Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/01/13


AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1016 PM CDT MON SEP 30 2013 .DISCUSSION... 838 PM CDT FOR EVENING UPDATE... NO SIGNIFICANT CHANGES TO FORECAST THIS EVENING. SOUTH-SOUTHWEST FLOW HAS DEVELOPED SURFACE AND ALOFT ACROSS THE FORECAST AREA. WHILE A FEW SPOTS HAVE COOLED OFF QUICKLY... LIGHT BUT PERSISTENT SOUTH GRADIENT AND WARMING ALOFT ARE EXPECTED TO LIMIT THE TEMP DROP OVERNIGHT AND WILL LIKELY EVEN SEE SOME OVERNIGHT RISES AS HIGHER THETA-E LOW LEVEL AIR MASS SPREADS NORTH. ONLY REAL TWEAKS MADE THIS EVENING ARE FOR HOURLY TEMP TRENDS WHICH HAVE BEEN COMPLICATED BY LAKE BREEZE AND INITIAL SHARP DROP AFTER SUNSET. VARIOUS GUIDANCE CONTINUE TO INDICATE STRATUS DEVELOPING LATE TONIGHT ACROSS EAST CENTRAL IL...SPREADING NORTH INTO THE SOUTHERN PARTS OF THE LOT CWA. SOME PATCHY FOG POTENTIAL AS WELL AS HIGHER DEW POINT AIR PUSHES NORTH. CURRENT FORECAST ALREADY HAS THIS COVERED AT THIS POINT...SO AGAIN NO CHANGES THERE. ANY FOG/LOW STRATUS SHOULD ERODE QUICKLY TUESDAY AFTER SUNRISE...WITH GUSTY SOUTH-SOUTHWEST WINDS DEVELOPING. RATZER //PREV DISCUSSION... 258 PM CDT PRIMARY CONCERN IS THE UNSEASONABLY WARM TEMPERATURES TUESDAY AND WEDNESDAY...FOLLOWED BY PRECIP CHANCES WEDNESDAY NIGHT THROUGH SATURDAY. GUIDANCE CONTINUES TO EXHIBIT LACK OF RUN TO RUN CONTINUITY WITH STRONG LATE WEEK SYSTEM AND LATEST TREND TODAY HAS BEEN FOR A MARKED SLOWING OF SYSTEM. SHORT TERM...TONIGHT THROUGH THURSDAY... TONIGHT...MOST OF THE CWA SHOULD ENJOY A MAINLY CLEAR AND MUCH MILDER NIGHT THAN LAST NIGHT...WITH THE EXCEPTION BEING SOUTH OF I-80 WHERE SIMILAR TO EARLY THIS MORNING...LOW STRATUS AND PATCHY FOG COULD SPREAD NORTH AS 1000-950 MB LAYER BECOMES NEARLY SATURATED. TUESDAY...ANY MORNING STRATUS/FOG IN THE SOUTH SHOULD ERODE FAIRLY QUICKLY. SOUTHWEST WINDS GUSTING TO 25-30 MPH AND 850 MB TEMPS 16-18C AND 925 TEMPS 18-20C WILL SUPPORT ONE OF THE WARMEST STARTS TO OCTOBER ON RECORD...AS ALLUDED TO BY PREVIOUS SHIFT. WILL CONTINUE WITH HIGHS INTO THE MID 80S FOR MOST OF THE CWA. GUIDANCE DOES SHOW 850 MB THERMAL RIDGE SLIDING SOUTH A BIT LATE DAY BUT 925 TEMPS REMAIN OFF THE CHARTS WITH RESPECT TO EARLY OCT UPPER AIR CLIMO SO BASICALLY LEFT PREVIOUS FORECAST UNCHANGED. TUESDAY NIGHT AND WEDNESDAY...THERE IS NOW SOLID AGREEMENT IN A DRY..WEAK COLD FRONT SLIPPING SOUTH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY WHICH WILL RESULT IN TEMPERATURES COOLING OFF NORTH OF I-80...MOST PROMINENTLY ALONG THE LAKE TO WITHIN A FEW DEGREES OF 70. TO THE SOUTH...VERY WARM 925 TEMPS STILL EXPECTED TO SUPPORT HIGHS IN THE LOW-MID 80S. SOME GUIDANCE INDICATING A FOCUS FOR TSRA IN THE WELL SOUTH ALONG STALLING OUT FRONT...BUT MAINTAINED DRY FORECAST FOR NOW. WEDNESDAY NIGHT AND THURSDAY...FRONT WILL LIFT BACK AS A WARM FRONT AND DISTURBED SOUTHWEST FLOW AND DECENT LOW LEVEL JET SUPPORT COULD SUPPORT A FEW PERIODS OF TSRA IN THIS TIME. CONFIDENCE IS NOT HIGH IN COVERAGE...AND CONCERNED THAT GUIDANCE IS OVERDONE WITH POPS...BUT KEPT CHANCE POPS GOING AFTER MIDNIGHT WEDNESDAY NIGHT THROUGH THURSDAY. SYNOPTIC SET-UP SEEMS TO BE ONE WHERE ATMOSPHERE COULD BE CAPPED...ESPECIALLY LATER THURSDAY AFTERNOON...WITH WARM FRONT HAVING LIFTED WELL NORTH. GIVEN 850 MB TEMPS IN THE MID TEENS AND 925 MB IN THE UPPER TEENS TO AROUND 20C...FORECAST HIGHS IN THE UPPER 70S TO AROUND 80 COULD EVEN BE SLIGHTLY COOL IF THERE IS LESS CLOUD COVER AND PRECIP THAN CURRENTLY ANTICIPATED. LONG TERM...THURSDAY NIGHT THROUGH MONDAY... STRONG SHORT WAVE ENERGY EMANATING FROM DEEP UPPER LOW OVER GULF OF ALASKA WILL REACH PAC NW SHORE ON WEDNESDAY...SO UNTIL SAMPLED BY RAOB NETWORK...FURTHER GUIDANCE CORRECTIONS ARE LIKELY WITH STRONG LATE WEEK UPPER TROUGH AND ASSOCIATED SURFACE LOW TAKING SHAPE OVER THE PLAINS AND LIFTING NORTHEAST. ENSEMBLES CONTINUE TO EXHIBIT LARGE SPREAD AS WELL. AS MENTIONED EARLIER...ALL OPERATIONAL MODELS TODAY HAVE TRENDED MUCH SLOWER WITH SYSTEM AND THE AREA NOW LOOKS TO BE FIRMLY ENTRENCHED IN THE WARM SECTOR ON FRIDAY. NUDGED MODEL BLEND INITIALIZATION MAX T A BIT HIGHER...WHICH COULD STILL BE TOO CONSERVATIVE IN THE LOW 80S...AND ALSO CAPPED POPS AT SLIGHT TO LOW END CHANCE. THE SYSTEM LOOKS TO CLOSE OFF AND OCCLUDE SOMEWHERE OVER THE UPPER MIDWEST FRIDAY NIGHT INTO SATURDAY...WITH COLD FRONT OR OCCLUDED FRONT NOW NOT EXPECTED TO REACH WESTERN CWA UNTIL SATURDAY MORNING...SO IT COULD BE ANOTHER WARM DAY ESPECIALLY FOR THE EASTERN HALF OF THE CWA. THUNDERSTORMS WILL BE POSSIBLE ALONG/AHEAD OF FRONT BEFORE IT SWEEPS THROUGH BY THE LATE AFTERNOON AND EARLY EVENING. THE GFS HAS BACKED OFF A BIT ON THE COLD SHOT BEHIND THE FRONT...WHILE THE 12Z ECMWF FEATURES 850 MB TEMPS PLUNGING TO THE MINUS SINGLE DIGITS BY EARLY SUNDAY. SO DEPENDING ON THE DEPTH OF THE COOL SHOT...TEMPS IN LOW 60S CURRENTLY FORECAST COULD BE REASONABLE OR DOWNRIGHT CHILLY MID TO UPPER 50S IF ECMWF SOLUTION COMES CLOSER TO PASS. THIS WILL BE FOLLOWED BY A QUICK WARM UP TO NEAR NORMAL TEMPERATURES BY NEXT MONDAY. CONFIDENCE IN LONG TERM FORECAST PERIOD...LOW. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * LOW POTENTIAL FOR LOW MVFR STRATUS TO APPROACH FROM THE SOUTH TOWARD DAYBREAK. * SSW WINDS 200-220 DEGREES GUSTING TO 20-25 KT DEVELOPING LATE MORNING/MIDDAY TUESDAY. WINDS MAY TURN TO 230-240 DEGREES LATE AFTERNOON...BUT MORE LIKELY TO EARLY EVENING AS GUSTS EASE. MDB //DISCUSSION...UPDATED 03Z... CONTINUING TO WATCH IFR/LOW MVFR STRATUS EXPAND ACROSS FAR SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI THIS EVENING. THIS STRATUS WILL CONTINUE TO EXPAND NORTHWARD OVERNIGHT AS LOW LEVEL MOISTURE STREAMS NORTHEAST ON STRENGTHENING WINDS A FEW THOUSAND FEET ABOVE THE GROUND. AT THIS POINT IT LOOKS THE STRATUS WILL REMAIN SOUTH OF THE TERMINALS BUT WILL NEED TO KEEP AN EYE ON THIS OVER THE NEXT FEW HOURS. ARRIVAL WOULD BE TOWARDS DAYBREAK IF IT MAKES IT THIS FAR NORTH. FROM 00Z... LAKE BREEZE CONTINUES TO SURGE INLAND AND IT WILL BE A RACE BETWEEN IT DISSIPATING AND IT MAKING IT TO ORD. EXPECT THAT IT WILL DISSIPATE JUST TO THE EAST...AT LEAST TO THE POINT WHERE ANY WIND SHIFT WOULD BE LESS DRAMATIC WITH SPEEDS UNDER 10 KT. THE BOUNDARY HAS PRETTY MUCH PARKED OVER THE NORTHEAST CORNER OF MDW AND WILL DISSIPATE THERE. OTHERWISE...EXPECT SOUTH WINDS TO REMAIN STEADY IN SPEED THIS EVENING...EVENTUALLY TURNING SOUTH-SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT ORGANIZES. LOW PRESSURE ACROSS THE DAKOTAS THIS EVENING WILL WEAKEN AS IT MOVES EASTWARD BUT BRING A WEAK COOL FRONT EASTWARD WITH IT LATER TUESDAY. SOUTH- SOUTHWEST WINDS WILL INCREASE TUESDAY MORNING WITH GUSTS IN THE 20-25 KT RANGE EXPECTED TO DEVELOP...WITH SLIGHTLY HIGHER GUSTS POSSIBLE AT RFD. WIND SPEED WILL EASE TUESDAY EVENING AS THE FRONTAL TROUGH APPROACHES WEAKENING THE PRESSURE GRADIENT. THE FRONT WILL CROSS THE AREA LATE EVENING/EARLY OVERNIGHT BRINGING A SHIFT TO LIGHT NORTHWEST WINDS. AM NOT EXPECTING ANY RAIN WITH THE FRONT BUT THERE MAY BE AN INCREASE IN VFR CLOUDINESS TUESDAY EVENING. MDB //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM CONFIDENCE THAT STRATUS WILL REMAIN SOUTH OF THE TERMINALS TUESDAY MORNING. * HIGH CONFIDENCE IN WINDS THROUGH MID TUESDAY AFTERNOON...MEDIUM CONFIDENCE IN TIMING TRANSITION TO 230/240 DEGREE DIRECTION. MDB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR WITH LOW SHRA/TSRA CHANCES WEDNESDAY NIGHT. THURSDAY THROUGH SATURDAY...PERIODIC SHRA/TSRA CHANCES WITH LOW CIGS POSSIBLE. SUNDAY...VFR. MDB && .MARINE... 241 PM...A MORE ACTIVE PATTERN IS EXPECTED INTO THIS WEEKEND WITH LOWER CONFIDENCE REGARDING SPECIFICS FRIDAY AND SATURDAY. STRONG LOW PRESSURE OVER SOUTH CENTRAL CANADA WILL MOVE NORTHEAST REACHING HUDSON BAY TUESDAY NIGHT. THE GRADIENT IS IN THE PROCESS OF TIGHTENING OVER THE NORTHERN PART OF THE LAKE AND THAT WILL CONTINUE TONIGHT INTO TUESDAY MORNING. ALONG A TRAILING COLD FRONT FROM THIS LOW...A WEAKER LOW WILL DEVELOP OVER THE DAKOTAS THIS EVENING. THIS LOW WILL QUICKLY BE STRETCHED ALONG THE FRONT OVERNIGHT...BUT JUST AHEAD OF THIS FRONT/TROUGH OF LOW PRESSURE... SOUTHERLY WINDS MAY INCREASE TO NEAR GALE FORCE OVER THE NORTHERN HALF OF THE LAKE THOUGH THE DURATION LOOKS TO BE FAIRLY SHORT... PERHAPS JUST 3-6 HOURS STARTING AROUND SUNRISE TUESDAY MORNING. WILL INCLUDED GUSTS TO 35 KTS FOR THIS POTENTIAL AND TRENDS WILL NEED TO BE MONITORED OVERNIGHT INTO TUESDAY MORNING. ONCE THIS FRONT MOVES EAST OF THE LAKE TUESDAY EVENING...WINDS WILL DIMINISH AND SHIFT WESTERLY OVER THE NORTHERN PART OF THE LAKE... TURNING LIGHT NORTHERLY THEN NORTHEASTERLY OVER THE SOUTH END OF THE LAKE AS HIGH PRESSURE BUILDS ACROSS THE SOUTHERN LAKES TUESDAY NIGHT AND SHIFTS NORTHEAST WEDNESDAY. ANOTHER STRONG AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE PLAINS WEDNESDAY NIGHT INTO THURSDAY AND THEN TURN NORTHEAST MOVING ACROSS THE GREAT LAKES REGION FRIDAY NIGHT OR SATURDAY. THE LATEST MODEL GUIDANCE SUGGESTS THAT THIS LOW WILL BE MOVING MUCH SLOWER AND STILL BE NEAR IOWA SATURDAY MORNING WITH A POSSIBLE WARM FRONT EXTENDING ACROSS THE NORTHERN OR CENTRAL PORTIONS OF LAKE MICHIGAN. A FRONTAL BOUNDARY WOULD RESULT IN SOME AMOUNT OF EASTERLY OR NORTHEASTERLY WINDS NORTH OF THE FRONT. IN ADDITION...STRONGER SOUTHERLY WINDS WILL BE DELAYED UNTIL THE LOW MOVES CLOSER TO THE LAKE. THUS CONFIDENCE REGARDING NOT ONLY THE TRACK OF THE LOW AND POTENTIAL FRONTAL BOUNDARY...BUT ALSO ITS SPEED IS LOW AND CHANGES TO THE CURRENT FORECAST CAN BE EXPECTED. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 903 PM CDT Mon Sep 30 2013 .DISCUSSION... ISSUED 900 PM CDT Mon Sep 30 2013 The stationary front seems to be losing its identity in terms of wind shift but the dewpoint gradient remains in our southeast area. A broad scale southerly flow will dominate the surface winds, while westerly flow aloft brings cirrus level moisture ahead of the next frontal boundary in the northern plains. Our weather should remain quiet the rest of the night through tomorrow, as high and low temperatures continue above normal through mid week. The lingering low level moisture in the southeast half of the area will evolve into ground fog as radiational cooling drops surface temps close to dewpoints. Locally dense fog is expected to develop as advertised by the HRRR and RUC. The staying power will be limited by the shallow nature of the fog, but it could still cause some travel issues around sunrise on Tuesday. We will keep a mention of fog in the grids tonight despite the drier low levels in the NAM and GFS. Overall the short term forecast grids were on track, and only minor updates were needed. No formal update is expected this evening. Shimon && .AVIATION... ISSUED 700 PM CDT Mon Sep 30 2013 The stalled stationary front will linger across Illinois from near St Louis to Champaign tonight into tomorrow. Lingering ground level moisture will cause another round of fog later tonight. The latest HRRR guidance is showing dense fog 1/4sm and 100 ft ceilings developing toward 11z/6am for SPI and DEC, and come close to BMI and CMI. The RUC also shows areas of dense fog, but in varying coverage from HRRR. The NAM and GFS show only MVFR fog potential. We decided to include a tempo for LIFR fog and ceilings in the tafs for SPI, DEC, and CMI that reside closer to the stalled front. VLIFR conditions will be possible. After the fog and stratus clear, we may see a brief period of mvfr clouds redevelop around 3k ft as southerly return flow begins to bring increases in low-mid level moisture. Enough dry air aloft should help to dissipate any bkn mvfr layers in the afternoon, as surface winds increase from the SW to 11-14kt. Shimon && .PREV DISCUSSION... ISSUED 303 PM CDT Mon Sep 30 2013 Forecast problems of today are the fog overnight, and the rain chances for the second half of this week. SHORT TERM...Tonight through Wednesday night. Morning analysis data shows stalled frontal zone over southern IN to southern IL and into MO. Moisture associated with the zone trapped beneath inversion during the morning and triggered fog and stratus. southerly flow over region will bring more of moisture back a little more northward overnight and so new grid forecast for tonight has fog in it. A second weak front dies over the northern half of IL Wednesday. With the continued advection of moisture northward, chance pops in the forecast Wednesday and Wednesday night with minor impulse moving from the southwest. LONG TERM...Thursday through Monday. Moist airmass over region through Thursday to continue to trigger chance pops. Then pops drops a little as frontal system in the plains takes shape on Thursday night to Friday and air becomes a little capped over IL. Models vary again on the timing of the cold front for the end of the week and this makes the exact timing of best chances for pop a little difficult. GFS now slower and EUR consistent on Friday night to Saturday crossing of region. Pops during that period remain in chance category. Cooler air flows into region Sunday. Goetsch && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
838 PM CDT MON SEP 30 2013 .DISCUSSION... 838 PM CDT FOR EVENING UPDATE... NO SIGNIFICANT CHANGES TO FORECAST THIS EVENING. SOUTH-SOUTHWEST FLOW HAS DEVELOPED SURFACE AND ALOFT ACROSS THE FORECAST AREA. WHILE A FEW SPOTS HAVE COOLED OFF QUICKLY... LIGHT BUT PERSISTENT SOUTH GRADIENT AND WARMING ALOFT ARE EXPECTED TO LIMIT THE TEMP DROP OVERNIGHT AND WILL LIKELY EVEN SEE SOME OVERNIGHT RISES AS HIGHER THETA-E LOW LEVEL AIR MASS SPREADS NORTH. ONLY REAL TWEAKS MADE THIS EVENING ARE FOR HOURLY TEMP TRENDS WHICH HAVE BEEN COMPLICATED BY LAKE BREEZE AND INITIAL SHARP DROP AFTER SUNSET. VARIOUS GUIDANCE CONTINUE TO INDICATE STRATUS DEVELOPING LATE TONIGHT ACROSS EAST CENTRAL IL...SPREADING NORTH INTO THE SOUTHERN PARTS OF THE LOT CWA. SOME PATCHY FOG POTENTIAL AS WELL AS HIGHER DEW POINT AIR PUSHES NORTH. CURRENT FORECAST ALREADY HAS THIS COVERED AT THIS POINT...SO AGAIN NO CHANGES THERE. ANY FOG/LOW STRATUS SHOULD ERODE QUICKLY TUESDAY AFTER SUNRISE...WITH GUSTY SOUTH-SOUTHWEST WINDS DEVELOPING. RATZER && .PREV DISCUSSION... 258 PM CDT PRIMARY CONCERN IS THE UNSEASONABLY WARM TEMPERATURES TUESDAY AND WEDNESDAY...FOLLOWED BY PRECIP CHANCES WEDNESDAY NIGHT THROUGH SATURDAY. GUIDANCE CONTINUES TO EXHIBIT LACK OF RUN TO RUN CONTINUITY WITH STRONG LATE WEEK SYSTEM AND LATEST TREND TODAY HAS BEEN FOR A MARKED SLOWING OF SYSTEM. SHORT TERM...TONIGHT THROUGH THURSDAY... TONIGHT...MOST OF THE CWA SHOULD ENJOY A MAINLY CLEAR AND MUCH MILDER NIGHT THAN LAST NIGHT...WITH THE EXCEPTION BEING SOUTH OF I-80 WHERE SIMILAR TO EARLY THIS MORNING...LOW STRATUS AND PATCHY FOG COULD SPREAD NORTH AS 1000-950 MB LAYER BECOMES NEARLY SATURATED. TUESDAY...ANY MORNING STRATUS/FOG IN THE SOUTH SHOULD ERODE FAIRLY QUICKLY. SOUTHWEST WINDS GUSTING TO 25-30 MPH AND 850 MB TEMPS 16-18C AND 925 TEMPS 18-20C WILL SUPPORT ONE OF THE WARMEST STARTS TO OCTOBER ON RECORD...AS ALLUDED TO BY PREVIOUS SHIFT. WILL CONTINUE WITH HIGHS INTO THE MID 80S FOR MOST OF THE CWA. GUIDANCE DOES SHOW 850 MB THERMAL RIDGE SLIDING SOUTH A BIT LATE DAY BUT 925 TEMPS REMAIN OFF THE CHARTS WITH RESPECT TO EARLY OCT UPPER AIR CLIMO SO BASICALLY LEFT PREVIOUS FORECAST UNCHANGED. TUESDAY NIGHT AND WEDNESDAY...THERE IS NOW SOLID AGREEMENT IN A DRY..WEAK COLD FRONT SLIPPING SOUTH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY WHICH WILL RESULT IN TEMPERATURES COOLING OFF NORTH OF I-80...MOST PROMINENTLY ALONG THE LAKE TO WITHIN A FEW DEGREES OF 70. TO THE SOUTH...VERY WARM 925 TEMPS STILL EXPECTED TO SUPPORT HIGHS IN THE LOW-MID 80S. SOME GUIDANCE INDICATING A FOCUS FOR TSRA IN THE WELL SOUTH ALONG STALLING OUT FRONT...BUT MAINTAINED DRY FORECAST FOR NOW. WEDNESDAY NIGHT AND THURSDAY...FRONT WILL LIFT BACK AS A WARM FRONT AND DISTURBED SOUTHWEST FLOW AND DECENT LOW LEVEL JET SUPPORT COULD SUPPORT A FEW PERIODS OF TSRA IN THIS TIME. CONFIDENCE IS NOT HIGH IN COVERAGE...AND CONCERNED THAT GUIDANCE IS OVERDONE WITH POPS...BUT KEPT CHANCE POPS GOING AFTER MIDNIGHT WEDNESDAY NIGHT THROUGH THURSDAY. SYNOPTIC SET-UP SEEMS TO BE ONE WHERE ATMOSPHERE COULD BE CAPPED...ESPECIALLY LATER THURSDAY AFTERNOON...WITH WARM FRONT HAVING LIFTED WELL NORTH. GIVEN 850 MB TEMPS IN THE MID TEENS AND 925 MB IN THE UPPER TEENS TO AROUND 20C...FORECAST HIGHS IN THE UPPER 70S TO AROUND 80 COULD EVEN BE SLIGHTLY COOL IF THERE IS LESS CLOUD COVER AND PRECIP THAN CURRENTLY ANTICIPATED. LONG TERM...THURSDAY NIGHT THROUGH MONDAY... STRONG SHORT WAVE ENERGY EMANATING FROM DEEP UPPER LOW OVER GULF OF ALASKA WILL REACH PAC NW SHORE ON WEDNESDAY...SO UNTIL SAMPLED BY RAOB NETWORK...FURTHER GUIDANCE CORRECTIONS ARE LIKELY WITH STRONG LATE WEEK UPPER TROUGH AND ASSOCIATED SURFACE LOW TAKING SHAPE OVER THE PLAINS AND LIFTING NORTHEAST. ENSEMBLES CONTINUE TO EXHIBIT LARGE SPREAD AS WELL. AS MENTIONED EARLIER...ALL OPERATIONAL MODELS TODAY HAVE TRENDED MUCH SLOWER WITH SYSTEM AND THE AREA NOW LOOKS TO BE FIRMLY ENTRENCHED IN THE WARM SECTOR ON FRIDAY. NUDGED MODEL BLEND INITIALIZATION MAX T A BIT HIGHER...WHICH COULD STILL BE TOO CONSERVATIVE IN THE LOW 80S...AND ALSO CAPPED POPS AT SLIGHT TO LOW END CHANCE. THE SYSTEM LOOKS TO CLOSE OFF AND OCCLUDE SOMEWHERE OVER THE UPPER MIDWEST FRIDAY NIGHT INTO SATURDAY...WITH COLD FRONT OR OCCLUDED FRONT NOW NOT EXPECTED TO REACH WESTERN CWA UNTIL SATURDAY MORNING...SO IT COULD BE ANOTHER WARM DAY ESPECIALLY FOR THE EASTERN HALF OF THE CWA. THUNDERSTORMS WILL BE POSSIBLE ALONG/AHEAD OF FRONT BEFORE IT SWEEPS THROUGH BY THE LATE AFTERNOON AND EARLY EVENING. THE GFS HAS BACKED OFF A BIT ON THE COLD SHOT BEHIND THE FRONT...WHILE THE 12Z ECMWF FEATURES 850 MB TEMPS PLUNGING TO THE MINUS SINGLE DIGITS BY EARLY SUNDAY. SO DEPENDING ON THE DEPTH OF THE COOL SHOT...TEMPS IN LOW 60S CURRENTLY FORECAST COULD BE REASONABLE OR DOWNRIGHT CHILLY MID TO UPPER 50S IF ECMWF SOLUTION COMES CLOSER TO PASS. THIS WILL BE FOLLOWED BY A QUICK WARM UP TO NEAR NORMAL TEMPERATURES BY NEXT MONDAY. CONFIDENCE IN LONG TERM FORECAST PERIOD...LOW. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * LAKE BREEZE DISSIPATING OVER MDW...LIKELY DISSIPATING JUST EAST OF ORD. * SSW WINDS 200-220 DEGREES GUSTING TO 20-25 KT DEVELOPING LATE MORNING/MIDDAY TUESDAY. WINDS MAY TURN TO 230-240 DEGREES LATE AFTERNOON...BUT MORE LIKELY TO EARLY EVENING AS GUSTS EASE. MDB //DISCUSSION...UPDATED 00Z... LAKE BREEZE CONTINUES TO SURGE INLAND AND IT WILL BE A RACE BETWEEN IT DISSIPATING AND IT MAKING IT TO ORD. EXPECT THAT IT WILL DISSIPATE JUST TO THE EAST...AT LEAST TO THE POINT WHERE ANY WIND SHIFT WOULD BE LESS DRAMATIC WITH SPEEDS UNDER 10 KT. THE BOUNDARY HAS PRETTY MUCH PARKED OVER THE NORTHEAST CORNER OF MDW AND WILL DISSIPATE THERE. OTHERWISE...EXPECT SOUTH WINDS TO REMAIN STEADY IN SPEED THIS EVENING...EVENTUALLY TURNING SOUTH-SOUTHWEST OVERNIGHT AS THE PRESSURE GRADIENT ORGANIZES. LOW PRESSURE ACROSS THE DAKOTAS THIS EVENING WILL WEAKEN AS IT MOVES EASTWARD BUT BRING A WEAK COOL FRONT EASTWARD WITH IT LATER TUESDAY. SOUTH- SOUTHWEST WINDS WILL INCREASE TUESDAY MORNING WITH GUSTS IN THE 20-25 KT RANGE EXPECTED TO DEVELOP...WITH SLIGHTLY HIGHER GUSTS POSSIBLE AT RFD. WIND SPEED WILL EASE TUESDAY EVENING AS THE FRONTAL TROUGH APPROACHES WEAKENING THE PRESSURE GRADIENT. THE FRONT WILL CROSS THE AREA LATE EVENING/EARLY OVERNIGHT BRINGING A SHIFT TO LIGHT NORTHWEST WINDS. AM NOT EXPECTING ANY RAIN WITH THE FRONT BUT THERE MAY BE AN INCREASE IN VFR CLOUDINESS TUESDAY EVENING. MDB //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE IN LAKE BREEZE DISSIPATING...MEDIUM-HIGH CONFIDENCE THAT IT WILL DO SO JUST EAST OF ORD. * HIGH CONFIDENCE IN WINDS THROUGH MID TUESDAY AFTERNOON...MEDIUM CONFIDENCE IN TIMING TRANSITION TO 230/240 DEGREE DIRECTION. MDB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR WITH LOW SHRA/TSRA CHANCES WEDNESDAY NIGHT. THURSDAY THROUGH SATURDAY...PERIODIC SHRA/TSRA CHANCES WITH LOW CIGS POSSIBLE. SUNDAY...VFR. MDB && .MARINE... 241 PM...A MORE ACTIVE PATTERN IS EXPECTED INTO THIS WEEKEND WITH LOWER CONFIDENCE REGARDING SPECIFICS FRIDAY AND SATURDAY. STRONG LOW PRESSURE OVER SOUTH CENTRAL CANADA WILL MOVE NORTHEAST REACHING HUDSON BAY TUESDAY NIGHT. THE GRADIENT IS IN THE PROCESS OF TIGHTENING OVER THE NORTHERN PART OF THE LAKE AND THAT WILL CONTINUE TONIGHT INTO TUESDAY MORNING. ALONG A TRAILING COLD FRONT FROM THIS LOW...A WEAKER LOW WILL DEVELOP OVER THE DAKOTAS THIS EVENING. THIS LOW WILL QUICKLY BE STRETCHED ALONG THE FRONT OVERNIGHT...BUT JUST AHEAD OF THIS FRONT/TROUGH OF LOW PRESSURE... SOUTHERLY WINDS MAY INCREASE TO NEAR GALE FORCE OVER THE NORTHERN HALF OF THE LAKE THOUGH THE DURATION LOOKS TO BE FAIRLY SHORT... PERHAPS JUST 3-6 HOURS STARTING AROUND SUNRISE TUESDAY MORNING. WILL INCLUDED GUSTS TO 35 KTS FOR THIS POTENTIAL AND TRENDS WILL NEED TO BE MONITORED OVERNIGHT INTO TUESDAY MORNING. ONCE THIS FRONT MOVES EAST OF THE LAKE TUESDAY EVENING...WINDS WILL DIMINISH AND SHIFT WESTERLY OVER THE NORTHERN PART OF THE LAKE... TURNING LIGHT NORTHERLY THEN NORTHEASTERLY OVER THE SOUTH END OF THE LAKE AS HIGH PRESSURE BUILDS ACROSS THE SOUTHERN LAKES TUESDAY NIGHT AND SHIFTS NORTHEAST WEDNESDAY. ANOTHER STRONG AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE PLAINS WEDNESDAY NIGHT INTO THURSDAY AND THEN TURN NORTHEAST MOVING ACROSS THE GREAT LAKES REGION FRIDAY NIGHT OR SATURDAY. THE LATEST MODEL GUIDANCE SUGGESTS THAT THIS LOW WILL BE MOVING MUCH SLOWER AND STILL BE NEAR IOWA SATURDAY MORNING WITH A POSSIBLE WARM FRONT EXTENDING ACROSS THE NORTHERN OR CENTRAL PORTIONS OF LAKE MICHIGAN. A FRONTAL BOUNDARY WOULD RESULT IN SOME AMOUNT OF EASTERLY OR NORTHEASTERLY WINDS NORTH OF THE FRONT. IN ADDITION...STRONGER SOUTHERLY WINDS WILL BE DELAYED UNTIL THE LOW MOVES CLOSER TO THE LAKE. THUS CONFIDENCE REGARDING NOT ONLY THE TRACK OF THE LOW AND POTENTIAL FRONTAL BOUNDARY...BUT ALSO ITS SPEED IS LOW AND CHANGES TO THE CURRENT FORECAST CAN BE EXPECTED. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 705 PM CDT Mon Sep 30 2013 .DISCUSSION... ISSUED 303 PM CDT Mon Sep 30 2013 Forecast problems of today are the fog overnight, and the rain chances for the second half of this week. SHORT TERM...Tonight through Wednesday night. Morning analysis data shows stalled frontal zone over southern IN to southern IL and into MO. Moisture associated with the zone trapped beneath inversion during the morning and triggered fog and stratus. southerly flow over region will bring more of moisture back a little more northward overnight and so new grid forecast for tonight has fog in it. A second weak front dies over the northern half of IL Wednesday. With the continued advection of moisture northward, chance pops in the forecast Wednesday and Wednesday night with minor impulse moving from the southwest. LONG TERM...Thursday through Monday. Moist airmass over region through Thursday to continue to trigger chance pops. Then pops drops a little as frontal system in the plains takes shape on Thursday night to Friday and air becomes a little capped over IL. Models vary again on the timing of the cold front for the end of the week and this makes the exact timing of best chances for pop a little difficult. GFS now slower and EUR consistent on Friday night to Saturday crossing of region. Pops during that period remain in chance category. Cooler air flows into region Sunday. Goetsch && .AVIATION... ISSUED 700 PM CDT Mon Sep 30 2013 The stalled stationary front will linger across Illinois from near St Louis to Champaign tonight into tomorrow. Lingering ground level moisture will cause another round of fog later tonight. The latest HRRR guidance is showing dense fog 1/4sm and 100 ft ceilings developing toward 11z/6am for SPI and DEC, and come close to BMI and CMI. The RUC also shows areas of dense fog, but in varying coverage from HRRR. The NAM and GFS show only MVFR fog potential. We decided to include a tempo for LIFR fog and ceilings in the tafs for SPI, DEC, and CMI that reside closer to the stalled front. VLIFR conditions will be possible. After the fog and stratus clear, we may see a brief period of mvfr clouds redevelop around 3k ft as southerly return flow begins to bring increases in low-mid level moisture. Enough dry air aloft should help to dissipate any bkn mvfr layers in the afternoon, as surface winds increase from the SW to 11-14kt. Shimon && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1246 AM CDT SUN SEP 29 2013 .DISCUSSION... 730 PM CDT THE FORECAST HAD BEEN UPDATED TO SLOW THE EASTWARD PROGRESS OF POPS AND TO DIMINISH THEM SOME...THOUGH STILL THINK MOST AREAS WILL SEE AT LEAST SOME LIGHT RAIN TONIGHT. ALSO DIMINISHED THE TIMING OF THE WINDOW OF SLIGHT CHANCE OF THUNDER. THE GOES WATER VAPOR LOOP EARLY THIS EVE DEPICTS THE WELL- DEVELOPED AUTUMN UPPER LOW LIFTING NORTHEAST OVER WESTERN QUEBEC. A DEEP BUT NARROW-IN-WIDTH MOIST PLUME EXTENDS FROM TX THROUGH WI ASSOCIATED WITH THIS. THE 00Z DVN RAOB INDICATED 1.66 IN OF PWAT...WHICH LIKELY REFLECTS THE UPPER MAGNITUDE AGAIN THAT IS IN AN EVEN NARROWER AXIS. THERE IS A DISJOINT IN BEST DYNAMICS AND MOISTURE TRANSPORT/MAGNITUDES WITH THIS SYSTEM OVER THE IMMEDIATE REGION NOW AND THAT IS LEADING TO MAINLY LIGHT PRECIP COVERAGE AND INTENSITY...AND EXPECT THIS TO CONTINUE THROUGH 9-11 PM OR SO. THE BEST UPPER DIFLUENCE IS CURRENTLY OVER WI AND NORTHWARD WHERE BETTER SHOWER COVERAGE EXISTS...WHILE ANOTHER SHEARED WAVE AND FOCUSED RIGHT ENTRANCE REGION OF THE UPPER JET IS MOVING NORTHEAST FROM MO. HAVE BEGUN TO SEE AN UPTICK IN PRECIP WITH THIS FEATURE ACROSS PARTS OF WEST CENTRAL IL. THE SURFACE FRONT ITSELF IS LOCATED FROM MADISON WI TO NEAR GALESBURG AND MOVING SLOWLY EAST...WITH POST FRONTAL FORCING /F-GEN AND SOME ELEVATED INSTABILITY/ ALLOWING FOR SHOWERS EVEN BEHIND THIS. AS THE SHEARED WAVE FROM MO TRANSLATES NORTHEAST AND IN TANDEM WITH A MORE PRONOUN ED LLJ/MOISTURE TRANSPORT...DO ANTICIPATE THE INCREASE IN SHOWER COVERAGE THAT HAS BEEN ADVERTISED TO MOVE NORTHEAST. IT LOOKS TO MAINLY BE CONFINED TO EAST OF IL HIGHWAY 47...AND IT IS POSSIBLE IT ENDS UP EVEN BEING FURTHER EAST. THIS SOMEWHAT MORE STEADIER RAIN/SHOWER ACTIVITY THAT IS FORECAST SHOULD BE FAIRLY NARROW...SO TRIED TO TIME THAT FOCUS FOR THE HIGHEST /CATEGORICAL/ POPS. THE NORTH AMERICAN RAPID REFRESH ENSEMBLE SYSTEM /NARRE-TL/ REALLY HAS A GOOD HANDLE ON WHAT IS HAPPENING AND WHAT IS EXPECTED TO UNFOLD...AND DOES SHOW A VERY NARROW AXIS OF HIGHER POPS. BEFORE THAT...MAINLY SOME SPOTTY LIGHT RAIN OR EVEN DRIZZLE IMMEDIATE AHEAD OF THE FRONT IS FAVORED. ALSO BEHIND THE FRONT EXPECT THAT SHOWER ACTIVITY SHOULD CONTINUE ALONG THE MID- LEVEL BAROCLINIC ZONE AND POTENTIALLY INCREASE IN COVERAGE AS THIS FURTHER TIGHTENS WITH THE UPPER JET RIDGING PARALLEL TO IT. SO KEEP LIKELY POPS AN HOUR OR TWO BEHIND THE FRONT BUT MENTION MAINLY LIGHT INTENSITY. OVERALL NONE OF THIS POINTS TOWARD GREAT THUNDER CHANCES AND HAVE DIMINISHED COVERAGE AND TIMING. NO LIGHTNING STRIKES SEEN ANYWHERE NEAR THE AREA THE PAST SEVERAL HOURS. TEMPERATURE TRENDS LOOK GOOD AND HAVE JUST ADJUSTED/NUDGED TO NEAR TERM FRONTAL POSITION. MTF //PREV DISCUSSION... 254 PM CDT MAIN CONCERNS TODAY REVOLVE AROUND TIMING PRECIPITATION ASSOCIATED WITH A COLD FRONT SWEEPING ACROSS THE REGION THIS EVENING. THIS EVENING AND TONIGHT... A COLD FRONT SPANS FROM THE ARROWHEAD OF MINNESOTA SOUTH INTO EASTERN IOWA THIS AFTERNOON WITH PRECIP GENERALLY OCCURRING ALONG AND JUST AHEAD OF THIS SYSTEM. LIGHTNING ACTIVITY WAS CONFINED MAINLY TO MISSOURI...BUT HAS REALLY DISSIPATED OVER THE PAST FEW HOURS. LATEST RAP GUIDANCE DOES INDICATE POTENTIALLY A LITTLE MORE ROBUST INSTABILITY THAN PREVIOUSLY THOUGHT THOUGH...AND ACCAS OVER THE AREA THIS MORNING WOULD ALSO SUGGEST THE PRESENCE OF SOME MID LEVEL INSTABILITY...SO WILL MAINTAIN AT LEAST A SLIGHT CHANCE MENTION FOR THUNDERSTORMS TODAY THOUGH MAINLY EXPECT RAIN WITH A FEW EMBEDDED MODERATE SHOWERS. WHILE THERMODYNAMICALLY UNIMPRESSIVE...DYNAMIC FORCING THIS EVENT CONTINUES TO LEAD TO HIGH CONFIDENCE IN THE ENTIRE CWA SEEING WETTING RAINS THIS EVENING. WATER VAPOR IMAGERY SHOWS A WELL DEFINED NEGATIVELY TILTED VORT MAX LIFTING ACROSS THE UPPER MIDWEST WITH DEEP MOISTURE EXTENDING SOUTH ALONG THE FRONT. PWATS COULD BE PUSHING 2 INCHES ALONG THE FRONT AS IT SWEEPS ACROSS THE REGION TONIGHT. WHILE THE BEST UPPER LEVEL FORCING LIES NORTH OF THE AREA...STILL EXPECT DECENT HEIGHT FALLS TO SPREAD OVER NORTHERN ILLINOIS...ESPECIALLY LATE THIS EVENING. NAM/GFS INDICATE COUPLED JET WITH THE BEST AREA OF DIVERGENCE ALOFT MOVING DIRECTLY OVERHEAD THIS EVENING. THESE COUPLED WITH THE STRONG LOW LEVEL CONVERGENCE ALONG THE FRONT SHOULD LEAD TO A DEEP VERTICAL RESPONSE...WITH ACTIVITY ALONG THE FRONT INCREASING IN COVERAGE/INTENSITY LATE THIS EVENING AS THE FRONT MOVES ACROSS THE CENTRAL AND EASTERN PORTIONS OF THE CWA. SUNDAY THROUGH TUESDAY... FLAT RIDGING WILL BUILD OVER THE LOCAL AREA THROUGH THIS PERIOD WITH THE MAIN JET STREAM SETTING UP FROM THE PACIFIC NORTHWEST INTO THE NORTHERN GREAT LAKES...RESULTING IN DRY WEATHER WITH PRECIP CHANCES STAYING NORTH OF THE AREA. AT THE SURFACE...HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING COLD FRONT SUNDAY. NORTH/NORTHEAST WINDS SUNDAY WILL KEEP CONDITIONS QUITE A BIT COOLER NEAR THE LAKE FRONT SUNDAY...LIKELY IN THE MID 60S...BUT TEMPERATURES FARTHER INLAND SHOULD BE ABLE TO RISE INTO THE LOW TO MID 70S. CLEAR SKIES AND CALM WINDS UNDER THE RIDGE AXIS SUNDAY NIGHT WILL ALLOW TEMPERATURES TO EFFECTIVELY RADIATE WITH OVERNIGHT LOWS EXPECTED IN THE LOW TO MID 40S OUTSIDE OF URBAN HEAT ISLAND OF CHICAGO...WHICH IS EXPECTED TO STAY PROPPED INTO THE MID 50S. WOULDNT BE SURPRISED IF SOME OF THE TYPICAL COLD SPOTS DIP INTO THE 30S. WILL HAVE TO KEEP AN EYE ON FOG SUNDAY NIGHT...BUT FOR NOW GUIDANCE SUGGESTS THAT DEW POINTS MAY BE TOO DRY FOR WIDESPREAD FOG DEVELOP. WITH RECENT RAINFALL THOUGH...NOT CONFIDENT THAT MODELS ARE HANDLING LOW LEVEL MOISTURE VERY WELL. WILL INCLUDE MENTION FOR PATCHY FOG OUTSIDE THE METRO AREA. WITH THE RIDGE AXIS GRADUALLY SHIFTING EAST OF THE AREA ON MONDAY...RETURN FLOW WILL LEAD TO A WARMING TREND WITH MID TO UPPER 70S MONDAY...AND 80S POSSIBLE AGAIN BY TUESDAY. GFS/EMCWF BOTH SHOW THERMAL RIDGE LEANING OVER THE REGION TUESDAY WITH H85 TEMPS A LITTLE WARMER THAN TODAY IN THE 16-18C RANGE...THOUGH IF RECENT MODEL PERFORMANCE IS ANY INDICATOR...THIS MAY BE A BIT TOO WARM. EVEN TAKING A CONSERVATIVE APPROACH...GUIDANCE APPEARS TO BE A BIT ON THE COOL SIDE SO WILL MAINTAIN THE WARMER FORECAST OF LOW TO MID 80S. WEDNESDAY THROUGH SATURDAY... MODELS IN DECENT AGREEMENT THROUGH WEDNESDAY...WITH THE DEVELOPMENT OF A DEEP TROUGH OVER THE WEST COAST WEDNESDAY NIGHT...THEN BEGIN TO DIVERGE WITH TIMING/STRENGTH INTO THE WEEKEND. THE UPPER TROUGH IS EXPECTED TO PROGRESS EAST ACROSS THE ROCKIES...WITH SURFACE LOW DEVELOPING OVER THE PLAINS AND A WARM FRONT LIFTING NORTH ACROSS THE LOCAL AREA. TIMING IS THE MAIN ISSUE. THE GFS IS FASTEST...FOLLOWED BY THE ECMWF AND THEN THE GFS ENSEMBLE MEAN. A SPAGHETTI PLOT OF GEFS MEMBERS SHOWING SIGNIFICANT SPREAD BY FRIDAY EVENING...WITH THE MOST PROGRESSIVE MEMBER SHOWING THE TROUGH AXIS NEARING THE MISSISSIPPI VALLEY BY FRIDAY EVENING...WHILE SLOWEST MEMBERS HAVE A DEEPER CLOSED LOW STILL OVER THE INTERMOUNTAIN WEST. ALL THIS BOILS DOWN TO VERY LOW CONFIDENCE IN THE EXTENDED...THUS MAINTAINED A BLENDED MODEL SOLUTION IN THE EXTENDED FORECAST...UNTIL DETAILS START TO BECOME MORE CLEAR. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * RAIN WITH PERIODIC IFR TO START TAF CYCLE * WIND SHIFT TO NORTHEAST WITH LAKE BREEZE SUNDAY AFTERNOON IZZI //DISCUSSION...UPDATED 06Z... WELL ADVERTISED FRONTAL BAND OF RAIN WITH SOME EMBEDDED HEAVIER ELEMENTS IS PROGRESSING ACROSS THE REGION. GENERALLY MVFR CIGS/VSBY THOUGH SOME BRIEF PERIODS OF IFR EXPECTED WITH THE HEAVIER RAIN. RAIN SHOULD END IN THE NEXT COUPLE HOURS WITH A RAPID TRANSITION TO VFR AND CLEAR SKIES. NORTHWEST WINDS MOSTLY LESS THAN 10 KT WILL SHIFT TO NORTHEAST OFF THE LAKE SUNDAY AFTERNOON BEFORE GOING LIGHT/VARIABLE SUNDAY EVENING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN TIMING OF WIND SHIFT TO NE SUN PM * HIGH CONFIDENCE IN ALL OTHER ELEMENTS IZZI //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY THROUGH WEDNESDAY...VFR. THURSDAY AND FRIDAY...CHANCE SHRA/TSRA. MDB && .MARINE... 220 PM CDT HIGH PRESSURE IS OVER NEW ENGLAND WHILE A LOW IS OVER NORTHERN MINNESOTA/SOUTHWEST ONTARIO. WINDS HAVE STRUGGLED TO STRENGTHEN OVER THE LAKE TODAY...BUT ARE FINALLY STARTING TO PICK UP. WILL KEEP THE SMALL CRAFT ADVISORY GOING AND END IT AT 7PM TONIGHT AS PLANNED. THE HIGH SLOWLY SHIFTS OFF THE NE ATLANTIC COAST WHILE THE LOW REACHES HUDSON BAY TOMORROW. GUIDANCE IS STILL SUGGESTING WINDS WILL PICK UP TO 30KT THIS EVENING OVER THE NORTH HALF TO THE LAKE. IN ADDITION...SOUNDINGS STILL INDICATE THAT GALE FORCE GUSTS LIE JUST 200 FT ABOVE THE SURFACE. WILL KEEP OCNL GALE FORCE GUSTS GOING THROUGH 03Z AND HIGHER VESSELS WILL PROBABLY ENCOUNTER MORE THAN JUST OCNL GALE FORCE GUSTS. THE LOWS COLD FRONT SWEEPS OVER THE LAKE LATE THIS EVENING WITH NW WINDS 15-20 KT BEHIND IT. A WEAK SURFACE RIDGE MOVES OVER THE LAKE TOMORROW AND WINDS QUICKLY DIMINISH. THE HIGH PUSHES EAST WITH SOUTH WINDS EXPECTED ACROSS THE LAKE MONDAY AND TUESDAY. ANOTHER LOW PASSES OVER THE SOUTHERN CANADIAN PRAIRIES EARLY NEXT WEEK...AND EXPECTING THE PRESSURE GRADIENT TO TIGHTEN OVER THE NORTHERN HALF OF THE LAKE. THEREFORE...HAVE 30KT WINDS OVER THE NORTHERN HALF OF THE LAKE MONDAY NIGHT AND TUESDAY. WINDS TURN WEST AS THE LOW PUSHES EAST AND ANOTHER WEAK SURFACE RIDGE SETS UP OVER THE LAKE. LATE NEXT WEEK STILL LOOKS INTERESTING WITH A LARGE LOW CROSSING THE PLAINS AND PASSING OVER LAKE SUPERIOR. MODEL TIMING IS NOT CONSISTENT BETWEEN THE MODELS AND MODEL RUNS. THAT BEING SAID GUIDANCE IS STILL SUGGESTING STRONG SOUTH WINDS LATE NEXT WEEK AHEAD OF THE LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS JACKSON KY
543 PM EDT SUN SEP 29 2013 .UPDATE... ISSUED AT 542 PM EDT SUN SEP 29 2013 LATEST RADAR IS SHOWING SOME LIGHT SHOWERS/SPRINKLES MOVING INTO THE FAR SOUTHWESTERN COUNTIES ABOUT AN HOUR OR SO FASTER THAN WAS PREVIOUSLY FORECASTED. NOT A BIG CHANGE...BUT WENT AHEAD AND SPED UP ISOLATED PRECIP ABOUT AN HOUR TO START AT 21Z /NOW/. ALSO LOADED IN THE LATEST OBSERVATIONAL DATA TO MAKE SURE ONGOING FORECAST WAS MATCHING UP WITH CURRENT TEMPERATURES AND WINDS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 355 PM EDT SUN SEP 29 2013 19Z SFC ANALYSIS SHOWS THE DYING FRONT SETTLING INTO CENTRAL KENTUCKY WHILE ITS ASSOCIATED SHOWERS AND WANING. A FEW OF THESE SHOULD BE ABLE TO MAKE INTO THE WESTERN PARTS OF THE CWA OVER THE NEXT FEW HOURS ALONG WITH A FEW POP UP SHOWERS FURTHER EAST. PLENTY OF CLOUDS ARE FOUND THROUGH EAST KENTUCKY OUT AHEAD OF THESE SHOWERS...BUT TEMPERATURES STILL MANAGED TO MAKE IT INTO THE LOWER AND MID 70S IN MOST LOCATIONS. MEANWHILE...WITH LIGHT SOUTHWEST WINDS...DEWPOINTS ARE HOLDING IN THE UPPER 50S AND LOWER 60S. THE MODELS ARE IN GOOD AGREEMENT ALOFT LIFTING A TROUGH TO THE NORTHEAST FROM THE GREAT LAKES AND SHEARING IT OUT AS IT MOVES DEEPER INTO EASTERN CANADA TONIGHT. SOME LEFTOVER ENERGY WILL DRIFT INTO THE LOWER OHIO VALLEY TONIGHT AND ALSO DIMINISH IN THE FACE OF WEAK FLOW AT MID LEVELS ON MONDAY AND RISING HEIGHTS THAT NIGHT. GIVEN THE AGREEMENT IN THE MODELS...HAVE FOLLOWED A GENERAL BLEND FOR WEATHER DETAILS WITH A STRONGER LEAN THAN NORMAL TOWARD THE NEAR-TERM...HIGHER RESOLUTION HRRR AND RAP13 MODELS. SENSIBLE WEATHER WILL FEATURE THE MUDDLED REMNANTS OF THE FRONT AND ITS DISSIPATING SHOWERS PUSHING INTO THE CWA TONIGHT AND LINGERING IN THE AREA ON MONDAY. THIS WILL NECESSITATE THE INCLUSION OF ISOLATED SHOWERS IN THE FORECAST...THOUGH MOST PLACES WILL STAY DRY AND QPF WILL AVERAGE BELOW A TENTH OF AN INCH WHERE ANY SHOWER MANAGE TO PASS OVER. WILL KEEP THE TEMPERATURES RATHER MILD TONIGHT AND MONDAY NIGHT GIVEN THE CLOUDS AND CONTINUED ELEVATED MOISTURE CONTENT. DID ADD LIGHT FOG IN THE VALLEYS BOTH NIGHTS SHOULD THE CLOUDS CLEAR ENOUGH TO ALLOW FOR SOME RADIATIONAL COOLING. AGAIN USED THE CONSSHORT AND ITS BC BROTHER TO JUMP START THE TD AND WIND GRIDS THROUGH 12Z MONDAY...AND THE CONSALL THEREAFTER. FOR TEMPERATURES...USED THE OBS DATABASE AS A BASIS FOR THE DIURNAL CURVE ALONG WITH MODIFIED CONSALL MAX AND MIN TEMPS...ONLY MINOR TERRAIN ADJUSTMENT TONIGHT AND MONDAY NIGHT. AS FOR POPS...ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH FIRST PART OF THE SHORT TERM. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 345 PM EDT SUN SEP 29 2013 THE EXTENDED FORECAST PERIOD BEGINS ON TUESDAY WITH A ZONAL AND PROGRESSIVE UPPER LEVEL PATTERN IN PLACE AS THE JET WILL WILL REMAIN ALONG THE CANADIAN BORDER. MID AND UPPER LEVEL RIDGING FURTHER DEVELOPS OVER THE SOUTHEAST TUESDAY AND WEDNESDAY. DURING LATE TUESDAY AND WEDNESDAY...A MID LEVEL WAVE MOVE NORTHWARD OUT OF THE GULF AND INTO THE OHIO VALLEY REGION. THIS DISTURBANCE COUPLED WITH AN INCREASE OF MOIST SOUTHERLY FLOW WILL BE THE FOCUS OF SOME PRECIP CHANCES BY THURSDAY AND FRIDAY. ALSO...THE 12Z RUN OF THE GFS AND 00Z RUN OF THE EURO SHOW SOME AGREEMENT ON THIS SOLUTION. THEREFORE...BASED ON THE ALL BLENDS SOLUTION...WILL LIKELY PUT SOME CHANCE POPS IN FOR THURSDAY. THE INTERESTING PART OF THE FORECAST COMES INTO PLAY BY FRIDAY AND SATURDAY AS A DEEP TROUGH DEVELOPS OVER THE FRONT RANGE AND SHIFTS EAST. AT THIS POINT...THE GFS AND EURO ARE ADVERTISING THE FIRST FALL STRONG COLD FRONT WITH QUITE A COOL SHOT BEHIND THIS SYSTEM. WILL INTRODUCE CHANCE POPS BY FRIDAY AGAIN BASED ON THE ALL MODEL BLEND SOLUTION. IN DEALING WITH THE WEEKEND SYSTEM...BASED ON THE NEW EURO RUN AND COLLABORATION WITH NEIGHBORING OFFICES...WENT WITH A GOOD CHANCE OF PRECIP ON SATURDAY AND SUNDAY. MODELS AT THIS POINT ARE IN GOOD AGREEMENT WITH A SIGNIFICANT FRONT MOVING THROUGH BY NEXT WEEKEND. WITH SOUTHERLY FLOW THROUGH THE EARLY PART OF THE EXTENDED...TEMPERATURES WILL BE 3 TO 5 DEGREES ABOVE NORMAL BEFORE THE COLD FRONT MOVES THROUGH BY SUNDAY RESULTING IN A SIGNIFICANT COOL DOWN WITH TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL. THIS WILL RESULT IN THE COOLEST AIR OF THE SEASON SO FAR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 230 PM EDT SUN SEP 29 2013 MID LEVEL AND VFR LOWER CLOUDS ACCOMPANY THE FRONT AND ITS DYING BATCH OF RAIN SHOWERS HEADING TOWARD THE CWA THIS AFTERNOON. HAVE ADDED A VCSH FOR THESE SHOWERS TO THE TAFS FOR LATE THIS AFTERNOON AND THROUGH THE EVENING. PATCHY MVFR FOG WILL BE POSSIBLE LATE TONIGHT BEFORE CLEARING OUT SHORTLY AFTER SUNRISE ON MONDAY. WINDS WILL BE GENERALLY BETWEEN 5 AND 10 KTS FOR THE REMAINDER OF THIS AFTERNOON...FROM THE SOUTHWEST...AND LIGHT AND VARIABLE TONIGHT INTO MONDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
355 PM EDT SUN SEP 29 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 355 PM EDT SUN SEP 29 2013 19Z SFC ANALYSIS SHOWS THE DYING FRONT SETTLING INTO CENTRAL KENTUCKY WHILE ITS ASSOCIATED SHOWERS AND WANING. A FEW OF THESE SHOULD BE ABLE TO MAKE INTO THE WESTERN PARTS OF THE CWA OVER THE NEXT FEW HOURS ALONG WITH A FEW POP UP SHOWERS FURTHER EAST. PLENTY OF CLOUDS ARE FOUND THROUGH EAST KENTUCKY OUT AHEAD OF THESE SHOWERS...BUT TEMPERATURES STILL MANAGED TO MAKE IT INTO THE LOWER AND MID 70S IN MOST LOCATIONS. MEANWHILE...WITH LIGHT SOUTHWEST WINDS...DEWPOINTS ARE HOLDING IN THE UPPER 50S AND LOWER 60S. THE MODELS ARE IN GOOD AGREEMENT ALOFT LIFTING A TROUGH TO THE NORTHEAST FROM THE GREAT LAKES AND SHEARING IT OUT AS IT MOVES DEEPER INTO EASTERN CANADA TONIGHT. SOME LEFTOVER ENERGY WILL DRIFT INTO THE LOWER OHIO VALLEY TONIGHT AND ALSO DIMINISH IN THE FACE OF WEAK FLOW AT MID LEVELS ON MONDAY AND RISING HEIGHTS THAT NIGHT. GIVEN THE AGREEMENT IN THE MODELS...HAVE FOLLOWED A GENERAL BLEND FOR WEATHER DETAILS WITH A STRONGER LEAN THAN NORMAL TOWARD THE NEAR-TERM...HIGHER RESOLUTION HRRR AND RAP13 MODELS. SENSIBLE WEATHER WILL FEATURE THE MUDDLED REMNANTS OF THE FRONT AND ITS DISSIPATING SHOWERS PUSHING INTO THE CWA TONIGHT AND LINGERING IN THE AREA ON MONDAY. THIS WILL NECESSITATE THE INCLUSION OF ISOLATED SHOWERS IN THE FORECAST...THOUGH MOST PLACES WILL STAY DRY AND QPF WILL AVERAGE BELOW A TENTH OF AN INCH WHERE ANY SHOWER MANAGE TO PASS OVER. WILL KEEP THE TEMPERATURES RATHER MILD TONIGHT AND MONDAY NIGHT GIVEN THE CLOUDS AND CONTINUED ELEVATED MOISTURE CONTENT. DID ADD LIGHT FOG IN THE VALLEYS BOTH NIGHTS SHOULD THE CLOUDS CLEAR ENOUGH TO ALLOW FOR SOME RADIATIONAL COOLING. AGAIN USED THE CONSSHORT AND ITS BC BROTHER TO JUMP START THE TD AND WIND GRIDS THROUGH 12Z MONDAY...AND THE CONSALL THEREAFTER. FOR TEMPERATURES...USED THE OBS DATABASE AS A BASIS FOR THE DIURNAL CURVE ALONG WITH MODIFIED CONSALL MAX AND MIN TEMPS...ONLY MINOR TERRAIN ADJUSTMENT TONIGHT AND MONDAY NIGHT. AS FOR POPS...ENDED UP MOST SIMILAR TO THE MET NUMBERS THROUGH FIRST PART OF THE SHORT TERM. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 345 PM EDT SUN SEP 29 2013 THE EXTENDED FORECAST PERIOD BEGINS ON TUESDAY WITH A ZONAL AND PROGRESSIVE UPPER LEVEL PATTERN IN PLACE AS THE JET WILL WILL REMAIN ALONG THE CANADIAN BORDER. MID AND UPPER LEVEL RIDGING FURTHER DEVELOPS OVER THE SOUTHEAST TUESDAY AND WEDNESDAY. DURING LATE TUESDAY AND WEDNESDAY...A MID LEVEL WAVE MOVE NORTHWARD OUT OF THE GULF AND INTO THE OHIO VALLEY REGION. THIS DISTURBANCE COUPLED WITH AN INCREASE OF MOIST SOUTHERLY FLOW WILL BE THE FOCUS OF SOME PRECIP CHANCES BY THURSDAY AND FRIDAY. ALSO...THE 12Z RUN OF THE GFS AND 00Z RUN OF THE EURO SHOW SOME AGREEMENT ON THIS SOLUTION. THEREFORE...BASED ON THE ALL BLENDS SOLUTION...WILL LIKELY PUT SOME CHANCE POPS IN FOR THURSDAY. THE INTERESTING PART OF THE FORECAST COMES INTO PLAY BY FRIDAY AND SATURDAY AS A DEEP TROUGH DEVELOPS OVER THE FRONT RANGE AND SHIFTS EAST. AT THIS POINT...THE GFS AND EURO ARE ADVERTISING THE FIRST FALL STRONG COLD FRONT WITH QUITE A COOL SHOT BEHIND THIS SYSTEM. WILL INTRODUCE CHANCE POPS BY FRIDAY AGAIN BASED ON THE ALL MODEL BLEND SOLUTION. IN DEALING WITH THE WEEKEND SYSTEM...BASED ON THE NEW EURO RUN AND COLLABORATION WITH NEIGHBORING OFFICES...WENT WITH A GOOD CHANCE OF PRECIP ON SATURDAY AND SUNDAY. MODELS AT THIS POINT ARE IN GOOD AGREEMENT WITH A SIGNIFICANT FRONT MOVING THROUGH BY NEXT WEEKEND. WITH SOUTHERLY FLOW THROUGH THE EARLY PART OF THE EXTENDED...TEMPERATURES WILL BE 3 TO 5 DEGREES ABOVE NORMAL BEFORE THE COLD FRONT MOVES THROUGH BY SUNDAY RESULTING IN A SIGNIFICANT COOL DOWN WITH TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL. THIS WILL RESULT IN THE COOLEST AIR OF THE SEASON SO FAR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 230 PM EDT SUN SEP 29 2013 MID LEVEL AND VFR LOWER CLOUDS ACCOMPANY THE FRONT AND ITS DYING BATCH OF RAIN SHOWERS HEADING TOWARD THE CWA THIS AFTERNOON. HAVE ADDED A VCSH FOR THESE SHOWERS TO THE TAFS FOR LATE THIS AFTERNOON AND THROUGH THE EVENING. PATCHY MVFR FOG WILL BE POSSIBLE LATE TONIGHT BEFORE CLEARING OUT SHORTLY AFTER SUNRISE ON MONDAY. WINDS WILL BE GENERALLY BETWEEN 5 AND 10 KTS FOR THE REMAINDER OF THIS AFTERNOON...FROM THE SOUTHWEST...AND LIGHT AND VARIABLE TONIGHT INTO MONDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
230 PM EDT SUN SEP 29 2013 .UPDATE... ISSUED AT 225 PM EDT SUN SEP 29 2013 A BAND OF SHOWERS ASSOCIATED WITH THE DISSIPATING FRONT CONTINUE TO APPROACH THE CWA FROM THE WEST...BUT THEY ARE DIMINISHING...TOO. STILL EXPECT THE MINIMAL THREAT TO CROSS INTO OUR AREA LATE THIS AFTERNOON AND SPREAD SLOWLY EAST THROUGH THE EVENING. EVEN SO...MOST PLACES WILL STAY DRY AND ANY SPOTS THAT GET A SHOWER WILL SEE MEASUREMENTS IN ONLY A FEW HUNDREDTHS OF AN INCH...AT WORST. HAVE UPDATED THE FORECAST TO CONTINUE THIS LINE OF THINKING AND MATCH UP THE LATEST OBS AND TRENDS FROM THE SKY/T/TD TO THE GRIDS. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 1025 AM EDT SUN SEP 29 2013 13Z SFC ANALYSIS SHOWS HIGH PRESSURE MOVING OFF TO THE EAST IN THE FACE OF AN INBOUND...BUT SHEARING...COLD FRONT. THIS FRONT HAS A SOLID BAND OF SHOWERS ALONG IT THROUGH THE WESTERN PARTS OF THE STATE UP INTO SOUTHEAST INDIANA...CURRENTLY. THE MODELS DIFFER ON THE EXTENT THAT THIS PCPN BAND CAN HOLD TOGETHER INTO EAST KENTUCKY LATE THIS AFTERNOON. THE HRRR AND 06Z NAM12 ARE RATHER BULLISH...THOUGH BOTH QUITE DIMINISHED FROM ITS CURRENT STATE. HOWEVER...THE RAP13 AND 00Z ECMWF KEEP EAST KENTUCKY DRY THROUGH THIS EVENING. THE 06Z GFS IS PROBABLY THE MOST AGGRESSIVE AND WET MODEL WITH THIS DIEING BOUNDARY AND SEEMS WAY OVERDONE. TAKING ALL TOGETHER...AM UNCOMFORTABLE WITH TRYING TO GO DRY THROUGH 12Z ACROSS THE AREA AS THE FRONT DIES OUT OVERHEAD OR JUST TO THE WEST. ACCORDINGLY...HAVE REINTRODUCED ISOLATED SHOWERS INTO THE FORECAST FOR THE CWA FROM LATER THIS AFTERNOON AND THROUGH THE NIGHT. THE BEST CHANCES WILL BE OVER OUR WESTERNMOST COUNTIES...BUT EVEN THERE MOST PLACES WILL LIKELY STAY DRY. OTHERWISE...THE FORECAST IS ON TRACK SO HAVE MADE ONLY SMALL CHANGES TO THE SKY COVER...T...AND TD GRIDS THROUGH THE REST OF THE DAY BASED ON THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH THE ISSUANCE OF A FRESH SET OF ZONES. UPDATE ISSUED AT 637 AM EDT SUN SEP 29 2013 ASIDE FROM INGESTING OBSERVATION DATA INTO THE FORECAST GRIDS TO ESTABLISH NEW TRENDS...NO CHANGES WERE MADE TO THE FORECAST. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 316 AM EDT SUN SEP 29 2013 A VERY QUIET FORECAST ON TAP FOR TODAY THROUGH TOMORROW. HIGH PRESSURE WILL KEEP THE WEATHER OF EASTERN KENTUCKY DRY AND MILD AGAIN TODAY AND TONIGHT...AS IT MOVES OFF TO THE NORTHEAST. THE FORECAST MODELS ARE HAVING A VERY DIFFICULT TIME OVERCOMING THE RIDGE OF HIGH PRESSURE THAT IS CURRENTLY PARKED OVER THE EASTERN THIRD OF THE CONUS. THE MODELS ALL HAVE A COLD FRONT APPROACHING THE AREA FROM THE WEST...WITH RAIN SHOWERS FORMING ALONG IT THIS EVENING AND EARLY TONIGHT ACROSS INDIANA AND CENTRAL KENTUCKY. THE ISSUE IS THAT THESE SAME MODELS ARE ALL WASHING THE FRONT OUT AND STALLING IT BEFORE IT HAS A CHANCE TO MOVE ACROSS EASTERN KENTUCKY OVERNIGHT. THE ONLY HINT OF THE FRONT OVERNIGHT WILL LIKELY BE A DIFFICULT TO DETECT WIND SHIFT. WITH THAT IN MIND...DECIDED TO GO WITH A RAIN FREE FORECAST FOR THE OVERNIGHT HOURS...AS THE LACK OF DAYTIME HEATING WILL LIKELY RENDER THE FRONT UNABLE TO PRODUCE EVEN AN ISOLATED RAIN SHOWER. HOWEVER...WITH THE REMNANTS OF THE FRONT STILL SHOWING UP IN THE MODELS ON MONDAY...DID DECIDE TO KEEP IN A SLIGHT CHANCE OF SHOWERS AS WHAT IS LEFT OF THE BOUNDARY COULD BECOME ACTIVE DURING DAYTIME HEATING. CONFIDENCE IN THAT SCENARIO IS ALSO LOW CONSIDERING HOW DIFFUSE THE FRONT APPEARS TO BE IN THE LATEST MODELS. TEMPERATURES TODAY AND TOMORROW WILL BE RUNNING AT OR SLIGHTLY ABOVE NORMAL...WITH THE WARMER DAY BEING TODAY...AS EASTERN KENTUCKY WILL BE EXPERIENCING A SOUTHERLY FLOW PATTERN AND ONLY PARTLY CLOUDY SKIES FOR THE FIRST HALF OF THE DAY. HIGHS ARE EXPECTED TO BE MOSTLY IN THE MID 70S TODAY AND IN THE LOW TO MID 70S ON MONDAY. THE RIVER VALLEYS WILL ALSO LIKELY EXPERIENCE AREAS OF FOG AGAIN TONIGHT...AS WINDS GO NEAR CALM AND MOISTURE RECOVERY BEGINS TO OCCUR AHEAD OF AN APPROACHING ALBEIT RAPIDLY DISINTEGRATING COLD FRONT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 316 AM EDT SUN SEP 29 2013 OTHER THAN AN AREA OF LOW PRESSURE OFF THE COAST OF CAPE COD...THE 50H PATTERN IS NEARLY ZONAL ACROSS THE CONUS. THERE IS A SHORT WAVE TRACKING ACROSS THE CANADIAN PLAINS. HOWEVER ANY EFFECTS OF THIS SHOULD REMAIN NORTH OF THE BORDER. BY WED AFTERNOON THE PATTERN BEGINS TO CHANGE WITH HIGH PRESSURE BUILDING OVER THE SERN STATES AND A TROF SWINGING INTO THE NRN ROCKIES. THIS PATTERN WILL CONTINUE TO DEVELOP UNTIL BY THU NIGHT A WELL DEVELOPED TROF RESIDES OVER THE NRN PLAINS WITH THE RIDGE MOVING INTO THE ATLANTIC OFF THE FLA COAST. AS THE HIGH PRESSURE CONTINUES TO MOVE FURTHER INTO THE ATLANTIC...THE PLAINS TROF WILL SURGE INTO THE GREAT LAKES UNTIL IT SITS OVER THE ERN CONUS BY SAT NIGHT WITH RIDGING ACROSS THE ROCKIES. AT THE SFC...MON NITE SEES THE REMNANTS OF THE COLD FRONT DISSIPATING AND WEATHER TURNING DRY. THE HIGH WILL KEEP ERN KY DRY UNTIL LATE THU NITE WHEN THE SFC REFLECTION OF THE 50H TROF SWINGS THE NEXT COLD FRONT INTO THE COMMONWEALTH. THIS FRONT APPEARS TO BE RELATIVELY PROGRESSIVE AND SHOULD BRING SHOWERS FRIDAY AND FRIDAY NITE WITH A FEW THUNDERSTORMS POSSIBLE FRIDAY AFTERNOON. BY SAT HIGH PRESSURE WILL ONCE AGAIN BUILD INTO THE OH/TN VALLEY AND RETURN DRY WEATHER TO THE AREA. HIGH TEMPS WILL REMAIN AROUND 80 UNTIL SAT WHEN THE COLD FRONT DROPS READINGS INTO THE MID 70S. LOOK FOR THE COOL TEMPS TO REMAIN THRU THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 230 PM EDT SUN SEP 29 2013 MID LEVEL AND VFR LOWER CLOUDS ACCOMPANY THE FRONT AND ITS DIEING BATCH OF RAIN SHOWERS HEADING TOWARD THE CWA THIS AFTERNOON. HAVE ADDED A VCSH FOR THESE SHOWERS TO THE TAFS FOR LATE THIS AFTERNOON AND THROUGH THE EVENING. PATCHY MVFR FOG WILL BE POSSIBLE LATE TONIGHT BEFORE CLEARING OUT SHORTLY AFTER SUNRISE ON MONDAY. WINDS WILL BE GENERALLY BETWEEN 5 AND 10 KTS FOR THE REMAINDER OF THIS AFTERNOON...FROM THE SOUTHWEST...AND LIGHT AND VARIABLE TONIGHT INTO MONDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...DUSTY AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1025 AM EDT SUN SEP 29 2013 .UPDATE... ISSUED AT 1025 AM EDT SUN SEP 29 2013 13Z SFC ANALYSIS SHOWS HIGH PRESSURE MOVING OFF TO THE EAST IN THE FACE OF AN INBOUND...BUT SHEARING...COLD FRONT. THIS FRONT HAS A SOLID BAND OF SHOWERS ALONG IT THROUGH THE WESTERN PARTS OF THE STATE UP INTO SOUTHEAST INDIANA...CURRENTLY. THE MODELS DIFFER ON THE EXTENT THAT THIS PCPN BAND CAN HOLD TOGETHER INTO EAST KENTUCKY LATE THIS AFTERNOON. THE HRRR AND 06Z NAM12 ARE RATHER BULLISH...THOUGH BOTH QUITE DIMINISHED FROM ITS CURRENT STATE. HOWEVER...THE RAP13 AND 00Z ECMWF KEEP EAST KENTUCKY DRY THROUGH THIS EVENING. THE 06Z GFS IS PROBABLY THE MOST AGGRESSIVE AND WET MODEL WITH THIS DIEING BOUNDARY AND SEEMS WAY OVERDONE. TAKING ALL TOGETHER...AM UNCOMFORTABLE WITH TRYING TO GO DRY THROUGH 12Z ACROSS THE AREA AS THE FRONT DIES OUT OVERHEAD OR JUST TO THE WEST. ACCORDINGLY...HAVE REINTRODUCED ISOLATED SHOWERS INTO THE FORECAST FOR THE CWA FROM LATER THIS AFTERNOON AND THROUGH THE NIGHT. THE BEST CHANCES WILL BE OVER OUR WESTERNMOST COUNTIES...BUT EVEN THERE MOST PLACES WILL LIKELY STAY DRY. OTHERWISE...THE FORECAST IS ON TRACK SO HAVE MADE ONLY SMALL CHANGES TO THE SKY COVER...T...AND TD GRIDS THROUGH THE REST OF THE DAY BASED ON THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE. THESE UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH THE ISSUANCE OF A FRESH SET OF ZONES. UPDATE ISSUED AT 637 AM EDT SUN SEP 29 2013 ASIDE FROM INGESTING OBSERVATION DATA INTO THE FORECAST GRIDS TO ESTABLISH NEW TRENDS...NO CHANGES WERE MADE TO THE FORECAST. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 316 AM EDT SUN SEP 29 2013 A VERY QUIET FORECAST ON TAP FOR TODAY THROUGH TOMORROW. HIGH PRESSURE WILL KEEP THE WEATHER OF EASTERN KENTUCKY DRY AND MILD AGAIN TODAY AND TONIGHT...AS IT MOVES OFF TO THE NORTHEAST. THE FORECAST MODELS ARE HAVING A VERY DIFFICULT TIME OVERCOMING THE RIDGE OF HIGH PRESSURE THAT IS CURRENTLY PARKED OVER THE EASTERN THIRD OF THE CONUS. THE MODELS ALL HAVE A COLD FRONT APPROACHING THE AREA FROM THE WEST...WITH RAIN SHOWERS FORMING ALONG IT THIS EVENING AND EARLY TONIGHT ACROSS INDIANA AND CENTRAL KENTUCKY. THE ISSUE IS THAT THESE SAME MODELS ARE ALL WASHING THE FRONT OUT AND STALLING IT BEFORE IT HAS A CHANCE TO MOVE ACROSS EASTERN KENTUCKY OVERNIGHT. THE ONLY HINT OF THE FRONT OVERNIGHT WILL LIKELY BE A DIFFICULT TO DETECT WIND SHIFT. WITH THAT IN MIND...DECIDED TO GO WITH A RAIN FREE FORECAST FOR THE OVERNIGHT HOURS...AS THE LACK OF DAYTIME HEATING WILL LIKELY RENDER THE FRONT UNABLE TO PRODUCE EVEN AN ISOLATED RAIN SHOWER. HOWEVER...WITH THE REMNANTS OF THE FRONT STILL SHOWING UP IN THE MODELS ON MONDAY...DID DECIDE TO KEEP IN A SLIGHT CHANCE OF SHOWERS AS WHAT IS LEFT OF THE BOUNDARY COULD BECOME ACTIVE DURING DAYTIME HEATING. CONFIDENCE IN THAT SCENARIO IS ALSO LOW CONSIDERING HOW DIFFUSE THE FRONT APPEARS TO BE IN THE LATEST MODELS. TEMPERATURES TODAY AND TOMORROW WILL BE RUNNING AT OR SLIGHTLY ABOVE NORMAL...WITH THE WARMER DAY BEING TODAY...AS EASTERN KENTUCKY WILL BE EXPERIENCING A SOUTHERLY FLOW PATTERN AND ONLY PARTLY CLOUDY SKIES FOR THE FIRST HALF OF THE DAY. HIGHS ARE EXPECTED TO BE MOSTLY IN THE MID 70S TODAY AND IN THE LOW TO MID 70S ON MONDAY. THE RIVER VALLEYS WILL ALSO LIKELY EXPERIENCE AREAS OF FOG AGAIN TONIGHT...AS WINDS GO NEAR CALM AND MOISTURE RECOVERY BEGINS TO OCCUR AHEAD OF AN APPROACHING ALBEIT RAPIDLY DISINTEGRATING COLD FRONT. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 316 AM EDT SUN SEP 29 2013 OTHER THAN AN AREA OF LOW PRESSURE OFF THE COAST OF CAPE COD...THE 50H PATTERN IS NEARLY ZONAL ACROSS THE CONUS. THERE IS A SHORT WAVE TRACKING ACROSS THE CANADIAN PLAINS. HOWEVER ANY EFFECTS OF THIS SHOULD REMAIN NORTH OF THE BORDER. BY WED AFTERNOON THE PATTERN BEGINS TO CHANGE WITH HIGH PRESSURE BUILDING OVER THE SERN STATES AND A TROF SWINGING INTO THE NRN ROCKIES. THIS PATTERN WILL CONTINUE TO DEVELOP UNTIL BY THU NIGHT A WELL DEVELOPED TROF RESIDES OVER THE NRN PLAINS WITH THE RIDGE MOVING INTO THE ATLANTIC OFF THE FLA COAST. AS THE HIGH PRESSURE CONTINUES TO MOVE FURTHER INTO THE ATLANTIC...THE PLAINS TROF WILL SURGE INTO THE GREAT LAKES UNTIL IT SITS OVER THE ERN CONUS BY SAT NIGHT WITH RIDGING ACROSS THE ROCKIES. AT THE SFC...MON NITE SEES THE REMNANTS OF THE COLD FRONT DISSIPATING AND WEATHER TURNING DRY. THE HIGH WILL KEEP ERN KY DRY UNTIL LATE THU NITE WHEN THE SFC REFLECTION OF THE 50H TROF SWINGS THE NEXT COLD FRONT INTO THE COMMONWEALTH. THIS FRONT APPEARS TO BE RELATIVELY PROGRESSIVE AND SHOULD BRING SHOWERS FRIDAY AND FRIDAY NITE WITH A FEW THUNDERSTORMS POSSIBLE FRIDAY AFTERNOON. BY SAT HIGH PRESSURE WILL ONCE AGAIN BUILD INTO THE OH/TN VALLEY AND RETURN DRY WEATHER TO THE AREA. HIGH TEMPS WILL REMAIN AROUND 80 UNTIL SAT WHEN THE COLD FRONT DROPS READINGS INTO THE MID 70S. LOOK FOR THE COOL TEMPS TO REMAIN THRU THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 650 AM EDT SUN SEP 29 2013 BROKEN TO OVERCAST CIGS HAVE BEEN AFFECTING THE TAF SITES SEVERAL HOURS EARLIER THAN EXPECTED IN THE PREVIOUS FORECAST. NOT EXPECTING ANY PRECIPITATION AT THE TAF SITES THROUGH THE END OF THE TAF PERIOD. THE FOG THAT IS IN PLACE SHOULD BE GONE BY 13Z AT MOST LOCATIONS. MID LEVEL CIGS CONTINUE WITH APPROACHING COLD FRONT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...DUSTY AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
731 PM EDT MON SEP 30 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 408 PM EDT MON SEP 30 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN WITH A 120-130 KNOT 250-300 MB JET FROM THE PAC NW INTO THE NRN PLAINS. ONE MID LEVEL LOW WAS LOCATED OVER NRN MANITOBA WHILE ANOTHER SHORTWAVE TROUGH WAS MOVING INTO SW SASK. AT THE SFC...A TIGHT PRES GRADIENT BTWN HIGH PRES OVER THE ERN CONUS AND A 988 MB LOW INTO NRN MANITOBA HAS BROUGHT INCREASING SRLY WINDS THROUGH THE NRN GREAT LAKES. A WEAK COLD FRONT EXTENDED FROM THE MANITOBA LOW INTO NW MN. VIS LOOP SHOWED CONSIDERABLE MID/HIGH CLOUDS OVER UPPER MI WITH MAINLY CLEAR SKIES OVER MN AND NW WI. TONIGHT...SOUTH WIND GUSTING TO 20-30 MPH ARE EXPECTED TO CONTINUE OVER THE NRN TIER OF THE FCST AREA WITH THE STRONGEST WINDS OVER DOWNSLOPING LOCATIONS ALONG LAKE SUPERIOR. MIXING WILL KEEP MIN TEMPS IN THE 50S ACROSS THE AREA WITH READINGS CLOSER TO 60F FOR DOWNSLOPING LOCATIONS ALONG LAKE SUPERIOR. TUESDAY...THE WEAK COLD FRONT MOVING THROUGH THE AREA WILL RESULT IN VEERING WINDS TO WESTERLY. OTHERWISE...WITH 850 MB TEMPS AROUND 10C-11C INTO THE WEST...MAX READINGS ARE STILL EXPECTED TO CLIMB INTO THE LOWER TO MID 70S. DOWNSLOPE LOCATIONS OVER S CENTRAL UPPER MI SHOULD SEE TEMPS CLOSER TO 80. UPSTREAM OBS AND MDLS SUGGEST THAT THAT DRY ADVECTION AND DEEPR AFTERNOON MIXING WILL DROP DEWPOINTS INTO UPPER 30S OVER THE WRN INTERIOR BY MID TO LATE AFTERNOON. THE SLIGHTLY COOLER AIR INTO THE WEST...HOWEVER...SHOULD LIMIT MIN RH DROP TO AROUND 30 PERCENT. THE DRY CONDITIONS COMBINED WITH WEST WINDS GUSTING TO AROUND 25 MPH WILL RESULT IN ANOTHER DAY OF ELEVATED WILDFIRE RISK AS NOTED IN THE UPDATED WILDFIRE POTENTIAL STATEMENT. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 420 PM EDT MON SEP 30 2013 WILL START OUT TUESDAY NIGHT WITH MAINLY ZONAL FLOW ALOFT...WITH THE EXITING INITIAL COLD FRONT OVER FAR E UPPER MI AND THE MAIN SFC LOW OVER FAR N ONTARIO AND S LAKE HURON. GIVEN THE MUCH OF THE ENERGY REMAINS WELL TO OUR N...THE MAIN RESULT WILL THE BE THE INCREASED PRESSURE GRADIENT. EXPECT W WINDS GUSTING 20-28KTS THROUGH TUESDAY NIGHT. THE SECONDARY TROUGH/COLD FRONT NEVER REALLY GETS HERE ON WEDNESDAY...AS THE SFC LOW EXITS INTO N QUEBEC AND A RIDGE OF HIGH PRESSURE BRIEFLY BUILDS. EXTENDED THE PERIOD OF DRY WEATHER A BIT LONGER...THROUGH WEDNESDAY EVENING. LOW PRESSURE SPINNING ACROSS THE CENTRAL PLAINS MID WEEK WILL EXTEND A TROUGH/WARM FRONT ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT...AS THE MAIN LOW SLOWLY NEARS FROM THE SW. THERE ARE SIGNIFICANT ENOUGH DIFFERENCES IN THE LOCATION OF THE NEAR 1000MB LOW SATURDAY TO RESULT IN A CONSENSUS APPROACH AT THIS TIME. THIS WILL LEAD TO HIGH CHC TO DEF POPS FOR THURSDAY THROUGH SATURDAY. WILL WAIT UNTIL WE GET A CLEARER SOLUTION BEFORE PIN POINTING EXACT LOCATIONS AND TIMING. THE CONSENSUS IS TO HAVE THE LOW SHIFT NE DURING THE DAY SUNDAY...WITH W-NW WINDS LINGERING BEHIND THE LOW. THE 12Z ECMWF DOES HAVE 850MB TEMPS FALLING TO AROUND -2C LATE SATURDAY NIGHT THROUGH SUNDAY....WHICH WILL LIKELY KEEP A BKN-OVC SKY OVERHEAD. ANOTHER BRIEF RIDGE IS FIGURED SUNDAY NIGHT BEFORE A QUICK LOW SKIRTING THE US/CANADIAN BORDER NEARS FOR MONDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 730 PM EDT MON SEP 30 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. WINDS SHOULD REMAIN FAIRLY GUSTY AOA 20KT TONIGHT AT KIWD BUT SHOULD DECOUPLE SOMEWHAT AT KCMX/KSAW WHERE LLWS WAS INCLUDED IN THE FCST. SHOULD CONTINUE TO BE GUSTY BEHIND A COLD FRONT TUE AT IWD AND CMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 408 PM EDT MON SEP 30 2013 SRLY WINDS TO 25 KNOTS ARE EXPECTED TO VEER TO THE WEST TUESDAY AND INCREASE TO 30 KNOTS AS A WEAK COLD FRONT MOVES THROUGH LAKE SUPERIOR. WEST WINDS WILL DIMINISH WED AS A RIDGE BUILDS INTO THE AREA. MODELS ARE IN BETTER AGREEMENT SHOWING A LOW PRESSURE SYSTEM DEVELOPING IN THE LEE OF THE ROCKIES WITH A TROUGH EXTENDING INTO THE UPPER GREAT LAKES THU INTO FRI. THIS PATTERN SHOULD RESULT IN E-SE WINDS OVER CENTRAL AND ERN LAKE SUPERIOR AND STRENGTHENING NE WINDS TO 25 KT OVER THE WRN PART OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EDT SUN SEP 29 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 405 PM EDT SUN SEP 29 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A 130 KNOT 250-300 MB JET INTO THE PAC NW AS A TROUGH LINGERS OFFSHORE FROM BC. DOWNSTREAM HEIGHTS WERE RISING ACROSS THE UPPER MS VALLEY AND WRN GREAT LAKES IN THE WEAK OF THE DEPARTING TROUGH INTO NE ONTARIO. AT THE SFC...SW WINDS WERE INCREASING AS SFC RIDGE FROM NRN LOWER MI TO SE KS GRADUALLY SLIDES TO THE SE. TONIGHT...CLEAR SKIES AND LIGHT WINDS ESPECIALLY INTO THE EARLY OVERNIGHT HOURS SHOULD ALLOW FOR MIN TEMPS TO DIP INTO THE LOWER TO MID 40S OVER THE INTERIOR CENTRAL AND EAST WHILE SOUTHERLY DOWNSLOPE WINDS AND ASSOC MIXING WILL KEEP TEMPS IN THE LOWER 50S ALONG LAKE SUPERIOR. PATCHY FOG OVER THE INTERIOR EAST HALF WILL BE POSSIBLE AS LIGHT SOUTHERLY UPSLOPE FLOW FROM LAKE MI WILL CONTRIBUTE ADDED LOW LEVEL MOISTENING. MONDAY...SW WAA WILL INCREASE...PUSHING 850 MB TEMPS INTO THE 12C TO 14C RANGE. DESPITE SOME INCREASE IN HIGH CLOUDS...PER 600-400 MB RH FCST...SUNSHINE AND MIXING INTO THE 875-850 MB LAYER SUPPORTS MAX TEMPS ON THE HIGHER SIDE OF GUIDANCE...INTO THE LOWER TO MID 70S. FCST MIXED LAYER WINDS INTO THE 25-30 KNOT RANGE SHOULD RESULT IN WIND WINDS GUSTING TO AROUND 30 MPH IN THE AFTERNOON. WITH DEWPOINTS ALSO DROPPING INTO THE LOWER 40S RESULTING IN RH VALUES OF AROUND 35 PERCENT...FIRE WEATHER RISKS WILL INCREASE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 405 PM EDT SUN SEP 29 2013 FOR MON NIGHT THROUGH WED...A LOW PRESSURE SYSTEM WILL MOVE ACROSS NRN ONTARIO ON TUESDAY...DRAGGING A WEAK SFC TROUGH/COLD FRONT ACROSS THE CWA TUE AFTERNOON INTO EARLY TUE NIGHT. 850MB TEMPS INCREASE BY 3-4C TO AROUND 17C MON NIGHT IN INCREASING SW FLOW AHEAD OF THE TROUGH. THIS WILL MAKE FOR A WARM AND GUSTY MON NIGHT...ESPECIALLY IN DOWNSLOPING REGIONS FROM THE NW WINDS. WHILE THE FRONT MOVES THROUGH ON TUE...DO NOT EXPECT ANY PRECIP. THE 00Z/29 ECMWF BROUGHT RAIN A BIT FARTHER S THAN THE PREVIOUS RUNS...BUT IT IS ONE OF THE ONLY MODELS SHOWING PRECIP THAT FAR S...AND IT DOES NOT SEEM REALISTIC SINCE THE BEST FORCING FROM THE LOW WILL BE N OF THE CWA AND THE RIGHT EXIT REGION OF THE UPPER JET WILL BE OVER THE AREA. WILL KEEP THE TIME PERIOD DRY AT THIS TIME. WITH WNW WINDS AND COOLER TEMPS OVERHEAD...WED LOOKS TO SEE CLOSER TO SEASONAL TEMPS...BUT STILL ABOVE NORMAL WITH HIGHS IN THE 60S TO AROUND 70. THINGS BECOME SIGNIFICANTLY MORE UNCERTAIN THU THROUGH SUN AS MODELS CONTINUE TO HAVE VERY POOR RUN TO RUN CONTINUITY AND MODEL TO MODEL AGREEMENT IS LACKING. THE UNCERTAINTY IS WITH MORE SIGNIFICANT UPPER LEVEL ENERGY THAT MODELS HAVE MOVING INTO THE CENTRAL CONUS LATE IN THE WEEK INTO NEXT WEEKEND...WHICH COMBINES WITH OTHER MORE SUBTLE PIECES OF UPPER ENERGY TO POSSIBLY CAUSE RAPID SFC CYCLOGENESIS OVER THE PLAINS. WITH THIS TYPE OF VOLATILE SYSTEM...SUBTLE FEATURES THAT ARE BEYOND THE PREDICTABLE CAPABILITIES OF LOWER RESOLUTION MODELS AT THIS RANGE WILL MAKE SIGNIFICANT DIFFERENCES IN THE STRENGTH AND TRACK OF THE SYSTEM...WHICH MAKES FOR HUGE CHANGES IN THE FORECAST...ESPECIALLY WITH MORE SPECIFIC DETAILS. IF THE SYSTEM DOES FOLLOW THE WORST CASE SCENARIO...WINDS WOULD BE THE PRIMARY THREAT AS THE SYSTEM WOULD DEEPEN WHILE MOVING ACROSS THE CWA BEFORE VERY QUICKLY MOVING OFF TO THE NE...CAUSING A RAPID PRESSURE CHANGE AND STRONG GRADIENT FLOW. THIS WORST CASE SCENARIO WOULD RESULT IN VERY STRONG WINDS /ESPECIALLY OVER THE GREAT LAKES/ WITH STORM FORCE WINDS POSSIBLE. OTHERWISE...PRECIP LOOKS TO FALL ENTIRELY...OR AT LEAST MOSTLY...IN THE FORM OF RAIN. HOWEVER...IT IS WORTH NOTING AGAIN THAT THE FORECAST FOR THIS SYSTEM IS VERY UNCERTAIN AND MODEL DEPICTIONS WILL SURELY CHANGE OVER THE NEXT FEW DAYS. WHILE THERE IS NO VALUE IN ADDING TOO MANY SPECIFIC DETAILS ABOUT THE SYSTEM...THOSE WITH VULNERABLE INTERESTS /ESPECIALLY TO WINDS/ SHOULD KEEP UPDATED ON THIS PART OF THE FORECAST. ONE THING THAT DOES LOOK MORE CERTAIN IS THAT COLDER TEMPS AND MORE UNSETTLED/WETTER WEATHER LOOKS IN STORE FOR THE LAST FEW DAYS OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 133 PM EDT SUN SEP 29 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. LLWS IS EXPECTED AT IWD AND CMX TONIGHT AS STRONG SW WINDS DEVELOP ABOVE THE DECOUPLED SFC LAYER. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 405 PM EDT SUN SEP 29 2013 AS HIGH PRESSURE SHIFTS TO THE SOUTHEAST AND A TROUGH DEVELOPS OVER THE NORTHERN PLAINS SOUTH WINDS WILL INCREASE TO 15 TO 25 KNOTS LATE TONIGHT AND MONDAY WITH A GRADUAL SHIFT TO THE SOUTHWEST ON TUESDAY. WINDS WILL DIMINISH WED AS A RIDGE BUILDS INTO THE AREA. CONFIDENCE IN THE WIND FORECAST DROPS OFF BY LATE THIS WEEK AS MODELS OFFER DIFFERING SOLUTIONS ON THE DEVELOPMENT AND MOVEMENT OF A SURFACE LOW INTO THE WESTERN GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 PM EDT SUN SEP 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 531 AM EDT SUN SEP 29 2013 08Z WV IMAGERY AND RUC ANALYSIS SHOW A PROMINENT SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES. THIS SHORTWAVE HAS PUSHED A SFC COLD FRONT EAST OF UPPER MI EARLY THIS MORNING. LATEST RADAR IMAGERY SHOWS THAT LAST OF SHRA ASSOC WITH FRONT HAS PUSHED EAST OF THE FCST AREA. GUSTY WESTERLY WINDS AT OR ABOVE 30 KT OVER THE PORTAGE CANAL AND CENTRAL/ERN LAKE SUPERIOR IN THE WAKE OF THE COLD FRONT SHOULD DIE DOWN QUICKLY IN THE NEXT FEW HOURS AS THE PRES GRADIENT SLACKENS WITH THE HIGH PRES RDG BUILDING IN FM THE WEST. TODAY...MODELS IN AGREEMENT SHOWING SHORTWAVE TROUGH LIFTING INTO NORTHERN ONTARIO AND REACHING JAMES BAY THIS AFTERNOON. SUBSIDENCE/DRYING IN THE WAKE OF THE COLD FRONT HAS RESULTED IN CLEAR SKIES ACROSS THE FCST AREA EARLY THIS MORNING. HOWEVER...THE 850 MB THERMAL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCT-BKN STRATOCU CLOUDS OVR THE CNTRL AND EASTERN FCST AREA BY LATE MORNING INTO EARLY AFTERNOON. MIXING TO 850 MB RESULTS IN MAX TEMPS IN THE MID TO UPPER 60S MOST LOCATIONS. TONIGHT...CLEAR SKIES AND LIGHT WINDS ESPECIALLY INTO THE EARLY OVERNIGHT HOURS SHOULD ALLOW FOR MIN TEMPS TO DIP INTO THE LOWER TO MID 40S OVER THE INTERIOR CENTRAL AND EAST WHILE SOUTHERLY DOWNSLOPE WINDS AND ASSOC MIXING WILL KEEP TEMPS CLOSER TO 50F ALONG THE LAKE SUPERIOR SHORE. LEFT IN PATCHY FOG OVER THE INTERIOR EAST HALF AS LIGHT SOUTHERLY UPSLOPE FLOW FROM LAKE MI COULD CONTRIBUTE ADDED MOISTENING FOR SOME FOG DEVELOPMENT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 531 AM EDT SUN SEP 29 2013 UPCOMING WEEK FEATURES A NEGATIVE PACIFIC AND NORTH AMERICAN /PNA/ TELECONNECTION PATTERN WITH BROAD ENERGETIC TROUGHING GULF OF ALASKA INTO PACIFIC NORTHWEST EARLY THIS WEEK EVENTUALLY TRANSLATING INTO A STRONG TROUGH INTO THE CNTRL CONUS MID TO LATE WEEK. AS TROUGH MOVES TO CNTRL CONUS...LOW LEVEL CYCLOGENESIS DEVELOPS FROM CNTRL PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY ON THURSDAY. SFC LOW AND A COLD FRONT SLIDES ACROSS UPPER GREAT LAKES ON FRIDAY THOUGH IT IS PRETTY UNCERTAIN HOW STRONG OF SYSTEM WILL OCCUR. MUCH COOLER AIR DROPS ACROSS UPPER LAKES IN WAKE OF THE LOW LATER FRIDAY INTO SATURDAY. AIRMASS LOOKS CERTAINTY COLD ENOUGH TO RESULT IN SOME LK EFFECT RAIN...BUT PROBABLY JUST STAYS WARM ENOUGH TO KEEP MIXED PRECIPITATION OUT OF THE PICTURE...AT LEAST FOR NOW. AHEAD OF THE DEVELOPING TROUGHING ALOFT AND EVENTUALLY AT THE SFC...WARM AIR ADVECTION ALOFT AND DIVERGENCE ALOFT WILL SPREAD VEILS OF MID AND HIGH CLOUDS ACROSS NORTHERN PLAINS AND UPPER LAKES EARLY THIS WEEK. LOW-LEVELS TOO DRY TO ADD ANY RAIN SHOWERS DESPITE THE WARM AIR ADVECTION. WITH A LOWER SUN ANGLE NOW BECOMING A FACTOR...CLOUDS WILL CUT INTO EXPECTED MAX TEMPS SOME BUT WILL STILL SEE TEMPS 10-15 DEGREES ABOVE NORMAL WITH READINGS TOPPING OUT IN THE LOW TO MID 70S. BOTH DAYS MAY BE ON THE BREEZY SIDE AS WELL...WITH BEST SHOT OF SEEING 30+ MPH GUSTS ON MONDAY AS LOW-LEVEL JET SLIDES ACROSS AREA. HIGHER CLOUDS WILL DAMPEN DEEPER MIXING POTENTIAL AND WILL LIKELY KEEP HUMIDITY VALUES FROM BOTTOMING OUT TOO MUCH...BUT STILL COULD SEE INTERIOR WEST CWA DROP TO 35 PCT BOTH MONDAY AND TUESDAY AFTN. IF TRENDS HOLD UP COULD SEE NEED FOR A WILDFIRE POTENTIAL STATEMENT OR AT LEAST A MENTION IN HAZARDOUS WEATHER OUTLOOK. LEAD SFC TROUGH CROSSES THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY. STILL TOO DRY FOR ANY RAIN...BUT SHOULD SEE YET ANOTHER SURGE OF MID CLOUDS AND WILL SEE TEMPS COOL 5-10F COMPARED TO MONDAY AND TUESDAY. WESTERLY WINDS RESULT IN THE MOST NOTEABLE COOLING OVER THE KEWEENAW. HUMIDITY VALUES ACTUALLY COULD BE LOWER ON WEDNESDAY AS DWPNTS DROP FURTHER. MAIN WEATHER FOCUS FOR THE WEEK WILL BE LATE THIS WEEK AND INTO NEXT WEEKEND AS DEEP TROUGH AFFECTS THE GREAT LAKES. UNCERTAINTY ABOUNDS. MODELS CONTINUE TO STRUGGLE IN HOW QUICKLY TO BRING INITIAL LOW-LEVEL TROUGHING AND THE RESULTANT SURGE OF WARM AIR ADVECTION AND UPPER DIVERGENCE GENERATED SHOWERS INTO THE UPPER LAKES. LATEST GFS SHOWING A QUICKER TREND IN BRINGING QPF ACROSS MOST OF CWA BY 12Z THURSDAY THAN PREVIOUS THREE RUNS DID. ECMWF WHICH HAS REALLY BEEN ALL OVER THE PLACE WITH ITS TIMING HAS JOINED GFS IN SHOWING QUICKER EASTWARD TREND. GEM-NH IS GENERALLY CONSISTENT WITH PREVIOUS RUNS IN KEEPING MOST OF THE QPF WEST OF CWA BY 12Z THURSDAY AND ONLY SLOWLY BRINGING IT ACROSS AS MAJORITY OF DIVERGENCE ALOFT HELPS TO FOCUS CONCENTRATED AREA OF RAIN OVR MINNESOTA INTO NW ONTARIO ALONG AND NORTH OF COOLER SIDE OF DEVELOPING SFC-H85 LOWS IN ENHANCED FGEN AREA. GIVEN UNCERTAINTY AND INCONSISTENCIES BTWN THE GFS...ECMWF AND GEM-NH HAVE STAYED CLOSE TO CONSENSUS HIGHER CHANCE POPS THURSDAY INTO FRIDAY. PROBABLY WILL BE ONE OR TWO PERIODS OF GREATER RAIN CHANCES...BUT DETAILS ARE FAR FM CERTAIN. ELEVATED INSTABILITY WITH SI/S BLO 0C LED TO ADDING TSRA OVER SCNTRL ON THURSDAY IN WHAT SHOULD BE THE WARMER SECTOR OF THE CYCLONE. FRONTAL BOUNDARY RAINS MOVE THROUGH THURSDAY NIGHT OR FRIDAY. MAIN STICKING POINT IS JUST HOW WRAPPED UP WILL SFC LOW TREND AS IT MOVES THROUGH...MAINLY LEADING TO RAIN COVERAGE ISSUES WITH POTENTIAL DRY SLOT. AT THIS POINT...APPEARS THAT UPPER LAKES WOULD BE ON COOLER/WETTER SIDE OF THE LOW WITH SOME POTENTIAL FOR HEAVIER RAIN WITH PWATS OF 1.5 INCHES OR 200 PCT OF NORMAL INTERACTING WITH LOW-LEVEL FGEN AND UPSLOPE FLOW OFF LK SUPERIOR. THOUGH DETAILS OF HOW WE GET THERE ARE UNCLEAR...IT EVENTUALLY TURNS MUCH COOLER LATER FRIDAY INTO SATURDAY AS THE LOW SLOWLY MOVES AWAY FROM REGION AS UPPER TROUGH DEEPENS OVER GREAT LAKES. H85 TEMPS TO AT LEAST -4C SEEM LIKE GOOD BET...LEADING TO PLENTY OF LK EFFECT CLOUDS /LK SFC TEMPS AROUND +12C ON AVERAGE/ AND PROBABLY SOME LK EFFECT SHOWERS FRIDAY NIGHT INTO SATURDAY MORNING IF THERE IS ENOUGH SYNOPTIC MOISTURE/CYCLONIC FLOW LINGERING DURING THIS TIME. THE MOISTURE WILL ALSO FACTOR IN ON WHETHER THE FIRST SNOWFLAKES OF THE YEAR WILL FLY OVER THE CWA. RIGHT NOW WILL KEEP THE SNOW OUT OF THE FORECAST AS LATEST RUNS ARE MORE PROGRESSIVE WITH THE LOW AND DRY OUT THE H85-H7 LAYER CONSIDERABLY. IN THE FOR WHAT IT IS WORTH DEPARTMENT...TWO CLOSEST SLU CIPS ANALOGS TURNED UP EVENTS FROM LATE SEPTEMBER AND MID OCTOBER THAT PRODUCED OVER AN INCH OF RAIN ACROSS PARTS OF CWA WITH SOME SNOW AS THOSE SYSTEMS DEPARTED. WE SHALL SEE ON THIS ONE. CERTAINLY WILL BE A CHILLY START TO NEXT WEEKEND WITH THE HIGHER TERRAIN OF THE NORTH STAYING IN THE 40S AS A GUSTY NW WIND ONLY ADDS TO THE CHILL. COOLER PATTERN DOES NOT LOOK TO PERSIST THOUGH AS BOTH GFS/ECMWF INDICATE WARMER TEMPS RETURNING IN SOME SHAPE OR FORM DAYS 7-10. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 133 PM EDT SUN SEP 29 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. LLWS IS EXPECTED AT IWD AND CMX TONIGHT AS STRONG SW WINDS DEVELOP ABOVE THE DECOUPLED SFC LAYER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 531 AM EDT SUN SEP 29 2013 THERE COULD BE A BRIEF PD OF GALE FORCE GUSTS ALONG AND EAST OF THE KEWEENAW PENINSULA EARLY THIS MORNING DUE TO FAVORED WESTERLY CONVERGENT FLOW IN THE WAKE OF THE COLD FRONT. HIGH PRESSURE WILL THEN BUILD IN TODAY AND QUICKLY DECREASE THE WINDS ACROSS THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR LATE MONDAY AND INTO TUE MORNING WITH A FEW GUSTS REACHING 25 KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...JLB MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
724 AM EDT SUN SEP 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 531 AM EDT SUN SEP 29 2013 08Z WV IMAGERY AND RUC ANALYSIS SHOW A PROMINENT SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES. THIS SHORTWAVE HAS PUSHED A SFC COLD FRONT EAST OF UPPER MI EARLY THIS MORNING. LATEST RADAR IMAGERY SHOWS THAT LAST OF SHRA ASSOC WITH FRONT HAS PUSHED EAST OF THE FCST AREA. GUSTY WESTERLY WINDS AT OR ABOVE 30 KT OVER THE PORTAGE CANAL AND CENTRAL/ERN LAKE SUPERIOR IN THE WAKE OF THE COLD FRONT SHOULD DIE DOWN QUICKLY IN THE NEXT FEW HOURS AS THE PRES GRADIENT SLACKENS WITH THE HIGH PRES RDG BUILDING IN FM THE WEST. TODAY...MODELS IN AGREEMENT SHOWING SHORTWAVE TROUGH LIFTING INTO NORTHERN ONTARIO AND REACHING JAMES BAY THIS AFTERNOON. SUBSIDENCE/DRYING IN THE WAKE OF THE COLD FRONT HAS RESULTED IN CLEAR SKIES ACROSS THE FCST AREA EARLY THIS MORNING. HOWEVER...THE 850 MB THERMAL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCT-BKN STRATOCU CLOUDS OVR THE CNTRL AND EASTERN FCST AREA BY LATE MORNING INTO EARLY AFTERNOON. MIXING TO 850 MB RESULTS IN MAX TEMPS IN THE MID TO UPPER 60S MOST LOCATIONS. TONIGHT...CLEAR SKIES AND LIGHT WINDS ESPECIALLY INTO THE EARLY OVERNIGHT HOURS SHOULD ALLOW FOR MIN TEMPS TO DIP INTO THE LOWER TO MID 40S OVER THE INTERIOR CENTRAL AND EAST WHILE SOUTHERLY DOWNSLOPE WINDS AND ASSOC MIXING WILL KEEP TEMPS CLOSER TO 50F ALONG THE LAKE SUPERIOR SHORE. LEFT IN PATCHY FOG OVER THE INTERIOR EAST HALF AS LIGHT SOUTHERLY UPSLOPE FLOW FROM LAKE MI COULD CONTRIBUTE ADDED MOISTENING FOR SOME FOG DEVELOPMENT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 531 AM EDT SUN SEP 29 2013 UPCOMING WEEK FEATURES A NEGATIVE PACIFIC AND NORTH AMERICAN /PNA/ TELECONNECTION PATTERN WITH BROAD ENERGETIC TROUGHING GULF OF ALASKA INTO PACIFIC NORTHWEST EARLY THIS WEEK EVENTUALLY TRANSLATING INTO A STRONG TROUGH INTO THE CNTRL CONUS MID TO LATE WEEK. AS TROUGH MOVES TO CNTRL CONUS...LOW LEVEL CYCLOGENESIS DEVELOPS FROM CNTRL PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY ON THURSDAY. SFC LOW AND A COLD FRONT SLIDES ACROSS UPPER GREAT LAKES ON FRIDAY THOUGH IT IS PRETTY UNCERTAIN HOW STRONG OF SYSTEM WILL OCCUR. MUCH COOLER AIR DROPS ACROSS UPPER LAKES IN WAKE OF THE LOW LATER FRIDAY INTO SATURDAY. AIRMASS LOOKS CERTAINTY COLD ENOUGH TO RESULT IN SOME LK EFFECT RAIN...BUT PROBABLY JUST STAYS WARM ENOUGH TO KEEP MIXED PRECIPITATION OUT OF THE PICTURE...AT LEAST FOR NOW. AHEAD OF THE DEVELOPING TROUGHING ALOFT AND EVENTUALLY AT THE SFC...WARM AIR ADVECTION ALOFT AND DIVERGENCE ALOFT WILL SPREAD VEILS OF MID AND HIGH CLOUDS ACROSS NORTHERN PLAINS AND UPPER LAKES EARLY THIS WEEK. LOW-LEVELS TOO DRY TO ADD ANY RAIN SHOWERS DESPITE THE WARM AIR ADVECTION. WITH A LOWER SUN ANGLE NOW BECOMING A FACTOR...CLOUDS WILL CUT INTO EXPECTED MAX TEMPS SOME BUT WILL STILL SEE TEMPS 10-15 DEGREES ABOVE NORMAL WITH READINGS TOPPING OUT IN THE LOW TO MID 70S. BOTH DAYS MAY BE ON THE BREEZY SIDE AS WELL...WITH BEST SHOT OF SEEING 30+ MPH GUSTS ON MONDAY AS LOW-LEVEL JET SLIDES ACROSS AREA. HIGHER CLOUDS WILL DAMPEN DEEPER MIXING POTENTIAL AND WILL LIKELY KEEP HUMIDITY VALUES FROM BOTTOMING OUT TOO MUCH...BUT STILL COULD SEE INTERIOR WEST CWA DROP TO 35 PCT BOTH MONDAY AND TUESDAY AFTN. IF TRENDS HOLD UP COULD SEE NEED FOR A WILDFIRE POTENTIAL STATEMENT OR AT LEAST A MENTION IN HAZARDOUS WEATHER OUTLOOK. LEAD SFC TROUGH CROSSES THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY. STILL TOO DRY FOR ANY RAIN...BUT SHOULD SEE YET ANOTHER SURGE OF MID CLOUDS AND WILL SEE TEMPS COOL 5-10F COMPARED TO MONDAY AND TUESDAY. WESTERLY WINDS RESULT IN THE MOST NOTEABLE COOLING OVER THE KEWEENAW. HUMIDITY VALUES ACTUALLY COULD BE LOWER ON WEDNESDAY AS DWPNTS DROP FURTHER. MAIN WEATHER FOCUS FOR THE WEEK WILL BE LATE THIS WEEK AND INTO NEXT WEEKEND AS DEEP TROUGH AFFECTS THE GREAT LAKES. UNCERTAINTY ABOUNDS. MODELS CONTINUE TO STRUGGLE IN HOW QUICKLY TO BRING INITIAL LOW-LEVEL TROUGHING AND THE RESULTANT SURGE OF WARM AIR ADVECTION AND UPPER DIVERGENCE GENERATED SHOWERS INTO THE UPPER LAKES. LATEST GFS SHOWING A QUICKER TREND IN BRINGING QPF ACROSS MOST OF CWA BY 12Z THURSDAY THAN PREVIOUS THREE RUNS DID. ECMWF WHICH HAS REALLY BEEN ALL OVER THE PLACE WITH ITS TIMING HAS JOINED GFS IN SHOWING QUICKER EASTWARD TREND. GEM-NH IS GENERALLY CONSISTENT WITH PREVIOUS RUNS IN KEEPING MOST OF THE QPF WEST OF CWA BY 12Z THURSDAY AND ONLY SLOWLY BRINGING IT ACROSS AS MAJORITY OF DIVERGENCE ALOFT HELPS TO FOCUS CONCENTRATED AREA OF RAIN OVR MINNESOTA INTO NW ONTARIO ALONG AND NORTH OF COOLER SIDE OF DEVELOPING SFC-H85 LOWS IN ENHANCED FGEN AREA. GIVEN UNCERTAINTY AND INCONSISTENCIES BTWN THE GFS...ECMWF AND GEM-NH HAVE STAYED CLOSE TO CONSENSUS HIGHER CHANCE POPS THURSDAY INTO FRIDAY. PROBABLY WILL BE ONE OR TWO PERIODS OF GREATER RAIN CHANCES...BUT DETAILS ARE FAR FM CERTAIN. ELEVATED INSTABILITY WITH SI/S BLO 0C LED TO ADDING TSRA OVER SCNTRL ON THURSDAY IN WHAT SHOULD BE THE WARMER SECTOR OF THE CYCLONE. FRONTAL BOUNDARY RAINS MOVE THROUGH THURSDAY NIGHT OR FRIDAY. MAIN STICKING POINT IS JUST HOW WRAPPED UP WILL SFC LOW TREND AS IT MOVES THROUGH...MAINLY LEADING TO RAIN COVERAGE ISSUES WITH POTENTIAL DRY SLOT. AT THIS POINT...APPEARS THAT UPPER LAKES WOULD BE ON COOLER/WETTER SIDE OF THE LOW WITH SOME POTENTIAL FOR HEAVIER RAIN WITH PWATS OF 1.5 INCHES OR 200 PCT OF NORMAL INTERACTING WITH LOW-LEVEL FGEN AND UPSLOPE FLOW OFF LK SUPERIOR. THOUGH DETAILS OF HOW WE GET THERE ARE UNCLEAR...IT EVENTUALLY TURNS MUCH COOLER LATER FRIDAY INTO SATURDAY AS THE LOW SLOWLY MOVES AWAY FROM REGION AS UPPER TROUGH DEEPENS OVER GREAT LAKES. H85 TEMPS TO AT LEAST -4C SEEM LIKE GOOD BET...LEADING TO PLENTY OF LK EFFECT CLOUDS /LK SFC TEMPS AROUND +12C ON AVERAGE/ AND PROBABLY SOME LK EFFECT SHOWERS FRIDAY NIGHT INTO SATURDAY MORNING IF THERE IS ENOUGH SYNOPTIC MOISTURE/CYCLONIC FLOW LINGERING DURING THIS TIME. THE MOISTURE WILL ALSO FACTOR IN ON WHETHER THE FIRST SNOWFLAKES OF THE YEAR WILL FLY OVER THE CWA. RIGHT NOW WILL KEEP THE SNOW OUT OF THE FORECAST AS LATEST RUNS ARE MORE PROGRESSIVE WITH THE LOW AND DRY OUT THE H85-H7 LAYER CONSIDERABLY. IN THE FOR WHAT IT IS WORTH DEPARTMENT...TWO CLOSEST SLU CIPS ANALOGS TURNED UP EVENTS FROM LATE SEPTEMBER AND MID OCTOBER THAT PRODUCED OVER AN INCH OF RAIN ACROSS PARTS OF CWA WITH SOME SNOW AS THOSE SYSTEMS DEPARTED. WE SHALL SEE ON THIS ONE. CERTAINLY WILL BE A CHILLY START TO NEXT WEEKEND WITH THE HIGHER TERRAIN OF THE NORTH STAYING IN THE 40S AS A GUSTY NW WIND ONLY ADDS TO THE CHILL. COOLER PATTERN DOES NOT LOOK TO PERSIST THOUGH AS BOTH GFS/ECMWF INDICATE WARMER TEMPS RETURNING IN SOME SHAPE OR FORM DAYS 7-10. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 720 AM EDT SUN SEP 29 2013 HIGH PRESSURE OVER THE REGION WILL RESULT IN VFR CONDITIONS AT ALL TAF SITES. SOME LLWS IS EXPECTED AT KIWD AND KCMX LATE TONIGHT AS A LOW-LEVEL JET MAX PUSHES IN FM THE WEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 531 AM EDT SUN SEP 29 2013 THERE COULD BE A BRIEF PD OF GALE FORCE GUSTS ALONG AND EAST OF THE KEWEENAW PENINSULA EARLY THIS MORNING DUE TO FAVORED WESTERLY CONVERGENT FLOW IN THE WAKE OF THE COLD FRONT. HIGH PRESSURE WILL THEN BUILD IN TODAY AND QUICKLY DECREASE THE WINDS ACROSS THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR LATE MONDAY AND INTO TUE MORNING WITH A FEW GUSTS REACHING 25 KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
556 AM EDT SUN SEP 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 531 AM EDT SUN SEP 29 2013 08Z WV IMAGERY AND RUC ANALYSIS SHOW A PROMINENT SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES. THIS SHORTWAVE HAS PUSHED A SFC COLD FRONT EAST OF UPPER MI EARLY THIS MORNING. LATEST RADAR IMAGERY SHOWS THAT LAST OF SHRA ASSOC WITH FRONT HAS PUSHED EAST OF THE FCST AREA. GUSTY WESTERLY WINDS AT OR ABOVE 30 KT OVER THE PORTAGE CANAL AND CENTRAL/ERN LAKE SUPERIOR IN THE WAKE OF THE COLD FRONT SHOULD DIE DOWN QUICKLY IN THE NEXT FEW HOURS AS THE PRES GRADIENT SLACKENS WITH THE HIGH PRES RDG BUILDING IN FM THE WEST. TODAY...MODELS IN AGREEMENT SHOWING SHORTWAVE TROUGH LIFTING INTO NORTHERN ONTARIO AND REACHING JAMES BAY THIS AFTERNOON. SUBSIDENCE/DRYING IN THE WAKE OF THE COLD FRONT HAS RESULTED IN CLEAR SKIES ACROSS THE FCST AREA EARLY THIS MORNING. HOWEVER...THE 850 MB THERMAL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCT-BKN STRATOCU CLOUDS OVR THE CNTRL AND EASTERN FCST AREA BY LATE MORNING INTO EARLY AFTERNOON. MIXING TO 850 MB RESULTS IN MAX TEMPS IN THE MID TO UPPER 60S MOST LOCATIONS. TONIGHT...CLEAR SKIES AND LIGHT WINDS ESPECIALLY INTO THE EARLY OVERNIGHT HOURS SHOULD ALLOW FOR MIN TEMPS TO DIP INTO THE LOWER TO MID 40S OVER THE INTERIOR CENTRAL AND EAST WHILE SOUTHERLY DOWNSLOPE WINDS AND ASSOC MIXING WILL KEEP TEMPS CLOSER TO 50F ALONG THE LAKE SUPERIOR SHORE. LEFT IN PATCHY FOG OVER THE INTERIOR EAST HALF AS LIGHT SOUTHERLY UPSLOPE FLOW FROM LAKE MI COULD CONTRIBUTE ADDED MOISTENING FOR SOME FOG DEVELOPMENT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 531 AM EDT SUN SEP 29 2013 UPCOMING WEEK FEATURES A NEGATIVE PACIFIC AND NORTH AMERICAN /PNA/ TELECONNECTION PATTERN WITH BROAD ENERGETIC TROUGHING GULF OF ALASKA INTO PACIFIC NORTHWEST EARLY THIS WEEK EVENTUALLY TRANSLATING INTO A STRONG TROUGH INTO THE CNTRL CONUS MID TO LATE WEEK. AS TROUGH MOVES TO CNTRL CONUS...LOW LEVEL CYCLOGENESIS DEVELOPS FROM CNTRL PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY ON THURSDAY. SFC LOW AND A COLD FRONT SLIDES ACROSS UPPER GREAT LAKES ON FRIDAY THOUGH IT IS PRETTY UNCERTAIN HOW STRONG OF SYSTEM WILL OCCUR. MUCH COOLER AIR DROPS ACROSS UPPER LAKES IN WAKE OF THE LOW LATER FRIDAY INTO SATURDAY. AIRMASS LOOKS CERTAINTY COLD ENOUGH TO RESULT IN SOME LK EFFECT RAIN...BUT PROBABLY JUST STAYS WARM ENOUGH TO KEEP MIXED PRECIPITATION OUT OF THE PICTURE...AT LEAST FOR NOW. AHEAD OF THE DEVELOPING TROUGHING ALOFT AND EVENTUALLY AT THE SFC...WARM AIR ADVECTION ALOFT AND DIVERGENCE ALOFT WILL SPREAD VEILS OF MID AND HIGH CLOUDS ACROSS NORTHERN PLAINS AND UPPER LAKES EARLY THIS WEEK. LOW-LEVELS TOO DRY TO ADD ANY RAIN SHOWERS DESPITE THE WARM AIR ADVECTION. WITH A LOWER SUN ANGLE NOW BECOMING A FACTOR...CLOUDS WILL CUT INTO EXPECTED MAX TEMPS SOME BUT WILL STILL SEE TEMPS 10-15 DEGREES ABOVE NORMAL WITH READINGS TOPPING OUT IN THE LOW TO MID 70S. BOTH DAYS MAY BE ON THE BREEZY SIDE AS WELL...WITH BEST SHOT OF SEEING 30+ MPH GUSTS ON MONDAY AS LOW-LEVEL JET SLIDES ACROSS AREA. HIGHER CLOUDS WILL DAMPEN DEEPER MIXING POTENTIAL AND WILL LIKELY KEEP HUMIDITY VALUES FROM BOTTOMING OUT TOO MUCH...BUT STILL COULD SEE INTERIOR WEST CWA DROP TO 35 PCT BOTH MONDAY AND TUESDAY AFTN. IF TRENDS HOLD UP COULD SEE NEED FOR A WILDFIRE POTENTIAL STATEMENT OR AT LEAST A MENTION IN HAZARDOUS WEATHER OUTLOOK. LEAD SFC TROUGH CROSSES THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY. STILL TOO DRY FOR ANY RAIN...BUT SHOULD SEE YET ANOTHER SURGE OF MID CLOUDS AND WILL SEE TEMPS COOL 5-10F COMPARED TO MONDAY AND TUESDAY. WESTERLY WINDS RESULT IN THE MOST NOTEABLE COOLING OVER THE KEWEENAW. HUMIDITY VALUES ACTUALLY COULD BE LOWER ON WEDNESDAY AS DWPNTS DROP FURTHER. MAIN WEATHER FOCUS FOR THE WEEK WILL BE LATE THIS WEEK AND INTO NEXT WEEKEND AS DEEP TROUGH AFFECTS THE GREAT LAKES. UNCERTAINTY ABOUNDS. MODELS CONTINUE TO STRUGGLE IN HOW QUICKLY TO BRING INITIAL LOW-LEVEL TROUGHING AND THE RESULTANT SURGE OF WARM AIR ADVECTION AND UPPER DIVERGENCE GENERATED SHOWERS INTO THE UPPER LAKES. LATEST GFS SHOWING A QUICKER TREND IN BRINGING QPF ACROSS MOST OF CWA BY 12Z THURSDAY THAN PREVIOUS THREE RUNS DID. ECMWF WHICH HAS REALLY BEEN ALL OVER THE PLACE WITH ITS TIMING HAS JOINED GFS IN SHOWING QUICKER EASTWARD TREND. GEM-NH IS GENERALLY CONSISTENT WITH PREVIOUS RUNS IN KEEPING MOST OF THE QPF WEST OF CWA BY 12Z THURSDAY AND ONLY SLOWLY BRINGING IT ACROSS AS MAJORITY OF DIVERGENCE ALOFT HELPS TO FOCUS CONCENTRATED AREA OF RAIN OVR MINNESOTA INTO NW ONTARIO ALONG AND NORTH OF COOLER SIDE OF DEVELOPING SFC-H85 LOWS IN ENHANCED FGEN AREA. GIVEN UNCERTAINTY AND INCONSISTENCIES BTWN THE GFS...ECMWF AND GEM-NH HAVE STAYED CLOSE TO CONSENSUS HIGHER CHANCE POPS THURSDAY INTO FRIDAY. PROBABLY WILL BE ONE OR TWO PERIODS OF GREATER RAIN CHANCES...BUT DETAILS ARE FAR FM CERTAIN. ELEVATED INSTABILITY WITH SI/S BLO 0C LED TO ADDING TSRA OVER SCNTRL ON THURSDAY IN WHAT SHOULD BE THE WARMER SECTOR OF THE CYCLONE. FRONTAL BOUNDARY RAINS MOVE THROUGH THURSDAY NIGHT OR FRIDAY. MAIN STICKING POINT IS JUST HOW WRAPPED UP WILL SFC LOW TREND AS IT MOVES THROUGH...MAINLY LEADING TO RAIN COVERAGE ISSUES WITH POTENTIAL DRY SLOT. AT THIS POINT...APPEARS THAT UPPER LAKES WOULD BE ON COOLER/WETTER SIDE OF THE LOW WITH SOME POTENTIAL FOR HEAVIER RAIN WITH PWATS OF 1.5 INCHES OR 200 PCT OF NORMAL INTERACTING WITH LOW-LEVEL FGEN AND UPSLOPE FLOW OFF LK SUPERIOR. THOUGH DETAILS OF HOW WE GET THERE ARE UNCLEAR...IT EVENTUALLY TURNS MUCH COOLER LATER FRIDAY INTO SATURDAY AS THE LOW SLOWLY MOVES AWAY FROM REGION AS UPPER TROUGH DEEPENS OVER GREAT LAKES. H85 TEMPS TO AT LEAST -4C SEEM LIKE GOOD BET...LEADING TO PLENTY OF LK EFFECT CLOUDS /LK SFC TEMPS AROUND +12C ON AVERAGE/ AND PROBABLY SOME LK EFFECT SHOWERS FRIDAY NIGHT INTO SATURDAY MORNING IF THERE IS ENOUGH SYNOPTIC MOISTURE/CYCLONIC FLOW LINGERING DURING THIS TIME. THE MOISTURE WILL ALSO FACTOR IN ON WHETHER THE FIRST SNOWFLAKES OF THE YEAR WILL FLY OVER THE CWA. RIGHT NOW WILL KEEP THE SNOW OUT OF THE FORECAST AS LATEST RUNS ARE MORE PROGRESSIVE WITH THE LOW AND DRY OUT THE H85-H7 LAYER CONSIDERABLY. IN THE FOR WHAT IT IS WORTH DEPARTMENT...TWO CLOSEST SLU CIPS ANALOGS TURNED UP EVENTS FROM LATE SEPTEMBER AND MID OCTOBER THAT PRODUCED OVER AN INCH OF RAIN ACROSS PARTS OF CWA WITH SOME SNOW AS THOSE SYSTEMS DEPARTED. WE SHALL SEE ON THIS ONE. CERTAINLY WILL BE A CHILLY START TO NEXT WEEKEND WITH THE HIGHER TERRAIN OF THE NORTH STAYING IN THE 40S AS A GUSTY NW WIND ONLY ADDS TO THE CHILL. COOLER PATTERN DOES NOT LOOK TO PERSIST THOUGH AS BOTH GFS/ECMWF INDICATE WARMER TEMPS RETURNING IN SOME SHAPE OR FORM DAYS 7-10. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 135 AM EDT SUN SEP 29 2013 MVFR CONDITIONS AT KCMX SHOULD IMPROVE TO VFR SHORTLY AFT 06Z AS DRIER AIR WORKS IN FROM THE WEST. VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT KIWD AND KSAW. SOME LLWS IS EXPECTED SUN NIGHT AT KIWD AS A LOW-LVL JET MAX NOSES IN FROM THE WEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 531 AM EDT SUN SEP 29 2013 THERE COULD BE A BRIEF PD OF GALE FORCE GUSTS ALONG AND EAST OF THE KEWEENAW PENINSULA EARLY THIS MORNING DUE TO FAVORED WESTERLY CONVERGENT FLOW IN THE WAKE OF THE COLD FRONT. HIGH PRESSURE WILL THEN BUILD IN TODAY AND QUICKLY DECREASE THE WINDS ACROSS THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR LATE MONDAY AND INTO TUE MORNING WITH A FEW GUSTS REACHING 25 KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...07/VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
539 AM EDT SUN SEP 29 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 531 AM EDT SUN SEP 29 2013 08Z WV IMAGERY AND RUC ANALYSIS SHOW A PROMINENT SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES. THIS SHORTWAVE HAS PUSHED A SFC COLD FRONT EAST OF UPPER MI EARLY THIS MORNING. LATEST RADAR IMAGERY SHOWS THAT LAST OF SHRA ASSOC WITH FRONT HAS PUSHED EAST OF THE FCST AREA. GUSTY WESTERLY WINDS AT OR ABOVE 30 KT OVER THE PORTAGE CANAL AND CENTRAL/ERN LAKE SUPERIOR IN THE WAKE OF THE COLD FRONT SHOULD DIE DOWN QUICKLY IN THE NEXT FEW HOURS AS THE PRES GRADIENT SLACKENS WITH THE HIGH PRES RDG BUILDING IN FM THE WEST. TODAY...MODELS IN AGREEMENT SHOWING SHORTWAVE TROUGH LIFTING INTO NORTHERN ONTARIO AND REACHING JAMES BAY THIS AFTERNOON. SUBSIDENCE/DRYING IN THE WAKE OF THE COLD FRONT HAS RESULTED IN CLEAR SKIES ACROSS THE FCST AREA EARLY THIS MORNING. HOWEVER...THE 850 MB THERMAL TROUGH SHOULD SUPPORT THE DEVELOPMENT OF SCT-BKN STRATOCU CLOUDS OVR THE CNTRL AND EASTERN FCST AREA BY LATE MORNING INTO EARLY AFTERNOON. MIXING TO 850 MB RESULTS IN MAX TEMPS IN THE MID TO UPPER 60S MOST LOCATIONS. TONIGHT...CLEAR SKIES AND LIGHT WINDS ESPECIALLY INTO THE EARLY OVERNIGHT HOURS SHOULD ALLOW FOR MIN TEMPS TO DIP INTO THE LOWER TO MID 40S OVER THE INTERIOR CENTRAL AND EAST WHILE SOUTHERLY DOWNSLOPE WINDS AND ASSOC MIXING WILL KEEP TEMPS CLOSER TO 50F ALONG THE LAKE SUPERIOR SHORE. LEFT IN PATCHY FOG OVER THE INTERIOR EAST HALF AS LIGHT SOUTHERLY UPSLOPE FLOW FROM LAKE MI COULD CONTRIBUTE ADDED MOISTENING FOR SOME FOG DEVELOPMENT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 531 AM EDT SUN SEP 29 2013 UPCOMING WEEK FEATURES A NEGATIVE PACIFIC AND NORTH AMERICAN /PNA/ TELECONNECTION PATTERN WITH BROAD ENERGETIC TROUGHING GULF OF ALASKA INTO PACIFIC NORTHWEST EARLY THIS WEEK EVENTUALLY TRANSLATING INTO A STRONG TROUGH INTO THE CNTRL CONUS MID TO LATE WEEK. AS TROUGH MOVES TO CNTRL CONUS...LOW LEVEL CYCLOGENESIS DEVELOPS FROM CNTRL PLAINS TO THE UPPER MISSISSIPPI RIVER VALLEY ON THURSDAY. SFC LOW AND A COLD FRONT SLIDES ACROSS UPPER GREAT LAKES ON FRIDAY THOUGH IT IS PRETTY UNCERTAIN HOW STRONG OF SYSTEM WILL OCCUR. MUCH COOLER AIR DROPS ACROSS UPPER LAKES IN WAKE OF THE LOW LATER FRIDAY INTO SATURDAY. AIRMASS LOOKS CERTAINTY COLD ENOUGH TO RESULT IN SOME LK EFFECT RAIN...BUT PROBABLY JUST STAYS WARM ENOUGH TO KEEP MIXED PRECIPITATION OUT OF THE PICTURE...AT LEAST FOR NOW. AHEAD OF THE DEVELOPING TROUGHING ALOFT AND EVENTUALLY AT THE SFC...WARM AIR ADVECTION ALOFT AND DIVERGENCE ALOFT WILL SPREAD VEILS OF MID AND HIGH CLOUDS ACROSS NORTHERN PLAINS AND UPPER LAKES EARLY THIS WEEK. LOW-LEVELS TOO DRY TO ADD ANY RAIN SHOWERS DESPITE THE WARM AIR ADVECTION. WITH A LOWER SUN ANGLE NOW BECOMING A FACTOR...CLOUDS WILL CUT INTO EXPECTED MAX TEMPS SOME BUT WILL STILL SEE TEMPS 10-15 DEGREES ABOVE NORMAL WITH READINGS TOPPING OUT IN THE LOW TO MID 70S. BOTH DAYS MAY BE ON THE BREEZY SIDE AS WELL...WITH BEST SHOT OF SEEING 30+ MPH GUSTS ON MONDAY AS LOW-LEVEL JET SLIDES ACROSS AREA. HIGHER CLOUDS WILL DAMPEN DEEPER MIXING POTENTIAL AND WILL LIKELY KEEP HUMIDITY VALUES FROM BOTTOMING OUT TOO MUCH...SO FIRE CONCERNS SHOULD BE MITIGATED. LEAD SFC TROUGH CROSSES THE REGION LATE TUESDAY NIGHT INTO WEDNESDAY. STILL TOO DRY FOR ANY RAIN...BUT SHOULD SEE YET ANOTHER SURGE OF MID CLOUDS AND WILL SEE TEMPS COOL 5-10F COMPARED TO MONDAY AND TUESDAY. WESTERLY WINDS RESULT IN THE MOST NOTEABLE COOLING OVER THE KEWEENAW. MAIN WEATHER FOCUS FOR THE WEEK WILL BE LATE THIS WEEK AND INTO NEXT WEEKEND AS DEEP TROUGH AFFECTS THE GREAT LAKES. UNCERTAINTY ABOUNDS. MODELS CONTINUE TO STRUGGLE IN HOW QUICKLY TO BRING INITIAL LOW-LEVEL TROUGHING AND THE RESULTANT SURGE OF WARM AIR ADVECTION AND UPPER DIVERGENCE GENERATED SHOWERS INTO THE UPPER LAKES. LATEST GFS SHOWING A QUICKER TREND IN BRINGING QPF ACROSS MOST OF CWA BY 12Z THURSDAY THAN PREVIOUS THREE RUNS DID. ECMWF WHICH HAS REALLY BEEN ALL OVER THE PLACE WITH ITS TIMING HAS JOINED GFS IN SHOWING QUICKER EASTWARD TREND. GEM-NH IS GENERALLY CONSISTENT WITH PREVIOUS RUNS IN KEEPING MOST OF THE QPF WEST OF CWA BY 12Z THURSDAY AND ONLY SLOWLY BRINGING IT ACROSS AS MAJORITY OF DIVERGENCE ALOFT HELPS TO FOCUS CONCENTRATED AREA OF RAIN OVR MINNESOTA INTO NW ONTARIO ALONG AND NORTH OF COOLER SIDE OF DEVELOPING SFC-H85 LOWS IN ENHANCED FGEN AREA. GIVEN UNCERTAINTY AND INCONSISTENCIES BTWN THE GFS...ECMWF AND GEM-NH HAVE STAYED CLOSE TO CONSENSUS HIGHER CHANCE POPS THURSDAY INTO FRIDAY. PROBABLY WILL BE ONE OR TWO PERIODS OF GREATER RAIN CHANCES...BUT DETAILS ARE FAR FM CERTAIN. ELEVATED INSTABILITY WITH SI/S BLO 0C LED TO ADDING TSRA OVER SCNTRL ON THURSDAY IN WHAT SHOULD BE THE WARMER SECTOR OF THE CYCLONE. FRONTAL BOUNDARY RAINS MOVE THROUGH THURSDAY NIGHT OR FRIDAY. MAIN STICKING POINT IS JUST HOW WRAPPED UP WILL SFC LOW TREND AS IT MOVES THROUGH...MAINLY LEADING TO RAIN COVERAGE ISSUES WITH POTENTIAL DRY SLOT. AT THIS POINT...APPEARS THAT UPPER LAKES WOULD BE ON COOLER/WETTER SIDE OF THE LOW WITH SOME POTENTIAL FOR HEAVIER RAIN WITH PWATS OF 1.5 INCHES OR 200 PCT OF NORMAL INTERACTING WITH LOW-LEVEL FGEN AND UPSLOPE FLOW OFF LK SUPERIOR. THOUGH DETAILS OF HOW WE GET THERE ARE UNCLEAR...IT EVENTUALLY TURNS MUCH COOLER LATER FRIDAY INTO SATURDAY AS THE LOW SLOWLY MOVES AWAY FROM REGION AS UPPER TROUGH DEEPENS OVER GREAT LAKES. H85 TEMPS TO AT LEAST -4C SEEM LIKE GOOD BET...LEADING TO PLENTY OF LK EFFECT CLOUDS /LK SFC TEMPS AROUND +12C ON AVERAGE/ AND PROBABLY SOME LK EFFECT SHOWERS FRIDAY NIGHT INTO SATURDAY MORNING IF THERE IS ENOUGH SYNOPTIC MOISTURE/CYCLONIC FLOW LINGERING DURING THIS TIME. THE MOISTURE WILL ALSO FACTOR IN ON WHETHER THE FIRST SNOWFLAKES OF THE YEAR WILL FLY OVER THE CWA. RIGHT NOW WILL KEEP THE SNOW OUT OF THE FORECAST AS LATEST RUNS ARE MORE PROGRESSIVE WITH THE LOW AND DRY OUT THE H85-H7 LAYER CONSIDERABLY. IN THE FOR WHAT IT IS WORTH DEPARTMENT...TWO CLOSEST SLU CIPS ANALOGS TURNED UP EVENTS FROM LATE SEPTEMBER AND MID OCTOBER THAT PRODUCED OVER AN INCH OF RAIN ACROSS PARTS OF CWA WITH SOME SNOW AS THOSE SYSTEMS DEPARTED. WE SHALL SEE ON THIS ONE. CERTAINLY WILL BE A CHILLY START TO NEXT WEEKEND WITH THE HIGHER TERRAIN OF THE NORTH STAYING IN THE 40S AS A GUSTY NW WIND ONLY ADDS TO THE CHILL. COOLER PATTERN DOES NOT LOOK TO PERSIST THOUGH AS BOTH GFS/ECMWF INDICATE WARMER TEMPS RETURNING IN SOME SHAPE OR FORM DAYS 7-10. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 135 AM EDT SUN SEP 29 2013 MVFR CONDITIONS AT KCMX SHOULD IMPROVE TO VFR SHORTLY AFT 06Z AS DRIER AIR WORKS IN FROM THE WEST. VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT KIWD AND KSAW. SOME LLWS IS EXPECTED SUN NIGHT AT KIWD AS A LOW-LVL JET MAX NOSES IN FROM THE WEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 531 AM EDT SUN SEP 29 2013 THERE COULD BE A BRIEF PD OF GALE FORCE GUSTS ALONG AND EAST OF THE KEWEENAW PENINSULA EARLY THIS MORNING DUE TO FAVORED WESTERLY CONVERGENT FLOW IN THE WAKE OF THE COLD FRONT. HIGH PRESSURE WILL THEN BUILD IN TODAY AND QUICKLY DECREASE THE WINDS ACROSS THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR LATE MONDAY AND INTO TUE MORNING WITH A FEW GUSTS REACHING 25 KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...VOSS LONG TERM...JLA AVIATION...07/VOSS MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
148 AM EDT SUN SEP 29 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 412 PM EDT SAT SEEP 28 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT SHORTWAVE TROUGH FROM ERN NORTH DAKOTA INTO SW MN. AN AREA OF RAIN ALONG AND BEHIND THE SFC COLD FRONT FROM NE MN THROUGH WRN WI WAS ADVANCING STEADILY TOWARD UPPER MI. THE COLD FRONT WAS DEFINED BY A VERY NARROW HEAVIER N-S RAIN BAND TO NEAR HYR AT 1930Z. TONIGHT...FCST ONSET OF PCPN WAS DELAYED SLIGHTLY COMPARED TO THE PREVIOUS FCSTS...PER RADAR TRENDS AND SHORT TERM MODELS. OTHERWISE... THE COMBINATION OF MODERATE TO STRONG 700-300 MB QVECTOR CONV...AROUND 100M 5H HEIGHT FALLS WITH TROUGH...STRONG 850-700MB FGEN AND RIGHT ENTRANCE REGION FORCING FROM A 120 KNOT 250-300 MB JET...AND GOOD MOISTURE AVAILABILITY WITH PWAT VALUES AT OR ABOVE 1.6 INCHES WILL SUSTAIN THE RAIN BAND AS IT MOVES THROUGH THE CWA TONIGHT. THE SPEED OF THE FRONT MAY LIMIT OVERALL QPF AMOUNTS TO 0.20-0.35 INCH WITH LESSER AMOUNTS IN LOW LEVEL SRLY DOWNSLOPE FLOW LOCATIONS NEAR LAKE SUPERIOR. THE FRONT AND POST-FRONTAL PCPN WILL EXIT THE ERN CWA SHORTLY AFTER 06Z SUN WITH GOOD SUBSIDENCE/CLEARING EXPECTED IN THE WAKE OF THE FRONT LATE TONIGHT. SUNDAY...THE SHORTWAVE TROUGH WILL CONTINUE TO LIFT INTO NORTHERN ONTARIO REACHING JAMES BAY BY SUN AFTERNOON. THOUGH SUBSIDENCE BEHIND THE WAVE SHOULD CLEAR OUT MOST OF THE CLOUDS BY SUNRISE ON SUNDAY...850-750 MB THERMAL TROUGH SUPPORT SCT-BKN STRATOCU CLOUDS DEVELOPING OVR CNTRL AND EAST. MIXING TO 850 MB RESULTS IN MAX TEMPS IN THE MID TO UPPERR 60S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 412 PM EDT SAT SEP 28 2013 STARTING 00Z MON...THE TROUGH/COLD FRONT THAT WILL MOVE THROUGH TONIGHT WILL BE WELL E OF THE CWA...AS WILL ALL ASSOCIATED PRECIP. MORE ZONAL UPPER LEVEL FLOW WILL BE PRESENT OVER THE REGION...WITH UPPER TROUGHING OVER THE NW CONUS. THROUGH WED...ZONAL FLOW LOOKS TO REMAIN THE DOMINANT UPPER PATTERN OVER THE CWA...WITH SEVERAL DISTURBANCES MOVING ACROSS CANADA BUT STAYING FAR ENOUGH N OF THE CWA TO RULE OUT SIGNIFICANT PRECIP. WITH A WEAK SFC TROUGH/COLD FRONT BUILDING TO OUR W MON AND MON NIGHT...THEN MOVING THROUGH THE CWA LATE TUE AND TUE NIGHT...WINDS WILL INCREASE OUT OF THE SW AHEAD OF THE TROUGH...THEN TURN W TO WNW LAT TUE THROUGH WED BEHIND THE TROUGH. THIS LEADS TO 850MB TEMPS INCREASING TO AROUND 15C BY 00Z TUE /AN INCREASE OF AROUND 9C FROM SUN/...AND POSSIBLY WARMING A BIT MORE THROUGH MON NIGHT. WHILE HIGHS ON SUN LOOK TO BE IN THE 60S...HIGHS ON MON ARE EXPECTED TO BE IN THE 70S TO NEAR 80 IN SOME SPOTS OVER WRN UPPER MI. LOWS ON MON NIGHT SHOULD THEN BE IN THE MID 40S IN THE COLDEST SPOTS OVER ERN UPPER MI TO THE MID 50S NEAR LAKE SUPERIOR AND W. LOOKS LIKE ANY PRECIP WITH FROPA ON TUE/TUE NIGHT WILL STAY N OF LAKE SUPERIOR WITH THE BETTER UPPER LEVEL FORCING. TUE SHOULD SEE SIMILAR TEMPS TO MON...OR POSSIBLY A COUPLE OF DEGREES WARMER GIVEN THE WARM LOW TEMPS MON NIGHT. COOLER AIR ARRIVES TUE NIGHT...BUT BREEZY WINDS BEHIND THE COLD FRONT WILL HELP KEEP LOW TEMPS FROM FALLING TOO LOW. WITH 850MB TEMPS OF 7-8C ON WED...TEMPS WILL BE COOLER THAN TUE WITH HIGHS PRIMARILY IN THE 60S TO AROUND 70. THINGS BECOME MUCH MORE UNCLEAR THU THROUGH NEXT SAT AS MODELS CONTINUE TO SHOW SOME SORT OF UPPER LEVEL ENERGY MOVING INTO THE CENTRAL CONUS. WHILE MODELS DO AGREE THAT THE ENERGY WILL BE STRONGER /AND EITHER A DEEP TROUGH OR A CLOSED LOW/...THEY HAVE POOR RUN TO RUN CONTINUITY AND POOR MODEL TO MODEL AGREEMENT. THIS LENDS VERY LITTLE CONFIDENCE IN DETAILS FOR THIS PORTION OF THE FORECAST. FOR THIS REASON...WILL LOAD A GENERAL CONSENSUS OF MODEL GUIDANCE...AND AM FINE WITH HIGHER END POPS AS ALL MODEL SCENARIOS WOULD LEAD TO PRECIP AT ONE TIME OR ANOTHER. IT IS WORTH POINTING OUT THAT ALL MODELS AT THIS TIME ARE WARM ENOUGH TO NOT WARRANT TALKING ABOUT MIXED PRECIP...SO IT SEEMS THAT THERE WILL NOT BE ANY WINTER QUITE YET. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 135 AM EDT SUN SEP 29 2013 MVFR CONDITIONS AT KCMX SHOULD IMPROVE TO VFR SHORTLY AFT 06Z AS DRIER AIR WORKS IN FROM THE WEST. VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT KIWD AND KSAW. SOME LLWS IS EXPECTED SUN NIGHT AT KIWD AS A LOW-LVL JET MAX NOSES IN FROM THE WEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 412 PM EDT SAT SEP 28 2013 A FRONT WILL SLIDE EAST ACROSS LAKE SUPERIOR THIS EVENING AND DURING THE EARLY OVERNIGHT HOURS...SHIFTING THE WINDS TO THE WEST. THERE COULD BE A FEW HOUR PERIOD OF GALE FORCE GUSTS OVER THE WESTERN LAKE THIS EVENING BEHIND THE FRONT. HIGH PRESSURE WILL THEN BUILD IN FOR SUNDAY AND QUICKLY DECREASE THE WINDS ACROSS THE LAKE. THIS HIGH WILL SHIFT SOUTHEAST LATE MONDAY...AS A LOW PRESSURE SYSTEM MOVES ACROSS CENTRAL CANADA. THIS WILL RESULT IN A BRIEF INCREASE IN SOUTHERLY WINDS OVER LAKE SUPERIOR MONDAY NIGHT WITH A FEW GUSTS REACHING 25 KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07/VOSS MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
910 PM CDT MON SEP 30 2013 .UPDATE... ISSUED AT 910 PM CDT MON SEP 30 2013 ADJUSTED POPS UPWARDS IN THE NORTHWESTERN COUNTIES FOR THE REST OF THE EVENING AS SHOWERS BEHIND THE FRONT IN NORTH CENTRAL ND CONTINUE TO PUSH EASTWARD. FURTHER SOUTH...ACTIVITY IS MORE WIDELY SCATTERED SO KEPT POPS LOW IN SOUTHEASTERN ND. THINK THAT THE SHOWERS SHOULD DROP A TENTH OR SO OF PRECIP BEFORE WEAKENING AND MOVING OFF TO THE NORTHEAST TOWARDS MORNING. WINDS WILL CONTINUE TO BE FAIRLY BREEZY OVERNIGHT AS THE FRONT MOVES THROUGH...BUT MIXING AND PRESSURE GRADIENT WILL TOP OUT DURING THE AFTERNOON HOURS SO WILL CONTINUE TO KEEP ADVISORY GOING FOR TOMORROW. UPDATE ISSUED AT 641 PM CDT MON SEP 30 2013 RADAR LOOP SHOWS A BIT MORE ACTIVITY IN SOUTHWESTERN ND AND NORTHWESTERN SD ALONG THE APPROACHING COLD FRONT THAN EXPECTED. NAM AND RAP STILL HAVE MOST OF THE PRECIP IMPACTING OUR NORTHERN COUNTIES...BUT DO NOT SEEM TO HAVE INITIALIZED WELL. HRRR HAS SOME SHOWERS ENTERING THE SOUTHERN CWA...MAINLY AFTER MIDNIGHT. INCLUDED AN ISOLATED MENTION ACROSS PORTIONS OF THE CWA AS NO SHORT RANGE MODEL SEEMS TO BE HANDLING CURRENT PRECIP VERY WELL. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 315 PM CDT MON SEP 30 2013 THE MAIN CHALLENGE WILL BE PRECIP CHANCES AND HIGH WINDS TOMORROW. MODELS ARE IN DECENT AGREEMENT THROUGH THU...WITH SOME DIFFERENCES THEREAFTER WITH A LARGE STORM BY THE WEEKEND. WILL USE A GFS/NAM BLEND FOR THE FIRST 4 DAYS OF THE FORECAST. FOR TONIGHT...EXPECT SOME SHOWERS MOVING ACROSS THE NORTHERN 1/3 OF THE AREA. A SHORTWAVE AND ASSOCIATED LARGE SCALE LIFT/SATURATION SHOULD PRODUCE A BAND OF SHOWERS IN THE NORTH. A COLD FRONT WILL ALSO MOVE IN BEHIND THE SHOWERS...AND WINDS SHOULD BECOME WESTERLY LATE AND INCREASE TOWARDS MORNING. ON TUE...EXPECT A VERY WINDY DAY WITH 40-45KT TO MIX EFFICIENTLY FROM THE WEST. A DEEP ADIABATIC LAYER UP TO AROUND 800MB WILL DEVELOP FROM WEST TO EAST BY 15Z...AND EXPECT WINDS FROM 30 TO 40 MPH WITH GUSTS TO AROUND 45 MPH POSSIBLE IN THE NORTHERN 2/3 OF THE FORECAST AREA. GIVEN THE HIGH CONFIDENCE STRONG WINDS...WE WILL ISSUE A WIND ADVISORY FOR ALL BUT THE SOUTHERN FORECAST AREA FROM 15Z-00Z TOMORROW. TEMPS WILL BE COOLER THAN TODAY AND BE AROUND NORMAL FOR THE FIRST DAY OF OCTOBER. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 PM CDT MON SEP 30 2013 FOR WED/THU...EXPECT INCREASING CHANCES FOR SHOWERS WITH PWATS INCREASING OVER AN INCH BY LATE WED NIGHT. THERE WILL ALSO BE A THREAT FOR ELEVATED THUNDER IN THE SOUTH WED NIGHT/THU AND WILL MENTION...WITH SHOWALTERS AROUND -2C AND STRONG LIFT NEAR THE WARM FRONT. TEMPS WILL BE COOL WITH CLOUDS AND PRECIP...AND IT MAY BE EVEN COLDER THU IF WE DON/T SEE ANY INSOLATION. FRIDAY TO MONDAY... WIDE SPREAD IN MORNING MODELS SOLNS FOR THE WEEKEND PERIOD. UNCERTAINTY ABOUNDS WITH STRENGTH AND EVOLUTION OF UPPER LEVEL TROUGH AS IT MOVES OUT OF INTERMOUNTAIN WEST AND INTO THE PLAINS FRIDAY. ECMWF WRAPS THE SYSTEM UP WITH A UPPER AND SFC LOW TRACK FROM NEBRASKA PANHANDLE TO THE MN ARROWHEAD BY SUN 12Z...PRODUCING A RAIN SNOW MIX. WHEREAS THE GEM/GFS TAKE A LESS INTENSE AND MORE WEST TO EAST TRACK AND CENTER THE LOW SUN MORNING IN SOUTHERN OR EASTERN WISCONSIN. NONETHELESS GIVEN THE SW FLOW AND AMPLE MOISTURE AHEAD OF THE SYSTEM A POTENTIALLY WET AND COOL FEW DAYS IN STORE WITH SIGNIFICANT RAINFALLS...HARVEST DELAYING... ACROSS THE SOUTHERN HALF OF FA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 641 PM CDT MON SEP 30 2013 VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH AT MOST SOME MID LEVEL CLOUDS AROUND 7000 FT. KDVL HAS BEEN GOING DOWN IN VIS AT TIMES TO 1-2SM BUT WEB CAMS SHOW NO RESTRICTIONS TO VISIBILITY AND THINK THAT IT IS IN ERROR. WINDS WILL PICK UP FROM THE WEST LATER TONIGHT AS A COLD FRONT MOVES THROUGH. AT THIS POINT DO NOT HAVE ANY PRECIP MENTIONED IN THE TAF SITES AS COVERAGE HAS BEEN ISOLATED TO SCATTERED. WINDS WILL PICK UP EVEN HIGHER TOMORROW AFTERNOON WITH SOME SUSTAINED WINDS AT 25 TO 30 KTS AND GUSTS UP TO 35 TO 40 KTS AT TIMES. WINDS WILL START TAPERING OFF LATE IN THE DAY. && .FIRE WEATHER... ISSUED AT 315 PM CDT MON SEP 30 2013 A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING AND TONIGHT...USHERING IN COOLER AND WINDY CONDITIONS FOR TUESDAY. TEMPERATURES WILL RANGE FROM THE MID 60S TO LOWER 70S. WESTERLY WINDS ARE EXPECTED TO BE FROM 25 TO 35 MPH...WITH GUSTS APPROACHING 45 MPH. DRIER AIR AND COOLER TEMPERATURES ON TUESDAY WILL DROP MINIMUM HUMIDITIES AGAIN INTO THE 30 TO 35 PERCENT RANGE...WITH SOME POCKETS OF 25 TO 30 PERCENT VALUES. CURRENT FIRE DANGER RATINGS ARE LOW FOR MINNESOTA...WITH LOW TO MEDIUM RATINGS IN EASTERN NORTH DAKOTA. HOWEVER...CONSIDERING THE FACTORS...INCLUDING THE POTENTIAL FOR DRY AIR AND VERY GUSTY WINDS...EXPECT NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS THE FORECAST AREA FOR TUESDAY. WILL HAVE TO MONITOR CONDITIONS FOR ANY POSSIBLE CHANGES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR NDZ006>008- 014>016-024-026>030-038-039-054. MN...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR MNZ001>009- 013>017-022-023-027. && $$ UPDATE...JR SHORT TERM...DK LONG TERM...JK/DK AVIATION...JR FIRE WEATHER...HOPKINS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
641 PM CDT MON SEP 30 2013 .UPDATE... ISSUED AT 641 PM CDT MON SEP 30 2013 RADAR LOOP SHOWS A BIT MORE ACTIVITY IN SOUTHWESTERN ND AND NORTHWESTERN SD ALONG THE APPROACHING COLD FRONT THAN EXPECTED. NAM AND RAP STILL HAVE MOST OF THE PRECIP IMPACTING OUR NORTHERN COUNTIES...BUT DO NOT SEEM TO HAVE INTIALIZED WELL. HRRR HAS SOME SHOWERS ENTERING THE SOUTHERN CWA...MAINLY AFTER MIDNIGHT. INCLUDED AN ISOLATED MENTION ACROSS PORTIONS OF THE CWA AS NO SHORT RANGE MODEL SEEMS TO BE HANDLING CURRENT PRECIP VERY WELL. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 315 PM CDT MON SEP 30 2013 THE MAIN CHALLENGE WILL BE PRECIP CHANCES AND HIGH WINDS TOMORROW. MODELS ARE IN DECENT AGREEMENT THROUGH THU...WITH SOME DIFFERENCES THEREAFTER WITH A LARGE STORM BY THE WEEKEND. WILL USE A GFS/NAM BLEND FOR THE FIRST 4 DAYS OF THE FORECAST. FOR TONIGHT...EXPECT SOME SHOWERS MOVING ACROSS THE NORTHERN 1/3 OF THE AREA. A SHORTWAVE AND ASSOCIATED LARGE SCALE LIFT/SATURATION SHOULD PRODUCE A BAND OF SHOWERS IN THE NORTH. A COLD FRONT WILL ALSO MOVE IN BEHIND THE SHOWERS...AND WINDS SHOULD BECOME WESTERLY LATE AND INCREASE TOWARDS MORNING. ON TUE...EXPECT A VERY WINDY DAY WITH 40-45KT TO MIX EFFICIENTLY FROM THE WEST. A DEEP ADIABATIC LAYER UP TO AROUND 800MB WILL DEVELOP FROM WEST TO EAST BY 15Z...AND EXPECT WINDS FROM 30 TO 40 MPH WITH GUSTS TO AROUND 45 MPH POSSIBLE IN THE NORTHERN 2/3 OF THE FORECAST AREA. GIVEN THE HIGH CONFIDENCE STRONG WINDS...WE WILL ISSUE A WIND ADVISORY FOR ALL BUT THE SOUTHERN FORECAST AREA FROM 15Z-00Z TOMORROW. TEMPS WILL BE COOLER THAN TODAY AND BE AROUND NORMAL FOR THE FIRST DAY OF OCTOBER. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 PM CDT MON SEP 30 2013 FOR WED/THU...EXPECT INCREASING CHANCES FOR SHOWERS WITH PWATS INCREASING OVER AN INCH BY LATE WED NIGHT. THERE WILL ALSO BE A THREAT FOR ELEVATED THUNDER IN THE SOUTH WED NIGHT/THU AND WILL MENTION...WITH SHOWALTERS AROUND -2C AND STRONG LIFT NEAR THE WARM FRONT. TEMPS WILL BE COOL WITH CLOUDS AND PRECIP...AND IT MAY BE EVEN COLDER THU IF WE DON/T SEE ANY INSOLATION. FRIDAY TO MONDAY... WIDE SPREAD IN MORNING MODELS SOLNS FOR THE WEEKEND PERIOD. UNCERTAINTY ABOUNDS WITH STRENGTH AND EVOLUTION OF UPPER LEVEL TROUGH AS IT MOVES OUT OF INTERMOUNTAIN WEST AND INTO THE PLAINS FRIDAY. ECMWF WRAPS THE SYSTEM UP WITH A UPPER AND SFC LOW TRACK FROM NEBRASKA PANHANDLE TO THE MN ARROWHEAD BY SUN 12Z...PRODUCING A RAIN SNOW MIX. WHEREAS THE GEM/GFS TAKE A LESS INTENSE AND MORE WEST TO EAST TRACK AND CENTER THE LOW SUN MORNING IN SOUTHERN OR EASTERN WISCONSIN. NONETHELESS GIVEN THE SW FLOW AND AMPLE MOISTURE AHEAD OF THE SYSTEM A POTENTIALLY WET AND COOL FEW DAYS IN STORE WITH SIGNIFICANT RAINFALLS...HARVEST DELAYING... ACROSS THE SOUTHERN HALF OF FA. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 641 PM CDT MON SEP 30 2013 VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH AT MOST SOME MID LEVEL CLOUDS AROUND 7000 FT. KDVL HAS BEEN GOING DOWN IN VIS AT TIMES TO 1-2SM BUT WEB CAMS SHOW NO RESTRICTIONS TO VISIBILITY AND THINK THAT IT IS IN ERROR. WINDS WILL PICK UP FROM THE WEST LATER TONIGHT AS A COLD FRONT MOVES THROUGH. AT THIS POINT DO NOT HAVE ANY PRECIP MENTIONED IN THE TAF SITES AS COVERAGE HAS BEEN ISOLATED TO SCATTERED. WINDS WILL PICK UP EVEN HIGHER TOMORROW AFTERNOON WITH SOME SUSTAINED WINDS AT 25 TO 30 KTS AND GUSTS UP TO 35 TO 40 KTS AT TIMES. WINDS WILL START TAPERING OFF LATE IN THE DAY. && .FIRE WEATHER... ISSUED AT 315 PM CDT MON SEP 30 2013 A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING AND TONIGHT...USHERING IN COOLER AND WINDY CONDITIONS FOR TUESDAY. TEMPERATURES WILL RANGE FROM THE MID 60S TO LOWER 70S. WESTERLY WINDS ARE EXPECTED TO BE FROM 25 TO 35 MPH...WITH GUSTS APPROACHING 45 MPH. DRIER AIR AND COOLER TEMPERATURES ON TUESDAY WILL DROP MINIMUM HUMIDITIES AGAIN INTO THE 30 TO 35 PERCENT RANGE...WITH SOME POCKETS OF 25 TO 30 PERCENT VALUES. CURRENT FIRE DANGER RATINGS ARE LOW FOR MINNESOTA...WITH LOW TO MEDIUM RATINGS IN EASTERN NORTH DAKOTA. HOWEVER...CONSIDERING THE FACTORS...INCLUDING THE POTENTIAL FOR DRY AIR AND VERY GUSTY WINDS...EXPECT NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS THE FORECAST AREA FOR TUESDAY. WILL HAVE TO MONITOR CONDITIONS FOR ANY POSSIBLE CHANGES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR NDZ006>008- 014>016-024-026>030-038-039-054. MN...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR MNZ001>009- 013>017-022-023-027. && $$ UPDATE...JR SHORT TERM...DK LONG TERM...JK/DK AVIATION...JR FIRE WEATHER...HOPKINS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1242 PM CDT SUN SEP 29 2013 .UPDATE... ISSUED AT 1240 PM CDT SUN SEP 29 2013 THICKENING CIRRUS OVERSPREADING THE NORTHWEST 2/3 OF THE CWFA HAVING A LITTLE IMPACT ON INSOLATION. TEMPERATURES ARE RISING FASTER ACROSS THE SOUTH BUT WITHIN A DEGREE OR TWO ACROSS THE NORTH. WILL TWEAK THE CURVE BUT OTHERWISE THE FORECAST APPEARS STILL ON TRACK. UPDATE ISSUED AT 1008 AM CDT SUN SEP 29 2013 ONLY MINOR CHANGES TO THIS UPDATE...MAINLY TO INCREASE THE CLOUD COVER ACROSS THE NORTH. VISIBLE SAT SHOWS WHAT APPEARS TO BE THICKER CIRRUS MOVING TO THE E/NE. CROSS-SECTIONS USING THE RAP AND GFS IN FAIR AGREEMENT WITH THE VISIBLE. OTHERWISE WITH SOUTHWEST FLOW SUSPECT TEMPERATURES ON TRACK FOR MIDDLE TO UPPER 70S MOST AREAS. UPDATE ISSUED AT 650 AM CDT SUN SEP 29 2013 FORECAST IS IN GOOD SHAPE WITH NO CHANGES NEEDED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 332 AM CDT SUN SEP 29 2013 CHALLENGES INCLUDE TEMPERATURES AND WIND THROUGH THE PERIOD. WILL FOLLOW A BLEND OF THE NAM/ECMWF/GEM AS THE LATEST GFS IS TOO FAST WITH THE FRONTAL PASSAGE MONDAY NIGHT. FOR TODAY...EXPECT PLENTY OF SUN BETWEEN PERIODS OF HIGH CLOUDS AS THE REGION REMAINS BETWEEN WEATHER SYSTEMS. MODEL SOUNDINGS SHOW A 7 TO 10 C RISE IN BOUNDARY LAYER TEMPERATURES COMPARED TO YESTERDAY... RESULTING IN AFTERNOON HIGHS IN THE LOWER TO MID 70S. WITH 25 TO 30 KTS TO MIX TO THE SURFACE...SOUTHERLY WINDS WILL BECOME BREEZY WITH SOME GUSTS TO 25 MPH. MONDAY WILL BE SIMILAR TODAY...EXCEPT A BIT WARMER WITH LESS WIND. HIGHS WILL TOP OUT IN THE MID TO UPPER 70S WITH SOUTH-SOUTHWEST WIND FROM 10 TO 15 MPH. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 332 AM CDT SUN SEP 29 2013 A COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA MONDAY NIGHT... BRINGING A SLIGHT CHANCE OF RAIN SHOWERS ACROSS THE NORTH. BEST FORCING AND MOISTURE IS NORTH OF THE CANADIAN BORDER...SO NOT EXPECTING MUCH ACCUMULATION IF ANYTHING DOES DEVELOP. BIGGER SENSIBLE WEATHER IMPACT WILL BE INCREASING WEST-SOUTHWEST WIND BEHIND THE FRONT. BOUNDARY LAYER DEEPENS TO NEAR 800 HPA BY TUESDAY MID-AFTERNOON WITH 35 TO 40 KTS TO MIX TO THE SURFACE. THIS COULD RESULT IN SUSTAINED WINDS IN EXCESS OF 30 MPH...THUS REQUIRING A WIND ADVISORY. WAY TOO EARLY TO CONSIDER ISSUANCE... BUT FOR SURE LOOKS TO BE A WINDY DAY. TEMPERATURES WILL ALSO DROP BEHIND THE FRONT WITH HIGHS FROM THE MID 60S TO MID 70S. LONG RANGE MODELS COMING INTO BETTER AGREEMENT WITH A MORE SOUTHERN SOLN FOR THU-FRI SYSTEM AS 500 TROUGH DIGS A BIT INTO WYOMING AND UPPER RIDGE TO THE EAST OVER THE GREAT LAKES IS FLATTER. 00Z EURO CAME IN RESEMBLING THE 18Z SAT AND 00Z SUN GFS IN SHOWING THIS. AFTER MUCH COORDINATION WENT CLOSER TO THIS SOLN WHICH REQUIRED SIGNIFICANT CHANGES TO THE ALL BLEND FCST. KEPT SOME LOW SHOWER CHANCES WEDNESDAY IN SE ND INTO NRN MN AS A WEAK SHORT WAVE MOVES THRU...THEN LIMITED ANY CHANCE OF SHOWERS TO SOUTHEAST HALF OF THE FCST AREA THU-THU NIGHT AND THEN DRY FRIDAY AS COLDER AIR MOVES SOUTH. 00Z EURO HAS 850 MB TEMPS -4 TO -5C IN NE ND/NW MN FRI WITH HIGH PRESSURE MOVING IN WHICH WOULD TRANSLATE TO A CHILLY FRI NIGHT WITH WIDESPREAD SUB FREEZING LOWS. GFS NOT AS COLD BUT STILL A BIT BLO 0C 850 MB TEMPS. LOWERED TEMPS A BIT FROM ALL BLEND TOOL TO SHOW WIDESPREAD LOW-MID 30S FOR SAT MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED AT 1240 PM CDT SUN SEP 29 2013 CIRRUS POSSIBLE THROUGH THE PERIOD. OTHERWISE...THE MAIN CONCERN WILL BE SOUTHERLY WINDS THIS AFTERNOON GUSTING UP TO 22-24 KNOTS. THE GUSTINESS WILL CEASE AROUND SUNSET...WITH WINDS REMAINING AROUND 10 KNOTS OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...EWENS SHORT TERM...ROGERS LONG TERM...ROGERS/RIDDLE AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1008 AM CDT SUN SEP 29 2013 .UPDATE... ISSUED AT 1008 AM CDT SUN SEP 29 2013 ONLY MINOR CHANGES TO THIS UPDATE...MAINLY TO INCREASE THE CLOUD COVER ACROSS THE NORTH. VISIBLE SAT SHOWS WHAT APPEARS TO BE THICKER CIRRUS MOVING TO THE E/NE. CROSS-SECTIONS USING THE RAP AND GFS IN FAIR AGREEMENT WITH THE VISIBLE. OTHERWISE WITH SOUTHWEST FLOW SUSPECT TEMPERATURES ON TRACK FOR MIDDLE TO UPPER 70S MOST AREAS. UPDATE ISSUED AT 650 AM CDT SUN SEP 29 2013 FORECAST IS IN GOOD SHAPE WITH NO CHANGES NEEDED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 332 AM CDT SUN SEP 29 2013 CHALLENGES INCLUDE TEMPERATURES AND WIND THROUGH THE PERIOD. WILL FOLLOW A BLEND OF THE NAM/ECMWF/GEM AS THE LATEST GFS IS TOO FAST WITH THE FRONTAL PASSAGE MONDAY NIGHT. FOR TODAY...EXPECT PLENTY OF SUN BETWEEN PERIODS OF HIGH CLOUDS AS THE REGION REMAINS BETWEEN WEATHER SYSTEMS. MODEL SOUNDINGS SHOW A 7 TO 10 C RISE IN BOUNDARY LAYER TEMPERATURES COMPARED TO YESTERDAY... RESULTING IN AFTERNOON HIGHS IN THE LOWER TO MID 70S. WITH 25 TO 30 KTS TO MIX TO THE SURFACE...SOUTHERLY WINDS WILL BECOME BREEZY WITH SOME GUSTS TO 25 MPH. MONDAY WILL BE SIMILAR TODAY...EXCEPT A BIT WARMER WITH LESS WIND. HIGHS WILL TOP OUT IN THE MID TO UPPER 70S WITH SOUTH-SOUTHWEST WIND FROM 10 TO 15 MPH. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 332 AM CDT SUN SEP 29 2013 A COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA MONDAY NIGHT... BRINGING A SLIGHT CHANCE OF RAIN SHOWERS ACROSS THE NORTH. BEST FORCING AND MOISTURE IS NORTH OF THE CANADIAN BORDER...SO NOT EXPECTING MUCH ACCUMULATION IF ANYTHING DOES DEVELOP. BIGGER SENSIBLE WEATHER IMPACT WILL BE INCREASING WEST-SOUTHWEST WIND BEHIND THE FRONT. BOUNDARY LAYER DEEPENS TO NEAR 800 HPA BY TUESDAY MID-AFTERNOON WITH 35 TO 40 KTS TO MIX TO THE SURFACE. THIS COULD RESULT IN SUSTAINED WINDS IN EXCESS OF 30 MPH...THUS REQUIRING A WIND ADVISORY. WAY TOO EARLY TO CONSIDER ISSUANCE... BUT FOR SURE LOOKS TO BE A WINDY DAY. TEMPERATURES WILL ALSO DROP BEHIND THE FRONT WITH HIGHS FROM THE MID 60S TO MID 70S. LONG RANGE MODELS COMING INTO BETTER AGREEMENT WITH A MORE SOUTHERN SOLN FOR THU-FRI SYSTEM AS 500 TROUGH DIGS A BIT INTO WYOMING AND UPPER RIDGE TO THE EAST OVER THE GREAT LAKES IS FLATTER. 00Z EURO CAME IN RESEMBLING THE 18Z SAT AND 00Z SUN GFS IN SHOWING THIS. AFTER MUCH COORDINATION WENT CLOSER TO THIS SOLN WHICH REQUIRED SIGNIFICANT CHANGES TO THE ALL BLEND FCST. KEPT SOME LOW SHOWER CHANCES WEDNESDAY IN SE ND INTO NRN MN AS A WEAK SHORT WAVE MOVES THRU...THEN LIMITED ANY CHANCE OF SHOWERS TO SOUTHEAST HALF OF THE FCST AREA THU-THU NIGHT AND THEN DRY FRIDAY AS COLDER AIR MOVES SOUTH. 00Z EURO HAS 850 MB TEMPS -4 TO -5C IN NE ND/NW MN FRI WITH HIGH PRESSURE MOVING IN WHICH WOULD TRANSLATE TO A CHILLY FRI NIGHT WITH WIDESPREAD SUB FREEZING LOWS. GFS NOT AS COLD BUT STILL A BIT BLO 0C 850 MB TEMPS. LOWERED TEMPS A BIT FROM ALL BLEND TOOL TO SHOW WIDESPREAD LOW-MID 30S FOR SAT MORNING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 650 AM CDT SUN SEP 29 2013 MOSTLY SUNNY/CLEAR SKIES WILL PERSIST AT ALL TAF SITES THE NEXT 24 HOURS. LIGHT SOUTHERLY WIND WILL INCREASE LATE MORNING WITH GUSTS UP TO 25 KTS BY MID AFTERNOON. WINDS WILL DECREASE AFTER SUNSET AND REMAIN NEAR 10 KTS OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...EWENS SHORT TERM...ROGERS LONG TERM...ROGERS/RIDDLE AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS NORMAN OK
839 PM CDT MON SEP 30 2013 .UPDATE... LATEST HRRR STILL INDICATING POTENTIAL FOR PATCHY FOG LATE TONIGHT ACROSS AREAS FROM NEAR THE ARBUCKLES EAST ACROSS SOUTHEAST OKLAHOMA. HAVE EXPANDED FOG WORDING A BIT FURTHER WEST... OTHERWISE FORECAST UNCHANGED. && .PREV DISCUSSION... /ISSUED 609 PM CDT MON SEP 30 2013/ AVIATION... 0Z TAFS... VFR CONDITIONS THROUGHOUT THE TAF PERIOD. PREV DISCUSSION... /ISSUED 344 PM CDT MON SEP 30 2013/ DISCUSSION... RATHER DRY AIR REMAINS OVER THE FA THIS AFTERNOON...BUT MORE HUMIDITY AIR IS LOCATED ACROSS FAR SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS/GULF COAST. SOME OF THIS AIR WILL BEGIN TO LIFT SLOWLY TO THE NORTH AND WEST TONIGHT INTO TUESDAY WHICH MAY RESULT IN SOME FOG ACROSS OUR FAR SOUTHEAST COUNTIES AND MORE CLOUDS TUESDAY AFTERNOON. BETTER MOISTURE RETURN WILL OCCUR WEDNESDAY...AS MID TO UPPER 60 DEWPOINTS RETURN TO AT LEAST THE EASTERN 1/2 TO 2/3RDS OF OKLAHOMA. THIS SHOULD RESULT IN SOME LOW CLOUD DEVELOPMENT WITH WITH AN OPPORTUNITY FOR A FEW SHOWERS IN SOUTHEAST OKLAHOMA. A RATHER STRONG SYSTEM WILL MOVE ACROSS THE PACIFIC NORTHWEST AROUND MID-WEEK AND THEN ACROSS THE ROCKIES BY THURSDAY/FRIDAY. SURFACE LOW PRESSURE WILL DEEPEN OVER EASTERN COLORADO ON THURSDAY WHICH WILL BRING RATHER WINDY CONDITIONS TO THE SOUTHERN PLAINS. BY MID TO LATE FRIDAY...A COLD FRONT IS EXPECTED TO ENTER FAR NORTHWEST OKLAHOMA. THE EC HAS ADJUSTED TO A SLOWER FRONTAL TIMING AND IS FAIRLY SIMILAR WITH THE GFS. WITH A DECENT AIR MASS IN PLACE...SCATTERED SHOWERS AND STORMS SHOULD DEVELOP ALONG THE FRONT FRIDAY AFTERNOON INTO FRIDAY EVENING/SATURDAY MORNING. THE BEST CHANCE APPEARS TO BE ACROSS SOUTH CENTRAL AND SOUTHEAST OKLAHOMA. A MUCH COOLER AND DRIER AIR MASS WILL OVERSPREAD THE REGION FOR THE WEEKEND WITH RATHER CHILLY OVERNIGHT LOWS SAT/SUN/MON MORNINGS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 59 87 65 84 / 0 0 0 10 HOBART OK 57 90 63 86 / 0 0 0 10 WICHITA FALLS TX 60 91 64 88 / 0 0 0 10 GAGE OK 53 85 60 84 / 0 0 0 10 PONCA CITY OK 57 86 64 84 / 0 0 0 10 DURANT OK 60 88 67 84 / 0 0 10 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 30/25
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1230 AM CDT SUN SEP 29 2013 .UPDATE... UPDATED FOR 06Z AVIATION DISCUSSION. && .DISCUSSION...02Z SURFACE ANALYSIS PLACES A COLD FRONT FROM MILWAUKEE TO SAINT LOUIS...AND WESTERN ARKANSAS. KLZK WSR-88D RADAR TRENDS OVER THE PAST COUPLE OF HOURS HAVE SHOWN CONSIDERABLE WEAKENING OF THE CONVECTIVE RAIN SHOWERS AND PERHAPS AN EMBEDDED THUNDERSTORM OR TWO OVER CENTRAL ARKANSAS AS THEY BEGIN TO APPROACH EAST AND NORTHEAST ARKANSAS LATE THIS EVENING AND ENCOUNTER A DRIER AND MORE STABLE AIRMASS OVER THE MID SOUTH. 00Z UPPER AIR SOUNDINGS AT JACKSON MS AND NASHVILLE INDICATE A SUBSTANTIAL 800-700 MB CAPPING INVERSION PRESENT ACROSS THE REMAINDER OF THE LOWER MISSISSIPPI VALLEY. LATEST 3KM HRRR AND 00Z WRF INDICATE MOST IF NOT ALL OF THE RAIN SHOWERS WILL STRUGGLE TO GET PAST THE MISSISSIPPI RIVER BEFORE 12Z. /7 AM CDT/ WILL MAKE FURTHER ADJUSTMENTS TO OVERNIGHT RAIN CHANCES TO REDUCE THUNDER MENTION AND KEEP MOST OF THE RAIN CHANCES ALONG/WEST OF THE MISSISSIPPI RIVER. WILL MAKE ANY OTHER ADJUSTMENTS TO GRIDS AS NEEDED TO ACCOUNT FOR LATEST TRENDS. UPDATED GRIDS WILL BE AVAILABLE SHORTLY. CJC && .DISCUSSION... A COLD FRONT CURRENTLY STRETCHES FROM NEAR KIRKSVILLE MISSOURI TO NEAR FORT SMITH ARKANSAS. A BAND OF SHOWERS HAS FORMED ALONG THE FRONT FROM SOUTHWEST MISSOURI TO EASTERN OKLAHOMA INTO NORTHWEST ARKANSAS. THIS FRONT WILL MOVE INTO THE MIDSOUTH LATE TONIGHT. CURRENTLY ACROSS THE MIDSOUTH...TEMPERATURES HAVE RISEN INTO THE 80S THANKS TO AN UPPER RIDGE THAT HAS BEEN POSITIONED ALONG THE GULF COAST FOR THE LAST COUPLE OF DAYS. THE RIDGE WILL RETREAT EASTWARD THIS EVENING. EXPECT BAND OF SHOWERS TO MOVE INTO RANDOLPH/LAWRENCE COUNTIES BETWEEN 9 PM AND MIDNIGHT. THE BAND OF SHOWERS WILL SLOWLY PUSH SOUTH AND EAST AFTER MIDNIGHT. EXPECT BAND TO BE ROUGHLY LOCATED ALONG THE MISSISSIPPI RIVER BETWEEN 6 AM-8 AM. CAN/T RULE OUT A FEW EMBEDDED THUNDERSTORMS DEVELOPING IN THE BAND SO WILL KEEP MENTION OF THUNDER. LOWS WILL BE IN THE 60S. SUNDAY...COLD FRONT IS STILL EXPECTED TO STALL OUT ACROSS THE MIDSOUTH LIKELY IN THE AREA FROM JACKSON TENNESSEE TO CLARKSDALE MISSISSIPPI. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND AHEAD OF THE FRONT. EXPECT HIGHS TO BE COOLER WITH READINGS IN THE MID 70S TO LOWER 80S. FRONT WILL EVENTUALLY PUSH BACK NORTHWARD AS A WARM FRONT ON MONDAY. AS A RESULT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE SUNDAY NIGHT AND MONDAY. BEST CHANCES WILL OCCUR ALONG THE FRONT. STILL HARD TO SAY WHAT EXACTLY WILL HAPPEN DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME. UPPER RIDGE WILL BUILD BACK OVER THE AREA BUT CHANCES FOR RAIN WILL DEPEND ON IF A DISTURBANCE GETS TRAPPED UNDERNEATH RIDGE. TOO MANY IF/S RIGHT NOW...SO WILL CONTINUE WITH FORECAST AS IS. DO EXPECT TEMPERATURES TO RETURN TO ABOVE NORMAL WITH THE RIDGE BUILDING BACK INTO THE REGION. 00Z MODELS PUSHED TIMING OF NEXT FRONT BACK 24 HOURS BUT 12Z ECMWF HAS PUSHED TIMING BACK TO THURSDAY NIGHT INTO FRIDAY. 12Z GFS REMAINS 24 HOURS SLOWER. WILL CONTINUE WITH SMALL POPS DURING THE THURSDAY NIGHT THROUGH SATURDAY TIME FRAME FOR NOW. TEMPERATURES WILL COOL DOWN BEHIND NEXT FRONT. KRM && .AVIATION... 06Z TAF CYCLE RAIN TONIGHT LOOKS EVEN LESS LIKELY AS SHOWERS ARE MOVING INTO A DRIER AIRMASS. SCALED BACK RAIN ON STATION TO VCSH TONIGHT...BRINGING IN SHRA AS WE BEGIN TO DESTABILIZE TOMORROW. A WEAKENING COLD FRONT WILL BECOME DIFFICULT TO IDENTIFY OVER THE NEXT 24 HOURS AS IT MOVES ACROSS THE MIDSOUTH...BECOMING MASKED BY OUTFLOW FROM SHOWERS AND THUNDERSTORMS. AS A RESULT THUS WINDS WILL BE HIGHLY VARIABLE TOMORROW INTO TOMORROW NIGHT. HOWEVER...WIND SPEEDS SHOULD REMAIN FAIRLY WEAK...LESS THAN 8 KTS. SHOWERS RESULTING IN MVFR CIGS AND VIS WILL LIKELY PREVAIL AT ALL SITES EXCEPT TUP FOR MOST OF THE DAY TOMORROW. CIGS SHOULD LOWER EVEN FURTHER AFTER SUNSET...POSSIBLE TO IFR LEVELS...BUT FEEL LIKE LOW MVFR WILL PREVAIL. SHOWERS WILL LIKELY LINGER AT MKL...MEM AND TUP AS WELL. JDS/AC3 && .PRELIMINARY POINT TEMPS/POPS... MEM 67 81 67 85 / 40 20 10 10 MKL 62 80 61 84 / 40 20 10 10 JBR 62 80 64 83 / 30 20 10 10 TUP 64 83 64 85 / 20 20 10 10 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
244 PM CDT SUN SEP 29 2013 .SHORT TERM /NOW THROUGH MONDAY NIGHT/...FAIRLY COMPLEX SYNOPTIC/MESOSCALE PATTERN THIS AFTERNOON. THERE APPEARS TO BE A WEAK SFC RIDGE ABOUT 50 MILES EAST OF SOUTH PADRE ISLAND...AND A WEAK PRESSURE TROUGH THAT HAS MOVED SOUTHEAST TO ROUGHLY A MCALLEN TO BAFFIN BAY LINE. AT THE SAME TIME RADAR AND VISIBLE SATELLITE SHOW AN MCV/CLOSED CYCLONE PATTERN ABOUT 20 MILES WEST OF ZAPATA COUNTY WHICH IS MORE FOCUSED THAN THE 850MB TROUGH THAT SHOWED UP ON THE 12Z UPPER AIR CHART. THIS FEATURE HAS LITTLE APPARENT SURFACE REFLECTION. UPPER LEVEL RIDGING STRETCHES FROM THE WESTERN GULF OF MEXICO INTO NORTH CENTRAL MEXICO AND A JET MAX ASSOCIATED WITH A DEEPENING WEST TEXAS TROUGH IS BECOMING SLIGHTLY MORE DIFFLUENT JUST TO OUR NORTHWEST AS IT PARTIALLY CURVES SOUTHWARD AROUND THE RIDGE. COLUMN MOISTURE APPEARS TO BE INCREASING PER SATELLITE PWAT ESTIMATES AND PERIODIC LOW CLOUD COVERAGE AND MODIFIED RAP AND OBSERVED SOUNDINGS SUGGEST THE BOUNDARY LAYER IS MODERATELY UNSTABLE BUT A RESIDUAL 850MB CAP IS VERY LIKELY HOLDING BACK INITIATION AT THIS HOUR WHICH BASED ON THE VERTICAL EXTENT OF CUMULUS CLOUDS SO FAR SEEMS TO MAKE SENSE. REST OF THE AFTERNOON...VWP SHOWS MODEST WESTERLY WINDS WHICH SHOULD BE TRANSPORTING THE RICHER COLUMN MOISTURE INTO THE REGION...WHICH IS FAIRLY COUNTER INTUITIVE FOR OUR GEOGRAPHY. DO NOT BELIEVE THAT THE VELOCITY OR TRAJECTORY WILL INCREASE OUR CAPPING...BUT IT MAY...AND THAT MAY KEEP CONVECTIVE INITIATION HELD BACK UNTIL UPPER TROUGHING GETS CLOSER. RESIDUAL OUTFLOW BOUNDARIES AND A SEABREEZE FRONT SHOULD BE ABLE TO GET AT LEAST SOMETHING GOING BY 4 PM HOWEVER. ANYTHING THAT GOES UP WILL BE VIRTUALLY STATIONARY AND WITH INCREASING PWATS A HEAVY RAIN/FLOODING THREAT EXISTS. TONIGHT...GFS IS THE SLOWEST BRINGING THE TROUGH THROUGH AND DOES NOT SUBSTANTIALLY INCREASE UPPER DIVERGENCE/LIFT UNTIL ABOUT MIDNIGHT TONIGHT AND KEEPS THE WINDOW OPEN FOR HIGHER CONVECTIVE COVERAGE MONDAY. RAP/HRRR/NAM START LARGE SCALE UPPER LIFT EARLIER...BY LATE AFTERNOON...AND CLEARS THE AREA FASTER ON MONDAY. WATER VAPOR AND GOES DERIVED WINDS LEAD ME TO BELIEVE AT LEAST SOME DIFFLUENCE WILL BEGIN SHORTLY AND LIKELY HELP GET A DECENT AMOUNT OF CONVECTION GOING OVER AT LEAST THE CENTRAL PART OF THE CWA BY 6 OR 7 PM...WITH THE CHANCE MOVING EASTWARD THROUGH THE EVENING. UPPER LIFT PEAKS AROUND 06Z/100 AM CDT OVER THE AREA AND THE FORECAST REFLECTS THE HIGHEST RAINFALL CHANCES AROUND THIS TIME. BUMPED UP TO LIKELY POPS OVER THE COASTAL WATERS WHERE INSTABILITY WILL BE STRONGER IN THE PRE DAWN HOURS. LOCALLY HEAVY RAINFALL/FLOODING WILL BE A CONCERN...ESPECIALLY UNTIL LATER IN THE NIGHT WHEN THE DEEPER LAYER STEERING WINDS INCREASE AND START TO MOVE THE CONVECTION ALONG MORE QUICKLY. MONDAY...BELIEVE THE GFS IS ON THE RIGHT TRACK AS FAR AS COMPLETE CLEARING OF THE SHORTWAVE TROUGH...AND THE 12Z ECMWF AGREES FAIRLY WELL. SO KEPT 30/40 PCT POPS THROUGH THE DAY ON MONDAY WITH THE CHANCE STARTING TO WANE AFTER ABOUT 2100Z/400 PM AS THE TROUGH AXIS CLEARS. CONVECTION SHOULD BE FASTER MOVING ON MONDAY. PREVAILING WINDS WILL BE FAIRLY LIGHT WITH TEMPERATURES FLUCTUATING AROUND CONVECTION WITH A WINDOW FOR HEATING BEFORE REDEVELOPMENT IN THE MORNING...AND AFTER STORMS START TO WANE IN THE LATE AFTERNOON. MONDAY NIGHT...BEHIND THE DEPARTING TROUGH UPPER SUBSIDENCE SHOULD LIMIT RAIN CHANCES TO THE COASTAL WATERS WITH LIGHT WINDS. DEPENDING ON HOW MUCH RAIN FALLS THERE MAY BE A THREAT FOR GROUND FOG OR RADIATION FOG GIVEN THE EXPECTED LIGHT WINDS...BUT DID NOT INCLUDE IN THE GRIDS FOR NOW. /68-JGG/ .LONG TERM /TUESDAY THROUGH SUNDAY/...500MB LOW ACROSS EAST TEXAS AND LOUISIANA TUESDAY SHOULD PROVIDE SUBSIDENCE ACROSS SOUTHWEST TX BUT LOW TO MID LEVEL MOISTURE IS PROGGED TO LINGER ACROSS NORTHEAST MEXICO AND THE NORTHWEST GULF OF MEXICO SO WILL KEEP A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE CWA TUESDAY. THE UPPER LEVEL FEATURE ACROSS THE NORTHWEST GULF COAST LINGERS WEDNESDAY BEFORE MOVING NORTHEAST THURSDAY. A 500MB TROUGH WILL DEVELOP ACROSS THE WESTERN UNITED STATES THURSDAY AND MOVE EASTWARD FRIDAY BRINGING A WEAK COLD FRONT INTO SOUTH TX SATURDAY. THIS WILL PROVIDE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FRI NIGHT INTO SATURDAY ACROSS THE RIO GRANDE VALLEY AS MOISTURE POOLS ALONG AND AHEAD OF THE FRONT. DRIER AND SLIGHTLY COOLER AIR WILL FILTER INTO THE AREA IN THE WAKE OF THE FRONT SAT NIGHT INTO SUNDAY. && .MARINE... NOW THROUGH MONDAY NIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO START BY LATE EVENING AND PERSIST THROUGH MONDAY. PREVAILING WINDS AND SEAS WILL BE FAIRLY LIGHT OUT OF THE EAST TO SOUTHEAST OVERNIGHT WITH LOW TO MODERATE SEAS. MORE MODERATE SOUTH TO SOUTHEAST WINDS ARE EXPECTED TO BUILD IN MONDAY MORNING PERSISTING THROUGH MONDAY NIGHT WITH LOW TO MODERATE SEAS. TUESDAY THROUGH FRIDAY...LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TUESDAY AND WEDNESDAY WITH HIGH PRESSURE ACROSS THE SOUTHEAST UNITED STATES. THE PRESSURE GRADIENT WILL INCREASE SLIGHTLY ACROSS THE WESTERN GULF OF MEXICO ON THURSDAY AS LOW PRESSURE DEVELOPS ACROSS THE LEE SIDE OF THE ROCKIES. MODERATE SOUTHEAST TO SOUTH WINDS WILL PREVAIL ACROSS THE LOWER TEXAS COAST THURSDAY INTO FRIDAY AS A WEAK COLD FRONT MOVES INTO NORTHWEST TX FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 77 91 78 90 / 50 40 20 20 BROWNSVILLE 77 91 76 91 / 50 40 20 20 HARLINGEN 75 91 76 93 / 50 40 20 20 MCALLEN 76 92 76 95 / 50 40 10 20 RIO GRANDE CITY 74 91 77 93 / 30 30 10 20 SOUTH PADRE ISLAND 79 87 79 87 / 60 40 20 20 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 68/61/MARTINEZ
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1056 PM PDT Sat Sep 28 2013 .SYNOPSIS... Tonight will be wet and windy with the passage of a strong cold front. Another stronger cold front will bring more wind and rain to the region Sunday night into Monday. High mountain snow is expected Monday into Tuesday. The wild weather will begin to settle down on Wednesday. The nicest weather of the week will occur Thursday and Friday, but temperatures will remain below average through the end of the week. && .DISCUSSION... The cold front is making its way through western WA early this evening with widespread moderate rainfall and pockets of heavy rainfall being reported along the front. Numerous reports of heavy rainfall of over 2 inches have been reported west of the Cascades so far with this system. The cold front is expected to push across eastern WA and into the ID Panhandle overnight. The HRRR model seems to have a good handle with the timing of the front and the forecast is reflective of this latest model solution. We are expecting the front to begin to push east of the Cascade Mountains after 1100 PM tonight. A strong moist warm sector ahead of the cold front combined with strong frontal dynamics is expected to produce moderate to heavy rainfall just out ahead of the cold front. Heaviest rainfall rates are anticipated closer to the leading edge of the front. I increased precipitation chances and rainfall amounts for tonight, primarily across the eastern half of the forecast area. 12 HR rainfall totals through 500 AM this morning are expected to generally be between a quarter and a half an inch across extreme eastern WA with the Panhandle seeing these totals between a half and three-quarters. The cold front is expected to have passed southeast of the region around the early morning hours on Sunday. A chance of showers will be possible across the ID Panhandle behind the front due to orographics across this area. The Cascade Crest will also continue to see showers with the higher elevations above 5500 feet likely switching over to snow. Locations in between these areas will likely dry out at least into the morning hours on Sunday. Winds will continue to be gusty ahead of and especially with frontal passage. Some observations across the Moses Lake Area, on the Waterville Plateau and in the Okanogan Valley have reported gusts of between 40 and 55 mph. Although these winds have not been quite as windy further east across the Upper Columbia Basin and into the Spokane/Coeur d`Alene Area and across the Palouse, I do think we will see a better chance for some stronger winds with cold front passage. Some locations may see a brief period of reaching advisory criteria winds where we have canceled the advisory earlier, but I think these stronger winds will be relatively brief as the cold front moves over the area. Thus, I do not anticipate making any updates to the Wind Advisory at this time. Winds should weaken a bit behind the front as strongest winds aloft will shift eastward with the cold front. /SVH && .AVIATION... 06Z TAFS: A cold front will sweep across eastern WA and into the ID Panhandle over the next 6 hours. The front is currently passing through KMWH at 06Z tonight and will continue east with time and is expected to pass through KGEG, KSFF, KCOE, KPUW and KLWS between 07Z and 11Z tonight. This front will result in some heavier rainfall across the region with a better chance for cigs/vis down into MVFR/IFR category. Low stratus is expected to develop across extreme eastern WA and into the Panhandle behind the cold front for at least a few hours. Winds will shift from the south-southeast to a southwesterly orientation and become more gusty with cold front passage. A second, similar system, will pass through the region Sunday evening into Sunday night with more rain and gusty winds expected. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 47 57 45 56 44 56 / 100 50 80 30 20 50 Coeur d`Alene 48 55 44 53 43 55 / 100 70 100 50 30 50 Pullman 48 56 46 56 43 57 / 100 80 90 30 10 30 Lewiston 54 62 50 63 46 64 / 70 70 80 20 10 20 Colville 50 58 45 57 43 57 / 100 60 100 50 30 50 Sandpoint 49 55 43 49 41 53 / 100 80 100 70 70 50 Kellogg 47 52 43 49 40 52 / 100 90 100 90 70 50 Moses Lake 50 66 47 65 45 64 / 40 20 50 10 10 20 Wenatchee 47 62 47 63 45 62 / 40 30 60 10 10 20 Omak 47 64 44 63 40 62 / 70 40 70 10 10 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Flood Watch through late Sunday night for Northern Panhandle. WA...Flood Watch through late Sunday night for East Slopes Northern Cascades. Wind Advisory until 2 AM PDT Sunday for Moses Lake Area-Upper Columbia Basin-Waterville Plateau. && $$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
930 PM PDT MON SEP 30 2013 .SYNOPSIS... WEST FLOW ALOFT WILL CONTINUE FAIR WEATHER THROUGH WEDNESDAY EXCEPT FOR INCREASING LOW CLOUDS AND FOG NEAR THE COAST. PATCHY DENSE FOG WILL DEVELOP VERY LATE TONIGHT AND EARLY TUESDAY MORNING NEAR THE COAST. THE LOW PRESSURE TROUGH OVER THE PACIFIC NORTHWEST WILL GRADUALLY DEEPEN OVER THE WEST COAST THROUGH THURSDAY AND BRING A COOLING TREND...AND SOME DRIZZLE WILL BE POSSIBLE THURSDAY MORNING. AS THE TROUGH MOVES EAST FRIDAY AND SATURDAY...OFFSHORE FLOW WILL BRING GUSTY WINDS THROUGH AND BELOW PASSES AND CANYONS AND VERY LOW HUMIDITY TO MOST AREAS ALONG WITH WARMER WEATHER. THE WARM DRY WEATHER WILL CONTINUE EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... SKIES WERE CLEAR...WITH NO SIGNS OF FOG YET. DEW POINTS ARE IN THE LOWER 60S ALONG THE IMMEDIATE COAST...WHICH WOULD BE FAVORABLE FOR FOG TO FORM...THOUGH 00Z WRF RUN USING THE RAP FOR INITIALIZATION HAS BOUNDARY LAYER AVERAGE RH VALUES OF 85-90 PERCENT ONLY AFTER ABOUT 5 AM TUE...AND MOS GUIDANCE IS MOSTLY CONSISTENT WITH FOG WAITING UNTIL AROUND 5 AM AS WELL. DENSE FOG ADVISORY IS IN EFFECT FROM 1 AM TO 9 AM...BUT THE EMPHASIS IN THE UPDATE WILL BE FOR FOG MOSTLY FROM 5 AM TO 9 AM. WEST FLOW CURRENTLY COVERS MOST OF CALIFORNIA WITH TIGHT HEIGHT GRADIENTS FROM CENTRAL CALIFORNIA NORTH TO THE LONGWAVE TROUGH OVER SW CANADA. STRONG SHORTWAVES WILL CONTINUE TO MOVE FROM WEST TO EAST OVER THE PAC NW...WITH THE NEXT ONE TUESDAY AND THEN ANOTHER ONE WEDNESDAY. HEIGHTS AND TEMPS ALOFT WILL GRADUALLY LOWER HERE THE NEXT FEW DAYS AND RESULT IN A COOLING TREND...ESPECIALLY WED...AND A DEEPER MARINE LAYER. TUESDAY NIGHT...THE MARINE LAYER SHOULD BE DEEP ENOUGH THAT THE COAST WILL JUST HAVE STRATUS...WITH THE AREAS OF FOG IN THE VALLEYS. THE WAVE MOVING THROUGH THE PAC NW WEDNESDAY WILL DIG INTO THE GREAT BASIN BY THU AND SHIFT EAST TO THE CENTRAL ROCKIES BY FRI. THE MARINE LAYER SHOULD BE ITS DEEPEST THU MORNING...ESPECIALLY IF A COASTAL EDDY FORMS. LATEST NAM HAS OFFSHORE FLOW DEVELOPING OVER SAN BERNARDINO COUNTY LATE THU NIGHT...THOUGH COASTAL AND POSSIBLY A FEW VALLEY AREAS FURTHER SOUTH COULD HAVE STRATUS EVEN INTO FRI MORNING DUE TO A LINGERING COASTAL EDDY. MODELS HAVE THE OFFSHORE FLOW SPREADING SOUTH TO SAN DIEGO COUNTY DURING THE DAY FRIDAY...AND THAT SHOULD WIPE OUT THE MARINE LAYER AND BRING VERY LOW HUMIDITIES TO THE REGION. THE STRENGTH OF THE WINDS...MAINLY THROUGH/BELOW PASSES/CANYONS...WILL LIKELY BE MODERATELY STRONG GIVEN THERE IS COLD AIR ADVECTION IN THE 850-700 MB LAYER AND DECENT OFFSHORE PRESSURE GRADIENTS OF 10 MB OR MORE FROM CENTRAL NEVADA TO SAN DIEGO. THE WINDS WILL START OUT MORE N/NE FRIDAY THEN BECOME MORE EASTERLY SATURDAY...SO SAN DIEGO COUNTY WILL LIKELY HAVE THEIR BEST WINDS SATURDAY. WINDS DIE DOWN SUNDAY...WITH GRADUALLY INCREASING SEA BREEZES EARLY NEXT WEEK TO BRING AN INCREASE IN HUMIDITY TO COASTAL AREAS...BUT WITH GENERALLY DRY CONDITIONS CONTINUING INLAND. && .AVIATION... 010306Z...THROUGH 01/1000 UTC...OVER NEAR SHORE WATERS/IMMEDIATE COAST...SCT CLDS 200-500 FT MSL WITH VSBY 3-5SM BR...ELSEWHERE SKC. 01/1000-1500 UTC...BKN-OVC STRATUS OVER WATER TO 10 SM INLAND WITH BASES 200-500 FT MSL AND TOPS 500-700 FT MSL...VSBY 2-4 SM BR WITH AREAS VSBY AOB 1SM BR FG. KCRQ LIKELY TO EXPERIENCE VIS AOB 1/4SM FG. CLEARING OF STRATUS/FOG 01/1500-1800 UTC. ELSEWHERE CONTINUED SKC P6SM. && .MARINE... AREAS OF DENSE FOG ARE LIKELY ACROSS THE COASTAL WATERS THROUGH MID-MORNING TUESDAY...WITH VISIBILITY LESS THAN 1 NM. && .FIRE WEATHER... THE MAIN OFFSHORE FLOW EVENT WILL BE VERY LATE THU NIGHT THROUGH SAT. LATEST MODEL GUIDANCE SHOWS THE OFFSHORE FLOW WITH AREAS OF WIND GUSTS OF 35+ KNOTS DEVELOPING OVER SW SAN BERNARDINO COUNTY BETWEEN ABOUT 2 AND 5 AM FRI...AND IN W RIVERSIDE/ORANGE COUNTY BETWEEN ABOUT 5 AND 8 AM FRI. SAN DIEGO COUNTY WILL MOST LIKELY DEVELOP GUSTY NE WINDS LATER FRI MORNING...THOUGH BEST SUPPORT FOR WINDS THERE WILL BE SAT MORNING AS THE FLOW BECOMES MORE EASTERLY. MOST INLAND AREAS WILL HAVE HUMIDITY BELOW 15 PERCENT BY FRI AFTERNOON...ESPECIALLY NORTH OF SAN DIEGO COUNTY. 6+ HOURLY DURATIONS OF 35 KNOT GUSTS AND BELOW 15 PERCENT RH ARE POSSIBLE IN SOME AREAS FRI AND/OR SAT. WINDS DECREASE PRETTY RAPIDLY LATE SAT...BUT RH WILL REMAIN LOW SUN/MON OVER INLAND AREAS. NIGHTTIME RECOVERIES WILL ALSO MOSTLY BE POOR FRI AND SAT NIGHTS. && .SGX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY FROM 1 AM TO 9 AM PDT TUESDAY FOR THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL AREAS. && $$ PUBLIC/FIRE...MAXWELL AVIATION/MARINE...BALFOUR
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
349 AM CDT TUE OCT 1 2013 .DISCUSSION... 328 AM CDT PRIMARY FORECAST CONCERNS THIS MORNING INCLUDE CLOUDS THIS MORNING...TEMPS THIS WEEK...AND THE INCREASING CONVECTIVE CHANCES BY THE MIDDLE AND END OF THE WEEK. STRONG AND DEEPENING LOW PRESSURE OVER SASKATCHEWAN IS RACING EASTWARD ACROSS SOUTHERN CANADA RESULTING IN A TIGHTENING SOUTHERLY GRADIENT ACROSS A PORTION OF THE CENTRAL CONUS INTO THE GREAT LAKES. THE RESULT IS A PRETTY QUICK NORTHWARD RETURN OF THE FAIRLY MOIST AIR MASS OVER THE OHIO VALLEY RAPIDLY NORTH INTO OUR AREA. STRATUS DECK HAS BEEN RAPIDLY EXPANDING NORTHEAST THE PAST COUPLE HOURS AND SHOULD CONTINUE TO DO SO THROUGH SUNRISE...LIKELY EVENTUALLY ENCOMPASSING ABOUT THE SOUTHEAST HALF OF OUR CWA. MODELS INDICATE THAT THE STRATUS WILL BE VERY QUICK TO ERODE AND BURN OFF AFTER SUNRISE...HOWEVER YESTERDAY IT TOOK UNTIL LATE MORNING FOR MOST OF THE STRATUS TO BREAK UP AND WITHOUT ANY ACARS FLIGHTS THIS MORNING TO GET A FEEL FOR THE DEPTH OF THE STRATUS AM CONCERNED THAT STRATUS MAY NOT BURN OFF AS QUICKLY AS MODEL SUGGEST GIVEN THE FAIRLY LOW SUN ANGLE. HAVE TRIMMED A 1-3F OFF GOING FORECAST TEMPS OVER THE SOUTHEAST CWA WHERE SO OF THE PRECIOUS LITTLE SUNSHINE WE GET THIS TIME OF YEAR WILL BE WASTED ON BATTLING STRATUS. OTHERWISE GOING FORECAST OF LOW TO MID 80S LOOKS RIGHT ON TRACK WITH A VERY NOTICEABLE INCREASE IN HUMIDITY LIKELY TO GIVE IT A BIT MORE MUGGY OF A FEEL TO THE AIR TODAY. WEAK FRONT TRAILING SOUTH FROM THAT STRONG CANADIAN LOW WILL SETTLE SOUTH INTO OUR CWA TONIGHT EVENTUALLY STALLING OUT OVER SOUTHERN PORTIONS OF THE CWA BY WEDNESDAY MORNING. BIGGEST IMPACT OF THE FRONT WILL BE TO KNOCK DOWN DEWPOINTS SUBSTANTIALLY AND TO TURN WINDS OFF THE LAKE AND RESULT IN A FAIRLY LARGE TEMP DROP CLOSER TO THE LAKE. FARTHER INLAND BEHIND THE FRONT TEMPS SHOULD REMAIN UNSEASONABLY WARM WEDNESDAY AND LIKELY GET UP TO AROUND 80 ACROSS NORTH CENTRAL ILLINOIS. SOUTH OF THE FRONT IN OUR SOUTHERN CWA IT WILL BE ANOTHER VERY WARM AND HUMID DAY (BY OCT STANDARDS) WITH HIGHS WELL INTO THE 80S AND DEWPOINTS IN THE 60S. FORECAST SOUNDINGS SHOW OVER 1000 J/KG OF CAPE WITH VERY WEAK INHIBITION WEDNESDAY AFTERNOON WITH MOST OF THE CONVECTIVELY PARAMETRIZED MODELS BREAKING OUT CONVECTION IN OUT SOUTHERN CWA WEDNESDAY AFTERNOON WITH THE CONVECTIVE ALLOWING MODELS LESS EXCITED ABOUT THE THREAT. HAVE LEANED MORE HEAVILY ON THE CONVECTIVE ALLOWING MODELS SINCE THEY ARE MORE IN LINE WITH OUR GOING FORECAST AND HAVE ONLY INTRODUCED SLIGHT CHANCE POPS FOR NOW WEDNESDAY AFTERNOON. SUBTLE WAVE RIPPLING THROUGH AMPLIFYING SOUTHWESTERLY FLOW ALOFT IS PROGGED TO RESULT IN AN INCREASE IN WAA DRIVEN CONVECTION WEDNESDAY INTO THURSDAY MORNING. WITH WARM FRONT LIFTING NORTH OF THE CWA THE BETTER FOCUS WOULD SYNOPTICALLY APPEAR TO BE TO OUR NORTH BUT GUIDANCE HAS BEEN HITTING AREAS FARTHER SOUTH HARDER WITH POPS/QPF. GIVEN THE UNCERTAINTIES KEPT POPS A BIT BELOW GUIDANCE. DOES APPEAR AS THOUGH WE COULD GET INTO MUCH MORE OF A LULL PRECIP-WISE THURSDAY AFTERNOON THROUGH FRIDAY AFTERNOON AS CWA GETS FIRMLY ENTRENCHED INTO THE WARM SECTOR OF THE FIRST POWERHOUSE NORTHERN PLAINS CYCLONE OF THE SEASON. FOR COLLABORATIVE PURPOSES AND TO COVER ANY SURPRISES HAVE LEFT SLIGHT CHANCE POPS IN THROUGH THIS PERIOD BUT SUSPECT MOST IF NOT ALL OF THIS TIME WILL BE PRECIP FREE. TEMPERATURES THURSDAY AFTERNOON THROUGH FRIDAY NIGHT WILL REMAIN WELL ABOVE AVERAGE AND POSSIBLY EVEN FLIRTING WITH RECORD WARM LOWS FRIDAY. MODERATE SOUTHERLY WINDS AND DEWPOINTS IN THE 60S SHOULD KEEP NIGHT TIME LOWS IN THE 60S...BUT THE RATHER HUMID CONDITIONS AND LONG NIGHTS COULD RESULT IN STRATUS BECOMING A PROBLEM THAT MAY BE SLOW TO BURN OFF IF AT ALL IN THE WAKE OF PRECIP THURSDAY AND THEN POTENTIALLY FRIDAY AS WELL. FORECAST HIGHS FOR THURS AND FRIDAY COULD END UP BEING NOT WARM ENOUGH SHOULD WE GET LESS PRECIP/CLOUDS ON THURS AND LESS CLOUDS ON FRIDAY...BUT UPPER 70S TO MID 80S SHOULD CERTAINLY CONVEY THE MESSAGE THAT IT WILL BE UNSEASONABLY WARM. STRONG COLD FRONT LOOKS TO SWEEP ACROSS THE AREA SATURDAY MORNING...SO FRIDAY NIGHT LOOKS TO REMAIN WINDY WARM AND HUMID WITH SATURDAY PROBABLY STARTING OUT THAT WAY...ESPECIALLY EASTERN CWA WITH FALLING TEMPS BEHIND THE STRONG COLD FRONT SATURDAY. TIMING OF THE FRONTAL PASSAGE STILL UNCERTAIN WITH ABOUT 12 HOURS OF SPREAD BETWEEN THE ECMWF/GEM/GFS. AS FRONTAL TIMING BECOMES MORE CERTAIN WILL PROBABLY NEED TO FINE TUNE TEMPS MORE FRIDAY NIGHT INTO SATURDAY. CONVECTIVE POTENTIAL CERTAINLY FAIRLY HIGH WITH SUCH A DYNAMIC SYSTEM WITH ACCESS TO UNSEASONABLY MOIST CONDITIONS. BEST THREAT OF SEVERE WEATHER APPEARS TO BE FRIDAY INTO FRIDAY EVENING AS THE SYSTEM IS RAPIDLY DEEPENING...WITH CURRENT TIMING SUGGESTING THAT THIS WILL PLACE THE BETTER SEVERE WEATHER RISK TO THE WEST OF OUR CWA. A LESSER...BUT NON-ZERO...SEVERE WIND THREAT WITH PROBABLE SQUALL LINE WILL CONTINUE LATE FRIDAY NIGHT INTO SATURDAY MORNING GIVEN THE STRONG DYNAMICS OF THE SYSTEM AS THE FRONT MOVES ACROSS OUR CWA. SEVERE THREAT LOOKS TO DIMINISH WITH TIME HEADING INTO SATURDAY AS THE SYSTEM OCCLUDES RESULTING IN WEAKER SHEAR PROFILES AND WEAKER INSTABILITY/MID LEVEL LAPSE RATES. IF SYSTEM WERE TO SPEED UP THEN OUR SEVERE WX THREAT MAY BE A BIT HIGHER FRIDAY EVENING BUT AT THIS POINT IT LOOKS MUCH MORE MARGINAL IN OUR CWA. BEHIND THE FRONT LOOK FOR A HEALTHY DUMP OF WHAT WILL FEEL LIKE VERY COLD AIR (THANKS TO THIS WEEK`S "HEAT WAVE")...BUT IN REALITY WILL ONLY BE ABOUT 10F BELOW AVERAGE FOR THIS TIME OF YEAR. MEDIUM RANGE MODELS OFTEN GET OVERLY GUNG HO WITH COLD AIR DUMPS IN THE MEDIUM RANGE PERIOD ONLY TO BACK OFF ON THE MAGNITUDE OF THE COLD AIR AS THE EVENT NEARS...SO THE 850MB TEMPS DROPPING BELOW ZERO IN OUR CWA SUNDAY WILL PROBABLY MODERATE SOME IN LATER RUNS...BUT EVEN WITH 850MB TEMPS A GOOD 5C WARMER IT WOULD LIKELY STILL RESULT IN HIGHS STAYING BELOW 60F. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * STRATUS DECK AROUND 500-600 FT MOVING OVER THE AIRFIELDS AFTER 930 UTC. DECK SHOULD BEGIN TO BURN OFF BY MID MORNING. * SSW WINDS 200-220 DEGREES GUSTING TO 20-25 KT DEVELOPING LATE MORNING/MIDDAY TODAY. KJB //DISCUSSION...UPDATED 06Z... THE MAIN WEATHER CONCERNS TODAY IS THE POTENTIAL FOR A FEW HOUR PERIOD OF IFR CIGS AROUND SUNRISE...AND ALSO THE GUSTY SOUTH-SOUTHWESTERLY WINDS DURING THE DAY. REGIONAL OBSERVATIONS INDICATE A GOOD SURGE OF LOW LEVEL MOISTURE STREAMING NORTHWARD ACROSS ILLINOIS EARLY THIS MORNING. DEW POINTS NEAR 60 ARE CURRENTLY MOVING ACROSS CENTRAL SECTIONS OF THE STATE. THIS RAPIDLY INCREASING LOW LEVEL MOISTURE IS PRODUCING SOME LOW IFR CIGS ACROSS DOWNSTATE ILLINOIS. THESE LOW CLOUDS ARE EVIDENT ON REGIONAL SATELLITE IMAGERY...AND IT IS SHOWING A RAPID MOVEMENT/DEVELOPMENT NORTHWARD. I AM CONCERNED THAT THESE LOW CLOUDS COULD AFFECT THE TERMINALS AFTER 10 UTC THIS MORNING...WITH THE POTENTIAL FOR A FEW HOURS OF SUB 1,000 FOOT CIGS. CONFIDENCE IS SOMEWHAT LOW ON THE EXTENT OF THIS ACTIVITY...BUT I DID BEGIN TO HINT AT THE POSSIBILITY OF LOWER CLOUDS WITH A SCT009 GROUP AFTER 10 UTC THIS MORNING. THIS WILL BE MONITORED OVER THE NEXT COUPLE HOURS TO SEE IF A MORE SUBSTANTIAL DECK OF CLOUDS WILL MATERIALIZE OVER NORTHERN ILLINOIS. THE GOOD NEWS IS THAT ANY LOWER CLOUDS THAT DEVELOP EARLY THIS MORNING WILL BE NOTHING BUT A DISTANT MEMORY BY MID MORNING AS THE WINDS BEGIN INCREASING OUT OF THE SOUTH-SOUTHWEST AND ALLOWING THE LOWER LEVELS TO MIX OUT THE LOWER LEVEL CLOUDS. THEREFORE...THE THREAT FOR ANY LOW CLOUDS WILL QUICKLY END AFTER 14-15 UTC THIS MORNING. I DID NOT MAKE ANY CHANGES TO THE GOING WIND FORECAST THIS AFTERNOON...AS IT APPEARS TO STILL BE ON TRACK TO HAVE GUSTS OF 20 TO 25 KT...ESPECIALLY LATE THIS MORNING AND THIS AFTERNOON. A WEAK COLD FRONT WILL DROP ACROSS THE TERMINALS TONIGHT...WITH WINDS BECOMING NORTHERLY AREA-WIDE BY EARLY WEDNESDAY. KJB //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM TO HIGH CONFIDENCE THAT STRATUS WILL MOVE OVER THE TERMINALS FOR A PERIOD THIS MORNING. * HIGH CONFIDENCE IN WINDS THROUGH MID TUESDAY AFTERNOON...MEDIUM CONFIDENCE IN TIMING TRANSITION TO 230/240 DEGREE DIRECTION. KJB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR WITH LOW SHRA/TSRA CHANCES WEDNESDAY NIGHT. THURSDAY THROUGH SATURDAY...PERIODIC SHRA/TSRA CHANCES WITH LOW CIGS POSSIBLE. SUNDAY...VFR. MDB && .MARINE... 346 AM CDT I HAVE ISSUED A GALE WARNING FOR THE NORTHERN THIRD TO HALF OF LAKE MICHIGAN FOR THE THE MORNING AND EARLY AFTERNOON TODAY. A DECENT SURFACE TROUGH OF LOW PRESSURE IS CURRENTLY SHIFTING EASTWARD ACROSS MINNESOTA...AND THIS FEATURE IS EXPECTED TO APPROACH NORTHERN LAKE MICHIGAN THIS MORNING. IT APPEARS THAT THE 20 TO 30 KT SOUTHERLY WINDS WILL BE ENHANCED A BIT AND ALSO BEGIN TO VEER SLIGHTLY TO A SOUTHEASTERLY DIRECTION DURING THE MORNING AS THE GRADIENT TIGHTENS IN ADVANCE OF THIS SURFACE TROUGH OF LOW PRESSURE. OVERALL...THIS APPEARS TO BE MARGINAL AND RATHER SHORT LIVED EVENT. HOWEVER...I FELT IT WAS BEST TO COVER THIS PERIOD WITH A HEADLINE. OTHERWISE...EXPECT 25 TO 30 KT WINDS TODAY ON THE SOUTHERN HALF OF THE OPEN WATERS TODAY. SOUTHWESTERLY WINDS WILL ALSO INCREASE UP TO 15 TO 25 KT FOR THE ILLINOIS AND INDIANA NEAR SHORES. HOWEVER...WITH THE OFFSHORE FETCH AND MARGINAL WIND SPEEDS...I CHOSE TO NOT ISSUE A SMALL CRAFT ADVISORY...WITH WAVES LIKELY REMAINING BELOW 4 FT FOR THE NEAR SHORES. A WEAK COLD FRONT WILL MOVE DOWN THE LAKE THIS EVENING...WITH HIGH PRESSURE BUILDING IN ACROSS THE CENTRAL SECTION OF THE LAKE INTO WEDNESDAY. THIS SHOULD RESULT IN LIGHTER NORTH-NORTHEASTERLY FLOW SOUTH HALF AND WEST TO SOUTHWEST NORTH HALF. THE MAIN STORY INTO THE WEEKEND CONTINUES TO BE WITH THE POTENT STORM SYSTEM EXPECTED TO DEVELOP ACROSS THE CENTRAL PLAINS AND THEN LIFT NORTHEASTWARD TOWARDS THE UPPER GREAT LAKES INTO THE WEEKEND. THIS STILL APPEARS TO BE THE CASE. THE ONLY QUESTIONS ARE THE TIMING OF THE STRONGEST WINDS. AT THIS TIME IT APPEARS THE SLOW MOVEMENT OF THE SYSTEM WILL KEEP THE STRONGER WINDS FROM DEVELOPING UNTIL LATE FRIDAY OR SATURDAY. A PERIOD OF GALE FORCE WINDS ARE STILL POSSIBLE DURING THE WEEKEND. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...7 AM TUESDAY TO 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion...Correction National Weather Service Lincoln IL 331 AM CDT Tue Oct 1 2013 .DISCUSSION... ISSUED 330 AM CDT Tue Oct 1 2013 SHORT TERM...Today through Friday Stratus clouds below 1k ft have reached as far nw as I-55 early this morning while patchy fog also prevailed se of I-55 with dense fog near the Wabash river at Robinson and Lawrencville where vsbys restricted to 1/4 mile. Will continue to mention fog this morning with dense fog near the Wabash river which should lift later this morning. Low stratus clouds to break up and give way to partly to mostly sunny skies this afternoon with more sunshine prevailing nw over the IL river valley. Warmer highs today in the low to mid 80s with sw breezes which is about 10 degrees warmer than normal for 1st day of October. This due to upper level ridge over region with summerlike 500 mb heights above 585 dm. Fair weather expected tonight with patchy fog near river valleys overnight in the ohio river valley and could affect parts of southeast IL again as winds becoming lighter with moist dewpoints in the lower 60s. 00Z models have trended a bit quicker returning short waves and moisture back northward across the ms valley into central and se IL by Wednesday afternoon and Wednesday night and have increase pops accordingly. Have 20 to 30% chance of showers and isolated thunderstorms Wednesday afternoon with 40 to 50% chance Wed night and as high as 50-60% chance Thursday especially eastern IL Thursday morning. Warm highs in the mid 80s on Wednesday and lower 80s Thursday, a bit cooler due to more cloud cover. Strong low pressure north of MT to track east to near Hudson/James Bay Canada tonight and brings a weakening cold front southward through the Great Lakes but does not quite make it into central IL due to strong upper level ridge over the central and southern states. A lull in precipitation chances Thursday night and Friday with warm conditions prevail Friday with highs in the low to mid 80s. Models have trended slower with stronger cold front late this week. LONG TERM...Friday night through Tuesday Strong cold front slated to move east across IL late Friday night into Saturday likely bringing showers and chance of thunderstorms to the region. Cooler and drier weather expected to return to IL during overnight Saturday night and Sunday. Fair weather expected early next week with upper level trof over the eastern states and keeping cooler temperatures for a few days with highs in the 60s Sunday through Tuesday. Next cold front appears to approach IL next Wednesday with next chance of precipitation, which is just beyond the 7 day forecast. 07 && .AVIATION... ISSUED 1150 PM CDT Mon Sep 30 2013 A steady southerly surface flow will provide a slow boost to the low level moisture, which will set the stage for ground fog and areas of stratus to form later tonight. Through 05z, the stratus and fog have generally remained south of the terminal sites. We expect a northward push to the fog/stratus, with IFR/LIFR vis and ceilings for our southern terminals of SPI, DEC, and CMI. The HRRR backed off significantly on its forecast of widespread 1/4sm fg and 100 ft ceilings across central IL, with very patchy coverage of those conditions surrounding our forecast area. The RUC is still indicating more widespread LIFR vis/cig, and the NAM/GFS still show areas of mvfr fog. We will go with IFR 1sm br and tempo for IFR cigs in the south. The shallow nature of the moisture will let daytime mixing dissipate the stratus/fog by 14z-15z. Winds will increase from the SSW in the 12-14g20kt range, as the surface pressure gradient tightens between the northern plains low and departing high pressure. Decoupling around sunset will allow winds to dip to 5-6kt. Shimon && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1242 AM CDT TUE OCT 1 2013 .DISCUSSION... 838 PM CDT FOR EVENING UPDATE... NO SIGNIFICANT CHANGES TO FORECAST THIS EVENING. SOUTH-SOUTHWEST FLOW HAS DEVELOPED SURFACE AND ALOFT ACROSS THE FORECAST AREA. WHILE A FEW SPOTS HAVE COOLED OFF QUICKLY... LIGHT BUT PERSISTENT SOUTH GRADIENT AND WARMING ALOFT ARE EXPECTED TO LIMIT THE TEMP DROP OVERNIGHT AND WILL LIKELY EVEN SEE SOME OVERNIGHT RISES AS HIGHER THETA-E LOW LEVEL AIR MASS SPREADS NORTH. ONLY REAL TWEAKS MADE THIS EVENING ARE FOR HOURLY TEMP TRENDS WHICH HAVE BEEN COMPLICATED BY LAKE BREEZE AND INITIAL SHARP DROP AFTER SUNSET. VARIOUS GUIDANCE CONTINUE TO INDICATE STRATUS DEVELOPING LATE TONIGHT ACROSS EAST CENTRAL IL...SPREADING NORTH INTO THE SOUTHERN PARTS OF THE LOT CWA. SOME PATCHY FOG POTENTIAL AS WELL AS HIGHER DEW POINT AIR PUSHES NORTH. CURRENT FORECAST ALREADY HAS THIS COVERED AT THIS POINT...SO AGAIN NO CHANGES THERE. ANY FOG/LOW STRATUS SHOULD ERODE QUICKLY TUESDAY AFTER SUNRISE...WITH GUSTY SOUTH-SOUTHWEST WINDS DEVELOPING. RATZER //PREV DISCUSSION... 258 PM CDT PRIMARY CONCERN IS THE UNSEASONABLY WARM TEMPERATURES TUESDAY AND WEDNESDAY...FOLLOWED BY PRECIP CHANCES WEDNESDAY NIGHT THROUGH SATURDAY. GUIDANCE CONTINUES TO EXHIBIT LACK OF RUN TO RUN CONTINUITY WITH STRONG LATE WEEK SYSTEM AND LATEST TREND TODAY HAS BEEN FOR A MARKED SLOWING OF SYSTEM. SHORT TERM...TONIGHT THROUGH THURSDAY... TONIGHT...MOST OF THE CWA SHOULD ENJOY A MAINLY CLEAR AND MUCH MILDER NIGHT THAN LAST NIGHT...WITH THE EXCEPTION BEING SOUTH OF I-80 WHERE SIMILAR TO EARLY THIS MORNING...LOW STRATUS AND PATCHY FOG COULD SPREAD NORTH AS 1000-950 MB LAYER BECOMES NEARLY SATURATED. TUESDAY...ANY MORNING STRATUS/FOG IN THE SOUTH SHOULD ERODE FAIRLY QUICKLY. SOUTHWEST WINDS GUSTING TO 25-30 MPH AND 850 MB TEMPS 16-18C AND 925 TEMPS 18-20C WILL SUPPORT ONE OF THE WARMEST STARTS TO OCTOBER ON RECORD...AS ALLUDED TO BY PREVIOUS SHIFT. WILL CONTINUE WITH HIGHS INTO THE MID 80S FOR MOST OF THE CWA. GUIDANCE DOES SHOW 850 MB THERMAL RIDGE SLIDING SOUTH A BIT LATE DAY BUT 925 TEMPS REMAIN OFF THE CHARTS WITH RESPECT TO EARLY OCT UPPER AIR CLIMO SO BASICALLY LEFT PREVIOUS FORECAST UNCHANGED. TUESDAY NIGHT AND WEDNESDAY...THERE IS NOW SOLID AGREEMENT IN A DRY..WEAK COLD FRONT SLIPPING SOUTH THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY WHICH WILL RESULT IN TEMPERATURES COOLING OFF NORTH OF I-80...MOST PROMINENTLY ALONG THE LAKE TO WITHIN A FEW DEGREES OF 70. TO THE SOUTH...VERY WARM 925 TEMPS STILL EXPECTED TO SUPPORT HIGHS IN THE LOW-MID 80S. SOME GUIDANCE INDICATING A FOCUS FOR TSRA IN THE WELL SOUTH ALONG STALLING OUT FRONT...BUT MAINTAINED DRY FORECAST FOR NOW. WEDNESDAY NIGHT AND THURSDAY...FRONT WILL LIFT BACK AS A WARM FRONT AND DISTURBED SOUTHWEST FLOW AND DECENT LOW LEVEL JET SUPPORT COULD SUPPORT A FEW PERIODS OF TSRA IN THIS TIME. CONFIDENCE IS NOT HIGH IN COVERAGE...AND CONCERNED THAT GUIDANCE IS OVERDONE WITH POPS...BUT KEPT CHANCE POPS GOING AFTER MIDNIGHT WEDNESDAY NIGHT THROUGH THURSDAY. SYNOPTIC SET-UP SEEMS TO BE ONE WHERE ATMOSPHERE COULD BE CAPPED...ESPECIALLY LATER THURSDAY AFTERNOON...WITH WARM FRONT HAVING LIFTED WELL NORTH. GIVEN 850 MB TEMPS IN THE MID TEENS AND 925 MB IN THE UPPER TEENS TO AROUND 20C...FORECAST HIGHS IN THE UPPER 70S TO AROUND 80 COULD EVEN BE SLIGHTLY COOL IF THERE IS LESS CLOUD COVER AND PRECIP THAN CURRENTLY ANTICIPATED. LONG TERM...THURSDAY NIGHT THROUGH MONDAY... STRONG SHORT WAVE ENERGY EMANATING FROM DEEP UPPER LOW OVER GULF OF ALASKA WILL REACH PAC NW SHORE ON WEDNESDAY...SO UNTIL SAMPLED BY RAOB NETWORK...FURTHER GUIDANCE CORRECTIONS ARE LIKELY WITH STRONG LATE WEEK UPPER TROUGH AND ASSOCIATED SURFACE LOW TAKING SHAPE OVER THE PLAINS AND LIFTING NORTHEAST. ENSEMBLES CONTINUE TO EXHIBIT LARGE SPREAD AS WELL. AS MENTIONED EARLIER...ALL OPERATIONAL MODELS TODAY HAVE TRENDED MUCH SLOWER WITH SYSTEM AND THE AREA NOW LOOKS TO BE FIRMLY ENTRENCHED IN THE WARM SECTOR ON FRIDAY. NUDGED MODEL BLEND INITIALIZATION MAX T A BIT HIGHER...WHICH COULD STILL BE TOO CONSERVATIVE IN THE LOW 80S...AND ALSO CAPPED POPS AT SLIGHT TO LOW END CHANCE. THE SYSTEM LOOKS TO CLOSE OFF AND OCCLUDE SOMEWHERE OVER THE UPPER MIDWEST FRIDAY NIGHT INTO SATURDAY...WITH COLD FRONT OR OCCLUDED FRONT NOW NOT EXPECTED TO REACH WESTERN CWA UNTIL SATURDAY MORNING...SO IT COULD BE ANOTHER WARM DAY ESPECIALLY FOR THE EASTERN HALF OF THE CWA. THUNDERSTORMS WILL BE POSSIBLE ALONG/AHEAD OF FRONT BEFORE IT SWEEPS THROUGH BY THE LATE AFTERNOON AND EARLY EVENING. THE GFS HAS BACKED OFF A BIT ON THE COLD SHOT BEHIND THE FRONT...WHILE THE 12Z ECMWF FEATURES 850 MB TEMPS PLUNGING TO THE MINUS SINGLE DIGITS BY EARLY SUNDAY. SO DEPENDING ON THE DEPTH OF THE COOL SHOT...TEMPS IN LOW 60S CURRENTLY FORECAST COULD BE REASONABLE OR DOWNRIGHT CHILLY MID TO UPPER 50S IF ECMWF SOLUTION COMES CLOSER TO PASS. THIS WILL BE FOLLOWED BY A QUICK WARM UP TO NEAR NORMAL TEMPERATURES BY NEXT MONDAY. CONFIDENCE IN LONG TERM FORECAST PERIOD...LOW. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * POTENTIAL FOR IFR STRATUS TO APPROACH FROM THE SOUTH TOWARD DAYBREAK. * SSW WINDS 200-220 DEGREES GUSTING TO 20-25 KT DEVELOPING LATE MORNING/MIDDAY TODAY. KJB //DISCUSSION...UPDATED 06Z... THE MAIN WEATHER CONCERNS TODAY IS THE POTENTIAL FOR A FEW HOUR PERIOD OF IFR CIGS AROUND SUNRISE...AND ALSO THE GUSTY SOUTH-SOUTHWESTERLY WINDS DURING THE DAY. REGIONAL OBSERVATIONS INDICATE A GOOD SURGE OF LOW LEVEL MOISTURE STREAMING NORTHWARD ACROSS ILLINOIS EARLY THIS MORNING. DEW POINTS NEAR 60 ARE CURRENTLY MOVING ACROSS CENTRAL SECTIONS OF THE STATE. THIS RAPIDLY INCREASING LOW LEVEL MOISTURE IS PRODUCING SOME LOW IFR CIGS ACROSS DOWNSTATE ILLINOIS. THESE LOW CLOUDS ARE EVIDENT ON REGIONAL SATELLITE IMAGERY...AND IT IS SHOWING A RAPID MOVEMENT/DEVELOPMENT NORTHWARD. I AM CONCERNED THAT THESE LOW CLOUDS COULD AFFECT THE TERMINALS AFTER 10 UTC THIS MORNING...WITH THE POTENTIAL FOR A FEW HOURS OF SUB 1,000 FOOT CIGS. CONFIDENCE IS SOMEWHAT LOW ON THE EXTENT OF THIS ACTIVITY...BUT I DID BEGIN TO HINT AT THE POSSIBILITY OF LOWER CLOUDS WITH A SCT009 GROUP AFTER 10 UTC THIS MORNING. THIS WILL BE MONITORED OVER THE NEXT COUPLE HOURS TO SEE IF A MORE SUBSTANTIAL DECK OF CLOUDS WILL MATERIALIZE OVER NORTHERN ILLINOIS. THE GOOD NEWS IS THAT ANY LOWER CLOUDS THAT DEVELOP EARLY THIS MORNING WILL BE NOTHING BUT A DISTANT MEMORY BY MID MORNING AS THE WINDS BEGIN INCREASING OUT OF THE SOUTH-SOUTHWEST AND ALLOWING THE LOWER LEVELS TO MIX OUT THE LOWER LEVEL CLOUDS. THEREFORE...THE THREAT FOR ANY LOW CLOUDS WILL QUICKLY END AFTER 14-15 UTC THIS MORNING. I DID NOT MAKE ANY CHANGES TO THE GOING WIND FORECAST THIS AFTERNOON...AS IT APPEARS TO STILL BE ON TRACK TO HAVE GUSTS OF 20 TO 25 KT...ESPECIALLY LATE THIS MORNING AND THIS AFTERNOON. A WEAK COLD FRONT WILL DROP ACROSS THE TERMINALS TONIGHT...WITH WINDS BECOMING NORTHERLY AREA-WIDE BY EARLY WEDNESDAY. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * LOW- MEDIUM CONFIDENCE THAT STRATUS WILL REMAIN SOUTH OF THE TERMINALS EARLY THIS MORNING. * HIGH CONFIDENCE IN WINDS THROUGH MID TUESDAY AFTERNOON...MEDIUM CONFIDENCE IN TIMING TRANSITION TO 230/240 DEGREE DIRECTION. KJB //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR WITH LOW SHRA/TSRA CHANCES WEDNESDAY NIGHT. THURSDAY THROUGH SATURDAY...PERIODIC SHRA/TSRA CHANCES WITH LOW CIGS POSSIBLE. SUNDAY...VFR. MDB && .MARINE... 241 PM...A MORE ACTIVE PATTERN IS EXPECTED INTO THIS WEEKEND WITH LOWER CONFIDENCE REGARDING SPECIFICS FRIDAY AND SATURDAY. STRONG LOW PRESSURE OVER SOUTH CENTRAL CANADA WILL MOVE NORTHEAST REACHING HUDSON BAY TUESDAY NIGHT. THE GRADIENT IS IN THE PROCESS OF TIGHTENING OVER THE NORTHERN PART OF THE LAKE AND THAT WILL CONTINUE TONIGHT INTO TUESDAY MORNING. ALONG A TRAILING COLD FRONT FROM THIS LOW...A WEAKER LOW WILL DEVELOP OVER THE DAKOTAS THIS EVENING. THIS LOW WILL QUICKLY BE STRETCHED ALONG THE FRONT OVERNIGHT...BUT JUST AHEAD OF THIS FRONT/TROUGH OF LOW PRESSURE... SOUTHERLY WINDS MAY INCREASE TO NEAR GALE FORCE OVER THE NORTHERN HALF OF THE LAKE THOUGH THE DURATION LOOKS TO BE FAIRLY SHORT... PERHAPS JUST 3-6 HOURS STARTING AROUND SUNRISE TUESDAY MORNING. WILL INCLUDED GUSTS TO 35 KTS FOR THIS POTENTIAL AND TRENDS WILL NEED TO BE MONITORED OVERNIGHT INTO TUESDAY MORNING. ONCE THIS FRONT MOVES EAST OF THE LAKE TUESDAY EVENING...WINDS WILL DIMINISH AND SHIFT WESTERLY OVER THE NORTHERN PART OF THE LAKE... TURNING LIGHT NORTHERLY THEN NORTHEASTERLY OVER THE SOUTH END OF THE LAKE AS HIGH PRESSURE BUILDS ACROSS THE SOUTHERN LAKES TUESDAY NIGHT AND SHIFTS NORTHEAST WEDNESDAY. ANOTHER STRONG AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE PLAINS WEDNESDAY NIGHT INTO THURSDAY AND THEN TURN NORTHEAST MOVING ACROSS THE GREAT LAKES REGION FRIDAY NIGHT OR SATURDAY. THE LATEST MODEL GUIDANCE SUGGESTS THAT THIS LOW WILL BE MOVING MUCH SLOWER AND STILL BE NEAR IOWA SATURDAY MORNING WITH A POSSIBLE WARM FRONT EXTENDING ACROSS THE NORTHERN OR CENTRAL PORTIONS OF LAKE MICHIGAN. A FRONTAL BOUNDARY WOULD RESULT IN SOME AMOUNT OF EASTERLY OR NORTHEASTERLY WINDS NORTH OF THE FRONT. IN ADDITION...STRONGER SOUTHERLY WINDS WILL BE DELAYED UNTIL THE LOW MOVES CLOSER TO THE LAKE. THUS CONFIDENCE REGARDING NOT ONLY THE TRACK OF THE LOW AND POTENTIAL FRONTAL BOUNDARY...BUT ALSO ITS SPEED IS LOW AND CHANGES TO THE CURRENT FORECAST CAN BE EXPECTED. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1150 PM CDT Mon Sep 30 2013 .DISCUSSION... ISSUED 900 PM CDT Mon Sep 30 2013 The stationary front seems to be losing its identity in terms of wind shift but the dewpoint gradient remains in our southeast area. A broad scale southerly flow will dominate the surface winds, while westerly flow aloft brings cirrus level moisture ahead of the next frontal boundary in the northern plains. Our weather should remain quiet the rest of the night through tomorrow, as high and low temperatures continue above normal through mid week. The lingering low level moisture in the southeast half of the area will evolve into ground fog as radiational cooling drops surface temps close to dewpoints. Locally dense fog is expected to develop as advertised by the HRRR and RUC. The staying power will be limited by the shallow nature of the fog, but it could still cause some travel issues around sunrise on Tuesday. We will keep a mention of fog in the grids tonight despite the drier low levels in the NAM and GFS. Overall the short term forecast grids were on track, and only minor updates were needed. No formal update is expected this evening. Shimon && .AVIATION... ISSUED 1150 PM CDT Mon Sep 30 2013 A steady southerly surface flow will provide a slow boost to the low level moisture, which will set the stage for ground fog and areas of stratus to form later tonight. Through 05z, the stratus and fog have generally remained south of the terminal sites. We expect a northward push to the fog/stratus, with IFR/LIFR vis and ceilings for our southern terminals of SPI, DEC, and CMI. The HRRR backed off significantly on its forecast of widespread 1/4sm fg and 100 ft ceilings across central IL, with very patchy coverage of those conditions surrounding our forecast area. The RUC is still indicating more widespread LIFR vis/cig, and the NAM/GFS still show areas of mvfr fog. We will go with IFR 1sm br and tempo for IFR cigs in the south. The shallow nature of the moisture will let daytime mixing dissipate the stratus/fog by 14z-15z. Winds will increase from the SSW in the 12-14g20kt range, as the surface pressure gradient tightens between the northern plains low and departing high pressure. Decoupling around sunset will allow winds to dip to 5-6kt. Shimon && .PREV DISCUSSION... ISSUED 303 PM CDT Mon Sep 30 2013 Forecast problems of today are the fog overnight, and the rain chances for the second half of this week. SHORT TERM...Tonight through Wednesday night. Morning analysis data shows stalled frontal zone over southern IN to southern IL and into MO. Moisture associated with the zone trapped beneath inversion during the morning and triggered fog and stratus. southerly flow over region will bring more of moisture back a little more northward overnight and so new grid forecast for tonight has fog in it. A second weak front dies over the northern half of IL Wednesday. With the continued advection of moisture northward, chance pops in the forecast Wednesday and Wednesday night with minor impulse moving from the southwest. LONG TERM...Thursday through Monday. Moist airmass over region through Thursday to continue to trigger chance pops. Then pops drops a little as frontal system in the plains takes shape on Thursday night to Friday and air becomes a little capped over IL. Models vary again on the timing of the cold front for the end of the week and this makes the exact timing of best chances for pop a little difficult. GFS now slower and EUR consistent on Friday night to Saturday crossing of region. Pops during that period remain in chance category. Cooler air flows into region Sunday. Goetsch && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
458 AM CDT TUE OCT 1 2013 .UPDATE... ISSUED AT 458 AM CDT TUE OCT 1 2013 I HAVE UPDATED THE GRIDS TO SPREAD THE LOW STRATUS THAT IS RAPIDLY SPREADING NORTHWARD FARTHER INTO THE CWA. THE HRRR BRINGS THE LOW CLOUDS NORTHWEST TO ROUGHLY A BURLINGTON-MOLINE-FREEPORT LINE EARLY THIS MORNING. HOWEVER...BY MID TO LATE MORNING THE CLOUDS SHOULD DISSIPATE AND WE WILL THEN HAVE A SUNNY AFTERNOON. && .SYNOPSIS... ISSUED AT 300 AM CDT TUE OCT 1 2013 STRONG LOW PRESSURE WAS LOCATED IN SASKATCHEWAN WITH ANOTHER LOW IN WESTERN MN. A COLD FRONT WAS PUSHING INTO THE EASTERN DAKOTAS AND INTO CENTRAL NEB WITH 7 MB 3HR PRESSURE RISES BEHIND THE FRONT. HOWEVER...DYNAMICS ARE WELL TO THE NORTH AND ONLY A FEW LIGHT SHOWERS AND SPRINKLES WERE FOUND IN NW MN. IN THE MEANTIME...LOW LEVEL MOISTURE WAS STREAMING NORTHWARD WITH SURFACE DEWPOINTS IN THE LOWER TO MID 60S FROM CENTRAL MO AND SOUTHERN IL AND POINTS SOUTH. THIS MOISTURE WAS CAUSING LOW STRATUS TO SPREAD RAPIDLY NORTHWARD INTO EASTERN MO AND CENTRAL AND EASTERN IL. MILD TEMPERATURES WERE SEEN AT THIS HOUR EVEN THOUGH WE HAVE FLIPPED THE CALENDAR TO OCTOBER. CURRENT READINGS WERE IN THE 60S THROUGHOUT MUCH OF THE MIDWEST AHEAD OF THE COLD FRONT...WITH 40S TO LOWER 50S BEHIND THE FRONT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 300 AM CDT TUE OCT 1 2013 FORECAST FOCUS ON DRY COLD FRONT PUSHING INTO THE CWA AND I WILL BE WATCHING THE LOW STRATUS THIS MORNING IN OUR SOUTHERN CWA. OTHERWISE A WARM DAY AHEAD FOR THE FIRST DAY OF OCTOBER. TODAY...RIDGE (RISING HEIGHTS) ACROSS THE DVN CWA AND PLENTY OF SUNSHINE SHOULD BOOST TEMPERATURES INTO THE LOWER TO MID 80S AT MOST LOCATIONS. THIS WILL BE 10 TO 15 DEGREES ABOVE NORMAL FOR EARLY OCTOBER BUT STILL WELL SHY OF ANY RECORDS. WILL INCREASE SKY COVER IN OUR FAR SOUTH/SE COUNTIES THIS MORNING TO ACCOUNT FOR SOME STRATUS SPREADING IN FROM THE SOUTH. HOWEVER...THIS SHOULD ALSO DISSIPATE BY AFTERNOON WITH THE HEATING TAKING PLACE. IN THE MEANTIME...STRONG LOW PRESSURE WILL BE TRACKING NORTH OF MN AND TO NEAR JAMES BAY BY THIS EVENING. THIS WILL SEND A COLD FRONT INTO OUR NORTHWEST CWA THIS AFTERNOON...BUT THE FRONT WILL ALSO BE WEAKENING AS IT RUNS INTO THE BUILDING RIDGE. AND WITH THE DYNAMICS WELL TO OUR NORTH THE FRONT WILL COME THROUGH DRY AND REALLY A WIND SHIFT TO THE NORTHWEST IS ALL. AHEAD OF THE FRONT SOUTHWEST WINDS WILL BE GUSTING TO AROUND 25 MPH. TONIGHT...OPERATIONAL MODELS SIMILAR IN SAGGING THE FRONT SOUTH OF I-80 AND THEN STALLING IT OVERNIGHT. NORTHEAST WINDS ACROSS OUR NORTHERN CWA WILL ALLOW MINIMUM TEMPERATURES TO DROP INTO THE LOWER TO MID 50S. HOWEVER...SOUTH OF THE FRONT IN OUR SOUTHERN CWA TEMPERATURES WILL BE MILD IN THE LOWER 60S. HAASE .LONG TERM...(WEDNESDAY THROUGH NEXT MONDAY) ISSUED AT 300 AM CDT TUE OCT 1 2013 WEDNESDAY AND THURSDAY...LATEST 00Z MODEL RUNS CONTINUE IDEA OF BROAD L/W TROFFINESS DIGGING AND GETTING IMPLANTED ACRS THE WESTERN CONUS THIS PERIOD...WITH A DELAYED UPPER JET SURGE INTO BASE NOT TIL LATE THU FOR FURTHER AMPLIFICATION BY THEN. INCREASING LLVL SOUTH TO SOUTHEASTERLY FETCH TO LEE OF DIGGING TROF COMPLEX ON WED TO TAP INTO HIGHER LLVL MOISTURE FIELDS FOR AN INCREASE IN SFC DPTS WELL UP INTO THE UPPER 50S TO AT LEAST LOWER 60S BY MID AFTERNOON. HIGHS WED IN THE UPPER 70S TO LOWER 80S ALTHOUGH A FEW MID 80S POSSIBLE IN THE FAR SOUTHERN CWA. WILL KEEP WED DRY FOR NOW THROUGH 00Z THU WITH DEVELOPING WARM FRONT PLACEMENT STILL SOMEWHAT AT QUESTION...BUT ISOLATED TO WDLY SCTRD SHOWERS AND SOME STORMS MAY STILL BE POSSIBLE BY LATE AFTERNOON. WED NIGHT...BULK OF 00Z MEDIUM RANGE MODELS SUGGEST MAIN FRONT TO GET ALIGNED UNDER DEVELOPING BROAD SOUTHWESTERLIES FROM THE CENTRAL PLAINS INTO THE NORTHWESTERN GRT LKS AND GENERALLY BE NORTHWEST OF THE DVN CWA. LEE-SIDE OF ROCKIES LLVL CYCLOGENESIS IN WEST CENTRAL PLAINS ENHANCING LLVL WARM MOIST CONVEYOR UP OFF THE GULF AND TOWARD THE NORTHERN PLAINS AND UPPER MIDWEST. SOME SIGNS OF SECONDARY WARM FRONT ACRS IA INTO NORTHERN IL TO ACT AS A FOCAL POINT FOR SW 25 KT LLJ AND RESULTANT NOCTURNAL CONVECTION/ELEVATED STORM CLUSTERS LATER WED NIGHT INTO THU MORNING AND WILL KEEP CHC POPS GOING FOR THIS POTENTIAL...BUT BETTER CHC TO THE NORTHWEST AND NORTH OF THE LOCAL AREA. THU MAY BE A LULL DAY WITH ANY CONVECTIVE DEBRIS DECAYING DIURNALLY...AND BULK OF SOLUTIONS KEEP QUASI-STATIONARY FRONTAL BOUNDARY UNDULATING TO THE NORTHWEST AND NORTH OF THE CWA FOR MORE CONVECTIVE FOCUS BY THU NIGHT. CONTINUED LLVL DPT ADVECTION AND POOLING ALONG AND SOUTH OF THIS FEATURE KEEPING LLVL RH VALUES HIGHER/MORE HUMID THAN NORMAL LOCALLY WITH DPTS WELL IN THE 60S. CURRENT INDICATIONS SUGGEST THU NIGHT MCS DEVELOPMENT AND TRACK SETTING UP FROM THE NORTH HALF OF THE PLAINS...WESTERN IA INTO MN/NW WI BUT SOME OF THIS MAY GET INTO THE WESTERN AND NORTHERN CWA AND WILL PLACE POPS ACCORDINGLY. THE NAM IS THE ONLY MODEL FURTHER TO THE SOUTH WITH MAIN FRONT BISECTING IA AND THUS MCS TRACK SETTING RIGHT ACRS THE DVN CWA FOR THU NIGHT INTO EARLY FRI MORNING. ESPECIALLY THE NORTHWEST HALF. WILL THROW THIS MODEL OUT FOR NOW BUT WATCH FOR TRENDS IN OTHER LATER MODEL RUNS. MORE CLOUDS/DEBRIS AND MOISTURE MAY KEEP THU HIGHS IN THE UPPER 70S TO LOWER 80S. FRIDAY AND SAT...LATEST 00Z MEDIUM RANGE SOLUTIONS ESPECIALLY THE 00Z ECMWF CONTINUE TO SHOW A CLASSIC EARLY SPRING LOOKING WRAPPING UP CYCLONE ACRS THE NORTHERN PLAINS AND UPPER MIDWEST. SOMEWHAT NEG TILT TO THE TROF AND 100+ KT UPPER JET STREAK FROM NW MO INTO THE WESTERN U.P. OF MI BY LATE FRI NIGHT IN DIFFLUENT SOUTHWESTERLY MID LEVEL FLOW. IF ADEQUATE THERMODYNAMICS CAN GET DRAWN UP TO THE LEE OF THESE STRONG KINEMATIC FIELDS...A CLASSIC SVR WX SET UP COULD UNFOLD IN OR VERY NEAR THE LOCAL AREA LATE FRI AND FRI EVENING. IT IS STILL EARLY AND MANY RUNS TO GO THROUGH WITH THE LATELY VARIABLE MODEL SOLUTIONS HAVING TROUBLE RESOLVING THE LATE WEEK WAVE ENERGY FLUX ACRS THE MID CONUS. BUT THIS SIGNAL HAS GENERALLY SHOWN UP TWO NIGHTS IN A ROW NOW...IT/S JUST NAILING DOWN THE TIMING IF INCOMING COLD FRONT SWEEPS INTO THE AREA IN PRIME HEATING OF FRI AFTERNOON/ EVENING OR LATER FRI NIGHT INTO SAT MORNING. WILL TARGET FRI NIGHT AS PRIME PRECIP WINDOW AND HIGHER POPS...HOW WARM AND UNSTABLE FRI WILL GET BEFORE THIS SYSTEM APPROACHES STILL AT QUESTION TO FUEL A POTENTIALLY VOLATILE SITUATION. STRONG OCCLUSION OF CYCLONE COMPLEX PROGGED ACRS WEST CENTRAL MN BY SAT MORNING BY BOTH THE 00Z ECMWF AND GFS. THIS PLACEMENT WOULD MAKE SAT A BLUSTERY DRY SLOT DAY WITH MORNING HIGHS AND STRONG COLD AIR ADVECTION/DROPPING TEMPS AS DAY PROGRESSES. SAT NIGHT MAY HAVE LOWS WELL DOWN IN THE 30S EVEN IF WINDS MAINTAIN AND WRAP AROUND STRATUS OFF CYCLONE MOVING ACRS THE NORTHWESTERN GRT LKS OCCURS...MODELS SUGGEST A UNSEASONABLY COLD LLVL CONVEYOR WRAPPING INTO THIS SYSTEM...THE ECMWF PROBABLY IS TOO COOL. SUNDAY INTO NEXT MONDAY...GENERALLY A DRY AN COOL POST STORM SCENARIO FOR SUNDAY WITH HIGHS POSSIBLY HELD DOWN IN THE 50S TO LOWER 60S ESPECIALLY WITH CAA CLOUD COVER. SOME RECOVERY POSSIBLY BY NEXT MONDAY AHEAD OF ANOTHER WAVE DIGGING DOWN IN ACTIVE FLOW PATTERN ACRS THE NORTHERN ROCKIES AND NW HIGH PLAINS. ..12.. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 458 AM CDT TUE OCT 1 2013 IFR CIGS IN LOW STRATUS WILL SPREAD RAPIDLY TO KBRL/KMLI BY 12Z BUT THEN DISSIPATE BY 15 OR 16Z. OTHERWISE VFR CONDS EXPECTED THROUGH THE TAF CYCLE. A WEAKENING COLD FRONT WILL PUSH ACROSS EASTERN IA THIS AFTERNOON AND THEN STALL SOUTH OF I-80 TONIGHT. SOUTHWEST WINDS 10 TO 20 KNOTS AHEAD OF THE FRONT WITH WINDS THEN BECOMING NORTHEAST TO EAST TONIGHT LESS THAN 10 KNOTS. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...HAASE SYNOPSIS...HAASE SHORT TERM...HAASE LONG TERM...12 AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
523 AM EDT TUE OCT 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM EDT TUE OCT 1 2013 BROAD TROUGH FROM ALASKA INTO MUCH OF WESTERN CANADA AND INTO NORTHERN PLAINS. LEAD SHORTWAVE WITHIN WESTERLY FLOW ALOFT LIFTING INTO NORTHWEST ONTARIO THIS MORNING. DECENT AMOUNT OF MID-HIGH CLOUDS ALONG AND AHEAD OF THE WAVE...BUT LOW LEVELS TOO DRY TO SUPPORT ANY RAIN...AT LEAST AS FAR EAST AS UPR MICHIGAN. SFC FRONT /ESSENTIALLY MORE OF A WIND SHIFT AND MOISTURE GRADIENT/ TIED TO SHORTWAVE MOVING ACROSS MINNESOTA WILL SWEEP INTO WESTERN UPR MICHIGAN THIS MORNING AND OUT OF EASTERN CWA BY MID AFTN. A LOT OF MID CLOUDS CURRENTLY OVER UPR MICHIGAN BACK INTO MINNESOTA SO BUMPED UP SKY COVER UNTIL EXPECTED TROUGH PASSAGE. CLUSTER OF SHRA LIFTING ENE ACROSS CNTRL MINNESOTA MAY GRAZE WESTERN LK SUPERIOR SO DID PUT MENTION OF SHRA FOR VCNTY OF ISLE ROYALE. REST OF CWA WILL STAY DRY WITH PERHAPS SOME VIRGA BASED ON SPOTTY RADAR ECHOES ACROSS NORTHERN WISCONSIN AND UPR MICHIGAN. ONCE THE SKIES CLEAR...ATTN TURNS TO FIRE WEATHER CONCERNS THIS AFTN. DEEP MIXED PROFILE AND VERY DRY AIR NOTED IN WAKE OF THE TROUGH WITH DWPNTS IN THE MID 20S TO MID 30S FM MONTANA INTO THE DAKOTAS LATE MONDAY AFTN AND STILL IN THE 30S THIS MORNING. EXPECT BLYR TO BUILD TO AT LEAST H8 AND POSSIBLY HIGHER BY MID AFTN. TEMPS SHOULD RISE INTO LOW-MID 70S EASILY...AND LIKELY HIGHER DUE TO THE FULL SUN. MAY HIT 80 WITH DOWNSLOPE WESTERLY WINDS OVR THE SCNTRL. SOUTH WINDS COULD GUST TO 25 MPH AHEAD OF TROUGH...THOUGH THICKER MID CLOUDS WILL CUT MIXING POTENTIAL DOWN. THIS AFTN THOUGH WITH FULL SUNSHINE/SUBSIDENCE DEVELOPING /DRYING NOTED ON LATEST WV LOOP BEHIND THE SHORTWAVE/ THE DEEP MIXING WILL LEAD TO UNIDIRECTIONAL GUSTY WEST WINDS. FORECAST SOUNDINGS MATCHING AIRMASS UPSTREAM ON 00Z BIS SOUNDING WITH 25-35 KTS IN THE BLYR. EXPECT STRONGEST GUSTS ACROSS HIGHER TERRAIN OF KEWEENAW. MAY SEE GUSTS TOWARD LOW-END WIND ADVY FOR A FEW HOURS THIS AFTN. ELSEWHERE...FREQUENT GUSTS OVER 30 MPH SEEM LIKELY JUST IN WAKE OF TROUGH AT LEAST FOR A FEW HOURS BEFORE THE WINDS BEGIN DECREASING LATE THIS AFTN. BUILDING BLYR WILL ALSO MIX DOWN THE VERY DRY AIR OUT OVR THE PLAINS. DWPNT FORECAST TODAY WAS VERY CHALLENGING WITH THE MAIN ISSUE IN HOW LOW TO BRING DWPNTS THIS AFTN. PLAYED THE LOWER MIDDLE GROUND FOR NOW...STAYING AWAY FM THE LOWER 20S DWPTS OFFERED UP BY THE MIXED TD TOOL AND RUC GUIDANCE. MAINLY LOW-MID 30S /SIMILAR TO NAM AND GEM-REGIONAL/ BUT DO HAVE SOME UPPER 20S DWPNTS OVER WESTERN INTERIOR 21Z-00Z AT END OF MIXING CYCLE AND BASED ON TIME/HEIGHT OF TEMPS/DWPNTS FM NAM/SREF. GRADIENT OF DWPNTS/RH THIS AFTN COULD BE STRIKING WITH NCEP WRF-ARW/NMM SHOWING A 30 DEGREE FALL IN DWPNTS IN JUST A FEW HOURS. REALLY DO NOT THINK THIS IS OUT OF THE QUESTION. POINT OF ALL THE DWPNT TALK IS THAT RESULTING RH VALUES PLUMMET BLO 25 PCT OVER THE INTERIOR WEST MID-LATE AFTN...LEADING TO CRITICAL FIRE WEATHER CONDITIONS WHEN THE WINDS ARE THE STRONGEST. WILDFIRE POTENTIAL STATEMENT WILL BE RE-ISSUED BUT WE MAY NEED ADDITIONAL FIRE WEATHER HEADLINES LATER TODAY BASED ON INPUT FROM FIRE USERS. DESPITE SUCH LOW DWPNTS LATE TODAY MINS TONIGHT WILL PROBABLY STAY MAINLY ABOVE 40 AS SOME WIND STIRS ALL NIGHT AS UPR MICHIGAN REMAINS IN SOME GRADIENT OF PRESSURE BTWN LOW OVER HUDSON BAY AND SFC RIDGE OVER UPPER MISSISSIPPI/OHIO VALLEY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 420 PM EDT MON SEP 30 2013 WILL START OUT TUESDAY NIGHT WITH MAINLY ZONAL FLOW ALOFT...WITH THE EXITING INITIAL COLD FRONT OVER FAR E UPPER MI AND THE MAIN SFC LOW OVER FAR N ONTARIO AND S LAKE HURON. GIVEN THE MUCH OF THE ENERGY REMAINS WELL TO OUR N...THE MAIN RESULT WILL THE BE THE INCREASED PRESSURE GRADIENT. EXPECT W WINDS GUSTING 20-28KTS THROUGH TUESDAY NIGHT. THE SECONDARY TROUGH/COLD FRONT NEVER REALLY GETS HERE ON WEDNESDAY...AS THE SFC LOW EXITS INTO N QUEBEC AND A RIDGE OF HIGH PRESSURE BRIEFLY BUILDS. EXTENDED THE PERIOD OF DRY WEATHER A BIT LONGER...THROUGH WEDNESDAY EVENING. LOW PRESSURE SPINNING ACROSS THE CENTRAL PLAINS MID WEEK WILL EXTEND A TROUGH/WARM FRONT ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT...AS THE MAIN LOW SLOWLY NEARS FROM THE SW. THERE ARE SIGNIFICANT ENOUGH DIFFERENCES IN THE LOCATION OF THE NEAR 1000MB LOW SATURDAY TO RESULT IN A CONSENSUS APPROACH AT THIS TIME. THIS WILL LEAD TO HIGH CHC TO DEF POPS FOR THURSDAY THROUGH SATURDAY. WILL WAIT UNTIL WE GET A CLEARER SOLUTION BEFORE PIN POINTING EXACT LOCATIONS AND TIMING. THE CONSENSUS IS TO HAVE THE LOW SHIFT NE DURING THE DAY SUNDAY...WITH W-NW WINDS LINGERING BEHIND THE LOW. THE 12Z ECMWF DOES HAVE 850MB TEMPS FALLING TO AROUND -2C LATE SATURDAY NIGHT THROUGH SUNDAY....WHICH WILL LIKELY KEEP A BKN-OVC SKY OVERHEAD. ANOTHER BRIEF RIDGE IS FIGURED SUNDAY NIGHT BEFORE A QUICK LOW SKIRTING THE US/CANADIAN BORDER NEARS FOR MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 131 AM EDT TUE OCT 1 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. WINDS SHOULD REMAIN FAIRLY GUSTY AOA 20KT TONIGHT AT KIWD BUT SHOULD DECOUPLE SOMEWHAT AT KCMX/KSAW WHERE LLWS WAS INCLUDED IN THE FCST. SHOULD CONTINUE TO BE GUSTY BEHIND A COLD FRONT TUE AT IWD AND CMX. THERE WILL BE SOME LLWS AT SAW TUE EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 523 AM EDT TUE OCT 1 2013 GUSTY SOUTH WINDS TO 25 KTS WILL SHIFT SHARPLY WEST EARLY TO MID AFTN BEHIND A SFC TROUGH CROSSING THE LAKE. EXPECT A BRIEF 2-4 HOUR PERIOD OF GUSTS TO 30 KTS BEHIND THE TROUGH...WITH A SMALL RISK OF A FEW GALE FORCE GUSTS TO 35 KTS. WEST WINDS TO 25 KTS LINGER THROUGH MUCH OF TONIGHT BEFORE THE WINDS DIMINISH ON WEDNESDAY. ATTN BY LATE WEEK IS ON LOW PRESSURE SYSTEM LIFTING OUT OF THE CENTRAL PLAINS TOWARD THE UPPER GREAT LAKES...MOST LIKELY TRACKING SOMEWHERE FROM MINNESOTA ACROSS WESTERN HALF OF LK SUPERIOR. RESULT WILL ESE WINDS TO 20 KTS OVER EASTERN LAKE SUPERIOR WITH A RATHER LONG DURATION OF ENE-NE WINDS OF 25-30 KTS LATER THURSDAY THROUGH SATURDAY OVER THE WESTERN PORTION OF LK SUPERIOR. WINDS SHIFT MORE WESTERLY LATE NEXT WEEKEND AS THE LOW LIFTS INTO CANADA. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...KF AVIATION...07 MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 AM EDT TUE OCT 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM EDT TUE OCT 1 2013 BROAD TROUGH FROM ALASKA INTO MUCH OF WESTERN CANADA AND INTO NORTHERN PLAINS. LEAD SHORTWAVE WITHIN WESTERLY FLOW ALOFT LIFTING INTO NORTHWEST ONTARIO THIS MORNING. DECENT AMOUNT OF MID-HIGH CLOUDS ALONG AND AHEAD OF THE WAVE...BUT LOW LEVELS TOO DRY TO SUPPORT ANY RAIN...AT LEAST AS FAR EAST AS UPR MICHIGAN. SFC FRONT /ESSENTIALLY MORE OF A WIND SHIFT AND MOISTURE GRADIENT/ TIED TO SHORTWAVE MOVING ACROSS MINNESOTA WILL SWEEP INTO WESTERN UPR MICHIGAN THIS MORNING AND OUT OF EASTERN CWA BY MID AFTN. A LOT OF MID CLOUDS CURRENTLY OVER UPR MICHIGAN BACK INTO MINNESOTA SO BUMPED UP SKY COVER UNTIL EXPECTED TROUGH PASSAGE. CLUSTER OF SHRA LIFTING ENE ACROSS CNTRL MINNESOTA MAY GRAZE WESTERN LK SUPERIOR SO DID PUT MENTION OF SHRA FOR VCNTY OF ISLE ROYALE. REST OF CWA WILL STAY DRY WITH PERHAPS SOME VIRGA BASED ON SPOTTY RADAR ECHOES ACROSS NORTHERN WISCONSIN AND UPR MICHIGAN. ONCE THE SKIES CLEAR...ATTN TURNS TO FIRE WEATHER CONCERNS THIS AFTN. DEEP MIXED PROFILE AND VERY DRY AIR NOTED IN WAKE OF THE TROUGH WITH DWPNTS IN THE MID 20S TO MID 30S FM MONTANA INTO THE DAKOTAS LATE MONDAY AFTN AND STILL IN THE 30S THIS MORNING. EXPECT BLYR TO BUILD TO AT LEAST H8 AND POSSIBLY HIGHER BY MID AFTN. TEMPS SHOULD RISE INTO LOW-MID 70S EASILY...AND LIKELY HIGHER DUE TO THE FULL SUN. MAY HIT 80 WITH DOWNSLOPE WESTERLY WINDS OVR THE SCNTRL. SOUTH WINDS COULD GUST TO 25 MPH AHEAD OF TROUGH...THOUGH THICKER MID CLOUDS WILL CUT MIXING POTENTIAL DOWN. THIS AFTN THOUGH WITH FULL SUNSHINE/SUBSIDENCE DEVELOPING /DRYING NOTED ON LATEST WV LOOP BEHIND THE SHORTWAVE/ THE DEEP MIXING WILL LEAD TO UNIDIRECTIONAL GUSTY WEST WINDS. FORECAST SOUNDINGS MATCHING AIRMASS UPSTREAM ON 00Z BIS SOUNDING WITH 25-35 KTS IN THE BLYR. EXPECT STRONGEST GUSTS ACROSS HIGHER TERRAIN OF KEWEENAW. MAY SEE GUSTS TOWARD LOW-END WIND ADVY FOR A FEW HOURS THIS AFTN. ELSEWHERE...FREQUENT GUSTS OVER 30 MPH SEEM LIKELY JUST IN WAKE OF TROUGH AT LEAST FOR A FEW HOURS BEFORE THE WINDS BEGIN DECREASING LATE THIS AFTN. BUILDING BLYR WILL ALSO MIX DOWN THE VERY DRY AIR OUT OVR THE PLAINS. DWPNT FORECAST TODAY WAS VERY CHALLENGING WITH THE MAIN ISSUE IN HOW LOW TO BRING DWPNTS THIS AFTN. PLAYED THE LOWER MIDDLE GROUND FOR NOW...STAYING AWAY FM THE LOWER 20S DWPTS OFFERED UP BY THE MIXED TD TOOL AND RUC GUIDANCE. MAINLY LOW-MID 30S /SIMILAR TO NAM AND GEM-REGIONAL/ BUT DO HAVE SOME UPPER 20S DWPNTS OVER WESTERN INTERIOR 21Z-00Z AT END OF MIXING CYCLE AND BASED ON TIME/HEIGHT OF TEMPS/DWPNTS FM NAM/SREF. GRADIENT OF DWPNTS/RH THIS AFTN COULD BE STRIKING WITH NCEP WRF-ARW/NMM SHOWING A 30 DEGREE FALL IN DWPNTS IN JUST A FEW HOURS. REALLY DO NOT THINK THIS IS OUT OF THE QUESTION. POINT OF ALL THE DWPNT TALK IS THAT RESULTING RH VALUES PLUMMET BLO 25 PCT OVER THE INTERIOR WEST MID-LATE AFTN...LEADING TO CRITICAL FIRE WEATHER CONDITIONS WHEN THE WINDS ARE THE STRONGEST. WILDFIRE POTENTIAL STATEMENT WILL BE RE-ISSUED BUT WE MAY NEED ADDITIONAL FIRE WEATHER HEADLINES LATER TODAY BASED ON INPUT FROM FIRE USERS. DESPITE SUCH LOW DWPNTS LATE TODAY MINS TONIGHT WILL PROBABLY STAY MAINLY ABOVE 40 AS SOME WIND STIRS ALL NIGHT AS UPR MICHIGAN REMAINS IN SOME GRADIENT OF PRESSURE BTWN LOW OVER HUDSON BAY AND SFC RIDGE OVER UPPER MISSISSIPPI/OHIO VALLEY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 420 PM EDT MON SEP 30 2013 WILL START OUT TUESDAY NIGHT WITH MAINLY ZONAL FLOW ALOFT...WITH THE EXITING INITIAL COLD FRONT OVER FAR E UPPER MI AND THE MAIN SFC LOW OVER FAR N ONTARIO AND S LAKE HURON. GIVEN THE MUCH OF THE ENERGY REMAINS WELL TO OUR N...THE MAIN RESULT WILL THE BE THE INCREASED PRESSURE GRADIENT. EXPECT W WINDS GUSTING 20-28KTS THROUGH TUESDAY NIGHT. THE SECONDARY TROUGH/COLD FRONT NEVER REALLY GETS HERE ON WEDNESDAY...AS THE SFC LOW EXITS INTO N QUEBEC AND A RIDGE OF HIGH PRESSURE BRIEFLY BUILDS. EXTENDED THE PERIOD OF DRY WEATHER A BIT LONGER...THROUGH WEDNESDAY EVENING. LOW PRESSURE SPINNING ACROSS THE CENTRAL PLAINS MID WEEK WILL EXTEND A TROUGH/WARM FRONT ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT...AS THE MAIN LOW SLOWLY NEARS FROM THE SW. THERE ARE SIGNIFICANT ENOUGH DIFFERENCES IN THE LOCATION OF THE NEAR 1000MB LOW SATURDAY TO RESULT IN A CONSENSUS APPROACH AT THIS TIME. THIS WILL LEAD TO HIGH CHC TO DEF POPS FOR THURSDAY THROUGH SATURDAY. WILL WAIT UNTIL WE GET A CLEARER SOLUTION BEFORE PIN POINTING EXACT LOCATIONS AND TIMING. THE CONSENSUS IS TO HAVE THE LOW SHIFT NE DURING THE DAY SUNDAY...WITH W-NW WINDS LINGERING BEHIND THE LOW. THE 12Z ECMWF DOES HAVE 850MB TEMPS FALLING TO AROUND -2C LATE SATURDAY NIGHT THROUGH SUNDAY....WHICH WILL LIKELY KEEP A BKN-OVC SKY OVERHEAD. ANOTHER BRIEF RIDGE IS FIGURED SUNDAY NIGHT BEFORE A QUICK LOW SKIRTING THE US/CANADIAN BORDER NEARS FOR MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 131 AM EDT TUE OCT 1 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. WINDS SHOULD REMAIN FAIRLY GUSTY AOA 20KT TONIGHT AT KIWD BUT SHOULD DECOUPLE SOMEWHAT AT KCMX/KSAW WHERE LLWS WAS INCLUDED IN THE FCST. SHOULD CONTINUE TO BE GUSTY BEHIND A COLD FRONT TUE AT IWD AND CMX. THERE WILL BE SOME LLWS AT SAW TUE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 408 PM EDT MON SEP 30 2013 SRLY WINDS TO 25 KNOTS ARE EXPECTED TO VEER TO THE WEST TUESDAY AND INCREASE TO 30 KNOTS AS A WEAK COLD FRONT MOVES THROUGH LAKE SUPERIOR. WEST WINDS WILL DIMINISH WED AS A RIDGE BUILDS INTO THE AREA. MODELS ARE IN BETTER AGREEMENT SHOWING A LOW PRESSURE SYSTEM DEVELOPING IN THE LEE OF THE ROCKIES WITH A TROUGH EXTENDING INTO THE UPPER GREAT LAKES THU INTO FRI. THIS PATTERN SHOULD RESULT IN E-SE WINDS OVER CENTRAL AND ERN LAKE SUPERIOR AND STRENGTHENING NE WINDS TO 25 KT OVER THE WRN PART OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 AM EDT TUE OCT 1 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 408 PM EDT MON SEP 30 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN WITH A 120-130 KNOT 250-300 MB JET FROM THE PAC NW INTO THE NRN PLAINS. ONE MID LEVEL LOW WAS LOCATED OVER NRN MANITOBA WHILE ANOTHER SHORTWAVE TROUGH WAS MOVING INTO SW SASK. AT THE SFC...A TIGHT PRES GRADIENT BTWN HIGH PRES OVER THE ERN CONUS AND A 988 MB LOW INTO NRN MANITOBA HAS BROUGHT INCREASING SRLY WINDS THROUGH THE NRN GREAT LAKES. A WEAK COLD FRONT EXTENDED FROM THE MANITOBA LOW INTO NW MN. VIS LOOP SHOWED CONSIDERABLE MID/HIGH CLOUDS OVER UPPER MI WITH MAINLY CLEAR SKIES OVER MN AND NW WI. TONIGHT...SOUTH WIND GUSTING TO 20-30 MPH ARE EXPECTED TO CONTINUE OVER THE NRN TIER OF THE FCST AREA WITH THE STRONGEST WINDS OVER DOWNSLOPING LOCATIONS ALONG LAKE SUPERIOR. MIXING WILL KEEP MIN TEMPS IN THE 50S ACROSS THE AREA WITH READINGS CLOSER TO 60F FOR DOWNSLOPING LOCATIONS ALONG LAKE SUPERIOR. TUESDAY...THE WEAK COLD FRONT MOVING THROUGH THE AREA WILL RESULT IN VEERING WINDS TO WESTERLY. OTHERWISE...WITH 850 MB TEMPS AROUND 10C-11C INTO THE WEST...MAX READINGS ARE STILL EXPECTED TO CLIMB INTO THE LOWER TO MID 70S. DOWNSLOPE LOCATIONS OVER S CENTRAL UPPER MI SHOULD SEE TEMPS CLOSER TO 80. UPSTREAM OBS AND MDLS SUGGEST THAT THAT DRY ADVECTION AND DEEPR AFTERNOON MIXING WILL DROP DEWPOINTS INTO UPPER 30S OVER THE WRN INTERIOR BY MID TO LATE AFTERNOON. THE SLIGHTLY COOLER AIR INTO THE WEST...HOWEVER...SHOULD LIMIT MIN RH DROP TO AROUND 30 PERCENT. THE DRY CONDITIONS COMBINED WITH WEST WINDS GUSTING TO AROUND 25 MPH WILL RESULT IN ANOTHER DAY OF ELEVATED WILDFIRE RISK AS NOTED IN THE UPDATED WILDFIRE POTENTIAL STATEMENT. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 420 PM EDT MON SEP 30 2013 WILL START OUT TUESDAY NIGHT WITH MAINLY ZONAL FLOW ALOFT...WITH THE EXITING INITIAL COLD FRONT OVER FAR E UPPER MI AND THE MAIN SFC LOW OVER FAR N ONTARIO AND S LAKE HURON. GIVEN THE MUCH OF THE ENERGY REMAINS WELL TO OUR N...THE MAIN RESULT WILL THE BE THE INCREASED PRESSURE GRADIENT. EXPECT W WINDS GUSTING 20-28KTS THROUGH TUESDAY NIGHT. THE SECONDARY TROUGH/COLD FRONT NEVER REALLY GETS HERE ON WEDNESDAY...AS THE SFC LOW EXITS INTO N QUEBEC AND A RIDGE OF HIGH PRESSURE BRIEFLY BUILDS. EXTENDED THE PERIOD OF DRY WEATHER A BIT LONGER...THROUGH WEDNESDAY EVENING. LOW PRESSURE SPINNING ACROSS THE CENTRAL PLAINS MID WEEK WILL EXTEND A TROUGH/WARM FRONT ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT...AS THE MAIN LOW SLOWLY NEARS FROM THE SW. THERE ARE SIGNIFICANT ENOUGH DIFFERENCES IN THE LOCATION OF THE NEAR 1000MB LOW SATURDAY TO RESULT IN A CONSENSUS APPROACH AT THIS TIME. THIS WILL LEAD TO HIGH CHC TO DEF POPS FOR THURSDAY THROUGH SATURDAY. WILL WAIT UNTIL WE GET A CLEARER SOLUTION BEFORE PIN POINTING EXACT LOCATIONS AND TIMING. THE CONSENSUS IS TO HAVE THE LOW SHIFT NE DURING THE DAY SUNDAY...WITH W-NW WINDS LINGERING BEHIND THE LOW. THE 12Z ECMWF DOES HAVE 850MB TEMPS FALLING TO AROUND -2C LATE SATURDAY NIGHT THROUGH SUNDAY....WHICH WILL LIKELY KEEP A BKN-OVC SKY OVERHEAD. ANOTHER BRIEF RIDGE IS FIGURED SUNDAY NIGHT BEFORE A QUICK LOW SKIRTING THE US/CANADIAN BORDER NEARS FOR MONDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 131 AM EDT TUE OCT 1 2013 VFR CONDITIONS WILL CONTINUE THROUGH THE FCST PERIOD. WINDS SHOULD REMAIN FAIRLY GUSTY AOA 20KT TONIGHT AT KIWD BUT SHOULD DECOUPLE SOMEWHAT AT KCMX/KSAW WHERE LLWS WAS INCLUDED IN THE FCST. SHOULD CONTINUE TO BE GUSTY BEHIND A COLD FRONT TUE AT IWD AND CMX. THERE WILL BE SOME LLWS AT SAW TUE EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 408 PM EDT MON SEP 30 2013 SRLY WINDS TO 25 KNOTS ARE EXPECTED TO VEER TO THE WEST TUESDAY AND INCREASE TO 30 KNOTS AS A WEAK COLD FRONT MOVES THROUGH LAKE SUPERIOR. WEST WINDS WILL DIMINISH WED AS A RIDGE BUILDS INTO THE AREA. MODELS ARE IN BETTER AGREEMENT SHOWING A LOW PRESSURE SYSTEM DEVELOPING IN THE LEE OF THE ROCKIES WITH A TROUGH EXTENDING INTO THE UPPER GREAT LAKES THU INTO FRI. THIS PATTERN SHOULD RESULT IN E-SE WINDS OVER CENTRAL AND ERN LAKE SUPERIOR AND STRENGTHENING NE WINDS TO 25 KT OVER THE WRN PART OF THE LAKE. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS DULUTH MN
324 AM CDT TUE OCT 1 2013 .SHORT TERM...(TODAY THROUGH EARLY WEDNESDAY EVENING) ISSUED AT 324 AM CDT TUE OCT 1 2013 A COLD FRONT WAS JUST ENTERING OUR WESTERN CWA AS OF 08Z...AND SHOULD MOVE THROUGH THE AREA QUICKLY THIS MORNING CLEARING OUR EASTERN CWA BETWEEN 15-18Z. THE UPPER LEVEL JET WAS COMING ONSHORE IN THE PACIFIC NORTHWEST AND EXTENDED EAST INTO MINNESOTA AND NORTHWEST ONTARIO. THIS JET WAS PUSHING THIS FRONT EAST ALONG WITH AN UPPER LEVEL LOW/SHORTWAVE THAT WAS BRUSHING BY OUR NORTHWEST CWA. THERE A FEW SHOWERS ALONG AND JUST BEHIND THE FRONT THAT MAY IMPACT A PORTION OF OUR WEST/FAR NORTHERN ZONES THROUGH ABOUT 12Z. WE HAVE A SMALL POP TO ACCOUNT FOR THIS. THE BULK OF THE CLOUDS SHOULD CLEAR OUT OF THE AREA THIS MORNING WITH TEMPERATURES REMAINING ABOVE NORMAL...RANGING FROM 65 TO 70 ACROSS MOST OF NORTHERN MINNESOTA...AND THE LOWER SEVENTIES OVER NORTHWEST WISCONSIN. WINDS WILL BE INCREASING THROUGH THE DAY...AND BE STRONGEST OVER NORTHERN MINNESOTA WHERE SOME GUSTS OF 35 TO 40 MPH WILL OCCUR. SOME ISOLATED HIGHER GUSTS WILL ALSO BE POSSIBLE AND THE HRRR WAS INDICATING THE BEST CHANCE FOR THAT WAS ALONG THE INTERNATIONAL BORDER. THE TWIN PORTS/TWO HARBORS/PORT WING AREAS COULD ALSO SEE SOME OF THOSE HIGHER GUSTS. THE PRESSURE GRADIENT WILL RELAX TONIGHT ALLOWING WINDS TO DIMINISH. IT SHOULD REMAIN MOSTLY CLEAR...WITH LOWS DROPPING INTO THE UPPER THIRTIES TO LOWER FORTIES FOR MOST AREAS. AN AREA OF STRONG WAA WILL MOVE INTO THE NORTHLAND ON WEDNESDAY ON SOUTHWESTERLY WINDS ALOFT. CONFLUENT FLOW WILL LEAD TO INCREASING FGEN ACROSS THE NORTHLAND AS SEEN FROM 825-700MB. THE BEST MID LEVEL FGEN WILL BE ACROSS OUR NORTHERN MINNESOTA ZONES...AND WE MAXIMIZED OUR POPS THERE IN THE AFTERNOON. THE WIND WILL BE MUCH LIGHTER THAN WE`LL SEE TODAY. EXPECT HIGHS FROM THE LOWER SIXTIES IN FAR NORTHERN MINNESOTA...TO AROUND SEVENTY ACROSS NORTHWEST WISCONSIN. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 324 AM CDT TUE OCT 1 2013 A STRONG MID/UPPER LEVEL TROUGH WILL MOVE INTO THE WESTERN UNITED STATES EARLY IN THE PERIOD...AND IT WILL SPAWN A COLORADO LOW PRESSURE SYSTEM WHICH WILL LIKELY BRING AN EXTENDED PERIOD OF COOL AND WET WEATHER TO THE NORTHLAND FOR THE LATTER HALF OF THE WEEK. A FRONT WILL EXTEND NE FROM THE CENTER OF THE SURFACE LOW PRESSURE SYSTEM IN EASTERN COLORADO OR WESTERN KANSAS/NEBRASKA TO THE SOUTHERN FORECAST AREA WEDNESDAY NIGHT. THE FRONT WILL REMAIN NEAR THE SOUTHERN FORECAST AREA THURSDAY AND FRIDAY. THE VICINITY OF THE FRONT WILL LIKELY BRING SOME SHOWERS TO NORTHLAND WEDNESDAY NIGHT THROUGH FRIDAY MORNING AS THE LOW PRESSURE SYSTEM BEGINS TO LIFT AND DEEPEN INTO THE CENTRAL PLAINS. IT IS THE FRIDAY NIGHT THROUGH SATURDAY NIGHT PERIOD THAT LOOKS REALLY WET FOR THE NORTHLAND AS THE LIFTING AND DEEPENING LOW MOVES THROUGH MINNESOTA/WISCONSIN REGION. THIS SHOULD BRING A LOT OF CLOUD COVER AND RAIN TO THE FORECAST AREA WHICH WILL RESULT IN COOL TEMPERATURES. THERE IS ALSO THE POSSIBILITY OF SNOW WITH THIS SYSTEM...ESPECIALLY ACROSS THE WESTERN AND NORTHERN FORECAST...DEPENDING ON HOW COLD AND SATURATED THE TEMPERATURES ARE ALOFT IN THE WRAP AROUND FLOW. THE ECMWF CONTINUES TO BE SIGNIFICANTLY COLDER THAN THE GFS AND GEM. I KEPT THE FORECAST RAIN BUT WE WILL NEED TO MONITOR THE GFS AND GEM FOR ANY SHIFTS TOWARDS COLDER TEMPERATURES...AND IF THIS HAPPENS...PERHAPS ADD SNOW TO THE FORECAST. IT APPEARS THIS SYSTEM COULD BRING WIDESPREAD RAINFALL TOTALS OF 1 TO 3 INCHES FROM WEDNESDAY NIGHT THROUGH EARLY SUNDAY. THE SYSTEM WILL BEGIN TO EXIT THE REGION SUNDAY. THERE COULD BE SOME LINGERING SHOWERS. I LOWERED THE HIGH TEMPERATURES A BIT. IT WOULD NOT BE SURPRISING IF WE NEED TO INCREASE CLOUD COVER AND LOWER TEMPERATURES EVEN MORE. THERE ARE LOW CHANCES OF SHOWERS FOR MONDAY DUE OT THE GFS BRINGING A COLD FRONT THROUGH THE NORTHLAND. HOWEVER...THE RAIN MIGHT STAY TO THE NORTH IN THE MANITOBA/ONTARIO...OR NOT HAPPEN AT ALL ON MONDAY IF THE SLOWER ECMWF IS ON THE RIGHT TRACK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1204 AM CDT TUE OCT 1 2013 A STRONG COLD FRONT WILL MOVE EASTWARD ACROSS THE NORTHLAND OVERNIGHT. THE RESULT WILL BE A FEW VERY LIGHT SHOWERS OR SPRINKLES...AND WIDESPREAD MID TO HIGH LEVEL CLOUDS. THERE IS A SMALL CHANCE THAT A SHOWER COULD BRIEFLY REDUCE CIGS TO MVFR...MAINLY AT KINL. WINDS WILL INCREASE CONSIDERABLY WITH DAYTIME HEATING ON TUESDAY...AS STRONG CAA BEHIND THE FRONT PROVIDES FAVORABLE MOMENTUM TRANSFER. && .PRELIMINARY POINT TEMPS/POPS... DLH 70 44 67 47 / 0 0 20 60 INL 67 41 61 42 / 10 10 40 20 BRD 70 43 69 48 / 0 10 30 60 HYR 72 40 71 49 / 0 0 10 70 ASX 73 44 70 48 / 10 0 10 60 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...MELDE LONG TERM...GROCHOCINSKI AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
415 AM CDT TUE OCT 1 2013 .DISCUSSION... MAIN FORECAST CONCERNS ARE CENTERED AROUND THUNDERSTORM CHANCES BEGINNING WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...THEN COLD CLOSED LOW MOVING TOWARD THE AREA SATURDAY. LATEST WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOW NEARLY ZONAL FLOW OVER A LARGE PORTION OF THE COUNTRY. TWO MAIN LOW PRESSURE CENTERS WERE LOCATED NEAR THE CANADIAN BORDER...THE FIRST OF WHICH WAS OVER SASKATCHEWAN WHILE THE OTHER UPSTREAM LOW WAS OFF THE PACIFIC NORTHWEST COAST. AT THE SURFACE...A COLD FRONT EXTENDED FROM NORTH CENTRAL MINNESOTA INTO SOUTH CENTRAL NEBRASKA. THIS WILL CONTINUE TO SLIDE SOUTHEAST WITH RELATIVELY LITTLE EFFECT ON THE AREA BESIDES A WIND SHIFT. AS THE PACIFIC NORTHWEST LOW MOVES INTO THE LOWER 48 STATES...THE MID/UPPER LEVEL FLOW OVER THE REGION BECOMES MORE SOUTHWESTERLY. STRONG WARM AIR ADVECTION RESUMES BRIEFLY WEDNESDAY BEFORE THE NEXT FRONTAL BOUNDARY DROPS SOUTH AHEAD OF THE APPROACHING WESTERN UPPER LOW. THIS FRONTAL BOUNDARY WILL BE THE FOCUS FOR CONVECTION WEDNESDAY NIGHT AND INTO THURSDAY. THE FRONT STALLS OVER THE CWA PROVIDING A CONTINUED CHANCE FOR CONVECTION. BY FRIDAY...THE UPPER LEVEL LOW WILL BE MOVING EAST INTO NEBRASKA WITH THE SURFACE LOW A FEW HUNDRED MILES EAST OF THE UPPER LOW. CONVECTION IS POSSIBLE FRIDAY AHEAD OF THE LOW IN THE WARM SECTOR WHILE STRATIFORM RAIN IS LIKELY BEHIND THE LOW. 850MB TEMPS BEHIND THE LOW DO DROP INTO THE LOWER SINGLE DIGITS WITH 850MB WINDS OF 50-70KTS LEADING TO A BLUSTERY SATURDAY. SOME LIGHT PCPN IS POSSIBLE IN DEFORMATION AREA...BUT LOOKS MINIMAL AT THIS TIME. DRY AND WARMER CONDITIONS WILL FOLLOW BEHIND THIS LOW INTO EARLY NEXT WEEK. KERN && .AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA. VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY EVENING WITH ONLY SCATTERED TO BROKEN HIGH CLOUDS PREVAILING. A WEAK COLD FRONT WILL SLIDE THROUGH EASTERN NEBRASKA BETWEEN 08Z AND 15Z TUESDAY. ONLY A WIND SHIFT FROM SOUTH TO NORTH IS EXPECTED WITH THE FRONT...BUT SPEEDS WILL BE 12KT OR LESS. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1133 PM CDT MON SEP 30 2013 .SYNOPSIS... ISSUED AT 331 PM CDT MON SEP 30 2013 AN ACTIVE H5 PATTERN CONTINUES ACROSS CANADA AND THE NRN TIER OF THE CONUS TDY. A STRONG UPPER LEVEL DISTURBANCE WAS LOCATED OVER CENTRAL SASKATCHEWAN WITH DECENT HT FALLS NOTED OVER CENTRAL MANITOBA THIS MORNING. A TANDEM OF UPPER LEVEL LOWS WERE PRESENT OVER THE GULF OF ALASKA AND OVER THE COAST OF CENTRAL BRITISH COLUMBIA. A 70+KT JET STREAK EXTENDED FROM 500 MILES WEST OF WASHINGTON STATE...INTO OREGON AND IDAHO. FURTHER EAST...A RIDGE EXTENDED FROM BERMUDA NORTH INTO NEWFOUNDLAND. AT THE SURFACE...A TIGHT PRESSURE GRADIENT WAS NOTED OVER WYOMING ATTM...WITH HIGH PRESSURE OVER THE FOUR CORNERS AND A SURFACE TROUGH OVER MT. STRONG WESTERLY AND SOUTHWESTERLY WINDS HAVE DEVELOPED OVER WYOMING THIS AFTERNOON AND SOME OF THIS WIND HAS PUSHED EAST INTO THE NEBRASKA PANHANDLE AND NWRN NEBRASKA WITH WINDS GUSTING TO 35 MPH AT VALENTINE. AT 3 PM CDT...TEMPERATURES WERE IN THE UPPER 80S ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. && .UPDATE... ISSUED AT 1033 PM CDT MON SEP 30 2013 TEMPERATURES HAVE COOLED INTO THE 60S AND 70S AND THIS IS PREVENTING STRONG WINDS ALOFT FROM MIXING DOWN. KLNX RADAR VELOCITY PRODUCTS INDICATE THE COLD FRONT HAS WEAKENED RELATIVE TO THE KUNR RADAR. GUSTY NORTHWEST WINDS TO 35 OR 40 MPH ARE POSSIBLE AS THE FRONT MOVES THROUGH BUT HIGH WINDS ARE UNLIKELY. SO THE HIGH WIND WARNING HAS BEEN CANCELLED. UPDATE ISSUED AT 737 PM CDT MON SEP 30 2013 THE FAST MOVING COLD FRONT IS MOVING AT 55 MPH ACCORDING TO TIMING TOOLS. THIS BRINGS THE FRONT INTO SHERIDAN COUNTY AROUND 01Z AND THROUGH KVTN AROUND 0330Z. GIVEN THAT MSAS 3 HR PRESSURE RISES ARE INCREASING AT THE RATE OF 1 MB PER HOUR...NOW SHOW 7 MB AT 00Z AND THAT THE HRRR AND RAP MODEL WIND GUSTS ARE MISSING THIS FEATURE...A HIGH WIND WARNING HAS BEEN ISSUED FOR SHERIDAN AND CHERRY COUNTIES UNTIL 05Z. THE FRONT AND WIND GUSTS SHOULD DECREASE BY MIDNIGHT AS A RESULT OF SFC COOLING. STILL SOME 40 MPH GUSTS COULD LAST OVERNIGHT FARTHER SOUTH. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 OVER THE NEXT 24 HOURS...A WEAK COLD FRONT WILL PUSH THROUGH WESTERN AND NORTH CENTRAL NEBRASKA AS A DISTURBANCE AND TRACKS ALONG THE US/CANADIAN BORDER. CAA WILL BE FAIRLY WEAK BEHIND THIS FEATURE...SO WINDS WILL BE FAIRLY LIGHT WITH THE FROPA...AND THIS WILL LIMIT MIXING...ALLOWING TEMPS TO FALL BACK INTO THE 40S FOR LOWS TONIGHT. FOR TUESDAY...WEAK HIGH PRESSURE WILL TRACK INTO NORTHEASTERN NEBRASKA. LIGHT EASTERLY WINDS WILL TRANSITION TO THE SOUTHEAST LATE IN THE DAY. TEMPERATURES FOR TUESDAY WILL RUN 10 TO 15 DEGREES COOLER THAN TODAYS HIGHS...WITH HIGHS FORECAST TO RANGE FROM THE LOWER 70S IN THE NORTHEAST TO NEAR 80 IN THE FAR SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 TUESDAY NIGHT THROUGH THURSDAY...IN THE MID RANGE...THE MAIN FORECAST CHALLENGE IS TEMPERATURES AND THUNDERSTORM CHANCES WEDNESDAY NIGHT INTO THURSDAY. FOR TUESDAY NIGHT...HIGH PRESSURE WILL BUILD EAST INTO THE UPPER MISSISSIPPI VALLEY INCREASING SRLY FLOW OVERNIGHT AND LEADING TO MILD LOWS IN THE LOWER 50S. DID INCLUDE SOME UPPER 40S IN EASTERN AREAS...AS WINDS WILL BE LIGHTER DURING THE LATE EVENING HOURS...AND LOWS MAY ACTUALLY BE MET WELL BEFORE SUNRISE. FOR WEDNESDAY...INCREASING SRLY WINDS WILL PUSH LOW LEVEL MOISTURE NWD INTO ALL OF THE FORECAST AREA WITH THE EXCEPTION OF THE PANHANDLE. BY AFTERNOON...A FRONTAL BOUNDARY WILL APPROACH THE NORTHWEST...INCREASING THE THREAT FOR THUNDERSTORMS. THE CAVEAT HERE IS CAP STRENGTH...WHICH MAY BE TOO STRONG INITIALLY ACROSS NORTH CENTRAL NEBRASKA TO FACILITATE CONVECTIVE INITIATION. INHERITED FCST HAS A NARROW BAND OF SLIGHT CHANCE POPS WEDS AFTERNOON IN THE CENTRAL AND NORTH CENTRAL ZONES. THIS AREA OF INHERITED POPS WAS BASED ON THE FRONTAL POSN IN LAST MONTH/S MODEL RUNS. GIVEN THE FRONT IS SLOWER NOW...SHIFTED POPS FURTHER NORTHWEST TO BETTER FIT FROPA TIMING. BY WEDNESDAY NIGHT...POPS WILL INCREASE FROM WEST TO EAST AS THE FRONT CROSSES WESTERN AND NORTH CENTRAL NEBRASKA. AS WAS THE CASE YESTERDAY...WEAKER CAPPING AND BETTER FORCING REMAINS ACROSS SOUTH DAKOTA AND NORTHERN NEBRASKA...AND WILL CONTINUE HIGHER POPS OVER NRN NEBRASKA. ON THURSDAY...THE UPPER PATTERN WILL AMPLIFY AS A TROUGH OF LOW PRESSURE LIFTS INTO THE CENTRAL ROCKIES. EAST OF THIS FEATURE...A MID LEVEL WARM FRONT WILL LIFT NORTH ACROSS NORTHERN NEBRASKA...INCREASING THE THREAT FOR PCPN IN THE CENTRAL AND EASTERN FORECAST AREA. THURSDAY NIGHT THROUGH MONDAY...THE MAIN FORECAST CHALLENGE IN THE EXTENDED IS PRECIPITATION CHANCES IN ASSOCIATION WITH A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE WHICH TRACKS ACROSS THE CENTRAL PLAINS FRIDAY INTO SATURDAY. BOTH THE GFS AND ECMWF SOLUTIONS SLOW THE PROGRESSION OF A POTENT UPPER LEVEL LOW FRIDAY INTO SATURDAY. THE GFS HAS A MORE SRN TRACK...TAKING THIS FEATURE FROM SWRN NEBRASKA INTO NERN NEBRASKA FROM 00Z SATURDAY THROUGH 12Z SATURDAY. THE ECMWF TRACKS THE SAME FEATURE FROM SWRN SD INTO NERN SD DURING THE SAME TIME PERIOD. THE CANADIAN SOLN IS EVEN SLOWER AND IS A COMPROMISE BETWEEN THE NRN EC AND SRN GFS SOLNS. REGARDLESS OF SOLNS...THE NRN CWA STANDS TO SEE THE BEST CHANCES FOR PCPN FRIDAY INTO FRIDAY NIGHT. FURTHER SOUTH...THERE IS A POTENTIAL FOR A DRY SLOT TO DEVELOP ACROSS SWRN AND SCENTRAL NEBRASKA...AND HAVE KEPT POPS LOW ATTM. THEN THERE IS THE THREAT FOR SNOW...AS THE MODELS ARE GENERATING SNOW ACCUMS WITH THIS SYSTEM. WET BULB ZEROES ARE NOT QUITE COLD ENOUGH ATTM FOR A MENTION OF SNOW...AND WILL KEEP IT OUT OF THE FCST. NO DOUBT PRECIP TYPE COULD CHANGE IF THE MID RANGE MODELS TREND COLDER...IE. TOWARD THE 12Z ECMWF SOLN. SINCE THIS SOLN TRENDED MUCH COLDER THAN THE PVS RUN...WILL HOLD OFF ON ANY SNOW MENTION AND CONTINUE TO MONITOR THE MID RANGE MODEL TRENDS. WINDS WILL BE STRONG WITH THIS SYSTEM...ESPECIALLY ON THE BACK SIDE OVERNIGHT FRIDAY NIGHT INTO SATURDAY. THE ECMWF HAS 50+ KT H85 WINDS...WHILE THE GFS HAS 70+ KT WINDS DURING THE PERIOD. EVEN WITHOUT ANY WINTRY PCPN...SOME SORT OF WIND HEADLINE APPEARS LIKELY FRIDAY NIGHT INTO SATURDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1133 PM CDT MON SEP 30 2013 VFR IS EXPECTED OVERNIGHT THROUGH TUESDAY EVENING. A COLD FRONT...CURRENTLY MOVING THROUGH THEDFORD...WILL EXIT THE FCST BY MORNING. THIS FRONT COULD PRODUCE GUSTY WINDS TO 35 MPH IN SOME AREAS. WEAK PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE FCST AREA TUESDAY PRODUCING SCATTERED MIDLEVEL CLOUDS AND LIGHT WINDS. && .FIRE WEATHER... ISSUED AT 331 PM CDT MON SEP 30 2013 A WEAK FRONT WILL MOVE ACROSS NEBRASKA OVERNIGHT WHICH WILL BRING SLIGHTLY COOLER AIR TO THE AREA FOR WEDNESDAY. DEWPOINTS WILL STAY FAIRLY SIMILAR TO READINGS OBSERVED TODAY...BUT WITH THE COOLER TEMPERATURES DON/T EXPECT RELATIVE HUMIDITY TO FALL BELOW 20 PERCENT ON TUESDAY. ALSO...WINDS SHOULD BE FAIRLY LIGHT TO KEEP CONCERNS FOR FIRE WEATHER LOW. WINDS WILL BE STRONGER AGAIN ON WEDNESDAY AS SOUTHERLY WINDS WILL BRING WARMER AIR BACK INTO THE REGION. THESE WINDS WILL ALSO BRING MORE MOISTURE NORTHWARD...SO RELATIVE HUMIDITY IS NOT EXPECTED TO DROP TO CRITICAL LEVELS. THEN FOR THE SECOND PART OF THE WEEK FIRE WEATHER CONCERNS WILL STAY LOW AS A STRONG STORM SYSTEM WILL IMPACT THE REGION BRINGING CHANCES FOR RAIN...THUNDERSTORMS...STRONG WINDS...AND COLDER TEMPERATURES && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...CLB AVIATION...CDC FIRE WEATHER...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1038 PM CDT MON SEP 30 2013 .SYNOPSIS... ISSUED AT 331 PM CDT MON SEP 30 2013 AN ACTIVE H5 PATTERN CONTINUES ACROSS CANADA AND THE NRN TIER OF THE CONUS TDY. A STRONG UPPER LEVEL DISTURBANCE WAS LOCATED OVER CENTRAL SASKATCHEWAN WITH DECENT HT FALLS NOTED OVER CENTRAL MANITOBA THIS MORNING. A TANDEM OF UPPER LEVEL LOWS WERE PRESENT OVER THE GULF OF ALASKA AND OVER THE COAST OF CENTRAL BRITISH COLUMBIA. A 70+KT JET STREAK EXTENDED FROM 500 MILES WEST OF WASHINGTON STATE...INTO OREGON AND IDAHO. FURTHER EAST...A RIDGE EXTENDED FROM BERMUDA NORTH INTO NEWFOUNDLAND. AT THE SURFACE...A TIGHT PRESSURE GRADIENT WAS NOTED OVER WYOMING ATTM...WITH HIGH PRESSURE OVER THE FOUR CORNERS AND A SURFACE TROUGH OVER MT. STRONG WESTERLY AND SOUTHWESTERLY WINDS HAVE DEVELOPED OVER WYOMING THIS AFTERNOON AND SOME OF THIS WIND HAS PUSHED EAST INTO THE NEBRASKA PANHANDLE AND NWRN NEBRASKA WITH WINDS GUSTING TO 35 MPH AT VALENTINE. AT 3 PM CDT...TEMPERATURES WERE IN THE UPPER 80S ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. && .UPDATE... ISSUED AT 1033 PM CDT MON SEP 30 2013 TEMPERATURES HAVE COOLED INTO THE 60S AND 70S AND THIS IS PREVENTING STRONG WINDS ALOFT FROM MIXING DOWN. KLNX RADAR VELOCITY PRODUCTS INDICATE THE COLD FRONT HAS WEAKENED RELATIVE TO THE KUNR RADAR. GUSTY NORTHWEST WINDS TO 35 OR 40 MPH ARE POSSIBLE AS THE FRONT MOVES THROUGH BUT HIGH WINDS ARE UNLIKELY. SO THE HIGH WIND WARNING HAS BEEN CANCELLED. UPDATE ISSUED AT 737 PM CDT MON SEP 30 2013 THE FAST MOVING COLD FRONT IS MOVING AT 55 MPH ACCORDING TO TIMING TOOLS. THIS BRINGS THE FRONT INTO SHERIDAN COUNTY AROUND 01Z AND THROUGH KVTN AROUND 0330Z. GIVEN THAT MSAS 3 HR PRESSURE RISES ARE INCREASING AT THE RATE OF 1 MB PER HOUR...NOW SHOW 7 MB AT 00Z AND THAT THE HRRR AND RAP MODEL WIND GUSTS ARE MISSING THIS FEATURE...A HIGH WIND WARNING HAS BEEN ISSUED FOR SHERIDAN AND CHERRY COUNTIES UNTIL 05Z. THE FRONT AND WIND GUSTS SHOULD DECREASE BY MIDNIGHT AS A RESULT OF SFC COOLING. STILL SOME 40 MPH GUSTS COULD LAST OVERNIGHT FARTHER SOUTH. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 OVER THE NEXT 24 HOURS...A WEAK COLD FRONT WILL PUSH THROUGH WESTERN AND NORTH CENTRAL NEBRASKA AS A DISTURBANCE AND TRACKS ALONG THE US/CANADIAN BORDER. CAA WILL BE FAIRLY WEAK BEHIND THIS FEATURE...SO WINDS WILL BE FAIRLY LIGHT WITH THE FROPA...AND THIS WILL LIMIT MIXING...ALLOWING TEMPS TO FALL BACK INTO THE 40S FOR LOWS TONIGHT. FOR TUESDAY...WEAK HIGH PRESSURE WILL TRACK INTO NORTHEASTERN NEBRASKA. LIGHT EASTERLY WINDS WILL TRANSITION TO THE SOUTHEAST LATE IN THE DAY. TEMPERATURES FOR TUESDAY WILL RUN 10 TO 15 DEGREES COOLER THAN TODAYS HIGHS...WITH HIGHS FORECAST TO RANGE FROM THE LOWER 70S IN THE NORTHEAST TO NEAR 80 IN THE FAR SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 TUESDAY NIGHT THROUGH THURSDAY...IN THE MID RANGE...THE MAIN FORECAST CHALLENGE IS TEMPERATURES AND THUNDERSTORM CHANCES WEDNESDAY NIGHT INTO THURSDAY. FOR TUESDAY NIGHT...HIGH PRESSURE WILL BUILD EAST INTO THE UPPER MISSISSIPPI VALLEY INCREASING SRLY FLOW OVERNIGHT AND LEADING TO MILD LOWS IN THE LOWER 50S. DID INCLUDE SOME UPPER 40S IN EASTERN AREAS...AS WINDS WILL BE LIGHTER DURING THE LATE EVENING HOURS...AND LOWS MAY ACTUALLY BE MET WELL BEFORE SUNRISE. FOR WEDNESDAY...INCREASING SRLY WINDS WILL PUSH LOW LEVEL MOISTURE NWD INTO ALL OF THE FORECAST AREA WITH THE EXCEPTION OF THE PANHANDLE. BY AFTERNOON...A FRONTAL BOUNDARY WILL APPROACH THE NORTHWEST...INCREASING THE THREAT FOR THUNDERSTORMS. THE CAVEAT HERE IS CAP STRENGTH...WHICH MAY BE TOO STRONG INITIALLY ACROSS NORTH CENTRAL NEBRASKA TO FACILITATE CONVECTIVE INITIATION. INHERITED FCST HAS A NARROW BAND OF SLIGHT CHANCE POPS WEDS AFTERNOON IN THE CENTRAL AND NORTH CENTRAL ZONES. THIS AREA OF INHERITED POPS WAS BASED ON THE FRONTAL POSN IN LAST MONTH/S MODEL RUNS. GIVEN THE FRONT IS SLOWER NOW...SHIFTED POPS FURTHER NORTHWEST TO BETTER FIT FROPA TIMING. BY WEDNESDAY NIGHT...POPS WILL INCREASE FROM WEST TO EAST AS THE FRONT CROSSES WESTERN AND NORTH CENTRAL NEBRASKA. AS WAS THE CASE YESTERDAY...WEAKER CAPPING AND BETTER FORCING REMAINS ACROSS SOUTH DAKOTA AND NORTHERN NEBRASKA...AND WILL CONTINUE HIGHER POPS OVER NRN NEBRASKA. ON THURSDAY...THE UPPER PATTERN WILL AMPLIFY AS A TROUGH OF LOW PRESSURE LIFTS INTO THE CENTRAL ROCKIES. EAST OF THIS FEATURE...A MID LEVEL WARM FRONT WILL LIFT NORTH ACROSS NORTHERN NEBRASKA...INCREASING THE THREAT FOR PCPN IN THE CENTRAL AND EASTERN FORECAST AREA. THURSDAY NIGHT THROUGH MONDAY...THE MAIN FORECAST CHALLENGE IN THE EXTENDED IS PRECIPITATION CHANCES IN ASSOCIATION WITH A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE WHICH TRACKS ACROSS THE CENTRAL PLAINS FRIDAY INTO SATURDAY. BOTH THE GFS AND ECMWF SOLUTIONS SLOW THE PROGRESSION OF A POTENT UPPER LEVEL LOW FRIDAY INTO SATURDAY. THE GFS HAS A MORE SRN TRACK...TAKING THIS FEATURE FROM SWRN NEBRASKA INTO NERN NEBRASKA FROM 00Z SATURDAY THROUGH 12Z SATURDAY. THE ECMWF TRACKS THE SAME FEATURE FROM SWRN SD INTO NERN SD DURING THE SAME TIME PERIOD. THE CANADIAN SOLN IS EVEN SLOWER AND IS A COMPROMISE BETWEEN THE NRN EC AND SRN GFS SOLNS. REGARDLESS OF SOLNS...THE NRN CWA STANDS TO SEE THE BEST CHANCES FOR PCPN FRIDAY INTO FRIDAY NIGHT. FURTHER SOUTH...THERE IS A POTENTIAL FOR A DRY SLOT TO DEVELOP ACROSS SWRN AND SCENTRAL NEBRASKA...AND HAVE KEPT POPS LOW ATTM. THEN THERE IS THE THREAT FOR SNOW...AS THE MODELS ARE GENERATING SNOW ACCUMS WITH THIS SYSTEM. WET BULB ZEROES ARE NOT QUITE COLD ENOUGH ATTM FOR A MENTION OF SNOW...AND WILL KEEP IT OUT OF THE FCST. NO DOUBT PRECIP TYPE COULD CHANGE IF THE MID RANGE MODELS TREND COLDER...IE. TOWARD THE 12Z ECMWF SOLN. SINCE THIS SOLN TRENDED MUCH COLDER THAN THE PVS RUN...WILL HOLD OFF ON ANY SNOW MENTION AND CONTINUE TO MONITOR THE MID RANGE MODEL TRENDS. WINDS WILL BE STRONG WITH THIS SYSTEM...ESPECIALLY ON THE BACK SIDE OVERNIGHT FRIDAY NIGHT INTO SATURDAY. THE ECMWF HAS 50+ KT H85 WINDS...WHILE THE GFS HAS 70+ KT WINDS DURING THE PERIOD. EVEN WITHOUT ANY WINTRY PCPN...SOME SORT OF WIND HEADLINE APPEARS LIKELY FRIDAY NIGHT INTO SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 659 PM CDT MON SEP 30 2013 VFR IS EXPECTED OVERNIGHT AND TUESDAY. A COLD FRONT...CURRENTLY MOVING THROUGH RAPID CITY...WILL MOVE THROUGH THE FCST AREA TONIGHT. THIS FRONT COULD PRODUCE GUSTY WINDS TO 40 MPH AS IT MOVES THROUGH NRN NEB THIS EVENING. THE EXTENT OF THE WINDS IS SOMEWHAT UNCERTAIN AS THE HRRR AND RAP MODELS SHOWS MUCH WEAKER WIND GUSTS. WEAK PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE FCST AREA TUESDAY PRODUCING SCATTERED MIDLEVEL CLOUDS AND LIGHT WINDS. && .FIRE WEATHER... ISSUED AT 331 PM CDT MON SEP 30 2013 A WEAK FRONT WILL MOVE ACROSS NEBRASKA OVERNIGHT WHICH WILL BRING SLIGHTLY COOLER AIR TO THE AREA FOR WEDNESDAY. DEWPOINTS WILL STAY FAIRLY SIMILAR TO READINGS OBSERVED TODAY...BUT WITH THE COOLER TEMPERATURES DON/T EXPECT RELATIVE HUMIDITY TO FALL BELOW 20 PERCENT ON TUESDAY. ALSO...WINDS SHOULD BE FAIRLY LIGHT TO KEEP CONCERNS FOR FIRE WEATHER LOW. WINDS WILL BE STRONGER AGAIN ON WEDNESDAY AS SOUTHERLY WINDS WILL BRING WARMER AIR BACK INTO THE REGION. THESE WINDS WILL ALSO BRING MORE MOISTURE NORTHWARD...SO RELATIVE HUMIDITY IS NOT EXPECTED TO DROP TO CRITICAL LEVELS. THEN FOR THE SECOND PART OF THE WEEK FIRE WEATHER CONCERNS WILL STAY LOW AS A STRONG STORM SYSTEM WILL IMPACT THE REGION BRINGING CHANCES FOR RAIN...THUNDERSTORMS...STRONG WINDS...AND COLDER TEMPERATURES && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...CLB AVIATION...CDC FIRE WEATHER...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
743 PM CDT MON SEP 30 2013 .SYNOPSIS... ISSUED AT 331 PM CDT MON SEP 30 2013 AN ACTIVE H5 PATTERN CONTINUES ACROSS CANADA AND THE NRN TIER OF THE CONUS TDY. A STRONG UPPER LEVEL DISTURBANCE WAS LOCATED OVER CENTRAL SASKATCHEWAN WITH DECENT HT FALLS NOTED OVER CENTRAL MANITOBA THIS MORNING. A TANDEM OF UPPER LEVEL LOWS WERE PRESENT OVER THE GULF OF ALASKA AND OVER THE COAST OF CENTRAL BRITISH COLUMBIA. A 70+KT JET STREAK EXTENDED FROM 500 MILES WEST OF WASHINGTON STATE...INTO OREGON AND IDAHO. FURTHER EAST...A RIDGE EXTENDED FROM BERMUDA NORTH INTO NEWFOUNDLAND. AT THE SURFACE...A TIGHT PRESSURE GRADIENT WAS NOTED OVER WYOMING ATTM...WITH HIGH PRESSURE OVER THE FOUR CORNERS AND A SURFACE TROUGH OVER MT. STRONG WESTERLY AND SOUTHWESTERLY WINDS HAVE DEVELOPED OVER WYOMING THIS AFTERNOON AND SOME OF THIS WIND HAS PUSHED EAST INTO THE NEBRASKA PANHANDLE AND NWRN NEBRASKA WITH WINDS GUSTING TO 35 MPH AT VALENTINE. AT 3 PM CDT...TEMPERATURES WERE IN THE UPPER 80S ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. && .UPDATE... ISSUED AT 737 PM CDT MON SEP 30 2013 THE FAST MOVING COLD FRONT IS MOVING AT 55 MPH ACCORDING TO TIMING TOOLS. THIS BRINGS THE FRONT INTO SHERIDAN COUNTY AROUND 01Z AND THROUGH KVTN AROUND 0330Z. GIVEN THAT MSAS 3 HR PRESSURE RISES ARE INCREASING AT THE RATE OF 1 MB PER HOUR...NOW SHOW 7 MB AT 00Z AND THAT THE HRRR AND RAP MODEL WIND GUSTS ARE MISSING THIS FEATURE...A HIGH WIND WARNING HAS BEEN ISSUED FOR SHERIDAN AND CHERRY COUNTIES UNTIL 05Z. THE FRONT AND WIND GUSTS SHOULD DECREASE BY MIDNIGHT AS A RESULT OF SFC COOLING. STILL SOME 40 MPH GUSTS COULD LAST OVERNIGHT FARTHER SOUTH. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 OVER THE NEXT 24 HOURS...A WEAK COLD FRONT WILL PUSH THROUGH WESTERN AND NORTH CENTRAL NEBRASKA AS A DISTURBANCE AND TRACKS ALONG THE US/CANADIAN BORDER. CAA WILL BE FAIRLY WEAK BEHIND THIS FEATURE...SO WINDS WILL BE FAIRLY LIGHT WITH THE FROPA...AND THIS WILL LIMIT MIXING...ALLOWING TEMPS TO FALL BACK INTO THE 40S FOR LOWS TONIGHT. FOR TUESDAY...WEAK HIGH PRESSURE WILL TRACK INTO NORTHEASTERN NEBRASKA. LIGHT EASTERLY WINDS WILL TRANSITION TO THE SOUTHEAST LATE IN THE DAY. TEMPERATURES FOR TUESDAY WILL RUN 10 TO 15 DEGREES COOLER THAN TODAYS HIGHS...WITH HIGHS FORECAST TO RANGE FROM THE LOWER 70S IN THE NORTHEAST TO NEAR 80 IN THE FAR SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 TUESDAY NIGHT THROUGH THURSDAY...IN THE MID RANGE...THE MAIN FORECAST CHALLENGE IS TEMPERATURES AND THUNDERSTORM CHANCES WEDNESDAY NIGHT INTO THURSDAY. FOR TUESDAY NIGHT...HIGH PRESSURE WILL BUILD EAST INTO THE UPPER MISSISSIPPI VALLEY INCREASING SRLY FLOW OVERNIGHT AND LEADING TO MILD LOWS IN THE LOWER 50S. DID INCLUDE SOME UPPER 40S IN EASTERN AREAS...AS WINDS WILL BE LIGHTER DURING THE LATE EVENING HOURS...AND LOWS MAY ACTUALLY BE MET WELL BEFORE SUNRISE. FOR WEDNESDAY...INCREASING SRLY WINDS WILL PUSH LOW LEVEL MOISTURE NWD INTO ALL OF THE FORECAST AREA WITH THE EXCEPTION OF THE PANHANDLE. BY AFTERNOON...A FRONTAL BOUNDARY WILL APPROACH THE NORTHWEST...INCREASING THE THREAT FOR THUNDERSTORMS. THE CAVEAT HERE IS CAP STRENGTH...WHICH MAY BE TOO STRONG INITIALLY ACROSS NORTH CENTRAL NEBRASKA TO FACILITATE CONVECTIVE INITIATION. INHERITED FCST HAS A NARROW BAND OF SLIGHT CHANCE POPS WEDS AFTERNOON IN THE CENTRAL AND NORTH CENTRAL ZONES. THIS AREA OF INHERITED POPS WAS BASED ON THE FRONTAL POSN IN LAST MONTH/S MODEL RUNS. GIVEN THE FRONT IS SLOWER NOW...SHIFTED POPS FURTHER NORTHWEST TO BETTER FIT FROPA TIMING. BY WEDNESDAY NIGHT...POPS WILL INCREASE FROM WEST TO EAST AS THE FRONT CROSSES WESTERN AND NORTH CENTRAL NEBRASKA. AS WAS THE CASE YESTERDAY...WEAKER CAPPING AND BETTER FORCING REMAINS ACROSS SOUTH DAKOTA AND NORTHERN NEBRASKA...AND WILL CONTINUE HIGHER POPS OVER NRN NEBRASKA. ON THURSDAY...THE UPPER PATTERN WILL AMPLIFY AS A TROUGH OF LOW PRESSURE LIFTS INTO THE CENTRAL ROCKIES. EAST OF THIS FEATURE...A MID LEVEL WARM FRONT WILL LIFT NORTH ACROSS NORTHERN NEBRASKA...INCREASING THE THREAT FOR PCPN IN THE CENTRAL AND EASTERN FORECAST AREA. THURSDAY NIGHT THROUGH MONDAY...THE MAIN FORECAST CHALLENGE IN THE EXTENDED IS PRECIPITATION CHANCES IN ASSOCIATION WITH A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE WHICH TRACKS ACROSS THE CENTRAL PLAINS FRIDAY INTO SATURDAY. BOTH THE GFS AND ECMWF SOLUTIONS SLOW THE PROGRESSION OF A POTENT UPPER LEVEL LOW FRIDAY INTO SATURDAY. THE GFS HAS A MORE SRN TRACK...TAKING THIS FEATURE FROM SWRN NEBRASKA INTO NERN NEBRASKA FROM 00Z SATURDAY THROUGH 12Z SATURDAY. THE ECMWF TRACKS THE SAME FEATURE FROM SWRN SD INTO NERN SD DURING THE SAME TIME PERIOD. THE CANADIAN SOLN IS EVEN SLOWER AND IS A COMPROMISE BETWEEN THE NRN EC AND SRN GFS SOLNS. REGARDLESS OF SOLNS...THE NRN CWA STANDS TO SEE THE BEST CHANCES FOR PCPN FRIDAY INTO FRIDAY NIGHT. FURTHER SOUTH...THERE IS A POTENTIAL FOR A DRY SLOT TO DEVELOP ACROSS SWRN AND SCENTRAL NEBRASKA...AND HAVE KEPT POPS LOW ATTM. THEN THERE IS THE THREAT FOR SNOW...AS THE MODELS ARE GENERATING SNOW ACCUMS WITH THIS SYSTEM. WET BULB ZEROES ARE NOT QUITE COLD ENOUGH ATTM FOR A MENTION OF SNOW...AND WILL KEEP IT OUT OF THE FCST. NO DOUBT PRECIP TYPE COULD CHANGE IF THE MID RANGE MODELS TREND COLDER...IE. TOWARD THE 12Z ECMWF SOLN. SINCE THIS SOLN TRENDED MUCH COLDER THAN THE PVS RUN...WILL HOLD OFF ON ANY SNOW MENTION AND CONTINUE TO MONITOR THE MID RANGE MODEL TRENDS. WINDS WILL BE STRONG WITH THIS SYSTEM...ESPECIALLY ON THE BACK SIDE OVERNIGHT FRIDAY NIGHT INTO SATURDAY. THE ECMWF HAS 50+ KT H85 WINDS...WHILE THE GFS HAS 70+ KT WINDS DURING THE PERIOD. EVEN WITHOUT ANY WINTRY PCPN...SOME SORT OF WIND HEADLINE APPEARS LIKELY FRIDAY NIGHT INTO SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 659 PM CDT MON SEP 30 2013 VFR IS EXPECTED OVERNIGHT AND TUESDAY. A COLD FRONT...CURRENTLY MOVING THROUGH RAPID CITY...WILL MOVE THROUGH THE FCST AREA TONIGHT. THIS FRONT COULD PRODUCE GUSTY WINDS TO 40 MPH AS IT MOVES THROUGH NRN NEB THIS EVENING. THE EXTENT OF THE WINDS IS SOMEWHAT UNCERTAIN AS THE HRRR AND RAP MODELS SHOWS MUCH WEAKER WIND GUSTS. WEAK PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE FCST AREA TUESDAY PRODUCING SCATTERED MIDLEVEL CLOUDS AND LIGHT WINDS. && .FIRE WEATHER... ISSUED AT 331 PM CDT MON SEP 30 2013 A WEAK FRONT WILL MOVE ACROSS NEBRASKA OVERNIGHT WHICH WILL BRING SLIGHTLY COOLER AIR TO THE AREA FOR WEDNESDAY. DEWPOINTS WILL STAY FAIRLY SIMILAR TO READINGS OBSERVED TODAY...BUT WITH THE COOLER TEMPERATURES DON/T EXPECT RELATIVE HUMIDITY TO FALL BELOW 20 PERCENT ON TUESDAY. ALSO...WINDS SHOULD BE FAIRLY LIGHT TO KEEP CONCERNS FOR FIRE WEATHER LOW. WINDS WILL BE STRONGER AGAIN ON WEDNESDAY AS SOUTHERLY WINDS WILL BRING WARMER AIR BACK INTO THE REGION. THESE WINDS WILL ALSO BRING MORE MOISTURE NORTHWARD...SO RELATIVE HUMIDITY IS NOT EXPECTED TO DROP TO CRITICAL LEVELS. THEN FOR THE SECOND PART OF THE WEEK FIRE WEATHER CONCERNS WILL STAY LOW AS A STRONG STORM SYSTEM WILL IMPACT THE REGION BRINGING CHANCES FOR RAIN...THUNDERSTORMS...STRONG WINDS...AND COLDER TEMPERATURES && .LBF WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL MIDNIGHT CDT /11 PM MDT/ TONIGHT FOR NEZ004-005-094. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...CLB AVIATION...CDC FIRE WEATHER...BROOKS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
659 PM CDT MON SEP 30 2013 .SYNOPSIS... ISSUED AT 331 PM CDT MON SEP 30 2013 AN ACTIVE H5 PATTERN CONTINUES ACROSS CANADA AND THE NRN TIER OF THE CONUS TDY. A STRONG UPPER LEVEL DISTURBANCE WAS LOCATED OVER CENTRAL SASKATCHEWAN WITH DECENT HT FALLS NOTED OVER CENTRAL MANITOBA THIS MORNING. A TANDEM OF UPPER LEVEL LOWS WERE PRESENT OVER THE GULF OF ALASKA AND OVER THE COAST OF CENTRAL BRITISH COLUMBIA. A 70+KT JET STREAK EXTENDED FROM 500 MILES WEST OF WASHINGTON STATE...INTO OREGON AND IDAHO. FURTHER EAST...A RIDGE EXTENDED FROM BERMUDA NORTH INTO NEWFOUNDLAND. AT THE SURFACE...A TIGHT PRESSURE GRADIENT WAS NOTED OVER WYOMING ATTM...WITH HIGH PRESSURE OVER THE FOUR CORNERS AND A SURFACE TROUGH OVER MT. STRONG WESTERLY AND SOUTHWESTERLY WINDS HAVE DEVELOPED OVER WYOMING THIS AFTERNOON AND SOME OF THIS WIND HAS PUSHED EAST INTO THE NEBRASKA PANHANDLE AND NWRN NEBRASKA WITH WINDS GUSTING TO 35 MPH AT VALENTINE. AT 3 PM CDT...TEMPERATURES WERE IN THE UPPER 80S ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 OVER THE NEXT 24 HOURS...A WEAK COLD FRONT WILL PUSH THROUGH WESTERN AND NORTH CENTRAL NEBRASKA AS A DISTURBANCE AND TRACKS ALONG THE US/CANADIAN BORDER. CAA WILL BE FAIRLY WEAK BEHIND THIS FEATURE...SO WINDS WILL BE FAIRLY LIGHT WITH THE FROPA...AND THIS WILL LIMIT MIXING...ALLOWING TEMPS TO FALL BACK INTO THE 40S FOR LOWS TONIGHT. FOR TUESDAY...WEAK HIGH PRESSURE WILL TRACK INTO NORTHEASTERN NEBRASKA. LIGHT EASTERLY WINDS WILL TRANSITION TO THE SOUTHEAST LATE IN THE DAY. TEMPERATURES FOR TUESDAY WILL RUN 10 TO 15 DEGREES COOLER THAN TODAYS HIGHS...WITH HIGHS FORECAST TO RANGE FROM THE LOWER 70S IN THE NORTHEAST TO NEAR 80 IN THE FAR SOUTHWEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 331 PM CDT MON SEP 30 2013 TUESDAY NIGHT THROUGH THURSDAY...IN THE MID RANGE...THE MAIN FORECAST CHALLENGE IS TEMPERATURES AND THUNDERSTORM CHANCES WEDNESDAY NIGHT INTO THURSDAY. FOR TUESDAY NIGHT...HIGH PRESSURE WILL BUILD EAST INTO THE UPPER MISSISSIPPI VALLEY INCREASING SRLY FLOW OVERNIGHT AND LEADING TO MILD LOWS IN THE LOWER 50S. DID INCLUDE SOME UPPER 40S IN EASTERN AREAS...AS WINDS WILL BE LIGHTER DURING THE LATE EVENING HOURS...AND LOWS MAY ACTUALLY BE MET WELL BEFORE SUNRISE. FOR WEDNESDAY...INCREASING SRLY WINDS WILL PUSH LOW LEVEL MOISTURE NWD INTO ALL OF THE FORECAST AREA WITH THE EXCEPTION OF THE PANHANDLE. BY AFTERNOON...A FRONTAL BOUNDARY WILL APPROACH THE NORTHWEST...INCREASING THE THREAT FOR THUNDERSTORMS. THE CAVEAT HERE IS CAP STRENGTH...WHICH MAY BE TOO STRONG INITIALLY ACROSS NORTH CENTRAL NEBRASKA TO FACILITATE CONVECTIVE INITIATION. INHERITED FCST HAS A NARROW BAND OF SLIGHT CHANCE POPS WEDS AFTERNOON IN THE CENTRAL AND NORTH CENTRAL ZONES. THIS AREA OF INHERITED POPS WAS BASED ON THE FRONTAL POSN IN LAST MONTH/S MODEL RUNS. GIVEN THE FRONT IS SLOWER NOW...SHIFTED POPS FURTHER NORTHWEST TO BETTER FIT FROPA TIMING. BY WEDNESDAY NIGHT...POPS WILL INCREASE FROM WEST TO EAST AS THE FRONT CROSSES WESTERN AND NORTH CENTRAL NEBRASKA. AS WAS THE CASE YESTERDAY...WEAKER CAPPING AND BETTER FORCING REMAINS ACROSS SOUTH DAKOTA AND NORTHERN NEBRASKA...AND WILL CONTINUE HIGHER POPS OVER NRN NEBRASKA. ON THURSDAY...THE UPPER PATTERN WILL AMPLIFY AS A TROUGH OF LOW PRESSURE LIFTS INTO THE CENTRAL ROCKIES. EAST OF THIS FEATURE...A MID LEVEL WARM FRONT WILL LIFT NORTH ACROSS NORTHERN NEBRASKA...INCREASING THE THREAT FOR PCPN IN THE CENTRAL AND EASTERN FORECAST AREA. THURSDAY NIGHT THROUGH MONDAY...THE MAIN FORECAST CHALLENGE IN THE EXTENDED IS PRECIPITATION CHANCES IN ASSOCIATION WITH A STRONG UPPER LEVEL TROUGH OF LOW PRESSURE WHICH TRACKS ACROSS THE CENTRAL PLAINS FRIDAY INTO SATURDAY. BOTH THE GFS AND ECMWF SOLUTIONS SLOW THE PROGRESSION OF A POTENT UPPER LEVEL LOW FRIDAY INTO SATURDAY. THE GFS HAS A MORE SRN TRACK...TAKING THIS FEATURE FROM SWRN NEBRASKA INTO NERN NEBRASKA FROM 00Z SATURDAY THROUGH 12Z SATURDAY. THE ECMWF TRACKS THE SAME FEATURE FROM SWRN SD INTO NERN SD DURING THE SAME TIME PERIOD. THE CANADIAN SOLN IS EVEN SLOWER AND IS A COMPROMISE BETWEEN THE NRN EC AND SRN GFS SOLNS. REGARDLESS OF SOLNS...THE NRN CWA STANDS TO SEE THE BEST CHANCES FOR PCPN FRIDAY INTO FRIDAY NIGHT. FURTHER SOUTH...THERE IS A POTENTIAL FOR A DRY SLOT TO DEVELOP ACROSS SWRN AND SCENTRAL NEBRASKA...AND HAVE KEPT POPS LOW ATTM. THEN THERE IS THE THREAT FOR SNOW...AS THE MODELS ARE GENERATING SNOW ACCUMS WITH THIS SYSTEM. WET BULB ZEROES ARE NOT QUITE COLD ENOUGH ATTM FOR A MENTION OF SNOW...AND WILL KEEP IT OUT OF THE FCST. NO DOUBT PRECIP TYPE COULD CHANGE IF THE MID RANGE MODELS TREND COLDER...IE. TOWARD THE 12Z ECMWF SOLN. SINCE THIS SOLN TRENDED MUCH COLDER THAN THE PVS RUN...WILL HOLD OFF ON ANY SNOW MENTION AND CONTINUE TO MONITOR THE MID RANGE MODEL TRENDS. WINDS WILL BE STRONG WITH THIS SYSTEM...ESPECIALLY ON THE BACK SIDE OVERNIGHT FRIDAY NIGHT INTO SATURDAY. THE ECMWF HAS 50+ KT H85 WINDS...WHILE THE GFS HAS 70+ KT WINDS DURING THE PERIOD. EVEN WITHOUT ANY WINTRY PCPN...SOME SORT OF WIND HEADLINE APPEARS LIKELY FRIDAY NIGHT INTO SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 659 PM CDT MON SEP 30 2013 VFR IS EXPECTED OVERNIGHT AND TUESDAY. A COLD FRONT...CURRENTLY MOVING THROUGH RAPID CITY...WILL MOVE THROUGH THE FCST AREA TONIGHT. THIS FRONT COULD PRODUCE GUSTY WINDS TO 40 MPH AS IT MOVES THROUGH NRN NEB THIS EVENING. THE EXTENT OF THE WINDS IS SOMEWHAT UNCERTAIN AS THE HRRR AND RAP MODELS SHOWS MUCH WEAKER WIND GUSTS. WEAK PACIFIC HIGH PRESSURE WILL BUILD THROUGH THE FCST AREA TUESDAY PRODUCING SCATTERED MIDLEVEL CLOUDS AND LIGHT WINDS. && .FIRE WEATHER... ISSUED AT 331 PM CDT MON SEP 30 2013 A WEAK FRONT WILL MOVE ACROSS NEBRASKA OVERNIGHT WHICH WILL BRING SLIGHTLY COOLER AIR TO THE AREA FOR WEDNESDAY. DEWPOINTS WILL STAY FAIRLY SIMILAR TO READINGS OBSERVED TODAY...BUT WITH THE COOLER TEMPERATURES DON/T EXPECT RELATIVE HUMIDITY TO FALL BELOW 20 PERCENT ON TUESDAY. ALSO...WINDS SHOULD BE FAIRLY LIGHT TO KEEP CONCERNS FOR FIRE WEATHER LOW. WINDS WILL BE STRONGER AGAIN ON WEDNESDAY AS SOUTHERLY WINDS WILL BRING WARMER AIR BACK INTO THE REGION. THESE WINDS WILL ALSO BRING MORE MOISTURE NORTHWARD...SO RELATIVE HUMIDITY IS NOT EXPECTED TO DROP TO CRITICAL LEVELS. THEN FOR THE SECOND PART OF THE WEEK FIRE WEATHER CONCERNS WILL STAY LOW AS A STRONG STORM SYSTEM WILL IMPACT THE REGION BRINGING CHANCES FOR RAIN...THUNDERSTORMS...STRONG WINDS...AND COLDER TEMPERATURES && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CLB SHORT TERM...CLB LONG TERM...CLB AVIATION...CDC FIRE WEATHER...BROOKS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1149 PM CDT MON SEP 30 2013 .UPDATE... ISSUED AT 1148 PM CDT MON SEP 30 2013 THE COLD FRONT HAS MOVED INTO THE NORTHWESTERN CWA...ALONG WITH SOME SHOWERS. BUFKIT SOUNDINGS SHOW A FAIRLY DECENT DRY LAYER BELOW 700MB. WITH RAIN FALLING INTO THAT DRY LAYER AND EVAPORATING...WINDS HAVE BECOME QUITE GUSTY WITH KDVL GOING UP MORE THAN 40 KTS BRIEFLY. HOWEVER...WINDS GO DOWN VERY QUICKLY AFTER THE SHOWERS AND FRONT PASS...SO WILL JUST COVER WITH A NOWCAST AND LEAVE OUT ADVISORY FOR NOW. WINDS SHOULD BE SOMEWHAT LESS AFTER MIDNIGHT AS THE BOUNDARY LAYER FURTHER DECOUPLES. BETTER WINDS TOMORROW AFTERNOON WITH DECENT MIXING. MADE A FEW ADDITIONAL TWEAKS TO POPS FOR TIMING...BUT KEPT 20-30 MAINLY AFTER MIDNIGHT AS RADAR LOOP AND SHORT RANGE MODELS CONTINUE TO SHOW A WEAKENING TREND. UPDATE ISSUED AT 910 PM CDT MON SEP 30 2013 ADJUSTED POPS UPWARDS IN THE NORTHWESTERN COUNTIES FOR THE REST OF THE EVENING AS SHOWERS BEHIND THE FRONT IN NORTH CENTRAL ND CONTINUE TO PUSH EASTWARD. FURTHER SOUTH...ACTIVITY IS MORE WIDELY SCATTERED SO KEPT POPS LOW IN SOUTHEASTERN ND. THINK THAT THE SHOWERS SHOULD DROP A TENTH OR SO OF PRECIP BEFORE WEAKENING AND MOVING OFF TO THE NORTHEAST TOWARDS MORNING. WINDS WILL CONTINUE TO BE FAIRLY BREEZY OVERNIGHT AS THE FRONT MOVES THROUGH...BUT MIXING AND PRESSURE GRADIENT WILL TOP OUT DURING THE AFTERNOON HOURS SO WILL CONTINUE TO KEEP ADVISORY GOING FOR TOMORROW. UPDATE ISSUED AT 641 PM CDT MON SEP 30 2013 RADAR LOOP SHOWS A BIT MORE ACTIVITY IN SOUTHWESTERN ND AND NORTHWESTERN SD ALONG THE APPROACHING COLD FRONT THAN EXPECTED. NAM AND RAP STILL HAVE MOST OF THE PRECIP IMPACTING OUR NORTHERN COUNTIES...BUT DO NOT SEEM TO HAVE INITIALIZED WELL. HRRR HAS SOME SHOWERS ENTERING THE SOUTHERN CWA...MAINLY AFTER MIDNIGHT. INCLUDED AN ISOLATED MENTION ACROSS PORTIONS OF THE CWA AS NO SHORT RANGE MODEL SEEMS TO BE HANDLING CURRENT PRECIP VERY WELL. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 315 PM CDT MON SEP 30 2013 THE MAIN CHALLENGE WILL BE PRECIP CHANCES AND HIGH WINDS TOMORROW. MODELS ARE IN DECENT AGREEMENT THROUGH THU...WITH SOME DIFFERENCES THEREAFTER WITH A LARGE STORM BY THE WEEKEND. WILL USE A GFS/NAM BLEND FOR THE FIRST 4 DAYS OF THE FORECAST. FOR TONIGHT...EXPECT SOME SHOWERS MOVING ACROSS THE NORTHERN 1/3 OF THE AREA. A SHORTWAVE AND ASSOCIATED LARGE SCALE LIFT/SATURATION SHOULD PRODUCE A BAND OF SHOWERS IN THE NORTH. A COLD FRONT WILL ALSO MOVE IN BEHIND THE SHOWERS...AND WINDS SHOULD BECOME WESTERLY LATE AND INCREASE TOWARDS MORNING. ON TUE...EXPECT A VERY WINDY DAY WITH 40-45KT TO MIX EFFICIENTLY FROM THE WEST. A DEEP ADIABATIC LAYER UP TO AROUND 800MB WILL DEVELOP FROM WEST TO EAST BY 15Z...AND EXPECT WINDS FROM 30 TO 40 MPH WITH GUSTS TO AROUND 45 MPH POSSIBLE IN THE NORTHERN 2/3 OF THE FORECAST AREA. GIVEN THE HIGH CONFIDENCE STRONG WINDS...WE WILL ISSUE A WIND ADVISORY FOR ALL BUT THE SOUTHERN FORECAST AREA FROM 15Z-00Z TOMORROW. TEMPS WILL BE COOLER THAN TODAY AND BE AROUND NORMAL FOR THE FIRST DAY OF OCTOBER. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 PM CDT MON SEP 30 2013 FOR WED/THU...EXPECT INCREASING CHANCES FOR SHOWERS WITH PWATS INCREASING OVER AN INCH BY LATE WED NIGHT. THERE WILL ALSO BE A THREAT FOR ELEVATED THUNDER IN THE SOUTH WED NIGHT/THU AND WILL MENTION...WITH SHOWALTERS AROUND -2C AND STRONG LIFT NEAR THE WARM FRONT. TEMPS WILL BE COOL WITH CLOUDS AND PRECIP...AND IT MAY BE EVEN COLDER THU IF WE DON/T SEE ANY INSOLATION. FRIDAY TO MONDAY... WIDE SPREAD IN MORNING MODELS SOLNS FOR THE WEEKEND PERIOD. UNCERTAINTY ABOUNDS WITH STRENGTH AND EVOLUTION OF UPPER LEVEL TROUGH AS IT MOVES OUT OF INTERMOUNTAIN WEST AND INTO THE PLAINS FRIDAY. ECMWF WRAPS THE SYSTEM UP WITH A UPPER AND SFC LOW TRACK FROM NEBRASKA PANHANDLE TO THE MN ARROWHEAD BY SUN 12Z...PRODUCING A RAIN SNOW MIX. WHEREAS THE GEM/GFS TAKE A LESS INTENSE AND MORE WEST TO EAST TRACK AND CENTER THE LOW SUN MORNING IN SOUTHERN OR EASTERN WISCONSIN. NONETHELESS GIVEN THE SW FLOW AND AMPLE MOISTURE AHEAD OF THE SYSTEM A POTENTIALLY WET AND COOL FEW DAYS IN STORE WITH SIGNIFICANT RAINFALLS...HARVEST DELAYING... ACROSS THE SOUTHERN HALF OF FA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1148 PM CDT MON SEP 30 2013 VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD. WINDS WILL BE THE MAIN ISSUE. THE COLD FRONT MOVING IN WILL BRING A BRIEF INCREASE TO AROUND 20 KTS WITH GUSTS ABOVE 30 KTS. INCREASED WINDS RIGHT AFTER 00Z AT KGFK...KTVF...AND KFAR BUT THINK THAT THEY WILL GO DOWN FAIRLY QUICKLY AS KDVL HAS ALREADY INCREASED AND GONE BACK DOWN TO 6 KTS. MORE SUSTAINED STRONG WEST WINDS WILL GET GOING BY LATE MORNING AND AFTERNOON TOMORROW. WINDS WILL BEGIN TO TAPER OFF AFTER SUNSET. && .FIRE WEATHER... ISSUED AT 315 PM CDT MON SEP 30 2013 A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING AND TONIGHT...USHERING IN COOLER AND WINDY CONDITIONS FOR TUESDAY. TEMPERATURES WILL RANGE FROM THE MID 60S TO LOWER 70S. WESTERLY WINDS ARE EXPECTED TO BE FROM 25 TO 35 MPH...WITH GUSTS APPROACHING 45 MPH. DRIER AIR AND COOLER TEMPERATURES ON TUESDAY WILL DROP MINIMUM HUMIDITIES AGAIN INTO THE 30 TO 35 PERCENT RANGE...WITH SOME POCKETS OF 25 TO 30 PERCENT VALUES. CURRENT FIRE DANGER RATINGS ARE LOW FOR MINNESOTA...WITH LOW TO MEDIUM RATINGS IN EASTERN NORTH DAKOTA. HOWEVER...CONSIDERING THE FACTORS...INCLUDING THE POTENTIAL FOR DRY AIR AND VERY GUSTY WINDS...EXPECT NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS THE FORECAST AREA FOR TUESDAY. WILL HAVE TO MONITOR CONDITIONS FOR ANY POSSIBLE CHANGES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR NDZ006>008- 014>016-024-026>030-038-039-054. MN...WIND ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR MNZ001>009- 013>017-022-023-027. && $$ UPDATE...JR SHORT TERM...DK LONG TERM...JK/DK AVIATION...JR FIRE WEATHER...HOPKINS
AREA FORECAST DISCUSSION
NWS NORMAN OK
1142 PM CDT MON SEP 30 2013 .AVIATION... 06Z TAFS... VFR CONDITIONS THROUGHOUT THE TAF PERIOD. && .PREV DISCUSSION... /ISSUED 839 PM CDT MON SEP 30 2013/ UPDATE... LATEST HRRR STILL INDICATING POTENTIAL FOR PATCHY FOG LATE TONIGHT ACROSS AREAS FROM NEAR THE ARBUCKLES EAST ACROSS SOUTHEAST OKLAHOMA. HAVE EXPANDED FOG WORDING A BIT FURTHER WEST... OTHERWISE FORECAST UNCHANGED. PREV DISCUSSION... /ISSUED 609 PM CDT MON SEP 30 2013/ AVIATION... 0Z TAFS... VFR CONDITIONS THROUGHOUT THE TAF PERIOD. PREV DISCUSSION... /ISSUED 344 PM CDT MON SEP 30 2013/ DISCUSSION... RATHER DRY AIR REMAINS OVER THE FA THIS AFTERNOON...BUT MORE HUMIDITY AIR IS LOCATED ACROSS FAR SOUTHEAST OKLAHOMA AND NORTHEAST TEXAS/GULF COAST. SOME OF THIS AIR WILL BEGIN TO LIFT SLOWLY TO THE NORTH AND WEST TONIGHT INTO TUESDAY WHICH MAY RESULT IN SOME FOG ACROSS OUR FAR SOUTHEAST COUNTIES AND MORE CLOUDS TUESDAY AFTERNOON. BETTER MOISTURE RETURN WILL OCCUR WEDNESDAY...AS MID TO UPPER 60 DEWPOINTS RETURN TO AT LEAST THE EASTERN 1/2 TO 2/3RDS OF OKLAHOMA. THIS SHOULD RESULT IN SOME LOW CLOUD DEVELOPMENT WITH WITH AN OPPORTUNITY FOR A FEW SHOWERS IN SOUTHEAST OKLAHOMA. A RATHER STRONG SYSTEM WILL MOVE ACROSS THE PACIFIC NORTHWEST AROUND MID-WEEK AND THEN ACROSS THE ROCKIES BY THURSDAY/FRIDAY. SURFACE LOW PRESSURE WILL DEEPEN OVER EASTERN COLORADO ON THURSDAY WHICH WILL BRING RATHER WINDY CONDITIONS TO THE SOUTHERN PLAINS. BY MID TO LATE FRIDAY...A COLD FRONT IS EXPECTED TO ENTER FAR NORTHWEST OKLAHOMA. THE EC HAS ADJUSTED TO A SLOWER FRONTAL TIMING AND IS FAIRLY SIMILAR WITH THE GFS. WITH A DECENT AIR MASS IN PLACE...SCATTERED SHOWERS AND STORMS SHOULD DEVELOP ALONG THE FRONT FRIDAY AFTERNOON INTO FRIDAY EVENING/SATURDAY MORNING. THE BEST CHANCE APPEARS TO BE ACROSS SOUTH CENTRAL AND SOUTHEAST OKLAHOMA. A MUCH COOLER AND DRIER AIR MASS WILL OVERSPREAD THE REGION FOR THE WEEKEND WITH RATHER CHILLY OVERNIGHT LOWS SAT/SUN/MON MORNINGS. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 59 87 65 84 / 0 0 0 10 HOBART OK 57 90 63 86 / 0 0 0 10 WICHITA FALLS TX 60 91 64 88 / 0 0 0 10 GAGE OK 53 85 60 84 / 0 0 0 10 PONCA CITY OK 57 86 64 84 / 0 0 0 10 DURANT OK 60 88 67 84 / 0 0 10 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 30/25/25
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND WEDNESDAY ISSUED AT 251 AM CDT TUE OCT 1 2013 STRONG ZONAL FLOW PATTERN OVER NORTHERN TIER OF U.S. WITH 100 KT JET PUSHING INTO LAKE SUPERIOR. COLD FRONT OVER WEST CENTRAL MN TO MOVE THROUGH STATE THIS MORNING. PASSAGE WILL BE DRY...THOUGH SOME STEEP MID LEVEL LAPSE RATES AHEAD OF SYSTEM PRODUCING BROKEN DECK OF CLOUDS OVER NORTHERN HALF OF STATE WITH CIGS MAINLY ABOVE 12K. CLOUDS ARE EXPECTED TO CLEAR THROUGH THE MORNING HOURS. SOUNDINGS SUGGEST MIXING TO BRING CONTINUED WARM TEMPS...GUSTY WEST WINDS AND LOW RH`S BY LATE AFTN. RUC 13 SUGGESTS DEWS OVER THE NORTH DROPPING INTO THE UPPER 20S. SOUNDINGS UPSTREAM SHOW THIS DRIER AIR. HAVE BROUGHT DEWS DOWN THIS AFTN...MODIFYING THEM SLIGHTLY GIVEN MORNING CLOUDS. HIGH PRESSURE SLIDING THROUGH TO OUR SOUTH TO KEEP LIGHT WEST GRADIENT GOING TONIGHT...KEEPING TEMPS FROM REALLY DROPPING. RETURN FLOW TO START ON WED AS LOW PRESSURE APPROACHES FROM THE PLAINS. WARM TEMPS TO CONTINUE...THOUGH WILL SEE SOME COOLING LAKESIDE WITH WIND SHIFT TO THE SOUTH. .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY ISSUED AT 251 AM CDT TUE OCT 1 2013 THE LATEST GFS ENSEMBLE MEAN INDICATES THAT THE DEEP WESTERN NORTH AMERICAN TROUGH WILL SHIFT EAST LATE IN THE WORK WEEK AND OVER THE WEEKEND TO THE GREAT LAKES REGION. MEDIUM RANGE MODELS ARE ON BOARD WITH THIS SCENARIO AND SHOW SIMILAR SOLUTIONS IN REGARDS TO THE TROUGHS TIMING ACROSS THE COUNTRY. THE ECMWF IS BY FAR THE STRONGEST AND FURTHEST NORTH SOLUTION AND HAS SOME SUPPORT FROM THE GFS ENSEMBLE MEAN WHILE THE GFS/GEM HAVE A SOUTHERN/WEAKER TRACK. MODELS ARE TRENDING SLOWER OVER THE PAST 24 HOURS...BUT WITH PLENTY OF DETAILS TO GET SORTED OUT THIS WEEKEND...WILL SIDE WITH A GFS/ECMWF BLEND FOR LATER PERIODS. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...LOW PRESSURE WILL BE EMERGING INTO THE CENTRAL PLAINS LATE WEDNESDAY NIGHT...WHILE A WARM FRONT WILL LIFT NORTHEAST IN CONJUNCTION WITH MID-LEVEL HEIGHT FALLS. THOUGH THERE IS MID-LEVEL FGEN ALONG THE 850MB WARM FRONT...FLOW OVER THE FRONT IS ON THE WEAKER SIDE AND THE COLUMN LOOKS TO HAVE TROUBLE SATURATING. BETTER FORCING/MOISTURE SEEMS TO RESIDE FARTHER WEST OVER THE NORTHERN MISSISSIPPI VALLEY...SO WILL HAVE THE HIGHEST POPS THERE OVER THE WESTERN CWA. THE SURFACE WARM FRONT WILL LIFT A BIT FURTHER NORTH INTO SOUTHERN WISCONSIN ON THURSDAY...OTHERWISE...SYNOPTIC FEATURES DO NOT CHANGE MUCH. STRONGER FGEN WILL WORK NORTHEAST INTO NORTHWEST AND NORTH-CENTRAL WISCONSIN WHERE WILL KEEP THE HIGHEST POPS ONCE AGAIN. THOUGH MID-LEVEL LAPSE RATES ARE POOR...SOME POTENTIAL FOR THUNDER. CHANCES OF PRECIP ARE UNCERTAIN OVER NORTHEAST WISCONSIN...AS THIS AREA WILL BE CLOSER TO THE DRY AIR SOURCE. THINK CHANCES WILL IMPROVE FOR THE AFTERNOON BUT TOUGH TO ADD MORE DETAIL TEMPORALLY. A CLOUDY BUT MILD DAY SOUTH OF NORTH-CENTRAL WISCONSIN WHERE PERIODS OF RAIN WILL OCCUR. THE SURFACE FRONT LIFTS INTO CENTRAL WISCONSIN THURSDAY NIGHT WITH FLOW INCREASING OVER THE BOUNDARY. SEEMS LIKE A GOOD CHANCE FOR PRECIP ACROSS THE REGION. WILL INCREASE POPS A LITTLE. REST OF THE FORECAST...THE LOW PRESSURE SYSTEM WILL START MAKING PROGRESS TO THE NORTHEAST ON FRIDAY WHILE THE WARM FRONT STALLS OUT OVER THE CENTRAL OR SOUTHERN PART OF THE STATE. SHOULD SEE PLENTY OF CLOUD COVER AND OCCASIONAL SHOWER ACTIVITY. THE BULK OF THE PRECIPITATION HOWEVER...LOOKS TO ARRIVE FRIDAY NIGHT INTO SATURDAY WHEN THE LOW TRACKS TOWARDS THE NORTHERN MISSISSIPPI VALLEY FOLLOWED BY THE COLD FRONT MOVING THROUGH. THE UPPER LOW TRAVERSES ACROSS THE REGION SATURDAY NIGHT AND SUNDAY. COOLER AIR WILL BE FILTERING IN BY THIS TIME BEHIND THE FRONT...AND WILL SEE PLENTY OF CLOUDY...SHOWERY WEATHER TOO. HAVE LOWERED HIGH TEMPS ON SUNDAY WITH COLLAB FROM OTHER OFFICES. TEMPS WILL REBOUND ON MONDAY AHEAD OF A REINFORCING NORTHERN STREAM SYSTEM...BUT MOISTURE WILL BE LIMITED SO NO POPS EXPECTED. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1027 PM CDT MON SEP 30 2013 VFR CONDITIONS WILL PREVAIL THE REST OF TONIGHT INTO TUESDAY NIGHT. LOW LEVEL WIND SHEAR CONDITIONS EXPECTED TO DEVELOP OVERNIGHT WITH 1500 FEET AGL WINDS FROM 240 DEGREES AT 35 KNOTS. EXPECT LLWS CONDITIONS TO END AROUND 14Z. A WEAK COLD FRONT SLIDING OVER THE REGION BETWEEN BETWEEN 14-20Z ON TUESDAY WILL BE DRY BUT WILL PRODUCE GUSTY SOUTHWEST TO WEST WINDS 15 TO 25 KNOTS BEFORE SUBSIDING LATE TUESDAY AFTERNOON OR EARLY TUESDAY EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....TE LONG TERM......MPC AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT MON SEP 30 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 327 PM CDT MON SEP 30 2013 AT 3 PM...A COLD FRONT WAS LOCATED FROM MINOT NORTH DAKOTA TO HURON SOUTH DAKOTA. MEANWHILE FURTHER SOUTHEAST A 1018 MB HIGH WAS CENTERED OVER THE TENNESSEE VALLEY. IN BETWEEN THESE TWO SYSTEMS... THERE IS A TIGHT PRESSURE GRADIENT LOCATED FROM EASTERN NEBRASKA NORTHEAST INTO UPPER MICHIGAN. THIS WAS PRODUCING SUSTAINED SOUTH WINDS IN THE 15 TO 25 MPH RANGE AND WIND GUSTS UP TO 35 MPH. FOR THIS EVENING...BOTH THE RAP AND GFS SOUNDINGS SUGGEST THAT WIND GUSTS WILL DROP OFF QUICKLY THIS EVENING. THIS CORRESPONDS TO THE LOSS OF DIURNAL HEATING. MEANWHILE THE NAM/WRF KEEPS THE WINDS GUSTING UP TO 40 MPH THROUGHOUT THE NIGHT. WITH THEM TENDENCY OF THE NAM/WRF BEING TOO HIGH WITH ITS WINDS...OPTED TO FOLLOW THE GFS AND RAP AND END THE WIND GUSTS AROUND 01.00Z. WHILE THE WIND GUSTS WILL BE ENDING...THE SUSTAINED WINDS WILL REMAIN IN THE 10 TO 20 MPH RANGE. FROM LATE TONIGHT THROUGH TUESDAY MORNING...THE MODELS CONTINUE TO SHOW THAT A COLD FRONT WILL MOVE EAST ACROSS THE AREA. WITH SOUNDINGS SHOWING QUITE A BIT OF DRY BELOW 600 MB...EXPECT A SCATTERED TO BROKEN DECK OF MID CLOUDS TO TRANSITION EAST ACROSS THE AREA. THE HIGHEST PROBABILITY OF SEEING THESE CLOUDS WILL BE NORTH OF INTERSTATE 94 DUE TO THE BEST FORCING TRANSITIONING EAST ACROSS NORTHERN MINNESOTA AND NORTHERN WISCONSIN. ON TUESDAY AFTERNOON...850 MB TEMPERATURES WILL BE FAIRLY SIMILAR TO WHAT THEY WERE THIS AFTERNOON...SO EXPECTING LITTLE CHANGE IN HIGH TEMPERATURES ACROSS THE FORECAST AREA. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 327 PM CDT MON SEP 30 2013 ON WEDNESDAY...THE 30.12Z MODELS SHOW QUITE A BIT OF DRY AIR BELOW 700 MB. HOWEVER THE MODELS ALSO SHOW THAT THE WIND SPEEDS ARE GENERALLY LESS THAN 10 KNOTS. THIS WOULD PROHIBIT SOME OF THE POTENTIAL MIXING THAT COULD POTENTIALLY TAKE PLACE. AS A RESULT... WENT WITH THE CONSALL WHICH LOWERS DEW POINTS TO AROUND 40 ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR. THIS IS STILL ABOUT 10 DEGREES HIGHER THAN WHAT SOME OF INDIVIDUAL DETERMINISTIC MODELS HAVE IN THEM. FROM WEDNESDAY NIGHT INTO THURSDAY NIGHT...THE MODELS ARE IN GENERAL AGREEMENT THAT A WARM FRONT WILL LIFT NORTHWARD ACROSS THE AREA. THIS IS IN RESPONSE TO A LONG WAVE 500 MB TROUGH DEVELOPING ACROSS THE WESTERN CONUS. MODERATE 925 TO 850 MB MOISTURE TRANSPORT WILL DEVELOP ACROSS THE AREA. THIS WILL HELP NOT ONLY MOISTEN THE AIR MASS ACROSS THE REGION...BUT HELP PROVIDE SOME ADDITIONAL LIFT FOR THE DEVELOPMENT OF SHOWERS AND SCATTERED THUNDERSTORMS. THE HIGHEST PROBABILITIES LOOK TO BE ACROSS THE NORTHERN 2/3RDS OF MINNESOTA AND NORTHERN HALF OF WISCONSIN. TEMPERATURES WILL HIGHLY TRICKY BASED ON HOW NORTH THE FRONT GETS. SOUTH OF THIS FRONT...TEMPERATURES WILL BE IN THE 70S. MEANWHILE THEY WILL BE IN THE 60S NORTH OF THE FRONT. FROM FRIDAY AFTERNOON THROUGH SATURDAY...THE 30.12Z MODELS HAVE TRANSITIONED MORE TOWARD THE 29.12Z GFS. THEY NOW SHOW THAT A CLOSED LOW WILL APPROACH THE AREA FROM THE CENTRAL PLAINS. AS THIS OCCURS...CYCLOGENESIS WILL DEVELOP ACROSS THE REGION. THIS WILL GREATLY ENHANCE THE MOISTURE TRANSPORT INTO THE REGION. MLCAPES CLIMB INTO THE 1000 TO 1500 J/KG. WHILE THE 0-6 KM SHEAR IS MARGINAL FOR THE DEVELOPMENT OF SUPERCELLS...THE 0-3 KM SHEAR IS FAVORABLE FOR DAMAGING WINDS. THE MAIN QUESTION IS HOW WILL THE SURFACE LOW TRACK THROUGH THE REGION. THE GFS AND GEM ARE THE FURTHEST SOUTHEAST AND WOULD SUGGEST THE BEST CHANCE /ALBEIT SMALL/ OF SEVERE WEATHER WOULD BE IN OUR AREA. MEANWHILE ECMWF WOULD SUGGEST THAT THIS LOW WOULD TRACK FURTHER NORTHWEST. THIS WOULD TRANSITION ANY SEVERE WEATHER THREAT MORE TOWARD SOUTHEAST MINNESOTA AND NORTHEAST WISCONSIN. DEFINITELY A TIME PERIOD...THAT WE WILL HAVE TO WATCH CLOSELY THIS WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY EVENING) ISSUED AT 1100 PM CDT MON SEP 30 2013 WINDS SHOULD STAY IN THE 8-12 KT RANGE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING FRONT...WITH A PASSAGE AT KRST BETWEEN 13-14Z AND NEAR 15Z AT KLSE. MORE IMPORTANTLY IS AN INCREASE IN THE LOW LEVEL WINDS...WITH RAP13/NAM12 BUFKIT SOUNDINGS SHOWING 45-50 KT WINDS IN THE 1-2 KFT LAYER TIL JUST ABOUT FRONTAL PASSAGE TIME. WILL CONTINUE LLWS AT KRST/KLSE. ASIDE FROM THE WIND CONCERNS...VFR CONDITIONS WILL PREVAIL THROUGH TUESDAY EVENING. WITH HIGH PRESSURE BUILDING IN OVERNIGHT TUE...THERE COULD BE A VALLEY FOG THREAT AT KLSE. NUMERICAL GUIDANCE AND SOUNDINGS SUGGEST THAT DRIER AIR MOVING IN POST FRONT WILL KEEP THE T/TD SPREAD LARGE ENOUGH THAT FOG WOULD NOT BE LIKELY. STILL...SOMETHING TO MONITOR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....BOYNE AVIATION.....RIECK