WINDS SHOULD BE OVER THE E NEAR LK SUPERIOR...WHERE WINDS COULD GUST TO 40-45MPH LATE IN THE AFTERNOON. SFC RIDGE QUICKLY MOVES FROM W TO E OVER THE CWA ON THURS NIGHT INTO FRI. MODELS SHOWING VERY PRONOUNCED H925-700 DRYING WITH THE ARRIVAL OF THE RIDGE...SO HAVE TRENDED BACK LES POPS...ESPECIALLY OVER THE WEST WHERE BUFKIT SOUNDINGS SHOWING INVERSION HEIGHTS FALLING TOWARDS 3KFT. DID KEEP LIKELY/S OVER THE NW WIND FAVORED E LOCATIONS THURS NIGHT INTO FRI MORNING...BUT DROPPED TO CHANCES IN THE AFTN AS THE DRY AIR LIMITS POTENTIAL. DAYS 4 THROUGH 7 /FRI NIGHT THROUGH NEXT TUESDAY/... WEAK SHORTWAVE MOVING ACROSS THE AREA FRI NIGHT WILL BRING A LITTLE MORE MOISTURE TO THE AREA AND KEEP COLDER AIR IN PLACE. EXPECT ONGOING LES TO CONTINUE OVER THE E...WITH WINDS GRADUALLY SHIFTING MORE WRLY. LES MAY TRY TO REDEVELOP OVER THE W WITH THE ARRIVAL OF THE SHORTWAVE AND ADDITIONAL LLVL MOISTURE. WILL GO WITH LOW CHANCES OVER THE KEWEENAW WITH THE MORE WRLY WINDS AND THEN LOW END LIKELY/S OVER THE EAST. UPPER TROUGH SHIFTS E ON SAT AND DRAGS A SFC TROUGH OVER NRN LK SUPERIOR AND SRN ONTARIO THROUGH THE DAY AND INTO SAT NIGHT. THERE HAS BEEN A STRONGER TREND WITH THE SFC FEATURES AND UPPER FORCING OVER THE LAST DAY FOR THE SAT AND SAT NIGHT PERIOD...SO HAVE BUMPED POPS UP TO SLIGHTS OVER THE NRN U.P. AND CHANCES OVER THE LAKE. SOME DIFFERENCES APPEAR IN THE EXTENDED MODELS ON SUN INTO MON WITH THE HANDLING OF A POTENTIAL RIDGE IN THE NRN STREAM AND A CLOSED LOW OVER THE SW CONUS. LATEST 12Z RUN OF THE GFS HAS TRENDED SLOWER WITH THE EXIT OF THE UPPER LOW OVER THE SW CONUS SUN INTO MON...AND MORE IN LINE WITH THE 00Z ECMWF...SO HAVE FOLLOWED THAT FOR THE REST OF THE EXTENDED. SFC RIDGE WILL MOVE ACROSS THE CWA ON SUN INTO SUN NIGHT. NRN STREAM SHORTWAVE WILL APPROACH THE AREA MON INTO TUES...BRINGING ANOTHER LOW CHANCE OF PCPN. HAS BEEN A GOOD AMOUNT OF FLUCTUATION IN H850 TEMPS AFTER SUN...SO HAVE LIMITED CONFIDENCE IN VALUES...BUT APPEARS THAT TEMPS WILL SLIGHTLY ABOVE NORMAL. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... LOW-LEVELS WILL REMAIN MOIST THROUGH THE TAF PERIOD AS A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS LIFTS NORTH INTO THE UPPER GREAT LAKES ON WEDNESDAY. LIMITED MIXING TONIGHT...MOIST LOW-LVLS AND LIGHT UPSLOPE SE FLOW SHOULD LEAD TO LIFR TO VLIFR CONDITIONS IN STRATUS/FOG AT KSAW. TRICKIER FCST IN STORE FOR KCMX AND KIWD OVERNIGHT AS SE FLOW IS MORE DOWNSLOPE FOR THESE LOCATIONS WHICH COULD MITIGATE STRATUS/FOG. LOOK FOR ONLY IFR CONDITIONS AT KCMX AND VFR TO POSSIBLY MVFR CIGS AT KIWD. IN GENERAL...SIGNIFICANT IMPROVEMENT IS NOT ANTICIPATED THROUGH WEDNESDAY MORNING AT ANY OF THE TAF SITES. RAIN IS EXPECTED BY WED AFTERNOON AS SYSTEM APPROACHES FROM THE CENTRAL PLAINS. THIS ADDITIONAL MOISTURE FROM THE RAIN COMBINED WITH A SHIFT TO MORE WESTERLY UPSLOPE WINDS BEHIND THE LOW PRES SYSTEM WILL LIKELY LOWER CONDITIONS TO LIFR OR VLIFR AT BOTH KCMX AND KIWD BY WED EVENING. AT KSAW...EXPECT LIFR CONDITIONS TO LOWER TO VLIFR BY LATE WED AFTERNOON IN CONTINUED MOIST UPSLOPE FLOW. ONLY CHANCE FOR MARGINAL IMPROVEMENT WOULD BE A SHIFT TO WRLY WINDS LATE EVENING BEHIND THE SYSTEM/S COLD FRONT. && .MARINE /FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE/... LIGHT SOUTHERLY WINDS WILL INCREASE INTO THE 15 TO 25 KT RANGE OVER THE CENTRAL AND EAST PORTIONS OF THE LAKE WED AHEAD OF LOW PRESSURE DEVELOPING IN THE PLAINS. THE LOW IS FCST TO DEEPEN AS IT LIFTS ACROSS THE UPPER LAKES BY THURSDAY MORNING. STRONGEST WINDS THIS WEEK WILL OCCUR JUST IN THE WAKE OF THE LOW THURSDAY MORNING THROUGH MIDNIGHT THURSDAY NIGHT. CONFIDENCE THAT 35-40 KT GALES WILL OCCUR IS HIGH SO THE WATCH CONTINUES FOR MUCH OF LK SUPERIOR. STRONG WINDS WILL DIMINISH ON FRI WITH THE SLOW APPROACH OF A HIGH PRESSURE RIDGE. A STRONGER SW FLOW WILL REDEVELOP ON SAT AFTER THIS HIGH SHIFTS TO THE SE WITH WINDS TO AROUND 30 KT OVER WEST AND CENTRAL PORTIONS OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR LSZ264>267. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...SRF AVIATION...VOSS MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
402 AM CST WED DEC 14 2011 .DISCUSSION... A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE. FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE. MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN. THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT OF NORMAL THROUGH THE CENTRAL PLAINS. BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME AREAS. THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE SOUTHWEST..EAST OF THE BUFFALO RIDGE. ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE WITH THIS ONE. && .AVIATION... /06Z TAF ISSUANCE/ VFR CONDITIONS OVER EASTERN AREAS WILL GRADUALLY GIVE WAY TO IFR CONDITIONS OVER THE NEXT FEW HOURS AS LIGHT RAIN GRADUALLY SATURATES LOWER LEVELS OF THE ATMOSPHERE. LIGHT RAIN/DRIZZLE TO CONTINUE INTO THE EARLY MORNING BEFORE TAPERING AS INITIAL SURGE OF FORCING MOVES THROUGH. WILL SEE INCREASING THREAT LIGHT RAIN DEVELOPING WED AFTERNOON AS SURFACE FRONT AND UPPER TROUGH MOVES THROUGH. THIS SLIDES EAST BY EARLY EVENING WITH PERHAPS SOME RAIN/SNOW CHANGING TO SNOW OVER EASTERN AREAS THROUGH 06Z THU. WILL GRADUALLY LIFT CEILINGS AND END PRECIPITATION FROM WEST TO EAST DURING THE NIGHT. LIGHT SOUTHEAST WIND FLOW AHEAD OF FRONT...BECOMING NORTHWEST WITH FROPA. KMSP...VFR CIGS GRADUALLY LOWERING TO IFR THROUGH THE EARLY MORNING. LIGHT RAIN SHOULD TAPER OR END AS DRIZZLE EARLY MORNING. AS UPPER TROUGH AND SURFACE FRONT APPROACHES...INCREASING CHANCE OF LIGHT RAIN DEVELOPING IN THE AFTERNOON/EARLY EVENING....PERHAPS ENDING AS A LIGHT RAIN/SNOW MIX BEFORE 06Z THU. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/DWE
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
647 AM CST WED DEC 14 2011 .UPDATE... UPDATED FOR THE 12Z AVIATION DISCUSSION BELOW. .DISCUSSION... A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE. FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE. MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN. THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT OF NORMAL THROUGH THE CENTRAL PLAINS. BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME AREAS. THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE SOUTHWEST..EAST OF THE BUFFALO RIDGE. ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE WITH THIS ONE. && .AVIATION.../12Z TAF ISSUANCE/ WITH LIFR CEILINGS ALMOST EVERYWHERE...THE CLOUD BASE FORECAST IS ACTUALLY NOT ALL THAT CHALLENGING FOR THE FIRST 6 HOURS. WITH THE BROAD SURFACE TROF SETTLING IN AND A NICE FETCH OF MOISTURE FROM THE SOUTHEAST...THESE CEILINGS AREN`T GOING ANYWHERE FOR MOST FOR THE DAY. ITS POSSIBLE SOME SPOTS SEE THE DECK LIFT 200-400FT BY THIS AFTERNOON...BUT SHOULD STILL REMAIN IFR. THE VISIBILITY FORECAST IS MORE CHALLENGING GIVEN THE AREAS OF FOG AND DRIZZLE MIXED WITH SCATTERED LIGHT RAIN SHOWERS. EVEN THOUGH IT FLIES IN THE FACE OF CLIMATOLOGY...WORRIED THAT THE VISIBILITY MAY ACTUALLY GET WORSE DURING A FEW HOUR WINDOW LATE THIS MORNING/THIS AFTERNOON...ESPECIALLY IF THE RAIN HANGS TO OUR SOUTH FOR A WHILE. WINDS SHOULD DECREASE UNDER THE TROF AND MAY GO CALM. PLENTY OF 1/4SM AND 1/2SM VISIBILITIES IN EASTERN SD AND WESTERN MN THIS MORNING. BETTER CHANCES FOR LIGHT RAIN IN SOUTHEAST MN AND WESTERN WI TODAY...WITH THE CHANGE OVER TO SNOW HAPPENING SOMETIME LATE THIS EVENING. KMSP...VISIBILITIES BELOW 2SM AND CEILINGS UNDER 500FT ARE NOT GOING ANYWHERE FOR THE NEXT 6 HOURS. IN FACT...HAVE INCLUDED A TEMPO GROUP FOR 1/2SM FOG EARLY THIS AFTERNOON WHEN WINDS DECREASE AND MAY GO CALM FOR A TIME BEFORE TURNING TO THE WEST/NORTHWEST LATE THIS EVENING. DON`T HAVE SUPREME CONFIDENCE WE`LL BUCK CLIMATOLOGY AND SEE VISBYS DECREASE IN THE AFTERNOON...BUT THESE ARE THE TYPES OF SITUATIONS WHEN IT DOES INDEED HAPPEN. THE WILD CARD IS THE RAIN SHOWERS...WHICH WHEN PRESENT WOULD ACTUALLY KEEP THE VISBYS FROM DROPPING TOO LOW. RIGHT NOW THE CHANGE OVER TO SNOW TO ANY REMAINING PRECIPITATION WILL LIKELY SOMETIME AROUND MIDNIGHT...WITH THE SURFACE AIR TEMPERATURE FALLING BELOW FREEZING 3-4 HOURS LATER. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/CLF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
720 AM CST WED DEC 14 2011 .UPDATE...DID A QUICK UPDATE TO DECREASE SKY COVER A TAD FOR LATE MORNING/THIS AFTERNOON. LATEST RUC GUIDANCE INITIALIZED VERY WELL BASED ON THE 12Z JAN RAOB...WITH THIS SAME GUIDANCE NOW MORE SUGGESTIVE OF THE CLOUDS TRYING TO BREAK UP AFTER 1 PM. HIGH TEMPS STILL LOOK GOOD THOUGH AND HAVENT MADE ANY ADJUSTMENTS...BUT THIS MAY VERY WELL CHANGE ONCE THE EXTENT OF THE CLOUD COVER IS BETTER KNOWN LATER THIS MORNING. /BK/ && .PREV DISCUSSION... /ISSUED 400 AM CST WED DEC 14 2011/ ..DENSE FOG OCCURRING OVER PORTIONS OF THE ARKLAMISS THIS MORNING... SHORT TERM...TODAY THROUGH THURSDAY NIGHT...WIDESPREAD STRATUS CONTINUES TO BLANKET THE ARKLAMISS THIS MORNING AS GENTLE MOIST UPGLIDE OCCURS FROM THE SOUTHEAST. VISIBILITY RESTRICTIONS HAVE BEEN A BIT EASIER TO COME BY TONIGHT AS OPPOSED TO LAST NIGHT... ESPECIALLY ACROSS AREAS EAST OF I-55 AND ALONG THE HIGHWAY 82 CORRIDOR AND INTO SOUTHEAST AR. SURFACE OBSERVATIONS ACROSS THESE AREAS SHOW FAIRLY WIDESPREAD RESTRICTIONS OF 1/2MI OR LESS AND WILL GO WITH A DENSE FOG ADVISORY ACCORDINGLY...WHICH MEANT AN EXPANSION OF THE CURRENT ADVISORY TO THE SOUTHEAST. LOOKING AT OBSERVATIONS FROM YESTERDAY MORNING AND CLIMATOLOGY IT LOOKS LIKE THE VIS SHOULD START COMING UP AFTER 9AM AND WILL END THE ADVISORY AT THAT TIME. A SLOWLY INCREASING PRESSURE GRADIENT ACROSS SOUTHWESTERN ZONES APPEARS TO BE LIMITING FOG POTENTIAL IN THIS AREA AS LATEST OBS FROM HEZ/TVR/MCB/MLU INDICATE 5MI OR BETTER VIS. THE DENSE FOG ADVISORY THAT WAS IN EFFECT FOR PORTIONS OF THIS AREA HAS BEEN CANCELLED AS A RESULT. WILL KEEP A CLOSE ON THE FOG SITUATION THIS MORNING SO STAY TUNED FOR UPDATES. WE MAY NEED TO EXPAND THE ADVISORY INTO THE JACKSON METRO AT SOME POINT. FOCUS THEN SHIFTS TO CLOUD COVER POTENTIAL THIS AFTERNOON AND HOW THAT WILL IMPACT AFTERNOON HIGHS. LATEST RUC GUIDANCE IS NOT CONFIDENT WE WILL SEE MUCH SUN THIS AFTERNOON AS LOW LEVEL MOISTURE FIELDS REMAIN SATURATED FOR ALL BUT FAR EASTERN AREAS WHERE SOME THINNING OF THE CLOUDS IS POSSIBLE. LATEST NAM/SREF INDICATE SOME THINNING POSSIBLE NORTH OF I-20 THIS AFTERNOON REMAINING SOCKED IN ELSEWHERE. OVERALL I LIKE WHAT THE RUC IS SHOWING AND HAVE GENERALLY STUCK WITH CLOUDY SKIES TODAY FOR ALL AREAS...SHOWING A FEW PEAKS OF SUN IN THE EAST THIS AFTERNOON. I DO HOWEVER THINK THERE IS SOME POTENTIAL FOR A FEW BREAKS IN THE CLOUDS ACROSS THE SOUTHWEST LATER ON AS THE LOW LEVEL FLOW PICKS UP IN RESPONSE TO A PRESSURE GRADIENT THAT CONTINUES TO TIGHTEN. SO...WITH CLOUD COVER REMAINING FAIRLY SOLID TODAY I HAVE GONE WITH THE LOWEST MEMBER OF THE GFS MOS SUITE(MID TO UPPER 60S) FOR TEMPS TODAY...WHICH MIGHT STILL BE TOO HIGH AS I THINK WE MIGHT STRUGGLE TO GET TO THE LOW 60S ACROSS A BIG PORTION OF THE AREA. TONIGHT INTO THURSDAY...A COLD FRONT WILL BE MOVING INTO SOUTH CENTRAL AR LATE TONIGHT ATTENDANT TO A S/WV LIFTING ACROSS THE CENTRAL PLAINS AND INTO THE GREAT LAKES REGION. LIGHT RAIN CHANCES WILL BE ON THE INCREASE LATE TONIGHT/EARLY TOMORROW MORNING ACROSS THE DELTA AS THIS FEATURE APPROACHES...WITH A FEW LIGHT NORTHWARD MOVING SHOWERS AHEAD OF THE FRONT POSSIBLE ALONG/WEST OF THE MS RIVER. THE FRONT WILL LIMP INTO MS LATE THURSDAY PUSHING SHOWER CHANCES FURTHER SOUTHEAST AS IT ADVANCES. INSTABILITY IS RATHER WEAK WITH THIS SYSTEM THANKS TO WARM MID/UPPER LEVEL TEMPS AND ASSOCIATED WEAK LAPSE RATES. FORCING IS REAL WEAK AS WE REMAIN UNDER THE INFLUENCE OF UPPER RIDGING ALOFT...ALL COMBINED I THINK THE POTENTIAL FOR ANY STRONG TO SEVERE STORMS IS LOW THURSDAY. BUT...IF THE INSTABILITY COMES IN A BIT HIGHER THAN FORECAST THERE COULD BE A MARGINAL RISK OF 50MPH WIND GUSTS ACROSS THE FAR NORTHWEST EARLY TO MID DAY THURSDAY. WILL GO AHEAD AND KEEP THAT MENTION IN THE HWO FOR NOW. THE FRONT WILL STALL ACROSS CENTRAL PORTIONS OF THE FA THURSDAY EVENING AS ANOTHER S/WV IN SOUTHWESTERLY FLOW LIFTS ACROSS THE SOUTHERN PLAINS AND INTO THE MID MS VALLEY EARLY FRI. AS THIS BETTER FORCING INTERACTS WITH THE FRONT WE COULD SEE A PERIOD OF MODERATE RAIN THURSDAY NIGHT AS THE WAVE PASSES. AS FOR TEMPS...LOWERED HIGHS FOR THURSDAY FOR MOST SITES AS CLOUD COVER/RAIN POTENTIAL KEEP US FROM CLIMBING MUCH ABOVE 70...ESPECIALLY ACROSS THE DELTA WHERE WE PROBABLY WONT EVEN GET TO 70. OVERNIGHT LOWS SEEMED REASONABLE THIS PERIOD. /BK/ LONG TERM...FRIDAY THROUGH WEDNESDAY...TWO PERIODS OF RAIN ARE EXPECTED IN THE LONG TERM. THIS FIRST IS FRIDAY AND THE SECOND IS MONDAY NIGHT. COME FRIDAY MORNING A NEARLY STATIONARY COLD FRONT IS EXPECTED TO BE ACROSS THE SOUTHEAST PORTION OF OUR CWA. THE NAM IS A LITTLE FARTHER NORTH...BUT MODEL CONSENSUS PLACES THE FRONT FROM SOUTH OF NATCHEZ TO JUST NORTH OF MERIDIAN AT SUNRISE. THERE IS EXPECTED TO BE PLENTY OF POST FRONTAL PRECIPITATION ACROSS OUR CWA AS A CLOSED LOW OVER THE DESERT SOUTHWEST DRAWS PACIFIC MOISTURE ACROSS THE SOUTHERN PLAINS AND OUR REGION ON SOUTHWEST WINDS ALOFT. A COUPLE OF NORTHERN STREAM SHORTWAVES WILL MOVE ACROSS THE PLAINS FRIDAY AND SATURDAY AND HELP A +1030MB SURFACE HIGH DROP SOUTH TO THE ARKLATEX REGION BY SATURDAY AFTERNOON. AS THIS HIGH DROPS SOUTH THE NEARLY STATIONARY FRONT WILL BE PUSHED SOUTH OF OUR CWA AND THE ASSOCIATED RAIN WILL END. THE BULK OF THE RAIN SHOULD END FROM THE NORTH FRIDAY EVENING BUT A SLIGHT CHANCE OF RAIN WILL CONTINUE IN THE SOUTH INTO SATURDAY MORNING. GUIDANCE POPS CAME IN A LITTLE HIGH AND TOO FAR NORTH. HAVE CUT GUIDANCE POPS ACROSS OUR CWA SATURDAY THROUGH SUNDAY. TEMPERATURES WILL BE WELL ABOVE NORMAL FRIDAY SOUTH OF THE FRONT AND NEAR NORMAL NORTH OF THE FRONT. COOLER...BUT NEAR NORMAL TEMPERATURES ARE EXPECTED SATURDAY. THE SURFACE HIGH WILL BECOME CENTERED OVER OUR CWA SUNDAY MORNING AND CONTINUE SHIFTING EAST DURING THE DAY. INDUCED RIDGING ALOFT WILL STRENGTHEN OVERHEAD DUE TO THE CLOSED LOW MOVING JUST SOUTH OF THE FOUR CORNERS REGION. THIS RIDGING SURFACE AND ALOFT SHOULD ALLOW TEMPERATURES TO RECOVER NICELY SUNDAY AND TOP OUT ABOVE NORMAL AGAIN. HIGHS WILL BE IN THE LOW TO MID 60S. RIDGING SURFACE AND ALOFT WILL SHIFT EAST MONDAY AS THE CLOSED LOW MOVES TO THE SOUTHERN PLAINS. WAA WILL STRENGTHEN OVER OUR CWA AHEAD OF THE APPROACHING SYSTEM LEADING TO RAIN CHANCES INCREASING FROM THE WEST MONDAY. THE GFS AND ECMWF DISAGREE ON THE PROGRESSION OF THE LOW MONDAY AND TUESDAY. THE GFS MAINTAINS THE CLOSED LOW AND LIFTS THE BOTH THE UPPER LEVEL LOW AND SURFACE LOW SLOWLY ACROSS THE OZARKS MONDAY NIGHT AND OVER THE TENNESSEE VALLEY BY TUESDAY MORNING. THE MORE PROGRESSIVE ECMWF OPENS UP THE CLOSED LOW AND MOVES BOTH THE UPPER LEVEL TROUGH AND SURFACE LOW TO THE UPPER GREAT LAKES REGION BY TUESDAY MORNING. BOTH SCENARIOS BRING A COLD FRONT WITH WIDESPREAD RAIN TO OUR CWA MONDAY NIGHT INTO TUESDAY BUT THE GFS PARAMETERS SUGGEST THE POSSIBILITY FOR SEVERE WEATHER MONDAY NIGHT FOR OUR CWA. WITH SUCH MODEL DISCREPANCIES WL HOLD OFF INTRODUCING MENTION OF SEVERE WEATHER POTENTIAL IN THE HWO BUT LOOK TO FUTURE RUNS FOR SOME CONTINUITY AND A MORE LIKELY CONSENSUS. WEDNESDAY CURRENTLY LOOKS TO BE COOLER AND DRY FOR OUR REGION. /22/ && .AVIATION... WDSPRD IFR CIG ARE PLAGUING THE REGION THIS MORNING...ACCOMPANIED BY VRBL VSBYS RANGING FROM 1/4 TO 6SM. CIG WILL LIKELY VARY BETWEEN 100 AND 800 FT UNTIL 17Z AT MOST SITES. CLIMATOLOGY SUGGESTS CIG WILL TREND MVFR BY 18-19Z ALTHOUGH CONFIDENCE IS LOW IN THIS BEING WDSPRD AS WE STRUGGLED TO LIFT MVFR YESTERDAY. BEST CHANCE OF SEEING ANY SCT LOW CLOUDS WILL BE AT MEI/HEZ THIS AFTN BUT THIS WILL PROB BE SHORT IF IT OCCURS AS IFR CIG RETURN THIS EVENING. VIS WILL TREND MVFR 13-14Z BUT A TREND BACK TOWARD IFR VSBY IS LIKELY TONIGHT. SFC WINDS WILL BE OUT OF THE SE TODAY BECMG SRLY TONIGHT. /BK/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 68 59 72 57 / 0 13 48 82 MERIDIAN 70 54 74 59 / 0 10 37 74 VICKSBURG 69 60 71 52 / 1 22 69 84 HATTIESBURG 69 57 76 58 / 4 10 25 49 NATCHEZ 70 63 74 55 / 1 16 63 83 GREENVILLE 66 59 67 48 / 3 43 78 81 GREENWOOD 67 62 69 51 / 1 31 75 80 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ018-019- 025>039-044>046-050>052-056>058-065-066-073-074. LA...NONE. AR...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ARZ074-075. && $$ BK/22
AREA FORECAST DISCUSSION
NWS JACKSON MS
400 AM CST WED DEC 14 2011 ...DENSE FOG OCCURRING OVER PORTIONS OF THE ARKLAMISS THIS MORNING... .SHORT TERM...TODAY THROUGH THURSDAY NIGHT...WIDESPREAD STRATUS CONTINUES TO BLANKET THE ARKLAMISS THIS MORNING AS GENTLE MOIST UPGLIDE OCCURS FROM THE SOUTHEAST. VISIBILITY RESTRICTIONS HAVE BEEN A BIT EASIER TO COME BY TONIGHT AS OPPOSED TO LAST NIGHT... ESPECIALLY ACROSS AREAS EAST OF I-55 AND ALONG THE HIGHWAY 82 CORRIDOR AND INTO SOUTHEAST AR. SURFACE OBSERVATIONS ACROSS THESE AREAS SHOW FAIRLY WIDESPREAD RESTRICTIONS OF 1/2MI OR LESS AND WILL GO WITH A DENSE FOG ADVISORY ACCORDINGLY...WHICH MEANT AN EXPANSION OF THE CURRENT ADVISORY TO THE SOUTHEAST. LOOKING AT OBSERVATIONS FROM YESTERDAY MORNING AND CLIMATOLOGY IT LOOKS LIKE THE VIS SHOULD START COMING UP AFTER 9AM AND WILL END THE ADVISORY AT THAT TIME. A SLOWLY INCREASING PRESSURE GRADIENT ACROSS SOUTHWESTERN ZONES APPEARS TO BE LIMITING FOG POTENTIAL IN THIS AREA AS LATEST OBS FROM HEZ/TVR/MCB/MLU INDICATE 5MI OR BETTER VIS. THE DENSE FOG ADVISORY THAT WAS IN EFFECT FOR PORTIONS OF THIS AREA HAS BEEN CANCELLED AS A RESULT. WILL KEEP A CLOSE ON THE FOG SITUATION THIS MORNING SO STAY TUNED FOR UPDATES. WE MAY NEED TO EXPAND THE ADVISORY INTO THE JACKSON METRO AT SOME POINT. FOCUS THEN SHIFTS TO CLOUD COVER POTENTIAL THIS AFTERNOON AND HOW THAT WILL IMPACT AFTERNOON HIGHS. LATEST RUC GUIDANCE IS NOT CONFIDENT WE WILL SEE MUCH SUN THIS AFTERNOON AS LOW LEVEL MOISTURE FIELDS REMAIN SATURATED FOR ALL BUT FAR EASTERN AREAS WHERE SOME THINNING OF THE CLOUDS IS POSSIBLE. LATEST NAM/SREF INDICATE SOME THINNING POSSIBLE NORTH OF I-20 THIS AFTERNOON REMAINING SOCKED IN ELSEWHERE. OVERALL I LIKE WHAT THE RUC IS SHOWING AND HAVE GENERALLY STUCK WITH CLOUDY SKIES TODAY FOR ALL AREAS...SHOWING A FEW PEAKS OF SUN IN THE EAST THIS AFTERNOON. I DO HOWEVER THINK THERE IS SOME POTENTIAL FOR A FEW BREAKS IN THE CLOUDS ACROSS THE SOUTHWEST LATER ON AS THE LOW LEVEL FLOW PICKS UP IN RESPONSE TO A PRESSURE GRADIENT THAT CONTINUES TO TIGHTEN. SO...WITH CLOUD COVER REMAINING FAIRLY SOLID TODAY I HAVE GONE WITH THE LOWEST MEMBER OF THE GFS MOS SUITE(MID TO UPPER 60S) FOR TEMPS TODAY...WHICH MIGHT STILL BE TOO HIGH AS I THINK WE MIGHT STRUGGLE TO GET TO THE LOW 60S ACROSS A BIG PORTION OF THE AREA. TONIGHT INTO THURSDAY...A COLD FRONT WILL BE MOVING INTO SOUTH CENTRAL AR LATE TONIGHT ATTENDANT TO A S/WV LIFTING ACROSS THE CENTRAL PLAINS AND INTO THE GREAT LAKES REGION. LIGHT RAIN CHANCES WILL BE ON THE INCREASE LATE TONIGHT/EARLY TOMORROW MORNING ACROSS THE DELTA AS THIS FEATURE APPROACHES...WITH A FEW LIGHT NORTHWARD MOVING SHOWERS AHEAD OF THE FRONT POSSIBLE ALONG/WEST OF THE MS RIVER. THE FRONT WILL LIMP INTO MS LATE THURSDAY PUSHING SHOWER CHANCES FURTHER SOUTHEAST AS IT ADVANCES. INSTABILITY IS RATHER WEAK WITH THIS SYSTEM THANKS TO WARM MID/UPPER LEVEL TEMPS AND ASSOCIATED WEAK LAPSE RATES. FORCING IS REAL WEAK AS WE REMAIN UNDER THE INFLUENCE OF UPPER RIDGING ALOFT...ALL COMBINED I THINK THE POTENTIAL FOR ANY STRONG TO SEVERE STORMS IS LOW THURSDAY. BUT...IF THE INSTABILITY COMES IN A BIT HIGHER THAN FORECAST THERE COULD BE A MARGINAL RISK OF 50MPH WIND GUSTS ACROSS THE FAR NORTHWEST EARLY TO MID DAY THURSDAY. WILL GO AHEAD AND KEEP THAT MENTION IN THE HWO FOR NOW. THE FRONT WILL STALL ACROSS CENTRAL PORTIONS OF THE FA THURSDAY EVENING AS ANOTHER S/WV IN SOUTHWESTERLY FLOW LIFTS ACROSS THE SOUTHERN PLAINS AND INTO THE MID MS VALLEY EARLY FRI. AS THIS BETTER FORCING INTERACTS WITH THE FRONT WE COULD SEE A PERIOD OF MODERATE RAIN THURSDAY NIGHT AS THE WAVE PASSES. AS FOR TEMPS...LOWERED HIGHS FOR THURSDAY FOR MOST SITES AS CLOUD COVER/RAIN POTENTIAL KEEP US FROM CLIMBING MUCH ABOVE 70...ESPECIALLY ACROSS THE DELTA WHERE WE PROBABLY WONT EVEN GET TO 70. OVERNIGHT LOWS SEEMED REASONABLE THIS PERIOD. /BK/ .LONG TERM...FRIDAY THROUGH WEDNESDAY...TWO PERIODS OF RAIN ARE EXPECTED IN THE LONG TERM. THIS FIRST IS FRIDAY AND THE SECOND IS MONDAY NIGHT. COME FRIDAY MORNING A NEARLY STATIONARY COLD FRONT IS EXPECTED TO BE ACROSS THE SOUTHEAST PORTION OF OUR CWA. THE NAM IS A LITTLE FARTHER NORTH...BUT MODEL CONSENSUS PLACES THE FRONT FROM SOUTH OF NATCHEZ TO JUST NORTH OF MERIDIAN AT SUNRISE. THERE IS EXPECTED TO BE PLENTY OF POST FRONTAL PRECIPITATION ACROSS OUR CWA AS A CLOSED LOW OVER THE DESERT SOUTHWEST DRAWS PACIFIC MOISTURE ACROSS THE SOUTHERN PLAINS AND OUR REGION ON SOUTHWEST WINDS ALOFT. A COUPLE OF NORTHERN STREAM SHORTWAVES WILL MOVE ACROSS THE PLAINS FRIDAY AND SATURDAY AND HELP A +1030MB SURFACE HIGH DROP SOUTH TO THE ARKLATEX REGION BY SATURDAY AFTERNOON. AS THIS HIGH DROPS SOUTH THE NEARLY STATIONARY FRONT WILL BE PUSHED SOUTH OF OUR CWA AND THE ASSOCIATED RAIN WILL END. THE BULK OF THE RAIN SHOULD END FROM THE NORTH FRIDAY EVENING BUT A SLIGHT CHANCE OF RAIN WILL CONTINUE IN THE SOUTH INTO SATURDAY MORNING. GUIDANCE POPS CAME IN A LITTLE HIGH AND TOO FAR NORTH. HAVE CUT GUIDANCE POPS ACROSS OUR CWA SATURDAY THROUGH SUNDAY. TEMPERATURES WILL BE WELL ABOVE NORMAL FRIDAY SOUTH OF THE FRONT AND NEAR NORMAL NORTH OF THE FRONT. COOLER...BUT NEAR NORMAL TEMPERATURES ARE EXPECTED SATURDAY. THE SURFACE HIGH WILL BECOME CENTERED OVER OUR CWA SUNDAY MORNING AND CONTINUE SHIFTING EAST DURING THE DAY. INDUCED RIDGING ALOFT WILL STRENGTHEN OVERHEAD DUE TO THE CLOSED LOW MOVING JUST SOUTH OF THE FOUR CORNERS REGION. THIS RIDGING SURFACE AND ALOFT SHOULD ALLOW TEMPERATURES TO RECOVER NICELY SUNDAY AND TOP OUT ABOVE NORMAL AGAIN. HIGHS WILL BE IN THE LOW TO MID 60S. RIDGING SURFACE AND ALOFT WILL SHIFT EAST MONDAY AS THE CLOSED LOW MOVES TO THE SOUTHERN PLAINS. WAA WILL STRENGTHEN OVER OUR CWA AHEAD OF THE APPROACHING SYSTEM LEADING TO RAIN CHANCES INCREASING FROM THE WEST MONDAY. THE GFS AND ECMWF DISAGREE ON THE PROGRESSION OF THE LOW MONDAY AND TUESDAY. THE GFS MAINTAINS THE CLOSED LOW AND LIFTS THE BOTH THE UPPER LEVEL LOW AND SURFACE LOW SLOWLY ACROSS THE OZARKS MONDAY NIGHT AND OVER THE TENNESSEE VALLEY BY TUESDAY MORNING. THE MORE PROGRESSIVE ECMWF OPENS UP THE CLOSED LOW AND MOVES BOTH THE UPPER LEVEL TROUGH AND SURFACE LOW TO THE UPPER GREAT LAKES REGION BY TUESDAY MORNING. BOTH SCENARIOS BRING A COLD FRONT WITH WIDESPREAD RAIN TO OUR CWA MONDAY NIGHT INTO TUESDAY BUT THE GFS PARAMETERS SUGGEST THE POSSIBILITY FOR SEVERE WEATHER MONDAY NIGHT FOR OUR CWA. WITH SUCH MODEL DISCREPANCIES WL HOLD OFF INTRODUCING MENTION OF SEVERE WEATHER POTENTIAL IN THE HWO BUT LOOK TO FUTURE RUNS FOR SOME CONTINUITY AND A MORE LIKELY CONSENSUS. WEDNESDAY CURRENTLY LOOKS TO BE COOLER AND DRY FOR OUR REGION. /22/ && .AVIATION...WDSPRD IFR CIG ARE PLAGUING THE REGION THIS MORNING...ACCOMPANIED BY VRBL VSBYS RANGING FROM 1/4 TO 6SM. CIG WILL LIKELY VARY BETWEEN 100 AND 800 FT UNTIL 17Z AT MOST SITES. CLIMATOLOGY SUGGESTS CIG WILL TREND MVFR BY 18-19Z ALTHOUGH CONFIDENCE IS LOW IN THIS BEING WDSPRD AS WE STRUGGLED TO LIFT MVFR YESTERDAY. BEST CHANCE OF SEEING ANY SCT LOW CLOUDS WILL BE AT MEI/HEZ THIS AFTN BUT THIS WILL PROB BE SHORT IF IT OCCURS AS IFR CIG RETURN THIS EVENING. VIS WILL TREND MVFR 13-14Z BUT A TREND BACK TOWARD IFR VSBY IS LIKELY TONIGHT. SFC WINDS WILL BE OUT OF THE SE TODAY BECMG SRLY TONIGHT. /BK/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 68 59 72 57 / 0 13 48 82 MERIDIAN 70 54 74 59 / 0 10 37 74 VICKSBURG 69 60 71 52 / 1 22 69 84 HATTIESBURG 69 57 76 58 / 4 10 25 49 NATCHEZ 70 63 74 55 / 1 16 63 83 GREENVILLE 66 59 67 48 / 3 43 78 81 GREENWOOD 67 62 69 51 / 1 31 75 80 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MSZ018-019- 025>039-044>046-050>052-056>058-065-066-073-074. LA...NONE. AR...DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR ARZ074-075. && $$ BK/22/BK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
934 AM EST WED DEC 14 2011 .SYNOPSIS... A WEAK WARM FRONT LIFTS TO OUR NORTH TODAY. A COLD FRONT CROSSES THURSDAY EVENING. DEEPER MOISTURE MAY KINK BACK NORTH AND BRUSH AREA ON FRIDAY. DRY WITH HIGH PRESSURE FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... BASED ON LATEST RADAR TRENDS AND THE HRRR MODEL...HAVE UPDATED POPS. MEASURABLE PRECIPITATION WAS MUCH FARTHER SOUTH THAN PREVIOUSLY EXPECTED. HOWEVER...HRRR MODEL INDICATES THE AREA OF SHOWERS SHOULD PUSH NORTH OF AREA THIS AFTERNOON. WILL LIKELY TWEAK SKY GRIDS DOWNWARD AS VISIBLE IMAGERY SHOWS ABUNDANT SUNSHINE TO OUR SOUTHWEST. CURRENT TEMPS ARE COOLER THAN FORECASTED...SO WILL TWEAK DOWNWARD DOWNWARD. HOWEVER...STILL FEEL FORECASTED HIGHS ARE REACHABLE...AND WILL NOT CHANGE. PREVIOUS DISCUSSION... ILL-DEFINED WARM FRONT SOMEWHERE NEAR THE JUNCTION OF THE MISSISSIPPI AND OHIO RIVERS EARLY THIS MORNING MOVES NE THROUGH THE FORECAST AREA THIS AFTERNOON. WARM ADVECTION RAIN OUT AHEAD OF THE FRONT ENCOMPASSING MUCH OF THE OHIO VALLEY NORTH OF THE RIVER EARLY THIS MORNING WILL STAY MAINLY ON THAT SIDE OF THE RIVER AS IT IMPACTS OUR SE OHO COUNTIES...BLEEDING INTO NORTHERN WV BEFORE LIFTING N THIS AFTERNOON. AREA WILL THEN BE ENTIRELY IN WARM SECTOR BY LATE TODAY AND REMAIN SO THROUGH TONIGHT. TIGHTENING GRADIENT SPELLS INCREASING WINDS TONIGHT ESPECIALLY ON THE RIDGES. MODELS IN GOOD AGREEMENT ON TIMING OF COLD FRONT APPROACHING FROM THE W...WITH SHOWERS AHEAD OF THE FRONT REACHING NEAR THE OHIO RIVER BY 12Z THU. HIGHS TODAY LOOKED GOOD...CLOSE TO ADJMETBC.,,WITH LITTLE CHANGE NEEDED. BLENDED IN ADJMET FOR LOWS TONIGHT WHICH ALSO ENTAILED ONLY SMALL CHANGES. DID WARM THE RIDGE AND HILLTOPS A BIT OVERNIGHT AS SW WINDS INCREASE THERE. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... NO MAJOR CHANGES NEEDED TO THE SHORT TERM PERIOD. COLD FRONT WILL MOVE INTO THE CWA AT THE BEGINNING OF THE PERIOD...SPREADING SHOWERS FROM WEST TO EAST WITH IT. THIS IS A RATHER MOIST SYSTEM...WITH PW VALUES EXPECTED TO CLIMB INTO THE 1.1 TO 1.3 RANGE...AIDED BY 50+KT LLJ. STILL NOT EXPECTING ANY WATER ISSUES WITH THIS SYSTEM HOWEVER DUE TO ITS OVERALL PROGRESSIVE NATURE...AND STILL FIGURING GENERALLY ABOUT 0.5 TO 0.75 INCHES QPF. WITH THE GOOD SOUTHERLY FLOW EXPECTED OUT AHEAD OF THE APPROACHING COLD FRONT...MAX TEMPERATURES ON THURSDAY ARE EXPECTED TO CLIMB WELL ABOVE NORMAL...WITH ALL OF THE CWA EXPECTED TO CLIMB INTO THE 50S TO LOWER 60S. WITH THE WARM AIR IN PLACE...SHOULD SEE A MAINLY RAIN EVENT...EXCEPT FOR THE POSSIBILITY OF SOME LIGHT RAIN/SNOW OR SNOW SHOWERS IN THE NORTHERN MOUNTAIN ZONES FRIDAY MORNING BEHIND THE FRONT. HOWEVER...THIS WILL DEPEND ON A VARIETY OF FACTORS INCLUDING AMOUNT OF ATMOSPHERIC MOISTURE REMAINING AND HOW MUCH COLD AIR IS ACTUALLY IN PLACE. REGARDLESS...ACCUMULATIONS DO NOT LOOK FAVORABLE. FRONTAL BOUNDARY WILL EXIT TO THE SOUTH ON FRIDAY WITH ANOTHER WAVE RIDING ALONG THE FRONT FROM THE SOUTH FRIDAY THROUGH FRIDAY NIGHT. THIS WILL MAINLY AFFECT THE SOUTHERN AND EASTERN ZONES. RECENT RUN OF THE NAM APPEARS TO KEEP MOISTURE ASSOCIATED WITH THIS FEATURE FARTHER TO THE SOUTH THAN THE GFS OR ECMWF...AND IF THIS SCENARIO TURNS OUT...WILL MAINLY AFFECT SOUTHWEST VA AND EXTREME SOUTHERN COAL FIELDS. GFS AND ECMWF OVERSPREAD MOISTURE FARTHER NORTH INTO THE AREA...AS FAR NORTH AS CRW. FOR NOW...KEPT ONLY CHANCE TO SLIGHT CHANCE POPS TO THE NORTH...WITH LIKELY OVER SOUTHWEST VA AND SOUTHERN COAL FIELDS DUE TO UNCERTAINTY. IF MOISTURE IS ABLE TO SPREAD FARTHER NORTH...AND DEPENDING ON THE EXACT TRACK OF THE WAVE...COULD SEE SOME LIGHT SNOW IN THE NORTHERN MOUNTAIN ZONES FRIDAY NIGHT. && .LONG TERM /SATURDAY THROUGH TUESDAY/... SFC HIGH BUILDS IN OVER THE WEEKEND TO PROVIDE FOR DRY AND SEASONABLE CONDITIONS...ALBEIT ON THE COLD SIDE FOR LOW TEMPS. NEXT SYS SLATED FOR MON NIGHT AND TUES AS SW LOW EJECTS NE TOWARD THE AREA...INCREASING THE CHANCES FOR RAIN. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... WARM FRONT WILL BE THE MAIN WEATHER MAKER THIS PERIOD...WITH ITS PASSAGE DURING THE DAY ON WED. PATCHY MVFR STRATOCU MAINLY NEAR OHIO RIVER AS THE WARM FRONT APPROACHES. LIGHT RAIN ASSOCIATED WITH THE FRONT AFFECTING EASTERN OHIO INTO NORTHERN WV THIS MORNING WITH NO APPRECIABLE VSBY RESTRICTIONS. THE RAIN WHICH WILL MOVE N OF THE AREA THROUGH LATE MORNING. CIGS WILL LIFT FROM S TO N...FOLLOWED BY CLEARING...AS THE FRONT MOVES N THROUGH THE AREA THIS AFTERNOON. EXPECT VFR AREA WIDE BY THIS EVENING IN THE WARM SECTOR. SHOWERS ASSOCIATED WITH A COLD FRONT APPROACHING FROM THE W WILL REACH THE OHIO RIVER AROUND 12Z THU. MVFR AND WORSE CONDITIONS SHOULD HOLD OFF UNTIL AFTER 12Z. LIGHT AND VARIABLE WINDS THIS MORNING WILL STRENGTHEN A BIT FROM THE S DURING THE DAY TODAY...AND MAY NOT DIMINISH MUCH TONIGHT. WINDS TONIGHT WILL ACTUALLY STRENGTHEN ON THE RIDGES...AS LIGHT W WINDS ALOFT THIS MORNING BACK TO SW BY WED EVENING AND BECOME STRONG THIS EVENING AND REMAIN STRONG OVERNIGHT. WIND SHEAR TOWARD THU MORNING COULD APPROACH LLWS CRITERIA OF 20KTS/200FT WITHIN 2KFT AGL. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING AND EXTENT OF THE MVFR CIGS THIS MORNING COULD VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 CRW CONSISTENCY M H H H H H H H H H H H HTS CONSISTENCY M H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L L L L L L L H H H H H PKB CONSISTENCY M M M M H H H H H H H H CKB CONSISTENCY H H M L H H H H H H H H AFTER 12Z THURSDAY... IFR POSSIBLE IN RAIN SHOWERS WITH COLD FRONT THURSDAY INTO THURSDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...JSH/TRM SHORT TERM...SL LONG TERM...30 AVIATION...TRM
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
941 AM CST WED DEC 14 2011 .UPDATE... ELONGATED TROF AXIS PERSISTS FROM THE CENTRAL PLAINS BACK INTO THE SOUTHWEST US WITH ONE SIGNIFICANT PIECE OF ENERGY EJECTING NORTHEAST THIS MORNING. THIS S/W WILL HELP PUSH A PACIFIC FRONT THROUGH THE REGION THIS AFTERNOON. REGIONAL RADAR IMAGERY ALREADY SHOWS A BROKEN LINE OF PRIMARILY SHOWERS DEVELOPING TO THE NORTHWEST OF THE CWA. THIS IS EXPECTED TO GRADUALLY FILL IN AND MOVE EAST THROUGH THE DAY AS THE FRONT GAINS MOMENTUM. ALL OF THE HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THAT A LINE OF CONVECTION WILL MOVE THROUGH NORTH TEXAS THROUGH THIS AFTERNOON ALONG THE FRONT...HOWEVER THERE IS SOME DISCREPANCY AS TO HOW INTENSE IT WILL BE. LATEST NAM IS MOST AGGRESSIVE WITH INSTABILITY AND STILL INDICATES AN AXIS OF 700-1000J/KG OF OF CAPE ACROSS NORTH TEXAS AND WEAKENS THE CAPPING AROUND 700MB. RUC SOUNDINGS ARE NOT SO QUICK TO ERODE THE CAPPING AND INDICATE THAT DEEP CONVECTION WILL BE HARD TO COME BY. GIVEN THE EXTENSIVE CLOUD COVER AND ONGOING DRIZZLE TEND TO THINK THE LESS AGGRESSIVE RUC MAY HAVE A BETTER HANDLE ON THINGS. WILL CONTINUE TO MENTION THUNDERSTORMS THROUGH THE AFTERNOON...BUT OVERALL SEVERE WEATHER THREAT MAY BE CONFINED TO A FEW ISOLATED CELLS. THIS IS ONE OF THOSE SITUATIONS THOUGH WHERE A LITTLE EXTRA HEATING OR SLIGHTLY MORE WEAKENING OF THE CAP COULD RESULT IN MORE WIDESPREAD SEVERE CONVECTION SO IT IS WORTH WATCHING THROUGH THE AFTERNOON. ONLY SOME MINOR TWEAKS TO POP/WEATHER WORDING THROUGH THE AFTERNOON OTHERWISE NO MAJOR CHANGES TO THE CURRENT FORECAST. DUNN && .AVIATION... .CONCERNS... MANY CHALLENGES WITH CIGS/VSBY AND TIMING OF SURFACE TROUGH AND ASSOCIATED TSRA/CB THIS AFTERNOON. COLD FRONT TIMING A LITTLE TRICKY THURSDAY MORNING. CURRENT REGIONAL RADAR AND AREA WX OBSERVATIONS INDICATE LIFT IS INCREASING ACROSS NORTHWEST TX/WRN OK THIS MORNING WITH SHRA/-RA BECOMING WIDESPREAD FROM KSPS TO KCDS/KOKC. GUSTY SE WINDS 13-23KTS ARE ASSISTING IN THE PRODUCTION OF SPOTTY -RA/-DZ AND IFR STRATUS. WHERE HEAVIER DZ OCCURS...CIGS ARE FALLING INTO LIFR CATEGORY BETWEEN 003-005 KFT. WILL HAVE A TEMPO GROUP FOR THIS POSSIBILITY THROUGH MID MORNING AT ALL TERMINALS. INCREASING LIFT THIS AFTERNOON WILL COMBINE WITH LOW LEVEL WARMING /GUSTY SOUTH WINDS TO LIFT CIGS BACK INTO THE MVFR...OR POSSIBLY A LOW VFR CATEGORY BY 21Z. BEST GUESS WINDOW FOR TSRA AT DFW TERMINALS WILL BE 20-22Z AND 22Z-00Z AT WACO. -SHRA/-RA LIKELY WILL LINGER THROUGH MID EVENING. WINDS GRADUALLY SHIFT SOUTHWEST AND DECREASE TO 5-10 KTS AFTER PASSAGE OF SURFACE TROUGH LATE THIS AFTERNOON...THEN BECOME NORTHWEST AROUND 10 KTS EARLY THURSDAY MORNING WITH THE COLD FRONT MOVING THROUGH THE AREA. 05/ && .PREV DISCUSSION... /ISSUED 344 AM CST WED DEC 14 2011/ MOIST ISENTROPIC ASCENT WILL CONTINUE TODAY AS THE LOW LEVEL JET REMAINS STRONG AND CONTINUES TO TRANSPORT RICH MOISTURE INTO THE REGION. SOME INSTABILITY WILL WORK INTO THE WESTERN COUNTIES THIS MORNING AND THEN SPREAD EASTWARD THIS AFTERNOON AND EVENING. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH HAIL AND DAMAGING WINDS DUE TO AN APPROACHING SHORTWAVE...A 90-100 KNOT JET ALOFT AND 400-1000 J/KG OF CAPE. BEST TIMING FOR SEVERE WILL BE MID/LATE AFTERNOON OVER THE WESTERN HALF AND THIS EVENING FOR THE EASTERN HALF. A COLD FRONT WILL SWING THROUGH NORTH TEXAS LATER TONIGHT AND BRING COOLER NORTHERLY WINDS BACK TO THE REGION. A STRONG SHORTWAVE WILL KICK OUT OF THE PERSISTENT SOUTHERN CALIFORNIA UPPER LOW AND PASS OVER THE REGION THURSDAY EVENING. HAVE HELD ONTO LOW POPS THURSDAY AND THURSDAY NIGHT AS MID LEVEL LIFT MOVES ACROSS THE REGION. AS THE SHORTWAVE MIGRATES EAST OF THE REGION...RAIN CHANCES WILL END FOR MOST OF THE CWA BUT LINGER OVER THE SOUTHERN COUNTIES THROUGH FRIDAY. THERE WILL BE A BRIEF LULL IN RAIN CHANCES ON SATURDAY...BUT THEY RETURN TO THE WESTERN COUNTIES SATURDAY NIGHT AS THE MAIN UPPER LOW OVER SOUTHERN CALIFORNIA BEGINS TO MOVE EAST. AS THE UPPER SYSTEM NEARS TEXAS... RAIN CHANCES WILL INCREASE WEST TO EAST SUNDAY THROUGH MONDAY...AND HAVE INCLUDED THUNDERSTORM POTENTIAL FOR MONDAY MORNING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION MONDAY EVENING. TEMPERATURES FOR THE MOST PART WILL BE SEASONAL WITH ABOVE NORMAL CONDITIONS AHEAD OF TONIGHT/S COLD FRONT AND MONDAY/S COLD FRONT. 75 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 50 58 39 53 / 100 50 30 40 10 WACO, TX 74 50 57 43 54 / 80 50 40 60 10 PARIS, TX 72 53 64 42 53 / 80 70 30 50 10 DENTON, TX 69 46 58 36 51 / 100 40 30 30 10 MCKINNEY, TX 69 49 60 40 52 / 100 50 30 40 10 DALLAS, TX 71 51 58 40 54 / 100 50 40 40 10 TERRELL, TX 70 53 61 42 55 / 90 60 40 50 10 CORSICANA, TX 72 55 59 45 55 / 70 60 40 60 10 TEMPLE, TX 73 53 58 43 56 / 60 50 50 60 20 MINERAL WELLS, TX 71 43 55 34 51 / 100 20 30 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DENVER CO
1045 AM MST WED DEC 14 2011 .UPDATE... && .SHORT TERM...NO CHANGES OF NOTES TO THE ZONES...MAY TWEAK SOME WINDS FOR TODAY IN THE GRIDS. WEAK SURGE CAME ACROSS PLAINS THIS MORNING BEHIND SYSTEM MOVING WELL TO OUR EAST BUT WIND DIRECTIONS QUITE TRICKY NEAR THE FRONT RANGE WITH THE NW FLOW MAINLY FARTHER OUT ON THE PLAINS AND IN AND NEAR THE FOOTHILLS RIGHT NOW. BUT ENOUGH SUN AND MIXING TO GEET MOST TEMPERATURES INTO THE 40S THIS AFTERNOON. A WEAK WAVE MOVING ACROSS WYOMING RIGHT NOW BUT THIS IS WEAKENING WITH TIME AND LOOKS LIKE THE MAIN THING WITH THIS COULD BE SOME INCREASE IN SNOW SHOWERS IN THE MOUNTAINS TONIGHT SO WILL ASSESS THIS. PERSISTENCE THOUGH WOULD SUGGEST NOT A LOT WITH THIS WAVE UNFORTUNATELY AND PLAINS LOOK DRY. .AVIATION...TRICKY PART IS WINDS. AT DIA QUITE UNCERTAIN ABOUT THEM EVER GOING NW AND INSTEAD BASED ON HRRR AND WRF SHORT RANGE MODEL RUNS BROUGHT A WEAKISH NORTHERLY TO NE SHIFT IN THIS AFTERNOON. THEN COMES AROUND TO SE THIS EVENING BEFORE DRAINAGE SETS IN. APPEARS TO BE GOOD CHANCE OF A DENVER CYCLONE THURSDAY AND PLAYED WINDS THAT WAY. BJC COULD HOWEVER SEE SOME W TO NW FLOW INCREASE ALTHOUGH FOR NOW STAYING NEAR THE FOOTHILLS SO TRICKY THERE AS WELL. && .PREV DISCUSSION... /ISSUED 318 AM MST WED DEC 14 2011/ SHORT TERM...UPPER TROUGH AXIS CURRENTLY OVER WESTERN COLORADO AS DEPICTED IN SATELLITE AND RADAR. SNOW IS INCREASING OVER THE HIGH COUNTRY AS UPPER FLOW TRANSITIONS FROM SOUTHWEST TO NORTHWEST AND LIFT INCREASES. NOT TOO MUCH MOISTURE LEFT WITH THIS SYSTEM THEN A SHORTWAVE CURRENTLY OVER IDAHO WILL MOVE SOUTHEAST TO BRING A LITTLE MORE SNOW THROUGH THE DAY AND TONIGHT. ALL TOGETHER THOUGH...ONLY A FEW INCHES AT MOST THROUGH THE DAY. TEMPERATURES TODAY WILL BE ABOUT 10 DEGREES LESS THAN YESTERDAY AS COLDER AIR SPREADS OVER COLORADO BEHIND THE UPPER TROUGH. WESTERLY SURFACE WINDS WILL ALSO BE INCREASING BEHIND THE TROUGH THROUGH THE DAY AS THE LOW PRESSURE MOVES EAST. WILL SEE GUSTY WINDS IN THE FOOTHILLS THIS AFTERNOON WITH SPEEDS OF 20 TO 35 MPH WITH GUSTS TO 45 MPH POSSIBLE. THE FOG OVER THE PLAINS CONTINUES TO PUSH SLIGHTLY EAST AS DRIER AIR MOVES IN FROM THE WEST. KEEPING IN THE SLIGHT CHANCE OF LIGHT SNOW OVER THE FAR EASTERN PLAINS AS THE AREA OF LIFT PASSES OVERHEAD THIS MORNING. AS THE SYSTEM PUSHES EAST AND CLOUDS CLEAR...SOME SUN AND THE MIXING FROM THE APPROACHING COLDER AIR FROM THE NORTH WILL ALLOW ANY INVERSIONS OVER THE PLAINS TO BREAK AND ALLOW TEMPERATURES TO WARM OVER YESTERDAYS READINGS. THE GUSTY WEST WINDS NEAR THE FOOTHILLS WILL LET TEMPERATURES WARM A LITTLE MORE THERE...ALREADY THIS MORNING THE NCAR MESA LAB HAS WARMED INTO THE UPPER 30S WITH WEST WINDS WHILE JUST A SHORT DISTANCE AWAY TO ERIE ITS IN THE MID TEENS. WEST TO NORTHWEST SURFACE WINDS ARE EXPECTED TO SPREAD OVER THE PLAINS TODAY WITH CLEARING SKIES. WILL LIKELY SEE COLDER MINIMUM TEMPERATURES TONIGHT WITH THE CLEAR SKIES AND COLDER AIRMASS FROM THE NORTH. LONG TERM...UPPER LEVEL RIDGE WILL BUILD OVER COLORADO ON THURSDAY AS NEXT UPPER LEVEL LOW DRIVES SOUTHWARD ALONG THE WEST COAST. THIS WILL RESULT IN MOSTLY SUNNY SKIES. HOWEVER...LACK OF DOWNSLOPE FLOW ALONG WITH REMAINING SNOW COVER SHOULD KEEP HIGH TEMPS A COUPLE DEGREES BELOW NORMAL. ON FRIDAY...A SHORT WAVE MOVING ACROSS THE NORTHERN PLAINS STATES WILL PUSH ANOTHER WEAK COLD FRONT ACROSS NORTHEAST COLORADO. THIS SHOULD DROP TEMPS A COUPLE DEGREES FROM THURSDAYS HIGHS. NO PRECIPITATION IS EXPECTED EVEN IN THE MOUNTAINS AS A GENERALLY DRY AND SUBSIDENT AIRMASS WILL PREVAIL IN BETWEEN THE NORTHERN PLAINS SHORT WAVE AND THE STRONGER UPPER LOW SPINNING NEAR THE COLORADO RIVER DELTA/NORTHERN BAJA. IN FACT...IT SHOULD BE ANOTHER MOSTLY SUNNY DAY. LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED SATURDAY INTO EARLY SUNDAY. HOWEVER...TEMPERATURES WILL TURN WARMER WITH SOME MODERATION IN THE AIRMASS. BY LATE SUNDAY AND MONDAY THE UPPER LOW OVER THE FAR SOUTHWEST IS EXPECTED TO GRADUALLY KICK EAST/NORTHEAST AS A WEAK UPSTREAM KICKER MOVES INTO THE PACIFIC NORTHWEST. THE CHANCE OF ANY PRECIPITATION AT THIS POINT LOOKS QUITE SLIM WITH THE MAIN TROUGH BEING TOO FAR SOUTH. THE NORTHERN SYSTEM WILL ALSO BE QUITE WEAK...SO ANY MENTION OF SNOW IN THE FORECAST WILL BE LIMITED TO THE MOUNTAINS FOR NOW. AVIATION...VFR CONDITIONS TO PREVAIL THROUGH THURSDAY MORNING. LOW CLOUDS AND FOG ARE EXPECTED TO REMAIN EAST OF THE DENVER AREA AIRPORTS. LIGHT DRAINAGE WINDS WILL CONTINUE EARLY THIS MORNING TRANSITIONING TO WEST AND NORTHWEST WINDS MIDMORNING...INCREASING AFTER 15Z AS DOWNSLOPE WINDS PREVAIL. CEILINGS TO REMAIN ABOVE 10000 FEET AGL THROUGH THE DAY. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SZOKE LONG TERM....99 AVIATION...SZOKE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
238 PM CST WED DEC 14 2011 .DISCUSSION... ISSUED 238 PM CST WED DEC 14 2011 SPRING-LIKE STORM SYSTEM BRINGING SHOWERS AND SCATTERED THUNDERSTORMS TO THE CENTRAL/NORTHERN CWA TODAY IN BROAD...WARM SOUTHWEST FLOW. HEAVIEST RAINS OF 1.5-2.5 INCHES HAVE FALLEN NORTH OF A BEARDSTOWN TO BLOOMINGTON LINE. MODERATE RAINFALL RATES AND UNFROZEN GROUND HAVE PRODUCED LITTLE IN THE WAY OF WATER PROBLEMS. UPPER LEVEL DYNAMICS HELPING DRIVE THIS ACTIVITY AS SFC LOW AND FRONT ANALYZED AT 19Z ACROSS EASTERN NEB/NRN KS. EVEN WITH THICK CLOUDS AND RAIN...EARLY AFTERNOON TEMPS WERE RUNNING 15-20 DEGREES ABOVE NORMAL. SHORT TERM FORECAST ISSUE IS ENDING OF RAIN WITH COLD FRONTAL PASSAGE LATE TONIGHT AND RETURN TO SEASONABLE TEMPS. BEYOND...NEXT MAJOR SYSTEM LOOKS TO IMPACT REGION EARLY NEXT WEEK. SHORT TERM...TONIGHT THROUGH THURSDAY UNSEASONABLY HIGH P/W VALUES AROUND 1.25 INCHES AND STRONG FORCING ALOFT WILL CONTINUE TO DRIVE MODERATE RAIN AND EMBEDDED THUNDERSTORMS THIS EVENING. LATEST HIGH RES NAM AND HRRR RUNS SHOW ROUNDS OF CONVECTION TRANSLATING EAST ACROSS THE CWA THROUGH LATE EVENING. PLENTY OF ELEVATED INSTABILITY FOR THUNDER...AND VERY STRONG LLJ OVERHEAD /1 KM AGL WINDS 50 KTS/ BUT DUE TO STRONG LOW LEVEL INVERSION DO NOT EXPECT ANY OF THIS TO MAKE IT DOWN TO THE SURFACE. MAIN BATCH OF RAIN ASSOCIATED WITH PRE-FRONTAL TROUGH LOOKS TO PUSH INTO INDIANA AFTER MIDNIGHT...WHEN THE ACTUAL COLD FRONT ENTERS THE NW CWA. EXPECT A LINE OF SCATTERED SHOWERS ALONG/AHEAD OF THE FRONT...WHICH WILL EXIT THE SE CWA AROUND 15Z THU. BRISK WEST WINDS GUSTING TO 20-25 MPH WILL MOVE IN BEHIND THE FRONT...BRINGING IN COOLER AND DRIER AIR. CLOUD FORECAST FOR THURSDAY IS PROBLEMATIC WITH DRY AIR ADVECTING IN...BUT FCST SOUNDINGS SHOW A SHALLOW LAYER OF MOISTURE TRAPPED BENEATH A SHARP SUBSIDENCE INVERSION AROUND 925 MB. THIS COMBINED WITH CYCLONIC FLOW ALOFT AND WEAK SUN ANGLE MAKES A LOW STRATUS DECK LOOK LIKELY TO HOLD AT LEAST INTO MID AFTERNOON. TEMPERATURES MAY HOLD STEADY FOR A FEW HOURS IN THE MORNING...THEN SLOWLY FALL THROUGH THE AFTERNOON WHEN STRONGER CAA KICKS IN. LONG TERM...FRIDAY THROUGH WEDNESDAY QUIET AND SEASONABLE WEATHER IS ON TAP FOR THE FRIDAY INTO SUNDAY PERIOD. ZONAL/WNW FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE WILL BE RESPONSIBLE FOR THE TRANQUIL CONDITIONS. AS THE HIGH SHIFTS OFF TO THE SOUTHEAST LATE IN THE WEEKEND SOUTHERLY FLOW DEVELOPS AHEAD OF THE NEXT SYSTEM IN THE SW. CURRENT INDICATIONS SHOW THIS EVENT MAY BE SIMILAR TO THE STORM THAT IS CURRENTLY IMPACTING THE AREA. THE 12Z ECMWF AND CANADIAN GEM ARE SIMILAR IN TRACKING A STRONG LOW FROM THE TX PANHANDLE REGION MONDAY MORNING...INTO THE LOWER GREAT LAKES BY TUESDAY EVENING. 12Z GFS IS MUCH SLOWER AND FARTHER SOUTH AND WAS NOT FOLLOWED FOR THIS FORECAST. EVENTUAL LOW TRACK WILL DETERMINE EXACT PRECIP TYPE AND AMOUNTS...BUT CURRENT SOLUTION WOULD POINT TO PRIMARILY ANOTHER MODERATE RAIN EVENT FOR THE CWA FOR SUNDAY NIGHT INTO TUESDAY. LATER MODEL RUNS WILL NEED TO BE MONITORED...AS ECMWF DIGS A NORTHERN STREAM WAVE INTO THE MIDWEST FOR A MORE PHASED SYSTEM AND POTENTIAL SNOW BAND ON THE NW SIDE OF THE STORM. AFTER A BRIEF SHOT OF COLDER AIR BEHIND THIS LOW...ZONAL FLOW LOOKS TO MODERATE TEMPS FOR MID WEEK. 25 && .AVIATION... ISSUED 1150 AM CST WED DEC 14 2011 CEILINGS BELOW 1K FT ALONG I-74 TAF SITES OF PIA...BMI AND CMI MAY LIFT FOR A TIME THIS AFTERNOON TO MVFR ESPECIALLY AT CMI WHILE MVFR CEILINGS EXPECTED AT SPI AND DEC WITH DEC CURRENTLY DOWN TO 1K FT BROKEN CEILING. CONTINUED RAIN SHOWERS ACROSS THE CENTRAL IL TERMINALS THIS AFTERNOON AND EVENING WITH ISOLATED THUNDERSTORMS POSSIBLE BUT TOO TOUGH TO PIN POINT DOWN EXACT LOCATION AND TIME. VISIBILITIES OF 1 TO 3 MILES AT PIA AND BMI WITH RAIN AND FOG COULD LIFT TO MVFR FOR A TIME THIS AFTERNOON. MEANWHILE CMI WILL HAVE MVFR VSBYS AND POSSIBLY VFR AT TIMES WHILE DEC AND SPI TO SEE MVFR VSBYS RETURN DURING THE AFTERNOON WITH RETURN OF MORE RAIN SHOWERS FROM THE SW. 1007 MB LOW PRESSURE OVER NORTHCENTRAL KS TO DEEPEN NE TO 1002 MB OVER EAST CENTRAL WI BY MIDNIGHT AND TO 992 MB OVER SW QUEBEC BY 18Z/NOON THU. THIS TO SWING A COLD FRONT SE THROUGH CENTRAL IL LATER TONIGHT...REACHING PIA BY 09Z AND CMI BY 12Z. SHOWERS END AFTER FRONTAL PASSAGE AS STRONG SOUTH WINDS WITH GUSTS INCREASING TO 23-28 KTS DURING THIS AFTERNOON...TURN W/NW BEHIND THE FRONT LATE TONIGHT AND THU MORNING. CONTINUE BROKEN TO OVERCAST CEILINGS OF 1-2K FT BEHIND THE COLD FRONT THU MORNING AS VFR VISBILITIES ARRIVE WITH FOG LIFTING. HUETTL && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
418 PM EST WED DEC 14 2011 .SHORT TERM... TONIGHT THROUGH THURSDAY NIGHT... KIWX RADAR DEPICTING BAND OF MOD/HVY RAIN ALONG/AHEAD OF WARM FRONT LIFTING NORTH THROUGH THE AREA THIS AFTERNOON. THIS IS IN ASSOCIATION WITH DEVELOPING SFC LOW IN CENTRAL PLAINS. WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS SHOWING LEAD SHORT WAVE EJECTING OUT OF FOUR CORNERS AND WILL COMBINE WITH COUPLED JET STRUCTURE FROM NORTHERN GREAT LAKES DOWN INTO THE CENTRAL PLAINS TO DEEPEN SFC LOW AND DRIVE IT INTO WESTERN GREAT LAKES THIS EVENING. THIS WILL PLACE THE FCST AREA IN ENHANCED MOIST SOUTHERLY FLOW IN THE WARM SECTOR AND SUPPORT ANOTHER ROUND OF PRECIPITATION TONIGHT. COLD FRONT WILL MOVE THROUGH THE AREA ON THURSDAY AND BRING AN END TO RAIN BY 18Z. SIGNIFICANT DRYING BEHIND THE FRONT ALONG WITH MARGINAL DELTA T WILL PROVIDE LITTLE SUPPORT FOR LES IN THE WAKE OF THIS SYSTEM SO FAVOR CURRENT GRIDS IN KEEPING JUST A MENTION OF FLURRIES ATTM. FIRST TWO PERIODS OF FCST WILL FEATURE NON-DIURNAL TEMP PATTERN AS WARM FRONT LIFTING NORTH OF THE AREA TONIGHT WILL KEEP TEMPS STEADY/SLOWLY RISING...THEN CAA BEHIND PASSAGE OF COLD FRONT THURSDAY WILL SEE HIGHS REACHED IN THE MORNING FOLLOWED BY FALLING TEMPS IN THE AFTERNOON. COOLER BUT SEASONABLE TEMPS THURSDAY NIGHT WITH LOWS IN THE MID-UPPER 20S. && .LONG TERM... FRIDAY THROUGH WEDNESDAY ACTIVE NORTHERN STREAM WILL INFLUENCE LOWER HEIGHTS INTO THE REGION THIS WEEKEND WITH COLDER/DRIER AIR PUSHING INTO THE GREAT LAKES...AS PERIPHERY DISTURBANCES ADVECT THROUGH THE FLOW. A SERIES OF THESE WEAK INFLUENCES MAY INFLUENCE ENOUGH LIFT AND COLUMN SATURATION TO SUPPORT LIGHT SNOW OR FLURRIES ACROSS THE NORTH...ALONG WITH A WEAK LAKE RESPONSE. OTHERWISE...MODELS AND ENSEMBLES CONTINUE TO SUPPORT THE EJECTION OF A SW CONUS DISTURBANCE INTO THE REGION BY EARLY NEXT WEEK...WITH SOME RATHER SIG DISCREPANCIES AMONG DETERMINISTIC SOLUTIONS. WILL STAY THE COURSE WITH PERSISTENCE...FAVORING THE WARMER ECMWF AND GEM. THIS WILL ESP BE TRUE IF FLOW PHASING IS REALIZED...WHICH IS CERTAINLY POSSIBLE GIVEN THE PATTERN. SMALL ADJUSTMENT MADE TO THE PREVIOUS FORECAST...GENERALLY TO POPS/WX. FRI-SUN...OVERALL DRY/SLIGHTLY DISTURBED FLOW WILL REMAIN IN THE GREAT LAKES REGION. CONTINUED TO OPT NOT TO INCLUDE A LAKE EFFECT SNOW SHOWER MENTION FRI-SAT FAR NW GIVEN MARGINAL SUPPORT FOR LAKE INDUCE CONVECTION...WITH ONLY A FLURRY MENTION ATTM...SPREAD OVER THE ENTIRE NORTH TO COVER THE POTENTIAL FOR LIGHT SNOW WITH ANY OF THE WEAK DISTURBANCES. PROFILES INDICATE SIG DRYING IN THE SFC TO H8 LAYER WITH MARGINAL DELTA T/S PRESENT. CANNOT RULE OUT A FEW FLURRIES OR LIGHT LAKE EFFECT SNOW SHOWERS IF COLDER PROFILES VERIFY...COUPLED WITH A WEAK NORTHERN STREAM DISTURBANCE PROGGED INTO THE REGION...WHICH COULD GENERATE ENOUGH INVERSION HEIGHT UNDULATION TO SUPPORT PERHAPS A FEW SNOW SHOWERS/FLURRIES IN SHORT FETCH WESTERLY FLOW. OTHERWISE...TEMPS ARE EXPECTED TO REMAIN AROUND NORMAL TO SLIGHTLY ABOVE IN THE PERIOD...WITH LAKE EFFECT CLOUDS ACROSS NORTHERN AREAS LINGERING THROUGH SAT. MON-WED...CHANCES FOR A DECENT STORM SYSTEM CONTINUE...AS AN ACTIVE NORTHERN STREAM IMPULSE LIKELY INTERACTS WITH ANOTHER SW CONUS UPPER LOW. ADVECTION TIMING/THERMAL FIELDS/AND HEIGHT FALL DEPTH INTO THE REGION IS STILL MUCH UNCERTAIN...BUT GIVEN THE GFS/S TENDENCY TOWARD PROGRESSIVE FLOW...LIKELY BIASING THE NAEFS SOLUTIONS...HAVE CONTINUED TO SIDE TOWARD THE MORE RELIABLE ECMWF. A TREND TO A DEEPER H5 SOLUTION WOULD CERTAINLY BE NEEDED...ESP IF WAVE PHASING RESULTS...WITH COUPLED JET DYNAMICS LIKELY SHIFTING THE SFC LOW TRACK NW OF THE FA...AS SEEN IN THE GEM. RETAINED A RAIN/SNOW MENTION IN MOST PERIODS...MAINLY TO COVER UNCERTAINTY...BUT IT CERTAINLY LOOKS LIKE RAIN WILL BE THE DOMINATE WEATHER TYPE IN THE PERIOD...ESP SE HALF. CONTINUE TO EXPECT MORE ADJUSTMENT IN THIS PERIOD. && .AVIATION.../18Z TAFS/ KIWX RADAR INDICATING BAND OF MODERATE TO HEAVY RAIN IMPACTING KSBN ATTM AND IS EXPECTED TO ARRIVE AT KFWA BETWEEN 19-20Z THIS AFTERNOON KEEPING IFR CONDITIONS OVER THE AREA THROUGH MUCH OF THE TAF PERIOD. LOW PRESSURE WILL TRACK UP INTO THE WESTERN GREAT LAKES THIS EVENING KEEPING GUSTY S/SW FLOW AND LLWS AT BOTH TAF SITES INTO THE EARLY MORNING HOURS THURSDAY. COLD FRONT WILL MOVE THROUGH THURSDAY MORNING AND BRING AN END TO THE RAIN BUT LOW LEVEL MOISTURE WILL KEEP IFR/MFVR CIGS OVER THE AREA THROUGH THE END OF THE TAF PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...GALE WATCH THROUGH THURSDAY EVENING FOR LMZ043-046. SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...LOGSDON LONG TERM...JC AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1143 AM EST WED DEC 14 2011 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... RAIN SHOWERS WILL IMPACT THE REGION THROUGH EARLY THURSDAY AS FIRST A WARM FRONT THEN A COLD FRONT PASS THROUGH THE OHIO VALLEY. IN THE WAKE OF THIS FRONT...HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH THE WEEKEND. A LOW PRESSURE SYSTEM MAY APPROACH THE AREA FROM THE SOUTHWEST EARLY NEXT WEEK. && .NEAR TERM /REST OF TODAY/... FORECAST CHALLENGES FOR THIS AFTERNOON INCLUDE TEMPERATURES AND HOW TO HANDLE POPS. A DECENT STRATUS LAYER HAS LINGERED ACROSS THE REGION HINDERING AN INCREASE IN TEMPERATURES...MAINLY ACROSS THE NORTHERN HALF. THEREFORE...DECREASED HIGHS 2-3 DEGREES ACROSS THIS AREA SINCE IT WILL ALSO BE THE FOCUS FOR ANY AFTERNOON SHOWERS WHICH WILL CONTINUE TO INHIBIT WARMING. TEMPERATURES ACROSS THE SOUTH APPEAR TO BE ON TRACK AND RISING AS EXPECTED SO DID NOT MESS WITH THE PREVIOUS FORECAST. SIGNIFICANTLY CUT POPS ACROSS THE CENTRAL PORTION OF THE FORECAST AREA AND COMPLETELY REMOVED ANY PRECIPITATION MENTION FOR THE SOUTH AND EAST BEFORE 21Z. THE LATEST RUC AND HRRR DATA DEPICT RAINFALL SHOULD REMAIN OUT OF THIS AREA FOR MOST OF THE NEAR TERM. ON THE OTHER HAND...CONTINUED LIKELY POPS ACROSS THE EXTREME NORTHWEST AS CURRENT RADAR TRENDS INDICATE THE MAIN PRECIPITATION SHIELD MOVING INTO THE NORTHWEST QUADRANT OF THE STATE. REGARDING THUNDER MENTION...WITHOUT ANY REAL INSTABILITY...LEFT ANY MENTION OUT OF THE GRIDS PRIOR TO 21Z. LEFT SLIGHT CHANCE WORDING IN THE NORTHWEST AS LATEST MODELS SOUNDINGS INDICATE SOME ELEVATED CONVECTION CANNOT BE COMPLETELY RULED OUT. LASTLY...DECREASED WINDS THROUGHOUT THE NEAR TERM. EVEN WITH A DECENT PRESSURE GRADIENT ACROSS THE AREA...OBSERVATIONS AND LATEST GUIDANCE INDICATE WINDS WILL BE MORE IN THE 10-15 KT RANGE THIS AFTERNOON AS COMPARED TO 15-20 KTS...OR HIGHER...AS INDICATED PREVIOUSLY. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... BREAK IN RAIN WILL BE SHORT LIVED AS THE AFFECTS OF THE APPROACHING EJECTING LOW AND SURFACE COLD FRONT BEGIN MOVING INTO THE NORTHWEST ZONES LATER THIS AFTERNOON AND THROUGH EVENING. MODELS REMAIN IN GOOD AGREEMENT WITH THIS FEATURE AND ARE ACTUALLY EVEN MORE PROGRESSIVE THAN PREVIOUS MODEL RUNS. 850 MB JET LOOKS EVEN STRONGER THIS RUN AROUND 60 KTS ACROSS CENTRAL INDIANA BY 06Z. LOOK FOR GUSTY WINDS AROUND 35 TO 40 MPH. WILL CONTINUE TO GO WITH 100% POPS...AND A CHANCE FOR THUNDERSTORMS TO ACCOUNT FOR THE ELEVATED INSTABILITY. WE ARE NOT IN A RISK FOR SEVERE WX. AS JUST MENTIONED...MODELS ARE MORE PROGRESSIVE WITH THE FRONT...BASICALLY CLEARING IT OF THE FORECAST ARE BY LATE THU MORN. THINK THIS MIGHT BE A LITTLE TOO FAST BASED ON PAST EVENTS...SO WENT WITH A SLIGHTLY SLOWER FROPA TIMING...REDUCING CHANCES FROM NW TO SE THROUGHOUT THE DAY THU. IT DOES APPEAR THAT THE BULK OF THE RAIN WILL BE OVER BY LATE THU MORNING FOR LOCATIONS NORTH OF I-70...WITH THE REST TO THE AREA TO FOLLOW SHORTLY THEREAFTER. TEMPERATURE FORECAST IS OF COURSE TRICKY...DEPENDING ON THE EXACT POSITION OF THE FRONT. SINCE THIS MODELS WERE MORE PROGRESSIVE THIS ROUND...DROPPED HIGHS ACROSS THE NW COUNTIES SLIGHTLY DURING THE DAY THU. HIGH PRESSURE BUILDS IN POST FROPA. LOOK FOR A RETURN TO COOLER AND DRY WX. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... FAIRLY WIDE DISCREPANCY IN GUIDANCE WITH HANDLING OF NEXT SIGNIFICANT WEATHER MAKER IN THE LONG TERM PERIOD...LATE IN THE WEEKEND INTO EARLY NEXT WEEK. HOWEVER...THERE REMAINS A GENERAL CONSENSUS IN FORMATION OF A LOW PRESSURE SYSTEM TO OUR WEST/SOUTHWEST LATE IN THE WEEKEND WHICH THEN PUSHES INTO THE REGION LATE SUNDAY NIGHT THROUGH TUESDAY NIGHT...AND ALLBLEND POPS REFLECT THIS WELL. GIVEN ANTICIPATED UPPER LEVEL PATTERN...TEMPS LOOK REASONABLE AS WELL. SEE NO REASON TO DEVIATE FROM ALLBLEND WITH SIGNIFICANT DISCREPANCIES IN GUIDANCE. && .AVIATION /UPDATE FOR 141530Z TAFS/... PREVIOUS DISCUSSION SUMMARIZES SITUATION WELL. AS IT INDICATES... FREQUENT UPDATING WILL BE NEEDED TODAY. THE PREVIOUS DISCUSSION FOLLOWS. POOR FLYING CONDITIONS THROUGH THE PERIOD AS AMPLE LOW LEVEL MOISTURE STREAMS ACROSS THE AREA AHEAD OF DEVELOPING LOW PRESSURE TO THE WEST. ALL SITES IFR IN ONE MANNER OR ANOTHER...MOST WITH BOTH CEILINGS AND VISIBILITIES. SHOULD SEE SOME IMPROVEMENT DURING THE COURSE OF THE DAY...MORE LIKELY AT IND/BMG AS IT APPEARS THESE SITES WILL BE A BIT NEARER THE EDGE OF THE WIDESPREAD IFR TO OUR WEST. THAT SAID...FLUCTUATIONS ARE LIKELY AND CONFIDENCE IS LOW IN THE EXACT DETAILS OF THE FORECAST...ALTHOUGH RELATIVELY HIGH IN SOME MANNER OF RESTRICTION THROUGH MUCH OF THE PERIOD. WILL BE A LULL IN PRECIP THROUGH MUCH OF TODAY WITH ADDITIONAL RAIN MOVING IN THIS EVENING. THUNDER CANNOT BE RULED OUT...BUT REMAINS LOW PROBABILITY AND WILL BE LEFT OUT AT THIS TIME. WINDS WILL INCREASE TO AROUND 15KT LATER TODAY AND REMAIN RELATIVELY STRONG THROUGHOUT. A FEW GUSTS CANNOT BE RULED OUT THIS AFTERNOON...BUT FEEL THAT CLOUD COVER WILL HELP TO SUPPRESS THIS SOMEWHAT. GUSTS WOULD ONLY BE TO AROUND 20-25KT. LATER TONIGHT...A STRONG LOW LEVEL JET /50-60KT/ WILL ACCOMPANY THE COLD FRONT AS IT APPROACHES. WILL INCLUDE LOW LEVEL WIND SHEAR AS MOMENTUM TRANSFER PROGS INDICATE LITTLE GUSTINESS OVERNIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SMF NEAR TERM...HOMANN/CP SHORT TERM...SMF LONG TERM....NIELD AVIATION...JK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
319 PM CST WED DEC 14 2011 .SYNOPSIS... 12Z UA ANALYSIS HAD AN 850MB WARM FRONT FROM SOUTH DAKOTA INTO SOUTHERN WISCONSIN. A LLJ RAN FROM THE WESTERN GREAT LAKES TO NORTH TEXAS WITH THE STRONG CORE OF 50-55 KNOTS FROM EASTERN KANSAS INTO NORTH TEXAS. A STRONG MOISTURE FEED RAN FROM THE GULF COAST INTO THE WESTERN GREAT LAKES. RADAR TRENDS SHOW THE CONVECTION AND THUNDERSTORMS HAVE SHIFTED INTO EASTERN ILLINOIS WITH PRECIPITATION INTENSITY DECREASING ACROSS IOWA AND MISSOURI. 18Z SFC ANALYSIS HAD A WEAK LOW NEAR KLNK WITH A WARM FRONT ALONG THE IA/MO BORDER INTO CENTRAL ILLINOIS. A COLD FRONT RAN FROM THE LOW BACK INTO SOUTHEAST COLORADO. DEW POINTS SOUTH OF THE WARM FRONT WERE IN THE 50S AND 60S. && .SHORT TERM...TONIGHT AND THURSDAY... THE RUC HAS BEEN DOING A REASONABLE JOB OF HANDLING THE IMMEDIATE SHORT TERM AND THE TRENDS OF THE RUC WERE FOLLOWED FOR INPUT TONIGHT. THE LIFT TOOL INDICATES THE THREAT OF THUNDER IS NOW OVER WITH THE PASSAGE OF A STRONG VORT MAX. OVERALL PRECIPITATION INTENSITY WILL NOW BE LIGHT DURING THE EVENING HOURS WITH EVERYTHING TRANSITIONING TO MORE DRIZZLE WITH TIME. THUS DRIZZLE WITH SOME RAIN WILL BE SEEN DURING THE EVENING HOURS ALONG WITH PATCHY FOG. AFTER MIDNIGHT... CONDENSATION PRESSURE DEFICITS SLOWLY RISE IN THE WEST WITH THE BETTER FORCING SHIFTING EAST OF THE MISSISSIPPI. THE RUC DOES SHOW ANOTHER ROUND OF FORCING ARRIVING AROUND MIDNIGHT IN THE WESTERN CWFA. THUS WILL CONTINUE THE DRIZZLE WITH OVERALL LOWER CHANCES OF RAIN. PATCHY FOG WILL STILL BE AN ISSUE AFTER MIDNIGHT. THE OVERALL DENSE FOG IS PATCHY IN NATURE AND GENERALLY CONFINED TO THE HWY 20 CORRIDOR. THE MORE WIDESPREAD AND LIKELY DENSE FOG SHOULD BE SEEN ACROSS WISCONSIN AND MINNESOTA WHERE THE SFC LOW TRACKS. THE COLD FRONT WILL MOVE THROUGH THE CWFA AFTER MIDNIGHT. WINDS SHOULD REMAIN UP WHICH WILL KEEP THE FOG FROM GETTING TOO DENSE AS THE OVERALL ATMOSPHERIC COLUMN COOLS. LOW TEMPERATURES SHOULD OCCUR BETWEEN 7 AND 9 AM THURSDAY MORNING. THURSDAY...THERE MAY OR MAY NOT BE SOME LINGERING DRIZZLE ACROSS THE EASTERN CWFA EARLY IN THE MORNING. CONDENSATION PRESSURE DEFICITS CONTINUE TO RISE AND NO FORCING IS PRESENT. HOWEVER...FORECAST SOUNDINGS DO SHOW CONSIDERABLE DRYING ABOVE THE LOW CLOUDS SO SOME DRIZZLE MAY BE POSSIBLE. CLEARING WILL BE SLOW TO OCCUR DURING THE MORNING. AS HIGH PRESSURE BEGINS BUILDING IN BY MID DAY A GENERAL CLEARING OF SKIES SHOULD BE SEEN FROM WEST TO EAST DURING THE AFTERNOON. MAX TEMPERATURES WILL OCCUR BETWEEN 7 AND 9 AM THURSDAY MORNING WITH TEMPERATURES SLOWLY FALLING THROUGH THE DAY. ..08.. .LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...THE LONG TERM BEGINS WITH A BRIEF COOL DOWN IN THE WAKE OF OUR CURRENT STORM...THEN AFTER ABOUT 48 HOURS OF NORTHWEST FLOW...WE BEGIN TO TREND TOWARD ANOTHER POTENTIAL SIGNIFICANT STORM SYSTEM FOR SUNDAY NIGHT THROUGH TUESDAY. MOISTURE WILL BE STARVED...BUT SOME POSSIBLE FLURRIES OR BRIEF LIGHT SNOW COULD OCCUR SATURDAY AFTERNOON IN THE FAR NORTH AS SHEARED OUT SHORT WAVE ARRIVES FROM THE NORTHWEST. THIS LOOKS TO MAIN PRODUCE MID CLOUDS DURING THE AFTERNOON AND EVENING HOURS SATURDAY. TEMPERATURES WILL BE COOL...BUT NOT COLD. WITH LOWS IN THE LOWER TO MID 20S...AND HIGHS GENERALLY IN THE LOWER TO UPPER 30S. SUNDAY...THERE BEGINS TO BE ANOTHER CHANGE TOWARD AN ACTIVE STORM SYSTEM. THERE ARE MAJOR DIFFERENCES IN THE POSITION OF A NORTHWEST FLOW WAVE THAT MAKES LANDFALL ON EITHER THE SOUTHWEST CANADIAN COAST/BRITISH COLUMBIA...OR NORTHWESTERN CONUS. THIS SMALL DIFFERENCE IN MODELS GREATLY INFLUENCED THE AMOUNT OF PHASING OF THE UPPER LOW WHICH SHOULD BE CUT OFF IN THE SOUTHWEST CONUS AT THAT TIME. THE UKMET...GEM...AND ECMWF CONTINUE TO SHOW THE NORTHWEST FLOW WAVE HITTING THE WA/OR COASTLINE THEN DRAWING THE CUT OFF LOW NORTHEAST SUNDAY NIGHT. THE GFS MAKES A MORE NORTHERLY ENTRY INTO CENTRAL BRITISH COLUMBIA WITH THE NORTHWESTERN SHORT WAVE...THUS...IT IS DELAYED BY 24 HOURS ON PHASING WITH THE LOW IN THE SOUTHWEST...AND LESS SO AT THAT. THUS...FOR THAT REASON ALONE...THE GFS REMAINS FAR SOUTH OF OTHER GLOBAL MODELS...AS WELL AS SLOWER. THE CURRENT STORM OVERHEAD WAS ALSO FORECAST BY THE GFS TO BE FARTHER SOUTH WHEN IT WAS OUT IN THIS DAY 6 PERIOD FOR SIMILAR REASONS...AND THEREFORE WHEN COMBINED WITH THE FACT THAT THERE IS LITTLE OR NO SNOW COVER IN THE MIDWEST AND THERE IS NO ARCTIC AIR IN PLACE TO KEEP A SYSTEM SOUTH...I BELIEVE IN A MORE PHASED NORTHERLY SOLUTION. THIS POTENTIAL STORM LOOKS TO HAVE ANOTHER OPEN GULF...AND MODEST TO STRONG UPPER FORCING. THUS...SHOULD IT OCCUR...ANOTHER ROUND OF MODERATE RAIN IS LIKELY. SNOW MAY OCCUR ON THE BACKSIDE PENDING THE SPEED OF THE SYSTEM AND ABILITY TO DYNAMICALLY COOL THE ATMOSPHERE. THERE IS LITTLE CONFIDENCE IN THAT PROCESS AT THIS TIME...BUT ENOUGH TO WARRANT INCLUDING A RAIN OR SNOW FORECAST FOR THE NORTHWEST HALF MONDAY NIGHT. TUESDAY MAY SEE SNOW...BUT THAT WILL DEPEND GREATLY ON THIS SYSTEM REMAINING CLOSED AT MID LEVELS. WEDNESDAY OF NEXT WEEK APPEARS DRY AND SEASONALLY COOL. ..ERVIN.. && .AVIATION... IFR TO LIFR CONDITIONS WILL CONTINUE THROUGH 12Z/15. THE PASSAGE OF A SHORTWAVE ALOFT HAS ENDED THE TS THREAT FOR KMLI/KBRL. WINDS SHOULD REMAIN UP TO PREVENT VSBYS FROM DROPPING BLO 3SM BUT BRIEF INCURSIONS BLO 3SM WILL BE POSSIBLE. OVERALL CONDITIONS WILL IMPROVE TO MVFR AFT 12Z/15 WITH CONDITIONS IMPROVING TO VFR AFT 18Z/15. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
506 PM EST WED DEC 14 2011 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH OF THE AREA THIS EVENING, WITH A BREAK IN PRECIPITATION EXPECTED EARLY TONIGHT. SHOWERS WILL BE MORE PERSISTENT THURSDAY WHEN A COLD FRONT CROSSES THE REGION. IN THE WAKE OF THE FRONT, SNOW SHOWERS WILL BE POSSIBLE EARLY FRIDAY ALONG THE I-80 CORRIDOR AND EASTERN RIDGES. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST RUC MID-LEVEL ANALYSIS INDICATES WEAK RIDGING MOVING ACROSS THE UPPER OHIO VALLEY. AT THE SURFACE, A 1006MB LOW IS CENTERED ACROSS THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING ACROSS THE MISSOURI AND LOWER OHIO VALLEYS. WELL UPSTREAM, A COLD FRONT EXTENDS SOUTH OF THE LOW INTO THE SOUTHERN PLAINS. AHEAD OF THE WARM FRONT, LIFT FROM OVERRUNNING IS ALLOWING FOR SCATTERED SHOWERS TO PUSH NORTHEAST OF THE AREA. A LAYER OF 850-500MB DRY AIR IN THE WARM SECTOR IS ALLOWING FOR CLEARING ACROSS PORTIONS OF EASTERN OHIO. TONIGHT...THE WARM FRONT WILL LIFT NORTH OF THE AREA. WITH LIFT FROM OVERRUNNING PUSHING NORTH OF THE AREA, EXPECT MOST OF THE FORECAST AREA TO BE DRY FROM 00Z THROUGH 06Z. AFTER 06Z, NAM12 AND WRF-NMM SUPPORT DEEPER MOISTURE ASSOCIATED AHEAD OF THE COLD FRONT IN ILLINOIS BEGINNING TO PUSH INTO EASTERN OHIO. THUS, THIS WILL ALLOW FOR AN AREA OF MORE PERSISTENT SHOWERS TO BEGIN TO SHIFT INTO THE AREA. CHC POPS IN OHIO WILL INCREASE TO CATEGORICAL POPS ACROSS WESTERN PA AND EASTERN OHIO BY DAWN ON THURSDAY. STRONG WARM AIR ADVECTION OVERNIGHT WILL ALLOW FOR NEAR STEADY TEMPS INITIALLY THAT WILL BEGIN TO INCREASE DURING THE PRE-DAWN HOURS. TEMPS OVERNIGHT WILL RANGE FROM THE MID 40S ACROSS THE EASTERN RIDGES TO THE LOWER 50S IN EASTERN OHIO. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... GFS/NAM/CANADIAN ARE IN REASONABLE AGREEMENT IN THE TIMING AND QPF WITH THE COLD FRONT AS IT PUSHES ACROSS THE OHIO VALLEY AND INTO THE AREA BY THURSDAY EVENING. CATEGORICAL POPS ARE FORECAST AHEAD OF THE FRONT WITH AROUND A HALF OF AN INCH OF RAIN EXPECTED ON THURSDAY. WARM AIR ADVECTION WILL BE ONGOING IN A SOUTHWESTERLY LOW-LEVEL FLOW IN THE WARM SECTOR. FORCING ALONG AND AHEAD OF THE FRONT ALONG WITH WEAK INSTABILITY AND STRONG SHEAR MAY BE JUST ENOUGH FOR A FEW THUNDERSTORMS EARLY THURSDAY AFTERNOON IN EASTERN OHIO. THUS, HAVE INCLUDED A SCHC FOR THUNDER THERE. IN ADDITION, A TIGHTENING PRESSURE GRADIENT AHEAD OF THE FRONTAL TROUGH WILL ALLOW FOR WIND GUSTS OF UP TO 25 TO 30 MPH THURSDAY AFTERNOON. MAV/MET GUIDANCE SEEM TO BE RESOLVING WARM AIR ADVECTION FAIRLY WELL AHEAD OF THE FRONT, SO FORECAST IS A MOS BLEND. THIS WILL ALLOW HIGHS ON THURSDAY TO BE 15-20 DEGREES ABOVE NORMAL. LOCATIONS IN NORTH-CENTRAL WV AND PORTIONS OF EASTERN OHIO HAVE A GOOD SHOT OF HITTING 60 TOMORROW. THURSDAY NIGHT...THE COLD FRONT IS PROGGED TO PUSH EAST OF PITTSBURGH AFTER 00Z FRIDAY WITH PRECIPITATION QUICKLY CUTTING OFF IN THE WAKE OF THE FRONT. WINDS WILL SHIFT TO NORTHWESTERLY BEHIND THE FRONT WITH COLD AIR ADVECTION ENSUING ACROSS LAKE ERIE. THE TEMP DIFFERENTIAL BETWEEN 850 TEMPS AND LAKE ERIE SHOULD BE ENOUGH TO INSTIGATE SOME LAKE EFFECT SNOW SHOWERS FOR THE I-80 CORRIDOR BY THE PRE-DAWN HOURS FRIDAY AND UPSLOPING SNOW SHOWERS BY DAWN FOR THE EASTERN RIDGES. COLD AIR ADVECTION WILL ALLOW FOR LOW TEMPS TO DROP OFF SHARPLY OVERNIGHT WITH LOWS IN THE LOWER 30S ACROSS MUCH OF THE AREA. FRIDAY...HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST WITH A COOL NORTHWESTERLY FLOW OFF THE GREAT LAKES CONTINUING. SNOW SHOWERS FOR THE I-80 CORRIDOR AND EASTERN RIDGES WILL DIMINISH BY THE AFTERNOON AS 850 TEMPS WARM AND WIND COMPONENT BECOMES MORE WESTERLY. ACCUMULATIONS WILL BE LIGHT, GENERALLY LESS THAN AN INCH WITH THE SNOW SHOWERS BEHIND THE FRONT. THE NORTHWESTERLY FLOW WILL ALSO SERVE TO KEEP THE AREA CLOUDY ON FRIDAY. WITH THE ARCTIC AIR MASS WORKING INTO THE AREA, TEMPERATURES WILL BE SLOW TO RECOVER THROUGHOUT THE DAY. HIGHS WILL RANGE FROM THE MID 30S ACROSS THE EASTERN RIDGES AND I-80 CORRIDOR TO THE LOWER 40S NORTH-CENTRAL WV. FRIDAY NIGHT AND SATURDAY...HIGH PRESSURE WILL ALLOW FOR MOSTLY DRY WEATHER FRIDAY NIGHT AND MOST OF THE DAY SATURDAY. LATE IN THE DAY, A SHORT WAVE TROUGH WILL BEGIN TO DIVE FROM THE GREAT LAKES SOUTHEASTWARD INTO THE AREA. THIS WILL RETURN THE CHANCE OF SNOW SHOWERS, ESPECIALLY NORTH OF PITTSBURGH, BY THE EVENING. TEMPERATURES WILL BE NEAR NORMAL SEASONAL VALUES. && .LONG TERM /SATURDAY NIGHT NIGHT THROUGH WEDNESDAY/... STILL VARYING MODEL SOLUTIONS THIS PERIOD REGARDING HOW MUCH ENERGY THE NORTHERN BRANCH OF THE UPPER LEVEL JET, COMING EAST FROM SOUTHERN CANADA, INPUTS INTO THE SOUTHERN JET STREAM BRANCH EMANATING FROM CALIFORNIA. DEFERRING TO HPC OPINION, FAVORED NAEFS SOLUTION OVER ECENS MODEL OUTPUT, WHICH SHOWED THE NORTHERN BRANCH HAVING GREATER INFLUENCE. THE EFFECT THIS HAS ON THE UPPER OHIO VALLEY WILL BE INITIALLY A COLDER AIRFLOW ACROSS THE GREAT LAKES, WHICH WILL SUBSEQUENTLY PROVIDE A LARGER COVERAGE OF LAKE ENHANCED CLOUDS AND LIGHT SNOW SHOWERS SUNDAY. IT ALSO MEANS A SLOWER-MOVING AND MORE DEVELOPED LOW PRESSURE SYSTEM COMING NORTHEAST FROM TEXAS EARLY NEXT WEEK. PER GFS MOS AND NAEFS MEDIAN VALUES, DAYTIME TEMPERATURES WILL BE NEAR SEASONABLE VALUES. ASSOCIATED CLOUDS CAN CAUSE NIGHTTIME TEMPERATURES TO BE WARMER THAN NORMAL, BUT NO WARMER THAN FREEZING FOR MOST LOCATIONS. SO HAVE FORECASTED MIXED PRECIPITATION LATE MONDAY INTO WEDNESDAY. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... PER RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED WITH RECENT HRRR, GFS LAMP AND NAM MODEL OUTPUT, EXPECT POST-WARM FRONTAL BAND OF IFR STRATUS TO BEGIN TO DISSIPATE THIS EVENING. THIS SCENARIO IS TYPICALLY NOT FAVORED FROM A DIURNAL CLIMATOLOGICAL VIEWPOINT. HOWEVER THERE APPEARS TO INCREASING LOW LEVEL DRYING IN THE WARM SECTOR THAT CONDITIONS IMPROVE TO AT LEAST MVFR. NAM MODEL PROFILES CONTINUE TO SHOW A LOW LEVEL JET, WITH SOUTHWEST WINDS NEAR 40KT AT 2KFT AGL, DEVELOPING AFTER 03Z. HENCE HAVE ADDED LOW LEVEL WIND SHEAR /LLWS/ TO ALL SITES 03Z-10Z. NAM MODEL PROFILES THEN SHOW PASSAGE OF A COLD FRONTAL BAND OF MODERATE SHOWERS LATE TONIGHT INTO MIDDAY THURSDAY, THAT SHOULD LOWER FLIGHT CONDITIONS BACK INTO THE IFR RANGE. THE COLD FRONTAL SHOWER BAND WILL PROVIDE SUFFICIENT VERTICAL MIXING TO COUPLE SOME FASTER WINDS TO THE SURFACE AND SO END THE LLWS THREAT. NEAR THE RIDGES, SURFACE SOUTHERLY WINDS CAN GUST TO 20-25 KTS. POST COLD FRONTAL VERTICAL MIXING CAN INDUCE SOUTHWEST WIND GUSTS TO 25-30 KTS FOR ALL SITES THROUGH THURSDAY AFTERNOON. AS SHOWER INTENSITY DECREASES, THE VERTICAL MIXING SHOULD IMPROVE FLIGHT CONDITIONS TO MVFR AS THE DAY WEARS ON. OUTLOOK... THURSDAY NIGHT THROUGH MONDAY... FOR THURSDAY NIGHT, FORESEE POSSIBLE LINGERING COLD POOL MVFR STRATOCUMULUS AREAWIDE. FOR FRIDAY INTO SUNDAY, LINGERING MVFR STRATOCUMULUS WILL BE POSSIBLE MAINLY NORTH AND MOUNTAINS. FOR MONDAY, INCOMING WARM FRONTAL SHOWERS MAY PRODUCE RESTRICTIONS LATE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
118 PM EST WED DEC 14 2011 .SYNOPSIS... A WARM FRONT WILL LIFT THROUGH THE UPPER OHIO VALLEY THIS AFTERNOON, BRINGING SHOWERS TO THE AREA. SHOWERS WILL BE MORE PERSISTENT THURSDAY WHEN A COLD FRONT CROSSES THE REGION. IN THE WAKE OF THE FRONT, SNOW SHOWERS WILL BE POSSIBLE EARLY FRIDAY ALONG THE I-80 CORRIDOR AND EASTERN RIDGES. && .NEAR TERM /THROUGH TONIGHT/... 18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT FOR THE LATEST RADAR TRENDS AS OVERRUNNING PRECIP HAS DECREASED SIGNIFICANTLY IN COVERAGE. THE LATEST RUC MID-LEVEL ANALYSIS INDICATES WEAK RIDGING MOVING ACROSS THE UPPER OHIO VALLEY. AT THE SURFACE, A 1006MB LOW IS CENTERED ACROSS THE CENTRAL PLAINS WITH A WARM FRONT EXTENDING ACROSS THE MISSOURI AND LOWER OHIO VALLEYS. WELL UPSTREAM, A COLD FRONT EXTENDS SOUTH OF THE FEATURE ACROSS THE SOUTHERN PLAINS. AHEAD OF THE WARM FRONT, LIFT FROM OVERRUNNING IS ALLOWING FOR SCATTERED SHOWERS TO PUSH ACROSS THE AREA. A LAYER OF 850-500MB DRY AIR IN THE WARM SECTOR IS ALLOWING FOR CLEARING ACROSS SOUTHERN WEST VIRGINIA. THIS AFTERNOON...THE WARM FRONT WILL CONTINUE TO PUSH NORTHWARD CLOSER TO THE AREA WITH THE BEST LIFT WILL SHIFTING NORTH OF THE AREA. THUS, SHOWERS WILL DECREASE IN COVERAGE ACROSS THE AREA AND COME TO AN END SOUTH OF PITTSBURGH. SOME CLOUD BREAKS ARE EXPECTED SOUTH OF PITTSBURGH AS THE LAYER OF DRY AIR MOVES INTO THE AREA ALONG WITH THE WARM SECTOR. HIGHS WILL BE AROUND 10 DEGREES ABOVE NORMAL, RANGING FROM THE MID 40S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES TO THE LOWER 50S IN NORTH-CENTRAL WV AND EASTERN OHIO. TONIGHT...THE WARM FRONT WILL LIFT NORTH OF THE AREA. WITH LIFT FROM OVERRUNNING PUSHING NORTH OF THE AREA, EXPECT MOST OF THE FORECAST AREA TO BE DRY FROM 00Z THROUGH 06Z. AFTER 06Z, NAM12 AND WRF-NMM SUPPORT DEEPER MOISTURE ASSOCIATED AHEAD OF THE COLD FRONT IN ILLINOIS BEGINNING TO PUSH INTO EASTERN OHIO. THUS, THIS WILL ALLOW FOR AN AREA OF MORE PERSISTENT SHOWERS TO BEGIN TO SHIFT INTO THE AREA. CHC POPS IN OHIO WILL INCREASE TO CATEGORICAL POPS ACROSS WESTERN PA AND EASTERN OHIO BY DAWN ON THURSDAY. STRONG WARM AIR ADVECTION OVERNIGHT WILL ALLOW FOR NEAR STEADY TEMPS INITIALLY AND BEGINNING TO INCREASE DURING THE PRE-DAWN HOURS. THUS, TEMPS OVERNIGHT WILL RANGE FROM THE MID 40S ACROSS THE EASTERN RIDGES TO THE LOWER 50S IN EASTERN OHIO. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... THE MODELS ARE IN REASONABLE AGREEMENT THAT AN AREA OF DRY AIR WILL PUSH INTO THE AREA WITH WAA IN THE WARM SECTOR AS A COLD FRONT APPROACHES FROM THE WEST TONIGHT. WITH A BREAK IN PRECIP EXPECTED, DRY OR SCHC POPS ARE FORECAST ACROSS MOST OF THE AREA. FORCING FROM A COLD FRONT WILL SUPPORT PRECIP FOR THE AREA WITH CATEGORICAL POPS REACHING THE PITTSBURGH METRO BY DAWN ON THURSDAY. MORE PERSISTENT RAINFALL IS EXPECTED THROUGH MUCH OF THE DAY THURSDAY AS THE FRONT SLOWLY PROGRESSES ACROSS THE OHIO VALLEY. ONGOING WARM AIR ADVECTION WILL ALLOW FOR TEMPS TO BE 15 TO 20 DEGREES ABOVE NORMAL. THE FRONT WILL CROSS THE AREA THURSDAY NIGHT WITH A LOW-LEVEL NORTHWESTERLY FLOW AND HIGH PRESSURE BUILDING IN FROM THE WEST IN ITS WAKE. 850MB AND LAKE ERIE TEMP DIFFERENTIAL WILL BE SUFFICIENT TO SUPPORT A FEW LAKE EFFECT SNOW SHOWERS IN THE WAKE OF THIS SYSTEM ON FRIDAY. TEMPS ON FRIDAY WILL BE SLIGHTLY BELOW NORMAL UNDER CAA. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... EXPECT A MAINLY DRY WEEKEND WITH NEAR TO BELOW NORMAL TEMPS. STILL A GOOD DEAL OF UNCERTAINTY FOR EARLY NEXT WEEK. DIFFERENCES IN MEDIUM RANGE MODELS WILL PROMOTE VERY LITTLE CHANGES TO LONG TERM FORECAST. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... PER RECENT RADAR, SATELLITE, AND SURFACE DATA, COUPLED WITH RECENT HRRR, GFS LAMP AND NAM MODEL OUTPUT, EXPECT POST-WARM FRONTAL BAND OF IFR STRATUS AND DRIZZLE TO SPREAD NORTHEASTWARD THROUGH MUCH OF THE UPPER OHIO VALLEY THIS AFTERNOON. HRRR FLIGHT RULE FORECASTS AND NAM MODEL PROFILES, IN PARTICULAR, SHOW THE IFR CONDITIONS CAN LINGER INTO EVENING. ITS POSSIBLE WITH LOWLEVEL SOUTHEAST WINDS THAT LOCATIONS, SUCH AS KLBE, MAY DETERIORATE TO MAINLY JUST MVFR CONDITIONS DUE TO DOWNSLOPING EFFECTS. ALTHOUGH NOT FAVORED FROM A DIURNAL CLIMATOLOGICAL VIEWPOINT, THERE MAY BE SUFFICIENT LOW LEVEL DRYING IN THE WARM SECTOR THAT CONDITIONS IMPROVE TO MVFR. NAM MODEL PROFILES CONTINUE TO SHOW A LOW LEVEL JET, WITH SOUTHWEST WINDS NEAR 40KT AT 2KFT AGL, DEVELOPING AFTER 03Z. HENCE HAVE ADDED LOW LEVEL WIND SHEAR /LLWS/ TO ALL SITES 03Z-10Z. NAM MODEL PROFILES THEN SHOW PASSAGE OF A COLD FRONTAL BAND OF MODERATE SHOWERS THAT SHOULD LOWER FLIGHT CONDITIONS INTO THE IFR RANGE. THE COLD FRONTAL SHOWER BAND WILL PROVIDE SUFFICIENT VERTICAL MIXING TO COUPLE SOME FASTER WINDS TO THE SURFACE AND SO END THE LLWS THREAT. NEAR THE RIDGES, SURFACE SOUTHERLY WINDS CAN GUST TO 20-25 KTS. POST COLD FRONTAL VERTICAL MIXING CAN INDUCE SOUTHWEST WIND GUSTS TO 25-30 KTS FOR ALL SITES THROUGH THURSDAY AFTERNOON. AS SHOWERS INTENSITY DECREASES, THIS VERTICAL MIXING SHOULD THEN IMPROVE FLIGHT CONDITIONS TO MVFR. OUTLOOK... THURSDAY NIGHT THROUGH SUNDAY... THURSDAY NIGHT AND FRIDAY, FORESEE POSSIBLE LINGERING COLD POOL MVFR STRATOCUMULUS AREAWIDE. SATURDAY AND SUNDAY, LINGERING MVFR STRATOCUMULUS POSSIBLE MAINLY NORTH AND MOUNTAINS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1235 PM CST WED DEC 14 2011 .UPDATE... 18Z AVIATION DISCUSSION ADDED BELOW. && .DISCUSSION... A BIT OF A TRICKY FORECAST THIS MORNING WITH THE FIRST WAVE MOVING THROUGH EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN. RAIN AND SNOW MIXED OCCURRING OVER PARTS OF CENTRAL MINNESOTA AND WESTERN WISCONSIN. THE LATEST RUC AND VSREF PICKING UP ON THE LOW LEVEL THICKNESS FIELDS AND MARGINAL 850 MB TEMPS AND IT COULD BE ALL SNOW FOR A TIME EARLY. NOT MENTIONING MUCH ACCUMULATION AT THIS POINT /LESS THAN AN INCH/ WITH MUCH OF THE FORCING MOVING OUT. OTHERWISE WE WILL BE LEFT WITH MOST OF THE REMAINDER OF THE MORNING WITH NOT REAL WIDESPREAD PRECIP...MOSTLY DRIZZLE. FORTUNATELY...TEMPS MAINLY ABOVE 32 OR JUST AT 32 WHERE SOME SNOW MOST ROAD TEMPS ON THE ARE NOT SUGGESTING A MAJOR THREAT FOR ICE. MAY STILL INCLUDE A MENTION OF FREEZING DRIZZLE IN CENTRAL MN. THE NAM AND GFS AND ARE GENERALLY IN LINE WITH BRINGING THE SOUTHERN ROCKIES VORT NORTHEAST TOWARD IOWA WITH SIG FORCING BRUSHING SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN DURING THE AFTERNOON AND EVENING. THE TEMP STRUCTURE IS STILL INITIALLY TOO WARM FOR MUCH SNOW BUT COOLING DOES TAKE PLACE AS THE 500 MB HEIGHT FALLS TRACK ACROSS NORTHEAST IOWA. HAVE INDICATED NEAR AN INCH OF SNOW FOR PARTS OF EAST CENTRAL MN AND WEST CENTRAL WISCONSIN BUT WILL NEED TO WATCH THE TRENDS DURING THE DAY. THERE IS CERTAINLY PLENTY OF MOISTURE WITH PWAT VALUES OVER 300 PERCENT OF NORMAL THROUGH THE CENTRAL PLAINS. BLUSTERY AND COLDER CONDITIONS MOVE IN FOR THURSDAY WITH COLD ADVECTION KEEPING TEMP TRENDS STEADY FROM OVERNIGHT LOWS IN SOME AREAS. THE CLIPPER TYPE SYSTEM MOVING INTO THE AREA ON FRIDAY LOOKS WELL DEFINED BUT LACKING MOISTURE. HAVE INTRODUCED AT LEAST A SLIGHT CHANCE FOR LIGHT SNOW IN THE WEST BUT THERE MAY BE A NEED TO EXPAND THAT IN LATER FORECASTS. SATURDAY LOOKS MILD BEHIND THAT SYSTEM WITH DECENT CHANCE OF BRINGING SOME LOW 40S INTO THE SOUTHWEST..EAST OF THE BUFFALO RIDGE. ANOTHER SYSTEM IN THE SPLIT FLOW WILL NEED TO BE WATCHED MID WEEK. THIS LOOKS TO BE MAINLY SOUTHEAST OF OF OUR AREA BUT THE TRACKS OF PAST SYSTEMS THIS EARLY WINTER HAVE AFFECTED THE SOUTHEAST HALF OF OUR FORECAST AREA...AND THE SAME MAY HOLD TUE WITH THIS ONE. && .AVIATION.../18Z TAF ISSUANCE/ DEEP UPPER TROUGH OVER THE THE CENTRAL CONUS SENDING A SWARM OF SHORTWAVES OUR DIRECTION AND WILL CONTINUE TO KEEP SIMPLY UGLY CONDITIONS IN PLACE...WITH WIDESPREAD LIFR/IFR CONDITIONS EXPECTED TO PERSIST AT ALL LOCATION THROUGH AT LEAST 06Z. THROUGH TONIGHT... A RWF TO SIREN...WI LINE WILL BE A GOOD SEPARATION OF EXPECTED WEATHER. NW OF THIS LINE...DENSE FOG HAS BEEN IN PLACE ALL MORNING. GFSLAMP FROM BOTH AXN/STC KEEP 1/2SM OR LESS VSBY IN PLACE THROUGH 6Z. DID NOT KEEP VIS THAT LOW FOR THAT LONG IN THESE TAFS...AS WAVE MOVING ACROSS THE CENTRAL DAKOTAS HAS BE SPREADING DZ/SN/RA EAST. THIS PRECIP SHOULD REACH CENTRAL/WRN MN AROUND 00Z WITH THE HOPE THAT AS IT DOES SO...THE PRECIP WILL HELP MIX THINGS ENOUGH TO GET THE VSBYS ABOVE 1/2SM. SE OF THE AFOREMENTIONED LINE...RA AND DZ WILL DOMINATE THE WEATHER THROUGH 06Z. CIGS SHOULD REMAIN AT OR BELOW 005 DURING THIS TIME...BUT THE FALLING RAIN WILL HELP HOLD VSBYS UP TO BETWEEN 2SM AND 4SM. P-TYPE WITH THIS LOOKS TO REMAIN MOSTLY RAIN...BUT BETWEEN 3Z AND 6Z A TRANSITION TO SNOW WILL BE POSSIBLE...BUT BY THEN THE PRECIP WILL BE MOVING OUT. ESTABLISHMENT OF W/NW WINDS AFTER 00Z FROM WEST TO EAST WILL HELP CLEAN OUT THE FG AND RAIN TONIGHT...BUT IFR CIGS LOOK TO REMAIN IN PLACE MOST OF THE NIGHT. GOING INTO THURSDAY MORNING...STRONG CAA MOVING IN FROM THE NW DURING THE MORNING WILL ALSO BRING ALONG A REINFORCING SHOT OF STRATUS...THOUGH BY THEN CIGS SHOULD IMPROVE TO MVFR LEVELS. KMSP...LOOKING AT LATEST RADAR TRENDS...-RA LOOKS TO BE THE PREDOMINATE PLAYER FOR THE NEXT FEW HOURS. MPXWRF/HRRR REFLECTIVITY FORECASTS BOTH HANDLING THIS PRECIP WELL...WITH THE BULK OF IT MOVING EAST OF MSP AFTER 04Z. FORECAST SOUNDINGS OFF THE RUC/GFS SHOW IT BECOMING COLD ENOUGH OF SN BETWEEN 3Z AND 6Z...BUT BY THEN MAJORITY OF PRECIP LOOKS TO BE EAST OF FIELD...SO ONLY HAVE A VCSH MENTION FOR NOW...BUT THERE COULD BE A BRIEF 2 OR 3 HOUR PERIOD WHERE -SN IS OBSERVED. RH PROFILE OFF THE NAM KEEPS IFR CIGS IN PLACE THROUGH 12Z...AND GIVEN EXTENT OF CLOUDS TO THE WEST...FAVORED A SLOWER SOLUTION FOR IMPROVING THINGS TO MVFR. CAA DURING THE COURSE OF THE DAY THURSDAY SHOULD KEEP AT LEAST MVFR CIGS IN PLACE INTO THE AFTERNOON...BUT HOPEFULLY WE WILL GET TO SEE SOME SUN LATE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPR/MPG
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
331 PM CST WED DEC 14 2011 .DISCUSSION... SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE ONGOING ACROSS NORTH TEXAS THIS AFTERNOON AS A PACIFIC COLD FRONT MOVES EAST. THE UPPER LEVEL SYSTEM RESPONSIBLE FOR DEEP LAYER ASCENT IS SHEARING OUT ACROSS THE SOUTHERN PLAINS AND WILL MOVE NORTHEAST THIS EVENING ALLOWING THE FRONTAL BOUNDARY TO SLOW DOWN AS IT MOVES EAST. LATEST RUC SOUNDINGS AND LOCALLY DERIVED CONVECTIVE PARAMETERS INDICATE THAT 700MB WARM NOSE HAS MOSTLY ERODED WITH ONLY WEAK INHIBITION PRESENT IN VICINITY OF THE FRONT. ANYWHERE FROM 500-700J/KG OF INSTABILITY REMAINS PRESENT AND WILL SUPPORT THUNDERSTORMS THROUGH THE REMAINDER OF THE EVENING INTO TONIGHT. OVERALL SEVERE WEATHER THREAT IS LOW BUT SOME HAIL WILL REMAIN POSSIBLE. FRONT WILL DRIFT SOUTH AND EAST LATER TONIGHT WITH PRECIP TAPERING FROM WEST TO EAST. ALTHOUGH SURFACE FRONT WILL BE SOUTH OF THE AREA ON THURSDAY AMPLE MOISTURE WILL RIDE ATOP THE SHALLOW COOLER AIR. REMNANTS OF THE UPPER LOW OVER THE SOUTHWEST IS EXPECTED TO EJECT NORTHEAST DURING THE DAY TOMORROW. THIS SYSTEM SHOULD PROVIDE SUFFICIENT FORCING TO LIFT MOISTURE IN THE 850-700MB LAYER. ELEVATED INSTABILITY WILL BE WEAK ALTHOUGH IT SHOULD BE SUFFICIENT FOR SHOWERY TYPE PRECIP TO DEVELOP EVEN THOUGH THE NEAR SURFACE LAYER WILL BE DRY. MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS SOLUTION AND HAVE RAISED POPS FOR THU/THU NIGHT ACROSS NORTH TEXAS. FRIDAY AND SATURDAY STILL LOOK LIKE THE QUIETEST DAYS THROUGH THE NEXT SEVERAL WITH MOST AREAS STAYING DRY. THE NEXT STRONG SYSTEM IS EXPECTED TO MOVE OUT OF THE SOUTHWEST US BY SUNDAY. MOISTURE WILL SURGE NORTHWARD AHEAD OF THIS UPPER LOW...WHICH IS FORECAST TO REMAIN CLOSED AS IT MOVES ACROSS NORTH TEXAS. THIS SYSTEM CONTINUES TO LOOK MORE POTENT AND AGAIN WE MAY SEE SOME SIGNIFICANT RAINFALL AS IT MOVES THROUGH. WILL HAVE TO MONITOR FOR SEVERE WEATHER POTENTIAL AS WE GET CLOSER TO THE EVENT. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 54 56 40 54 38 / 60 50 70 10 10 WACO, TX 58 58 42 53 42 / 90 60 70 20 20 PARIS, TX 55 57 39 51 37 / 90 40 70 20 10 DENTON, TX 51 54 38 51 33 / 40 40 70 10 10 MCKINNEY, TX 54 56 41 52 36 / 70 40 70 20 10 DALLAS, TX 55 58 41 54 41 / 70 50 70 20 10 TERRELL, TX 57 59 42 52 40 / 90 50 70 20 10 CORSICANA, TX 59 62 45 54 42 / 90 60 70 30 20 TEMPLE, TX 59 59 42 53 43 / 80 70 70 20 20 MINERAL WELLS, TX 48 52 37 50 35 / 10 40 60 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1119 AM CST WED DEC 14 2011 .AVIATION... IFR CONDITIONS REMAIN FAIRLY EXTENSIVE ACROSS NORTH TEXAS LATE THIS MORNING. LOCAL AIRPORTS ALONG THE I 35 CORRIDOR CONTINUE TO REPORT CIGS AT OR BELOW 010 AND FEEL THIS WILL CONTINUE THROUGH THE MID AFTERNOON HOURS. CONDITIONS SHOULD THEN IMPROVE SOME AS TEMPERATURES APPROACH 70 AND WINDS BEGIN TO VEER AHEAD OF THE PACIFIC FRONT TO THE WEST. INSTABILITY SHOULD NOT BE OVERLY IMPRESSIVE AS INITIAL SHORTWAVE MOVES ACROSS THE AREA THIS AFTERNOON. HOWEVER...CONVERGENCE ALONG THE SURFACE BOUNDARY COMBINED WITH SB CAPES BETWEEN 500 AND 1000 J/KG SHOULD BE SUFFICIENT FOR THE DEVELOPMENT OF THUNDERSTORMS. WILL TIME THE ONSET OF OCCASIONAL TS IN THE METROPLEX SIMILAR TO THE 12Z LOCAL WRF SOLUTION...WHICH WOULD BEGIN AROUND 22Z. WINDS WILL VEER TO THE SW BEHIND THE LEADING EDGE OF THE HEAVIER PRECIP. MAIN PUSH OF COOLER DRIER AIR AT THE SURFACE WOULD BE LATE TONIGHT AND WILL CONTINUE WITH THE NORTHWEST WINDS PRIOR TO SUNRISE TOMORROW. IT LOOKS LIKE THE FRONT MAY HANG UP JUST SOUTH OF THE FORECAST AREA TOMORROW. OVERRUNNING PRECIP WILL THEN BECOME A POSSIBILITY BY TOMORROW AFTERNOON AS THE NEXT SHORTWAVE PROPAGATES EASTWARD INTO THE AREA. 30 && .UPDATE... ELONGATED TROF AXIS PERSISTS FROM THE CENTRAL PLAINS BACK INTO THE SOUTHWEST US WITH ONE SIGNIFICANT PIECE OF ENERGY EJECTING NORTHEAST THIS MORNING. THIS S/W WILL HELP PUSH A PACIFIC FRONT THROUGH THE REGION THIS AFTERNOON. REGIONAL RADAR IMAGERY ALREADY SHOWS A BROKEN LINE OF PRIMARILY SHOWERS DEVELOPING TO THE NORTHWEST OF THE CWA. THIS IS EXPECTED TO GRADUALLY FILL IN AND MOVE EAST THROUGH THE DAY AS THE FRONT GAINS MOMENTUM. ALL OF THE HIGH RESOLUTION SHORT TERM GUIDANCE SUGGESTS THAT A LINE OF CONVECTION WILL MOVE THROUGH NORTH TEXAS THROUGH THIS AFTERNOON ALONG THE FRONT...HOWEVER THERE IS SOME DISCREPANCY AS TO HOW INTENSE IT WILL BE. LATEST NAM IS MOST AGGRESSIVE WITH INSTABILITY AND STILL INDICATES AN AXIS OF 700-1000J/KG OF OF CAPE ACROSS NORTH TEXAS AND WEAKENS THE CAPPING AROUND 700MB. RUC SOUNDINGS ARE NOT SO QUICK TO ERODE THE CAPPING AND INDICATE THAT DEEP CONVECTION WILL BE HARD TO COME BY. GIVEN THE EXTENSIVE CLOUD COVER AND ONGOING DRIZZLE TEND TO THINK THE LESS AGGRESSIVE RUC MAY HAVE A BETTER HANDLE ON THINGS. WILL CONTINUE TO MENTION THUNDERSTORMS THROUGH THE AFTERNOON...BUT OVERALL SEVERE WEATHER THREAT MAY BE CONFINED TO A FEW ISOLATED CELLS. THIS IS ONE OF THOSE SITUATIONS THOUGH WHERE A LITTLE EXTRA HEATING OR SLIGHTLY MORE WEAKENING OF THE CAP COULD RESULT IN MORE WIDESPREAD SEVERE CONVECTION SO IT IS WORTH WATCHING THROUGH THE AFTERNOON. ONLY SOME MINOR TWEAKS TO POP/WEATHER WORDING THROUGH THE AFTERNOON OTHERWISE NO MAJOR CHANGES TO THE CURRENT FORECAST. DUNN && .PREV DISCUSSION... /ISSUED 344 AM CST WED DEC 14 2011/ MOIST ISENTROPIC ASCENT WILL CONTINUE TODAY AS THE LOW LEVEL JET REMAINS STRONG AND CONTINUES TO TRANSPORT RICH MOISTURE INTO THE REGION. SOME INSTABILITY WILL WORK INTO THE WESTERN COUNTIES THIS MORNING AND THEN SPREAD EASTWARD THIS AFTERNOON AND EVENING. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH HAIL AND DAMAGING WINDS DUE TO AN APPROACHING SHORTWAVE...A 90-100 KNOT JET ALOFT AND 400-1000 J/KG OF CAPE. BEST TIMING FOR SEVERE WILL BE MID/LATE AFTERNOON OVER THE WESTERN HALF AND THIS EVENING FOR THE EASTERN HALF. A COLD FRONT WILL SWING THROUGH NORTH TEXAS LATER TONIGHT AND BRING COOLER NORTHERLY WINDS BACK TO THE REGION. A STRONG SHORTWAVE WILL KICK OUT OF THE PERSISTENT SOUTHERN CALIFORNIA UPPER LOW AND PASS OVER THE REGION THURSDAY EVENING. HAVE HELD ONTO LOW POPS THURSDAY AND THURSDAY NIGHT AS MID LEVEL LIFT MOVES ACROSS THE REGION. AS THE SHORTWAVE MIGRATES EAST OF THE REGION...RAIN CHANCES WILL END FOR MOST OF THE CWA BUT LINGER OVER THE SOUTHERN COUNTIES THROUGH FRIDAY. THERE WILL BE A BRIEF LULL IN RAIN CHANCES ON SATURDAY...BUT THEY RETURN TO THE WESTERN COUNTIES SATURDAY NIGHT AS THE MAIN UPPER LOW OVER SOUTHERN CALIFORNIA BEGINS TO MOVE EAST. AS THE UPPER SYSTEM NEARS TEXAS... RAIN CHANCES WILL INCREASE WEST TO EAST SUNDAY THROUGH MONDAY...AND HAVE INCLUDED THUNDERSTORM POTENTIAL FOR MONDAY MORNING. ANOTHER COLD FRONT WILL MOVE THROUGH THE REGION MONDAY EVENING. TEMPERATURES FOR THE MOST PART WILL BE SEASONAL WITH ABOVE NORMAL CONDITIONS AHEAD OF TONIGHT/S COLD FRONT AND MONDAY/S COLD FRONT. 75 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 72 50 58 39 53 / 100 50 30 40 10 WACO, TX 74 50 57 43 54 / 80 50 40 60 10 PARIS, TX 72 53 64 42 53 / 80 70 30 50 10 DENTON, TX 69 46 58 36 51 / 100 40 30 30 10 MCKINNEY, TX 69 49 60 40 52 / 100 50 30 40 10 DALLAS, TX 71 51 58 40 54 / 100 50 40 40 10 TERRELL, TX 70 53 61 42 55 / 90 60 40 50 10 CORSICANA, TX 72 55 59 45 55 / 70 60 40 60 10 TEMPLE, TX 73 53 58 43 56 / 60 50 50 60 20 MINERAL WELLS, TX 71 43 55 34 51 / 100 20 30 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 30/
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
316 PM CST WED DEC 14 2011 .TONIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. SHEARED VORT MAX STRETCHING FROM NORTHEAST NEW MEXICO TO EASTERN NEBRASKA APPARENT IN 1945Z WATER VAPOR IMAGERY AND RUC ANALYSIS. RAIN SPREAD BACK INTO SOUTHERN WI EARLY THIS AFTERNOON...SUPPORTED BY 500MB VORT MAX PUSHING INTO SOUTH CENTRAL WI...WARM AIR ADVECTION AND CONTINUED ISENTROPIC LIFT. OMEGA VALUES WILL ALSO INCREASE BETWEEN NOW AND 7 PM AS WELL...PER RUC AND NAM MODEL SNDGS. REGIONAL RADAR NOW ROUGHLY SHOWING DRY SLOT MOVING INTO CENTRAL IOWA...CORRESPONDING TO THE CENTER OF SFC LOW PRESSURE. OBS STILL SHOWING DRIZZLE IN THE VICINITY. SFC LOW WILL MOVE INTO NORTHEAST IOWA AROUND 00Z...AND CLIP THE NORTHWEST FORECAST AREA AS IT MOVES ACROSS CENTRAL WI AT 03Z. THE SFC TROUGH/COLD FRONT WILL THEN TREK ACROSS SOUTHEAST WI FROM 05Z TO 09Z...USHERING IN COLDER AND DRIER AIR...AS THE SFC LOW MOVES INTO EASTERN UPPER MICHIGAN. LOW LEVELS WILL REMAIN MOIST BEHIND THE FRONT...BUT DRY OUT ALOFT...THUS CAUSING DRIZZLE BEHIND THE DEPARTING LOW THROUGH AROUND 15Z/9AM THU MORNING. THE BAGGY PRESSURE GRADIENT OVER THE WESTERN FORECAST AREA WILL ALLOW FOR AREAS OF DENSE FOG THROUGH LATE EVENING UNTIL THE COLD FRONT COMES THROUGH AND THE WINDS INCREASE. DENSE FOG ADVY POSTED. TEMPERATURES WILL KEEP RISING THROUGH THE EVENING...REACHING OUR DAILY HIGH IN THE UPPER 40S/LOWER 50S AROUND MIDNIGHT. TEMPS WILL GRADUALLY FALL THROUGH THE DAY THU...DROPPING DOWN TO AROUND FREEZING FROM NW TO SE DURING THE AFTERNOON HOURS. PRECIP IS EXPECTED TO END BY LATE THU MORNING...AND CLOUDS SHOULD BREAK UP DURING THE AFTERNOON HOURS...BECOMING PARTLY CLOUDY BY EVENING. .THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE IS HIGH. SKIES CONTINUE TO CLEAR OUT EARLY THURSDAY EVENING AS THE LOW PULLS AWAY AND HIGH PRESSURE BUILDS IN. THINGS COOL DOWN...BUT REMAIN AT OR SLIGHTLY ABOVE NORMAL. .FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE IS MEDIUM. A COUPLE OF WEAK MID LEVEL SHORT WAVES COME THROUGH THE FAST NORTHWEST FLOW FRIDAY NIGHT AND AGAIN SATURDAY AFTERNOON. MOISTURE BEGINS TO RETURN AND THERE IS SOME INDICATION WE COULD GET ENOUGH COLUMN SATURATION TO SQUEEZE OUT A FEW FLAKES OF SNOW. HAVE INTRODUCED A SLIGHT CHANCE OF LIGHT SNOW...BUT LITTLE OR NO ACCUMULATION IS EXPECTED. THE GFS AND THE NAM ARE HINTING AT SOME VERY LIGHT QPF THROUGH THIS PERIOD. .SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE IS MEDIUM. QUIET CONDITIONS EXPECTED THIS PERIOD AS WEAK RIDGING MOVES THROUGH. TEMPS REMAIN AT OR ABOVE NORMAL. .SUNDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE IS LOW. THERE IS MAJOR MODEL UNCERTAINTY FOR EARLY NEXT WEEK. AT ISSUE IS WHETHER WE/LL SEE A LOW MOVE UP INTO THE GREAT LAKES AND GIVE US RAIN...OR STAY WELL TO THE SOUTH AND KEEP US DRY...OR TAKE A COMPROMISE OF THE TWO AND POSSIBLY GIVE US SOME ACCUMULATING SNOW. THE GFS HAS MAINTAINED IT/S SOUTHERN DRY SOLUTION FOR US...THE CANADIAN LOOKS FAIRLY WARM/RAINY WITH A LOW MOVING INTO THE CENTRAL GREAT LAKES...WHILE THE ECMWF IS A COMPROMISER TAKING A LOW THROUGH CENTRAL ILLINOIS/INDIANA. THE ECMWF WOULD BE COOLER DURING THE PRECIP AND THIS COULD RESULT IN SOME ACCUMULATING SNOW...NOTHING MAJOR AT THIS POINT. THE MODELS ARE HAVING A VERY DIFFICULT TIME PHASING ENERGY FROM THE SOUTHERN AND NORTHERN STREAMS. HAVE KEPT POPS IN THE CHC CATEGORY UNTIL WE GET A LITTLE MORE CONSENSUS. && .AVIATION/00Z TAFS/...SURFACE LOW PRESSURE WILL TRACK ACROSS NORTHEAST IOWA...CENTRAL WI AND EASTERN UPPER MICHIGAN THROUGH TONIGHT. BAGGY PRESSURE GRADIENT BENEATH THE SFC LOW WILL COVER SOUTH CENTRAL WI...ALLOWING AREAS OF DENSE FOG TO DEVELOP/PERSIST THROUGH THE EVENING. RAIN ASSOCIATED WITH THE 500MB SHORTWAVE...850MB WARM AIR ADVECTION...AND STRONG OMEGA WILL DIMINISH AS THE SFC LOW COMES OVERHEAD...AS THE DRY SLOT HITS THE REGION. COLD FRONTAL PASSAGE WILL OCCUR BETWEEN 05Z AND 08Z TONIGHT. STRONG COLD ADVECTION THU AM WILL IMPROVE CONDITIONS BY RAISING THE CEILINGS AND IMPROVING VISIBILITY. WIND GUSTS TO 30 KNOTS POSSIBLE...ESPECIALLY AT MKE. CLOUDS SHOULD SCATTER OUT DURING THU AFTERNOON. && .MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 6 PM TNT THROUGH 9 PM THU EVENING. BREEZY SSWLY WINDS AND HIGH WAVES WILL DEVELOP THIS EVENING WITH A COLD FRONTAL PASSAGE EXPECTED TO SHIFT THE WINDS TO THE WEST BY 09Z TNT. STRONG COLD ADVECTION WILL COMBINE WITH THE RELATIVELY MILD LAKE MI WATER TEMPS TO PRODUCE UNSTABLE CONDITIONS IN THE LOW LEVEL ATMOSPHERE. THIS WILL ENHANCE THE ALREADY MODERATE WIND FIELD WITH WIND GUSTS EXPECTED TO REACH 30 KTS. THE WAVES WILL DECREASE AFTER COLD FROPA DUE TO THE WLY COMPONENT OF THE WIND AND THEREFORE LESS FETCH TO GENERATE WAVES. HOWEVER...HIGH WAVES WILL STILL OCCUR OVER THE OPEN WATERS OF LAKE MI. THE WINDS WILL SUBSIDE BY LATE THU EVENING AS A LARGE HIGH PRESSURE AREA APPROACHES FROM THE WEST. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 3 AM CST THURSDAY FOR WIZ046-047-056- 057-062-063-067-068. LM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THURSDAY FOR LMZ643>646. && $$ TONIGHT/THURSDAY AND AVIATION/MARINE...MRC THURSDAY NIGHT THROUGH WEDNESDAY...DAVIS