Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 03/08/12


AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
615 AM EST Tue Mar 6 2012 .UPDATE...Aviation section. && .SYNOPSIS... 08Z water vapor and H4 RUC analysis shows northern stream flow carving out a significant trough over the Pacific Northwest coast this morning. This flow then develops downstream ridging over the high plains/Great Lakes before digging yet another trough over the Northeastern States. Further south, flow is more zonal along the northern Gulf coast. WV imagery shows the mid/upper levels overhead are quite dry this morning, and this is confirmed by the 00Z KTLH sounding which shows a dry profile throughout the troposphere and a resulting PW of only around 0.3". The dry column and lack of any synoptic forcing is resulting in clear skies region-wide this early this morning. At the surface, 1035mb high pressure centered over VA/NC extends southwest to control the northern Gulf coast. The ridge center to our north is providing the area with a steady NE breeze this morning. This breeze is keeping the boundary layer mixed, and as a result, our temps are not falling as expected in many locations. It now appears that widespread 30s will be difficult to achieve and will adjust temperatures up the next few hours to better blend with the post-sunrise forecast. && .SHORT TERM (Today through Thursday)... Today and Tonight, Dry and seasonable weather expected across the region. Zonal mid and upper level flow prevails along the northern Gulf coast while at the surface a strong ridge of high pressure slides off the eastern seaboard. Skies will be clear this morning, and then give way to a few fair weather cu during the afternoon, as easterly flow begins to deliver increasing low level Atlantic moisture. Decent diurnal mixing up to around 850mb where temps are 6-7C will allow temps to top out in the upper 60s to lower 70s this afternoon. A tight gradient in place will prevent boundary layer de-coupling tonight and should once again prevent temps from rapidly dropping. Went with a MAV/MET blend for low temps which yields mid/upper 40s inland and generally 50s along the immediate coast. Wednesday/Wednesday Night, Potent trough/upper low will drift eastward over the inter-mountain west and toward the central/southern Plains. In response to these height falls, amplified ridging/heights rises will be experienced over the Gulf and SE states. This mid/upper level ridging will keep our forecast dry and increasingly warm. Skies will generally remain partly cloudy due to the influx of low level Atlantic moisture with high temps creeping up into the low/mid 70s. Along the immediate coast (especially Franklin/Gulf counties) temps will likely hold in the 60s with the flow off the cooler shelf waters. Low temps Wed Night in the 50s. Thursday, Upper level trough and associated surface front will reach the mid/lower MS valley with a round of shower and storms. However, for our region, the protective upper ridge will remain in control and keep rain chances out the forecast. Temperatures will also continue to rise with highs approaching 80 for many inland locations. Similar to Wednesday, a southeast flow off the shelf waters will keep the immediate coast cooler. && .LONG TERM (Friday through next Tuesday)... Overall confidence in this part of the forecast will remain below normal as we continue to see large differences in the solutions presented by various models. Once thing that is certain is that the 00Z operational GFS run appears to be an outlier in its handling of the energy that cuts off over the Desert SW on Thursday. The 05/12Z Euro appears to have support from the latest NAM and also quite a few of the GFS ensemble members in holding that energy in place for a longer period of time than the latest GFS shows. We will try to work the Euro solution into the forecast as much as possible and take a look at the new 00Z Euro before putting on the finishing touches. Overall, we favor a slower evolution in the pattern than indicated by the GFS. We will however see the surface ridge continue to slide slowly south and that will veer our low level winds and bring in increasing moisture toward the end of the week. We will stick with the recent forecasts of returning PoPs to the forecast on Friday and keeping in at least some PoP through the weekend and on into early next week. Temperature will be above normal through the period with lows generally in the 50s to around 60 and highs in the mid to upper 70s. A few spots could reach 80 on Friday, Saturday and Sunday, especially across inland portions of the FL Big Bend. && .AVIATION (THROUGH 12Z WEDNESDAY). VFR conditions are forecast prevail across the area through the TAF period with clear skies holding into the afternoon. East winds will be sustained around 12 knots at times from mid morning on through the afternoon with a few higher gusts possible. Scattered stratocu will move in from the east during the mid to late afternoon hours and persist through the evening. There is a small chance that MVFR ceilings will work into the VLD area late tonight, but confidence was too low to place in the forecast at this time. && .MARINE... A strong area of high pressure will move east to the Carolina coast later today and then off the eastern seaboard Wednesday. Associated with this area of high pressure, a tight gradient will remain in place through the middle of the week. Easterly flow is expected to reach advisory levels at times this morning, and then again tonight into Wednesday morning. Moderate east to southeast flow will continue through Thursday ahead of an approaching frontal system. && .FIRE WEATHER... Red flag conditions are once again forecast for today across most of our FL zones due to a combination of RH below 35 percent and dispersion indices above 75. The RH forecast has come up across the eastern FL Big Bend zones, but it is very close to 35 percent and dispersion indices are higher there. Feel more comfortable leaving the warning in place for these borderline conditions considering the dispersion numbers. An increase in RH will preclude red flag conditions from being reached for the remainder of the week after today and then on through the weekend. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 71 48 75 51 79 / 0 0 0 0 10 Panama City 69 53 71 57 74 / 0 0 0 0 10 Dothan 69 49 73 53 78 / 0 0 0 0 10 Albany 68 47 72 52 78 / 0 0 10 0 10 Valdosta 68 48 73 52 80 / 0 0 10 0 10 Cross City 73 49 77 53 81 / 0 0 0 0 10 Apalachicola 66 53 68 58 71 / 0 0 0 0 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...Red Flag Warning from Noon EST /11 AM CST/ today to 6 PM EST /5 PM CST/ this evening for Calhoun-Central Walton-Coastal Bay- Coastal Dixie-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty- Madison-South Walton-Washington. GM...Small Craft Advisory until 10 AM EST Wednesday for Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM-Coastal waters from Apalachicola to Destin FL out 20 NM- Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM. && $$ Synopsis/Short term/Marine...Mroczka Long Term/Aviation/Fire Wx...Wool
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
335 AM EST Tue Mar 6 2012 .SYNOPSIS... 08Z water vapor and H4 RUC analysis shows northern stream flow carving out a significant trough over the Pacific Northwest coast this morning. This flow then develops downstream ridging over the high plains/Great Lakes before digging yet another trough over the Northeastern States. Further south, flow is more zonal along the northern Gulf coast. WV imagery shows the mid/upper levels overhead are quite dry this morning, and this is confirmed by the 00Z KTLH sounding which shows a dry profile throughout the troposphere and a resulting PW of only around 0.3". The dry column and lack of any synoptic forcing is resulting in clear skies region-wide this early this morning. At the surface, 1035mb high pressure centered over VA/NC extends southwest to control the northern Gulf coast. The ridge center to our north is providing the area with a steady NE breeze this morning. This breeze is keeping the boundary layer mixed, and as a result, our temps are not falling as expected in many locations. It now appears that widespread 30s will be difficult to achieve and will adjust temperatures up the next few hours to better blend with the post-sunrise forecast. && .SHORT TERM (Today through Thursday)... Today and Tonight, Dry and seasonable weather expected across the region. Zonal mid and upper level flow prevails along the northern Gulf coast while at the surface a strong ridge of high pressure slides off the eastern seaboard. Skies will be clear this morning, and then give way to a few fair weather cu during the afternoon, as easterly flow begins to deliver increasing low level Atlantic moisture. Decent diurnal mixing up to around 850mb where temps are 6-7C will allow temps to top out in the upper 60s to lower 70s this afternoon. A tight gradient in place will prevent boundary layer de-coupling tonight and should once again prevent temps from rapidly dropping. Went with a MAV/MET blend for low temps which yields mid/upper 40s inland and generally 50s along the immediate coast. Wednesday/Wednesday Night, Potent trough/upper low will drift eastward over the inter-mountain west and toward the central/southern Plains. In response to these height falls, amplified ridging/heights rises will be experienced over the Gulf and SE states. This mid/upper level ridging will keep our forecast dry and increasingly warm. Skies will generally remain partly cloudy due to the influx of low level Atlantic moisture with high temps creeping up into the low/mid 70s. Along the immediate coast (especially Franklin/Gulf counties) temps will likely hold in the 60s with the flow off the cooler shelf waters. Low temps Wed Night in the 50s. Thursday, Upper level trough and associated surface front will reach the mid/lower MS valley with a round of shower and storms. However, for our region, the protective upper ridge will remain in control and keep rain chances out the forecast. Temperatures will also continue to rise with highs approaching 80 for many inland locations. Similar to Wednesday, a southeast flow off the shelf waters will keep the immediate coast cooler. && .LONG TERM (Friday through next Tuesday)... Overall confidence in this part of the forecast will remain below normal as we continue to see large differences in the solutions presented by various models. Once thing that is certain is that the 00Z operational GFS run appears to be an outlier in its handling of the energy that cuts off over the Desert SW on Thursday. The 05/12Z Euro appears to have support from the latest NAM and also quite a few of the GFS ensemble members in holding that energy in place for a longer period of time than the latest GFS shows. We will try to work the Euro solution into the forecast as much as possible and take a look at the new 00Z Euro before putting on the finishing touches. Overall, we favor a slower evolution in the pattern than indicated by the GFS. We will however see the surface ridge continue to slide slowly south and that will veer our low level winds and bring in increasing moisture toward the end of the week. We will stick with the recent forecasts of returning PoPs to the forecast on Friday and keeping in at least some PoP through the weekend and on into early next week. Temperature will be above normal through the period with lows generally in the 50s to around 60 and highs in the mid to upper 70s. A few spots could reach 80 on Friday, Saturday and Sunday, especially across inland portions of the FL Big Bend. && .AVIATION (THROUGH 06Z WEDNESDAY). VFR conditions will prevail across the forecast area through the TAF period with clear skies holding into the afternoon. East winds will be sustained around 12 knots at times from mid morning on through the afternoon with a few higher gusts possible. Scattered SC will move in from the east during the mid to late afternoon hours and persist through the evening. && .MARINE... A strong area of high pressure will move east to the Carolina coast later today and then off the eastern seaboard Wednesday. Associated with this area of high pressure, a tight gradient will remain in place through the middle of the week. Easterly flow is expected to reach advisory levels at times this morning, and then again tonight into Wednesday morning. Moderate east to southeast flow will continue through Thursday ahead of an approaching frontal system. && .FIRE WEATHER... Red flag conditions are once again forecast for today across most of our FL zones due to a combination of RH below 35 percent and dispersion indices above 75. The RH forecast has come up across the eastern FL Big Bend zones, but it is very close to 35 percent and dispersion indices are higher there. Feel more comfortable leaving the warning in place for these borderline conditions considering the dispersion numbers. An increase in RH will preclude red flag conditions from being reached for the remainder of the week after today and then on through the weekend. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 71 48 75 51 79 / 0 0 0 0 10 Panama City 69 53 71 57 74 / 0 0 0 0 10 Dothan 69 49 73 53 78 / 0 0 0 0 10 Albany 68 47 72 52 78 / 0 0 10 0 10 Valdosta 68 48 73 52 80 / 0 0 10 0 10 Cross City 73 49 77 53 81 / 0 0 0 0 10 Apalachicola 66 53 68 58 71 / 0 0 0 0 10 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...Red Flag Warning from Noon EST /11 AM CST/ today to 6 PM EST /5 PM CST/ this evening for Calhoun-Central Walton-Coastal Bay- Coastal Dixie-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty- Madison-South Walton-Washington. GM...Small Craft Advisory until 10 AM EST Wednesday for Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM-Coastal waters from Apalachicola to Destin FL out 20 NM- Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM. && $$ Synopsis/Short term/Marine...Mroczka Long Term/Aviation/Fire Wx...Wool
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
533 PM CST WED MAR 7 2012 .AVIATION... A STRONG COLD FRONT MOVING THROUGH THE REGION NOW WILL BE EAST OF ALL TAF SITES BY 03Z. A NARROW BAND OF SHRA WILL ACCOMPANY THE FRONT. A CB WAS IN INCLUDED EARLY THIS EVENING AT KDBQ/KMLI/KBRL TO COVER A LOW PROBABILITY OF ISOLATED TSRA. SCATTERED SHRA WITH MAINLY MVFR CIGS WILL TRAIL THE FRONT. AN AREA OF IFR CIGS OVER NORTH CENTRAL IA MAY BRUSH KDBQ LATE THIS EVENING. THE SHRA SHOULD BE EAST OF THE TAF SITES BY 09Z. IF THE SHRA REMAIN LONGER THAN EXPECTED THERE COULD BE A MIX OF LIGHT RN/SN JUST AS THE PRECIPITATION IS ENDING. CIGS TO IMPROVE TO VFR LATE TONIGHT WITH VFR CONDITIONS CONTINUING FOR THE REMAINDER OF THE FORECAST PERIOD. GUSTY NORTHWEST WINDS WILL DEVELOP BEHIND THE FRONT AND CONTINUE INTO THURSDAY AFTERNOON. ..DLF.. && .PREV DISCUSSION... /ISSUED 315 PM CST WED MAR 7 2012/ SYNOPSIS... 12Z UA ANALYSIS HAS A STRONG LLJ RUNNING FROM THE GULF COAST INTO THE NORTHEAST. A STRONG CANADIAN COLD FRONT RAN FROM THE ARROWHEAD OF MINNESOTA INTO SOUTHEAST COLORADO. A VERY PRONOUNCED MOISTURE PLUME WAS OVER THE MID CONUS WITH 850MB DEW POINTS GETTING INTO THE LOW TEENS IN SOUTH TEXAS. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON SHOW A LARGE EXPANSE OF MID CLOUDS WITH LOW CLOUDS ALONG AND BEHIND THE COLD FRONT. RADARS SHOW PRECIPITATION DEVELOPING ALONG AND BEHIND THE FRONT FROM IOWA INTO MINNESOTA. 18Z SFC ANALYSIS HAD A WEAK LOW NEAR KRPD IN NORTHWEST WISCONSIN WITH THE COLD FRONT FROM NEAR THE LOW BACK INTO THE OKLAHOMA PANHANDLE NEAR KGUY. A SUBTLE PRE-FRONTAL TROF RAN FROM NEAR KRST TO KFNB. DEW POINTS AHEAD OF THE FRONT WERE IN THE 40S AND 50S THAT QUICKLY DROP INTO THE 20S AND 30S AND FINALLY TEENS BEHIND THE FRONT. SHORT TERM...TONIGHT AND THURSDAY... GFS MOISTURE INITIALIZATION WAS WAY TOO MOIST AGAIN WITH ERRORS OF 3-5C COMMON IN THE LOWEST LAYERS. THE WRF WAS BETTER BUT STILL TOO MOIST. ALTHOUGH THE RUC WAS SLIGHTLY TOO MOIST...IT WAS DEPICTING QUITE WELL WHAT WAS HAPPENING AND ITS TRENDS WERE USED HEAVILY FOR TONIGHT. THE ECMWF/GEM/UKMET WERE FAVORED FOR THURSDAY. RUC TRENDS COMBINED WITH RECENT RADAR TRENDS INDICATE THAT PRECIP WILL BE MAINLY ALONG/BEHIND THE FRONT. THE WAA TOOL USING THE RUC AT THE 925MB SFC AGREES QUITE WELL ON HOW PRECIP HAS DEVELOPED SO FAR. THUS PRECIP WILL DEVELOP/MOVE INTO THE NORTHWEST CWFA LATE THIS AFTERNOON/EVENING. SOME PRE-FRONTAL SHOWERS MAY OCCUR LATE THIS AFTERNOON WITH PEAK HEATING. PER THE LIFT TOOL...THE BEST CHANCES FOR ANY ISOLATED TSRA WILL BE OVER THE NEXT 4-6 HRS IN THE NORTHWEST PART OF THE CWFA. THUS WILL INCLUDE A MENTION OF ISOLATED THUNDER THERE. ONCE THE COLD FRONT PASSES ANY ONE AREA...TEMPERATURES SHOULD DROP ABOUT 15 DEGREES IN JUST OVER AN HOUR. BETWEEN MID EVENING AND MIDNIGHT AREAL COVERAGE OF THE RAIN WILL EXPAND AS THE FRONT CONTINUES MOVING SOUTHEAST. THE EVENING HOURS WILL BE THE MOST LIKELY TIME PERIOD FOR THE RELATIVELY HEAVIER RAIN AMOUNTS BUT EVEN THAT AMOUNT WILL BE UNDER ONE QUARTER INCH. JUST PRIOR TO MIDNIGHT SOME SNOW MAY MIX IN WITH THE RAIN BEFORE IT ENDS ACROSS THE FAR NORTHWEST CWFA. AT THE VERY WORST A LOCALIZED DUSTING MAY OCCUR. AFTER MIDNIGHT THE RAIN WILL END FROM NORTHWEST TO SOUTHEAST AS CONDENSATION PRESSURE DEFICITS RISE AND THE BETTER FORCING MOVES EAST OF THE CWFA. MOST OF THE CWFA SHOULD BE PRECIPITATION FREE BY SUNRISE. THE INCOMING HIGH PRESSURE MAY ALLOW SKIES TO PARTIALLY CLEAR. LOW TEMPERATURES WILL OCCUR AT OR SHORTLY AFTER SUNRISE THURSDAY. ON THURSDAY...SOME LINGERING SPRINKLES MAY BE SEEN IN THE FAR EAST AND SOUTHEAST PARTS OF THE CWFA BEFORE ENDING BY MID MORNING. HIGH PRESSURE BUILDING IN SHOULD ALLOW SKIES TO CLEAR FURTHER BEFORE HIGH CLOUDS MOVE BACK INTO THE AREA. LOW LEVEL LAPSE RATES ARE REASONABLY STEEP AND SHOULD PROMOTE GOOD MIXING AND RESULT IN ANOTHER BREEZY IF NOT WINDY DAY. HIGH TEMPERATURES SHOULD BE 15-20 DEGREES COLDER BUT STILL ABOVE NORMAL. ..08.. LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY... ABOVE NORMAL TO WELL ABOVE NORMAL WITH LIGHT RAIN CHANCES SUNDAY INTO MONDAY. OVERALL...INITIALIZATION AND VERIFICATION AVERAGE WITH ONCE AGAIN SIGNIFICANT BL PROBLEMS WITH LOW LEVEL THERMAL (TOO COOL) AND MOISTURE FIELDS (TOO HIGH). HI-RES ECMWF HANDLING THIS AND ALSO RUN TO RUN CONTINUITY THE BEST. LIKELY GUIDANCE TEMPERATURES DAYS 3-7 ARE AT LEAST A CATEGORY OR TWO TOO LOW...OR MAY NEED RAISING 3-5 DEGREES FOR HIGHS MOST DAYS. THURSDAY NIGHT...WINDS MAY DECOUPLE UNDER A FAIR SKY...IF SO THEN MINS MAY NEED TO BE TRIMMED BY UP TO 3 DEGREES. THIS WOULD RESULT IN LOWS IN THE LOWER TO MIDDLE 20S. FRIDAY THROUGH SATURDAY...FAIR SKIES AND WARMING TREND. LIGHT SOUTH WINDS AND COPIOUS SUNSHINE TO MAKE FOR COMFORTABLE MARCH WEATHER. HIGHS MAY APPROACH 60S IN SOME SECTIONS ON SATURDAY. MINS SATURDAY AM WITHIN A FEW DEGREES OF 32F AND SUNDAY AM AROUND 40F. SUNDAY AND MONDAY...AREAS OF LIGHT TO POSSIBLY MODERATE RAIN...MOSTLY SUNDAY. HAVE KEPT CHANCE POPS AS TREND HAS BEEN A TRACK A BIT SOUTH THE PAST 3 DAYS. BEST FORCING SOUTH AND SUGGEST TOTAL RAIN AMOUNTS TO BE GENERALLY BELOW A QUARTER INCH MOST LOCATIONS. HIGHS SUNDAY TO BE IMPACTED BY AMOUNT OF CLOUD COVER. SKIES TO CLEAR MONDAY WITH HIGHS WELL INTO THE 60S. MINS SUNDAY AND MONDAY MORNING IN THE 40S MOST LOCATIONS. TUESDAY AND WEDNESDAY...DRY WITH WELL ABOVE NORMAL TEMPERATURES. HIGHS IN THE 60S WITH LOWS IN THE 40S AND LOWER 50S ON THURSDAY MORNING. SOME LOW LEVEL THERMAL FIELDS SUGGEST 70S POSSIBLE ON ONE OR MORE DAYS WITH ENOUGH HEATING FOR LATER SHIFTS TO RECONSIDER. THESE TEMPERATURES ARE 15-20 DEGREES ABOVE NORMAL. ..NICHOLS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1118 AM CST TUE MAR 6 2012 .AVIATION... CLEAR SKIES...BUT WINDY SOUTH TO SOUTHWEST WINDS OF 16 TO 25 KTS...GUSTING TO 26 TO 33 KTS...WILL CONTINUE TO BLOW OVER IOWA AND ILLINOIS THROUGH SUNSET THIS EVENING...FOLLOWED BY LESS GUSTY...BUT STILL SUSTAINED 15 TO 20 KT WINDS OVERNIGHT. AFTER 14Z TOMORROW...STRATUS MAY MOVE OVER ALL SITES..AND THIS COULD BE MVFR...BUT FOR NOW...I WILL ONLY PUT DBQ AT 3000 FT...WITH OTHER SITES AROUND 3500 FT. WINDS WILL AROUND 14 KTS SOUTHWEST TOMORROW...GUSTING TO THE 20 TO 25 KT RANGE. && .PREV DISCUSSION... /ISSUED 652 AM CST TUE MAR 6 2012/ UPDATE... 12Z DVN RAOB SHOWS IMPRESSIVE LOW LEVEL INVERSION... WHICH WHEN MIXED OUT YIELDS TEMPS AROUND 70 DEGS. NO REASON WITH REMAINING SNOW COVER TO QUICKLY ERODE TO THINK THIS WON/T OCCUR... AND SENT UPDATE TO NUDGE UP TEMPS ALL AREAS WITH WIDESPREAD 60S WITH L70S SOUTH. THIS ALSO DEPICTED WELL IN 2M TEMP FCST OF HRRR IN LAST SEVERAL RUNS. COULD END UP BEING WITHIN A FEW DEGS OF RECORDS AT SOME SITES MAINLY SOUTH. THE RECORDS FOR TDY ARE AS FOLLOWS... BRL (72 IN 2005 AND PREVIOUS YRS)... MLI (73 IN 2005) CID (73 IN 2005) AND DBQ (69 IN 2000). PREV DISCUSSION... /ISSUED 319 AM CST TUE MAR 6 2012/ SYNOPSIS... LATEST SFC ANALYSIS PLACES MAIN LOW OVER MT WITH SECONDARY LOWS OVER NW ND AND CENTRAL SD. WARM FRONT EXTENDS SE FROM THE LOWS THROUGH SW IA AND NORTHEAST MO. GUSTY SE WINDS WITH INCREASING MSLP GRADIENT COUPLED WITH LOW LEVEL WARM ADVECTION RESULTING IN NEAR STEADY TEMPS. BUT WARM FRONT ON THE MARCH NWD WITH KIRKSVILLE MO HAVING GONE FROM 34 TO 48 DEGS BETWEEN 06Z- 08Z. FLOW PATTERN ALOFT HAS TEMPORARILY FLATTENED AND IS NEARLY ZONAL BUT IN PROCESS OF BECOMING SOUTHWESTERLY AS SHORTWAVE ENERGY DIVES TOWARD GREAT BASIN. SHORT TERM...TODAY AND TONIGHT... MAIN CONCERNS ARE WITH WINDS AND TEMPS. SFC COLD FRONT TO EMERGE INTO THE PLAINS TDY AND MODELS IN GOOD AGREEMENT ON LAYING OUT THE FRONT FROM NEAR THE ARROWHEAD OF MN THROUGH NW IA BY 12Z WED. THUS CWA WILL RESIDE IN THE PRE-FRONTAL WARM SECTOR ENVIRONMENT THROUGHOUT THE PERIOD CHARACTERIZED BY DRY AND UNSEASONABLY WARM CONDITIONS WITH E/SE WINDS SHIFTING TO SOUTH AND BECOMING QUITE BREEZY TO WINDY AT TIMES WITH STRENGTHENING PRESSURE GRADIENT. THE INITIAL CHALLENGE IS WHETHER HEADLINES FOR WIND NECESSARY. THERE ARE SOME BIG DIFFERENCES IN MIXING HEIGHTS BETWEEN NAM AND GFS WITH BIG IMPLICATIONS TO TEMPS AND WINDS. THE DIFFERENCES MOST LIKELY DUE TO MODELED SNOW COVER WITH 00Z NAM MODELING WIDESPREAD 1.5 TO 2 INCHES BASICALLY NORTH OF HWY 34. CLOSE LOOK AT LATE DAY SATL IMAGE FROM YSTDY SHOWED MAIN BATCH OF SNOW COVER OF 1-2 INCHES IN AREA BOUNDED BY KAWG-KDBQ-KVTI. TEMPS HAVE BEEN JUST ABOVE FREEZING THIS REGION MOST OF NIGHT THUS SOME CONTINUED MELT. BOTTOM LINE... DISCARDING NAM SOLUTION AND SIDING WITH DEEPER MIXED GFS. GFS BUFR SOUNDINGS AND MSLP GRADIENT SUPPORT WINDS GENERALLY 20-30 MPH WITH SOME HIGHER GUSTS. COULD SEE A COUPLE SITES REACH LOW END ADVISORY CRITERIA MAINLY ON SUSTAINED WINDS AOA 30 MPH... WHICH WAS OBSERVED YSTDY IN THE PLAINS... BUT DOESN/T LOOK WIDESPREAD ENOUGH AND MARGINAL ATTIM TO PRECLUDE ANY HEADLINES FOR WIND. GUSTY WINDS AND LOW RH VALUES MAY INCREASE FIRE DANGER FOR DRY GRASS FUELS ELEVATED ABOVE THE MELTING SNOW AND CONTINUE MENTION IN HWO AND GRAPHICAL WX STORY. AS FOR HIGHS... GOING FCST LOOKS GOOD BASED OFF GFS BUFR SOUNDINGS AND PROGGED LOW LEVEL THICKNESS AND VERIFICATION FROM YSTDY IN THE PLAINS. EXPECT WIDESPREAD 60S... WITH COUPLE SITES POSSIBLY NEAR 70 DEGS FAR SOUTH AND FEW 50S FAR N/NE. TNGT... UNSEASONABLY MILD WITH SOUTH WINDS 15 TO 25 MPH AND INCREASE IN CLOUDS SUPPORTING GOING ABOVE GUIDANCE ON MINS. SOME SUGGESTIONS OF MORE WIDESPREAD 50S AND POSSIBLY NEEDING TO RAISE COUPLE MORE DEGS BUT CONTINUE WITH GENERALLY U40S TO L50S. ..05.. LONG TERM...WEDNESDAY THROUGH NEXT MONDAY... PRIMARY FOCUS IS ON RAIN AND THUNDERSTORM CHANCES WED...AND ESPECIALLY WED NIGHT WITH THE COLD FRONTAL PASSAGE. STILL A LARGE DEGREE OF UNCERTAINTY WITH THE NEXT POTENTIAL SYSTEM LATE IN THE WEEKEND. WEDNESDAY CERTAINLY LOOKS TO BE ANOTHER WINDY AND WARM DAY. THE AMOUNT OF LOW LEVEL MOISTURE RETURN IS LIKELY OVERDONE IN THE MODELS...BASED ON RECENT MODEL PERFORMANCE AND REAL TIME VERIFICATION. THUS...SIMILAR TO THE THOUGHTS IN THE PREVIOUS FORECAST...THE POTENTIAL FOR SHOWERS WILL BE LIMITED IN THE EAST...BUT MORE LIKELY IN THE WEST IN THE AFTERNOON AS ISENTROPIC LIFT DEVELOPS AND CONDENSATION PRESSURE DEFICITS LOWER. EVEN WITHOUT WIDESPREAD LOW CLOUDS...INCREASING HIGH LEVEL MOISTURE SHOULD RESULT IN MOSTLY CLOUDY SKIES AND LIMITED INSOLATION. THE PREFRONTAL AIRMASS WILL EASILY SUPPORT TEMPERATURES IN THE UPPER 50S TO UPPER 60S...WHICH COULD POTENTIALLY BE EVEN WARMER IF CLOUD COVER IS THIN. ALL OPERATIONAL MODELS...EXCEPT THE OUTLIER FASTER ECMWF...KEEP THE COLD FRONT NORTHWEST OF THE FORECAST AREA DURING THE DAYTIME. SOUTH TO SOUTHWEST WINDS SHOULD BE AT LEAST IN THE RANGE OF 20 TO 30 MPH RANGE IN THE EAST...AND 15 TO 25 MPH RANGE IN THE WEST CLOSER TO THE APPROACHING FRONT. MODELS CONTINUE TO PORTRAY A WARM AND DRY LAYER AROUND 700 MB ABOVE THE MOISTENING LOW LEVELS...THAT SHOULD LIMIT THE DEPTH OF ANY CONVECTION THAT DEVELOPS AS LOW LEVEL LAPSE RATES STEEPEN. HAVE THUS LIMITED THE POTENTIAL FOR ISOLATED THUNDERSTORMS TO THE WEST IN THE LATE AFTERNOON...WHERE 700 MB TEMPERATURES BEGIN TO COOL. WEDNESDAY NIGHT...WILL CONTINUE CATEGORICAL POPS FOR RAIN AS THE COLD FRONT DRIVES SOUTHEAST THROUGH THE FORECAST AREA. GULF MOISTURE CONVERGING ON THIS BOUNDARY IS SHOWN DRIVING PW VALUES TO AROUND 1 INCH BY 06Z OVER THE FORECAST AREA...AND HIGHER TRENDING ECMWF AND GEM MODEL QPF LOOKS REASONABLE WITH WIDESPREAD HALF INCH EVENT TOTALS. THERE WILL BE A PERIOD OF NEGATIVE THETAE LAPSE RATES OVER ESPECIALLY THE SOUTH IN THE EVENING AND HAVE KEPT ISOLATED THUNDERSTORM WORDING. FORECAST SOUNDINGS CONTINUE TO INDICATE A POTENTIAL FOR A BRIEF PERIOD OF MIXED PRECIPITATION OR PERHAPS LIGHT SNOW ALONG THE BACK EDGE OF THE SYSTEM AS IT WINDS DOWN IN THE NW LATE. HAVE CONTINUED THIS TREND IN THE FORECAST BUT DO NOT ANTICIPATE ANY ACCUMULATIONS. MODELS ARE IN DECENT AGREEMENT WITH THE SURFACE COLD FRONT EXITING THE SOUTHEAST BY SUNRISE...WITH SUNRISE MINS RANGING FROM THE UPPER 20S NORTHWEST TO THE LOWER 40S SOUTHEAST. SOME POST FRONTAL LIGHT RAIN MAY BE LINGERING IN THE SOUTH THU MORNING. OTHERWISE...HIGH PRESSURE BUILDING INTO THE AREA SHOULD PROVIDE MOSTLY CLEAR SKIES AND DAYTIME TEMPERATURES RETURNING CLOSER TO MARCH NORMALS IN THE 40S BOTH THU AND FRI. A DEVELOPING LOW LEVEL RETURN FLOW SHOULD MODERATE TEMPERATURES BACK INTO THE 50S SATURDAY THROUGH MONDAY. OVERALL...MODELS CONTINUE TO ADVERTISE A DEVELOPING UPPER LOW OVER THE SW U.S. LIFTING NORTHEAST TO BRING PRECIPITATION TO THE LOCAL AREA SUNDAY INTO SUNDAY NIGHT. THE GFS CONTINUES TO EXHIBIT THE POOREST RUN TO RUN CONTINUITY...AND ALSO TRENDS FASTER AND MORE SOUTHEASTERLY WITH THE TRACK OF THIS FEATURE. WHILE CONFIDENCE IN ANY GIVEN SOLUTION IS LOW...TRENDS AND CONSENSUS SUPPORT CHANCE POPS FOR RAIN SUNDAY INTO SUNDAY NIGHT...THEN SLIGHT TO LOW END CHANCES INTO MONDAY. ..SHEETS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ ..ERVIN..
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
652 AM CST TUE MAR 6 2012 .UPDATE... 12Z DVN RAOB SHOWS IMPRESSIVE LOW LEVEL INVERSION... WHICH WHEN MIXED OUT YIELDS TEMPS AROUND 70 DEGS. NO REASON WITH REMAINING SNOW COVER TO QUICKLY ERODE TO THINK THIS WON/T OCCUR... AND SENT UPDATE TO NUDGE UP TEMPS ALL AREAS WITH WIDESPREAD 60S WITH L70S SOUTH. THIS ALSO DEPICTED WELL IN 2M TEMP FCST OF HRRR IN LAST SEVERAL RUNS. COULD END UP BEING WITHIN A FEW DEGS OF RECORDS AT SOME SITES MAINLY SOUTH. THE RECORDS FOR TDY ARE AS FOLLOWS... BRL (72 IN 2005 AND PREVIOUS YRS)... MLI (73 IN 2005) CID (73 IN 2005) AND DBQ (69 IN 2000). && .PREV DISCUSSION... /ISSUED 548 AM CST TUE MAR 6 2012/ AVIATION... MAINLY VFR CONDITIONS EXPECTED THROUGH TONIGHT. TIGHTENING MSLP GRADIENT BETWEEN LOW PRESSURE EMERGING INTO THE PLAINS AND DEPARTING HIGH WILL RESULT IN WINDY CONDITIONS WITH SOUTH WINDS 20-30 KTS AND GUSTY BY LATE AM THROUGH AFTN. STRONG INVERSION EARLY THIS AM WILL LEAD TO LLWS POTENTIAL UNTIL MID AM WITH 12Z KDVN RAOB SHOWING 54 KTS FROM 210 DEGS AT 2000 FT AGL. WINDS TO REMAIN GUSTY FROM SOUTH AT 10-20 KTS TNGT. MAY SEE SOME STRATUS DEVELOP AND/OR MOVE INTO EASTERN IA LATE TNGT AS LOW LEVEL MOISTURE AXIS BEGINS TO MAKE INROADS AHEAD OF APPROACHING COLD FRONT. KEPT CIGS IN VFR CAT THOUGH CAN/T RULE OUT SOME MVFR CIGS BUT CONFIDENCE ON LOWER CIGS IS LOW GIVEN THAT MODELS VERIFYING TOO MOIST AND OVERDONE WITH NWD EXTENT OF BETTER LOW LEVEL MOISTURE EARLY THIS AM. PREV DISCUSSION... /ISSUED 319 AM CST TUE MAR 6 2012/ SYNOPSIS... LATEST SFC ANALYSIS PLACES MAIN LOW OVER MT WITH SECONDARY LOWS OVER NW ND AND CENTRAL SD. WARM FRONT EXTENDS SE FROM THE LOWS THROUGH SW IA AND NORTHEAST MO. GUSTY SE WINDS WITH INCREASING MSLP GRADIENT COUPLED WITH LOW LEVEL WARM ADVECTION RESULTING IN NEAR STEADY TEMPS. BUT WARM FRONT ON THE MARCH NWD WITH KIRKSVILLE MO HAVING GONE FROM 34 TO 48 DEGS BETWEEN 06Z- 08Z. FLOW PATTERN ALOFT HAS TEMPORARILY FLATTENED AND IS NEARLY ZONAL BUT IN PROCESS OF BECOMING SOUTHWESTERLY AS SHORTWAVE ENERGY DIVES TOWARD GREAT BASIN. SHORT TERM...TODAY AND TONIGHT... MAIN CONCERNS ARE WITH WINDS AND TEMPS. SFC COLD FRONT TO EMERGE INTO THE PLAINS TDY AND MODELS IN GOOD AGREEMENT ON LAYING OUT THE FRONT FROM NEAR THE ARROWHEAD OF MN THROUGH NW IA BY 12Z WED. THUS CWA WILL RESIDE IN THE PRE-FRONTAL WARM SECTOR ENVIRONMENT THROUGHOUT THE PERIOD CHARACTERIZED BY DRY AND UNSEASONABLY WARM CONDITIONS WITH E/SE WINDS SHIFTING TO SOUTH AND BECOMING QUITE BREEZY TO WINDY AT TIMES WITH STRENGTHENING PRESSURE GRADIENT. THE INITIAL CHALLENGE IS WHETHER HEADLINES FOR WIND NECESSARY. THERE ARE SOME BIG DIFFERENCES IN MIXING HEIGHTS BETWEEN NAM AND GFS WITH BIG IMPLICATIONS TO TEMPS AND WINDS. THE DIFFERENCES MOST LIKELY DUE TO MODELED SNOW COVER WITH 00Z NAM MODELING WIDESPREAD 1.5 TO 2 INCHES BASICALLY NORTH OF HWY 34. CLOSE LOOK AT LATE DAY SATL IMAGE FROM YSTDY SHOWED MAIN BATCH OF SNOW COVER OF 1-2 INCHES IN AREA BOUNDED BY KAWG-KDBQ-KVTI. TEMPS HAVE BEEN JUST ABOVE FREEZING THIS REGION MOST OF NIGHT THUS SOME CONTINUED MELT. BOTTOM LINE... DISCARDING NAM SOLUTION AND SIDING WITH DEEPER MIXED GFS. GFS BUFR SOUNDINGS AND MSLP GRADIENT SUPPORT WINDS GENERALLY 20-30 MPH WITH SOME HIGHER GUSTS. COULD SEE A COUPLE SITES REACH LOW END ADVISORY CRITERIA MAINLY ON SUSTAINED WINDS AOA 30 MPH... WHICH WAS OBSERVED YSTDY IN THE PLAINS... BUT DOESN/T LOOK WIDESPREAD ENOUGH AND MARGINAL ATTIM TO PRECLUDE ANY HEADLINES FOR WIND. GUSTY WINDS AND LOW RH VALUES MAY INCREASE FIRE DANGER FOR DRY GRASS FUELS ELEVATED ABOVE THE MELTING SNOW AND CONTINUE MENTION IN HWO AND GRAPHICAL WX STORY. AS FOR HIGHS... GOING FCST LOOKS GOOD BASED OFF GFS BUFR SOUNDINGS AND PROGGED LOW LEVEL THICKNESS AND VERIFICATION FROM YSTDY IN THE PLAINS. EXPECT WIDESPREAD 60S... WITH COUPLE SITES POSSIBLY NEAR 70 DEGS FAR SOUTH AND FEW 50S FAR N/NE. TNGT... UNSEASONABLY MILD WITH SOUTH WINDS 15 TO 25 MPH AND INCREASE IN CLOUDS SUPPORTING GOING ABOVE GUIDANCE ON MINS. SOME SUGGESTIONS OF MORE WIDESPREAD 50S AND POSSIBLY NEEDING TO RAISE COUPLE MORE DEGS BUT CONTINUE WITH GENERALLY U40S TO L50S. ..05.. LONG TERM...WEDNESDAY THROUGH NEXT MONDAY... PRIMARY FOCUS IS ON RAIN AND THUNDERSTORM CHANCES WED...AND ESPECIALLY WED NIGHT WITH THE COLD FRONTAL PASSAGE. STILL A LARGE DEGREE OF UNCERTAINTY WITH THE NEXT POTENTIAL SYSTEM LATE IN THE WEEKEND. WEDNESDAY CERTAINLY LOOKS TO BE ANOTHER WINDY AND WARM DAY. THE AMOUNT OF LOW LEVEL MOISTURE RETURN IS LIKELY OVERDONE IN THE MODELS...BASED ON RECENT MODEL PERFORMANCE AND REAL TIME VERIFICATION. THUS...SIMILAR TO THE THOUGHTS IN THE PREVIOUS FORECAST...THE POTENTIAL FOR SHOWERS WILL BE LIMITED IN THE EAST...BUT MORE LIKELY IN THE WEST IN THE AFTERNOON AS ISENTROPIC LIFT DEVELOPS AND CONDENSATION PRESSURE DEFICITS LOWER. EVEN WITHOUT WIDESPREAD LOW CLOUDS...INCREASING HIGH LEVEL MOISTURE SHOULD RESULT IN MOSTLY CLOUDY SKIES AND LIMITED INSOLATION. THE PREFRONTAL AIRMASS WILL EASILY SUPPORT TEMPERATURES IN THE UPPER 50S TO UPPER 60S...WHICH COULD POTENTIALLY BE EVEN WARMER IF CLOUD COVER IS THIN. ALL OPERATIONAL MODELS...EXCEPT THE OUTLIER FASTER ECMWF...KEEP THE COLD FRONT NORTHWEST OF THE FORECAST AREA DURING THE DAYTIME. SOUTH TO SOUTHWEST WINDS SHOULD BE AT LEAST IN THE RANGE OF 20 TO 30 MPH RANGE IN THE EAST...AND 15 TO 25 MPH RANGE IN THE WEST CLOSER TO THE APPROACHING FRONT. MODELS CONTINUE TO PORTRAY A WARM AND DRY LAYER AROUND 700 MB ABOVE THE MOISTENING LOW LEVELS...THAT SHOULD LIMIT THE DEPTH OF ANY CONVECTION THAT DEVELOPS AS LOW LEVEL LAPSE RATES STEEPEN. HAVE THUS LIMITED THE POTENTIAL FOR ISOLATED THUNDERSTORMS TO THE WEST IN THE LATE AFTERNOON...WHERE 700 MB TEMPERATURES BEGIN TO COOL. WEDNESDAY NIGHT...WILL CONTINUE CATEGORICAL POPS FOR RAIN AS THE COLD FRONT DRIVES SOUTHEAST THROUGH THE FORECAST AREA. GULF MOISTURE CONVERGING ON THIS BOUNDARY IS SHOWN DRIVING PW VALUES TO AROUND 1 INCH BY 06Z OVER THE FORECAST AREA...AND HIGHER TRENDING ECMWF AND GEM MODEL QPF LOOKS REASONABLE WITH WIDESPREAD HALF INCH EVENT TOTALS. THERE WILL BE A PERIOD OF NEGATIVE THETAE LAPSE RATES OVER ESPECIALLY THE SOUTH IN THE EVENING AND HAVE KEPT ISOLATED THUNDERSTORM WORDING. FORECAST SOUNDINGS CONTINUE TO INDICATE A POTENTIAL FOR A BRIEF PERIOD OF MIXED PRECIPITATION OR PERHAPS LIGHT SNOW ALONG THE BACK EDGE OF THE SYSTEM AS IT WINDS DOWN IN THE NW LATE. HAVE CONTINUED THIS TREND IN THE FORECAST BUT DO NOT ANTICIPATE ANY ACCUMULATIONS. MODELS ARE IN DECENT AGREEMENT WITH THE SURFACE COLD FRONT EXITING THE SOUTHEAST BY SUNRISE...WITH SUNRISE MINS RANGING FROM THE UPPER 20S NORTHWEST TO THE LOWER 40S SOUTHEAST. SOME POST FRONTAL LIGHT RAIN MAY BE LINGERING IN THE SOUTH THU MORNING. OTHERWISE...HIGH PRESSURE BUILDING INTO THE AREA SHOULD PROVIDE MOSTLY CLEAR SKIES AND DAYTIME TEMPERATURES RETURNING CLOSER TO MARCH NORMALS IN THE 40S BOTH THU AND FRI. A DEVELOPING LOW LEVEL RETURN FLOW SHOULD MODERATE TEMPERATURES BACK INTO THE 50S SATURDAY THROUGH MONDAY. OVERALL...MODELS CONTINUE TO ADVERTISE A DEVELOPING UPPER LOW OVER THE SW U.S. LIFTING NORTHEAST TO BRING PRECIPITATION TO THE LOCAL AREA SUNDAY INTO SUNDAY NIGHT. THE GFS CONTINUES TO EXHIBIT THE POOREST RUN TO RUN CONTINUITY...AND ALSO TRENDS FASTER AND MORE SOUTHEASTERLY WITH THE TRACK OF THIS FEATURE. WHILE CONFIDENCE IN ANY GIVEN SOLUTION IS LOW...TRENDS AND CONSENSUS SUPPORT CHANCE POPS FOR RAIN SUNDAY INTO SUNDAY NIGHT...THEN SLIGHT TO LOW END CHANCES INTO MONDAY. ..SHEETS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
800 PM MST WED MAR 7 2012 .UPDATE... ISSUED AT 752 PM MST WED MAR 7 2012 TONIGHT-THURSDAY NIGHT...18Z GFS/NAM/ECWMF AND MOST RECENT 00Z NAM/RUC ALL SHOWING A MORE SOUTHERLY TRACK TO THE 500 LOW CURRENTLY OVER EAST CENTRAL ARIZONA. 850-500 MOISTURE RATHER LACKING TONIGHT EXCEPT ALONG THE HIGHER TERRAIN NEAR FLAGLER IN EASTERN COLORADO BUT THAT WILL BE BRIEF AS IT CONTINUES TO MOVE SOUTH AND OUT OF THE AREA. WILL NEED TO WATCH THE FAR EAST/SOUTHEAST/SOUTH LATE TONIGHT AS RUC ONLY MODEL TO GENERATE SOME LIGHT PRECIP AROUND 09Z DESPITE THE BETTER MOISTURE BEING FURTHER SOUTH. WITH THE MORE SOUTHERN TRACK MORE OF THE FORECAST AREA WILL SEE PLENTIFUL SUNSHINE. WINDS WILL AGAIN BE FROM THE NORTH AT 15 TO 25 MPH. LATEST NAM/SREF 2M TEMPS AND MAV/MET MOS GUIDANCE ALL IN AGREEMENT THAT AFTERNOON TEMPERATURES WILL PEAK GENERALLY IN THE 40S WITH A FEW 50S NEAR NORTON AND HILL CITY. THURSDAY NIGHT...STILL LOOKS DRY. 00Z NAM TRIES TO INCREASE THE LOW AND MID LEVEL MOISTURE ACROSS GREELEY AND WICHITA COUNTIES AS THE UPPER LOW STARTS TO ROTATE INTO NORTHEAST NEW MEXICO/TEXAS PANHANDLE. NOT MANY CHANGES MADE TO GRIDS DURING THIS PERIOD AT PRESENT TIME. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 212 PM MST WED MAR 7 2012 MAIN CONCERN WILL BE POSSIBILITY OF PRECIPITATION AND PRECIPITATION TYPE. IN THE PAST 24 HRS...THERE HAS BEEN MUCH UNCERTAINTY REGARDING PRECIP OVER THE AREA ASSOCIATED WITH THE UPPER TROUGH WEST OF THE REGION...BUT THE GENERAL TREND HAS MADE PRECIP LESS AND LESS LIKELY. BASED ON THIS TREND AND THE LATEST GUIDANCE...HAVE LOWERED PROBABILITIES FURTHER...AND KEPT THE HIGHEST CHANCES NEAREST TO THE TROUGH IN THE SOUTHWESTERN PART OF THE AREA. NAM MODEL SOUNDINGS INDICATE THAT THERE IS STILL POTENTIAL FOR A PERIOD OF FREEZING RAIN IN THE EARLY MORNING IF ANY PRECIP WERE TO FALL...BUT SNOW SHOULD QUICKLY BECOME THE PREDOMINANT PRECIP TYPE AS THE WESTERLY COMPONENT OF WINDS ALOFT MODIFIES THE AIR MASS. AS THE LOW MOVES FURTHER SOUTHEAST DURING THE DAYTIME ON THURSDAY...THE CHANCE FOR PRECIP SHOULD MINIMIZE DURING THE AFTERNOON HOURS. SKIES WILL CLEAR IN THE NORTHERN PORTION OF THE AREA...ALLOWING WARMER TEMPERATURES IN THE NORTH COMPARED TO FURTHER SOUTH. GUSTY NORTHERLY WINDS CAN BE EXPECTED DURING THE DAYTIME DUE TO THE MOVEMENT AND POSITION OF THE TROUGH. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 212 PM MST WED MAR 7 2012 THERE ARE STILL SOME MODEL DIFFERENCES WITH THE UPPER LOW DURING THIS TIMEFRAME. BOTH THE NAM/GFS BRING THE UPPER LOW INTO THE TEXAS PANHANDLE THURSDAY NIGHT/FRIDAY. THE GFS HOLDS THE LOW IN THE TEXAS PANHANDLE FRIDAY NIGHT WHILE THE NAM HAS IT POSITIONED A LITTLE FURTHER NORTH IN THE OKLAHOMA PANHANDLE. BOTH HAVE THE GFS/NAM HAVE THE UPPER LOW OVER THE OKLAHOMA PANHANDLE SATURDAY MORNING. THE GFS TAKES THE LOW INTO CENTRAL KANSAS SATURDAY NIGHT. OTHER THAN THURSDAY EVENING, LATE FRIDAY NIGHT AND SATURDAY BOTH MODELS KEEP THE DYNAMICS/MOISTURE OUTSIDE OF THE FA. FOR THE PERIODS JUST MENTIONED THERE IS SOME VERY MARGINAL MOISTURE OVER THE SOUTHEAST FRINGE OF THE FA. FORECAST SOUNDINGS NEAR THE BEST PLAN VIEW MOISTURE FIELD LOOK VERY DRY SO AM NOT OPTIMISTIC ABOUT ANY MEASURABLE PRECIPITATION. FOR THIS REASON HAVE INCLUDED ONLY SPRINKLES/FLURRIES THURSDAY EVENING AND LATE FRIDAY NIGHT. SOME LIGHT RAIN MAY BE POSSIBLE IN THE FAR EAST SATURDAY MORNING. OTHERWISE THE REMAINING PERIODS ARE DRY WITH NIL POPS. MIN TEMPERATURES WILL MODERATE FROM THE LOWER 20S THURSDAY NIGHT TO THE UPPER 20S/LOWER 30S FRIDAY/SATURDAY NIGHTS. MAX TEMPERATURES WILL GENERALLY REACH THE MID 50S FRIDAY/SATURDAY. FOR SUNDAY - WEDNESDAY...THE GFS SHOWS A RIDGE OVER THE FA SUNDAY FOLLOWED BY WEST SOUTHWESTERLY FLOW MONDAY THROUGH WEDNESDAY. LACK OF ANY SIGNIFICANT SHORTWAVE/FORCING WILL KEEP POPS NIL THROUGH THIS PART OF THE FORECAST. 850MB TEMPERATURES INDICATE THAT MAX TEMPERATURES SHOULD BE ABOUT 10 TO ALMOST 20 DEGREES ABOVE NORMAL IN THE 60S TO AROUND 70. MIN TEMPERATURES IN THE 30S/LOW 40S WILL BE ABOUT 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 420 PM MST WED MAR 7 2012 VFR THROUGH THE PERIOD AT BOTH KGLD AND KMCK. STRATO-CU AT 4000-4500 FT EXPECTED AROUND THE KGLD TERMINAL BUT MORE DIRECTLY IMPACTING THE KMCK TERMINAL THROUGH 06Z OR SO BEFORE AIRMASS SLIDES SOUTH AWAY FROM THE AREA. RAPID CLEARING EXPECTED FROM NORTH TO SOUTH EARLY THURSDAY MORNING WITH ONLY A FEW CIRRUS CLOUDS EXPECTED SHORTLY THEREAFTER. NW-NE WINDS HAVE ALREADY LOST THEIR GUSTS AS OF 23Z AND THROUGH 15Z SHOULD REMAIN IN THE 8-11KT RANGE FROM THE N/NW. AROUND 15Z THURSDAY MIXING/HEATING WILL PRODUCE 15G25KT WINDS FROM THE N. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...007 SHORT TERM...CJS LONG TERM....FS AVIATION...007
AREA FORECAST DISCUSSION
NWS WICHITA KS
536 PM CST WED MAR 7 2012 .UPDATE... ADJUSTED THE SHORT TERM GRIDS TO BETTER REFLECT CURRENT OBSERVATIONS/ TRENDS. APPEARS THAT HRRR HAS BEST HANDLE ON FRONT/TIMING/TEMPERATURES IN THE VERY SHORT TERM...WITH A BLEND INTO THE NAM LATER TONIGHT. WILL LIKELY BE MAKING SOME TWEAKS TO POPS IN A BIT. && .AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS ARE POTENTIAL THUNDERSTORMS THIS EVENING AND MVFR CEILINGS AT KCNU LATER TONIGHT. THERE APPEARS TO BE A NARROW WINDOW OF OPPORTUNITY FOR ELEVATED STORMS TO DEVELOP THIS EVENING AT KICT/KCNU AND POSSIBLY AS FAR NORTH AS KHUT. NAM/RUC MODEL FORECAST HAS 500+ J/G MUCAPE ACROSS SOUTH CENTRAL/SOUTHEAST KS ROUGHLY BETWEEN 03-08 UTC. CEILINGS WILL DECREASE IN THE RAIN AT KCNU WITH MVFR CEILINGS LOOKING LIKELY OVERNIGHT. SOME IMPROVEMENT IS ANTICIPATED ALL SITES DURING THE DAY. -HOWERTON && .PREV DISCUSSION... /ISSUED 317 PM CST WED MAR 7 2012/ DISCUSSION... MAIN FORECAST CONCERN IS THE PRECIPITATION CHANCES THIS EVENING AND LATER THIS WEEK. SYNOPSIS: A POTENT UPPER LEVEL TROUGH IS MOVING EASTWARD ACROSS THE INTER-MOUNTAIN WEST. AT THE SURFACE A COLD FRONT IS MAKING ITS WAY ACROSS KANSAS. AS OF 3PM THE FRONT IS APPROACHING WICHITA WHICH IS A LITTLE AHEAD OF WHAT WAS PREVIOUSLY THOUGHT. TEMPERATURES HAVE SURGED AHEAD OF THE FRONT AIDED BY THE GUSTY SOUTHERLY WINDS. TONIGHT - SATURDAY: THE UPPER TROUGH THAT ENTERED THE GREAT BASIN YESTERDAY HAS SPLIT...WITH THE CUT OFF PORTION LOCATED OVER NORTHERN ARIZONA/SOUTHERN UTAH...AND MOVING SLOWLY THROUGH THE FOUR CORNERS AREA. LEE CYCLOGENESIS HAS A SURFACE LOW CURRENTLY OVER NEW MEXICO WITH THE SURFACE TROUGH FOLLOWING THE COLD FRONT THROUGH KANSAS TO THE GREAT LAKES REGION. GUSTY SOUTH WINDS TODAY HAVE ADVECTED MID TO UPPER 50 DEWPOINTS TO THE SOUTHEASTERN TWO-THIRDS OF THE CWA. AS THIS COLD FRONT MOVES SOUTHEAST THROUGH THE AREA THIS EVENING...SHOWERS AND SCATTERED THUNDERSTORMS ARE LIKELY MAINLY ALONG AND BEHIND THE FRONT. THE LATEST GUIDANCE CONTINUES TO SHOW THAT PRECIPITATION WILL DEVELOP BEYOND 00Z THIS EVENING MAINLY OVER SOUTHEASTERN KANSAS. SUFFICIENT INSTABILITY AND SHEAR MAY SUPPORT A FEW STRONGER STORMS AND HAIL WITH THOSE CELLS...ESPECIALLY NEAR THE KANSAS/OKLAHOMA. NORTHERN EXTENT OF THE PRECIPITATION APPEARS TO BE GREATER WITH THE NAM THAN THE OTHER MODELS...THINK THE PRECIPITATION WILL RESIDE MAINLY OVER SOUTH CENTRAL AND SOUTHEASTERN KANSAS BUT THERE REMAINS A SLIGHT CHANCE OVER CENTRAL KANSAS. THE UPPER LEVEL LOW STALLS OVER THE TEXAS PANHANDLE FOR THURSDAY THROUGH SATURDAY...AND WILL PUSH ANOTHER SURGE OF MOISTURE NORTH THROUGHOUT THE DAY SATURDAY. ONCE AGAIN THE SOUTHEASTERN TWO-THIRDS ARE MORE FAVORED FOR THE PRECIPITATION SATURDAY...BUT THIS WILL HAVE TO BE MONITORED. PRECIP TYPE SHOULD STAY MOSTLY LIQUID FORM...BUT SLIGHT CHANCE THAT SOME COULD BE FREEZING DRIZZLE ON THE NORTHERN FRINGES. LAUGEMAN SUNDAY - WEDNESDAY: THE CUT OFF UPPER LOW WILL BE KICKED EASTWARD BY THE NEXT UPPER LEVEL WAVE MOVING INTO THE NORTHWEST. PRECIPITATION WILL BE POSSIBLE SUNDAY MORNING AS THE UPPER LOW LIFTS OVER THE AREA...BUT CHANCES DO NOT LOOK TO BE HIGH. THE SYSTEM WILL EXIT BY SUNDAY NIGHT AND WHILE ANOTHER DISTURBANCE WILL LIFT OVER US...IT LOOKS TO BE FAR ENOUGH EAST TO KEEP PRECIPITATION CHANCES AT BAY. WARM AIR ADVECTION THROUGH THE BEGINNING OF THE WEEK WILL HELP TEMPERATURES REACH WELL ABOVE NORMAL THROUGH THE PERIOD. BILLINGS FIRE WEATHER... THE GRASSLAND FIRE DANGER INDEX REMAINS VERY HIGH THROUGH THE REST OF THIS AFTERNOON WITH GUSTY SOUTHERLY WINDS AHEAD OF THE FRONT...BUT AS THE WINDS DECREASE THIS EVENING CONDITIONS WILL IMPROVE. BEHIND THE COLD FRONT WINDS WILL AGAIN BE GUSTY DURING THE DAY THURSDAY AND VERY HIGH FIRE DANGER WILL AGAIN BE POSSIBLE ACROSS PORTIONS OF CENTRAL KANSAS. OTHERWISE WITH THE CHANCES FOR PRECIPITATION AND LIGHTER WINDS DURING THE WEEKEND THE FIRE DANGER INDEX WILL MAX OUT IN THE HIGH CATEGORY. BILLINGS AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION CONCERN IS THE STRONG WINDS...COLD FRONT TIMING AND MVFR CONDITIONS POSSIBLE THIS AFTERNOON AND OVERNIGHT. THE COLD FRONT AS OF 18Z HAS JUST REACHED KSLN AND IT WILL CONTINUE A SLOW SOUTHWARD TREK THIS AFTERNOON/EVENING. EXPECT IT TO REACH KICT AFTER 00Z. AHEAD OF THE FRONT SOUTHERLY WINDS ARE VERY STRONG WITH SUSTAINED SPEEDS BETWEEN 25-30 KTS AND GUSTS UPWARDS TO 35-40 KTS. AS THE FRONT APPROACHES AND MOVES THROUGH WINDS WILL DECREASE AND BECOME NORTHERLY. NORTHERLY WINDS WILL BE GUSTY...BUT NOT AS STRONG AS AHEAD OF THE FRONT. CEILINGS ARE BOUNCING AROUND THE MVFR/VFR THRESHOLD IN THE 2500-3500 FT RANGE AHEAD AND BEHIND THE FRONT. HAVE REMAINED SOMEWHAT PESSIMISTIC WITH THE TAF FORECAST IN MVFR. PRECIPITATION CHANCES INCREASE AS THE FRONT MOVES INTO SOUTHERN KANSAS BETWEEN 02-06Z WHERE MOISTURE IS MORE PLENTIFUL. HAVE -SHRA AT KICT AND KCNU WHERE CONFIDENCE IS HIGHEST...WITH VCSH POSSIBLE AT ALL OTHER TERMINALS EXCEPT KRSL. COLDER AIR IS EXPECTED TO PUSH INTO CENTRAL KANSAS...BUT HAVE KEPT FREEZING PRECIPITATION OUT OF THE FORECAST AT THIS TIME AS THAT IS FURTHER OUT IN THE FORECAST AND CONFIDENCE ON THAT FEATURE IS LOW. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 36 45 34 53 / 70 40 20 10 HUTCHINSON 35 46 32 53 / 50 30 20 10 NEWTON 35 46 33 53 / 50 40 10 10 ELDORADO 37 45 33 53 / 70 50 10 10 WINFIELD-KWLD 40 44 35 52 / 80 60 20 10 RUSSELL 31 49 29 54 / 20 10 10 10 GREAT BEND 32 48 29 53 / 20 10 20 10 SALINA 34 48 30 55 / 30 10 10 10 MCPHERSON 34 47 31 54 / 40 30 10 10 COFFEYVILLE 44 47 37 54 / 80 80 20 10 CHANUTE 39 45 34 55 / 80 70 10 10 IOLA 39 45 33 54 / 80 70 10 10 PARSONS-KPPF 42 44 35 54 / 80 70 20 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
236 PM CST TUE MAR 6 2012 ...UPDATED LONG TERM DISCUSSION... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 359 AM CST TUE MAR 6 2012 SYNOPSIS: WATER VAPOR LOOP AND LAST NIGHT`S RAOB ANALYSIS CONFIRMED THE DEVELOPMENT OF SIGNIFICANT MID LEVEL TROUGH OVER THE PACIFIC NORTHWEST REGION. 12-HR 500MB HEIGHT FALLS OF 130-170 METERS WERE OBSERVED OVER WESTERN OREGON AND WASHINGTON. THE BASE OF THIS TROUGH WAS CONTINUING TO DIG SOUTHEAST INTO NORTHERN CALIFORNIA AS OF 09Z THIS MORNING. STRONG WEST-SOUTHWESTERLY MID LEVEL FLOW WAS OCCURRING EAST OF THIS ACROSS THE GREAT BASIN REGION INTO THE ROCKIES. THIS WAS RESULTING IN A LARGE AREA OF LOWER TROPOSPHERIC WARMING WITH LOWER ELEVATION STATIONS ACROSS THE GREAT BASIN/ROCKIES SEEING 850MB TEMPS IN THE MID TO UPPER TEENS. 700MB TEMPERATURES WERE +4 TO +5C ACROSS ARIZONA AND NEW MEXICO. THE FRONT SEPARATING THE COLD, POLAR AIRMASS FROM THE WARM INTERMOUNTAIN WEST AIRMASS WAS POSITIONED FROM SOUTHWESTERN ALBERTA...EAST-SOUTHEASTWARD ALONG THE CANADA-US BORDER TO A WEAK CYCLONIC CENTER AT 850MB NEAR THE MANITOBA BORDER WITH MINNESOTA AND NORTH DAKOTA. STRONG SOUTHERLY FLOW WAS NOTED ACROSS THE SOUTHERN PLAINS BETWEEN THE LEE-SIDE TROUGH AND A GULF OF MEXICO HIGH. TODAY: THE VERY WARM AND DRY LOWER TROPOSPHERIC DOWNSLOPE AIRMASS WILL YIELD ANOTHER UNSEASONABLY WARM DAY ACROSS SOUTHWEST KANSAS. GIVEN THE RESULTS OF YESTERDAY AND AN EVEN WARMER THERMODYNAMIC ENVIRONMENT TODAY...THERE IS MUCH MORE CONFIDENCE IN HIGHS TODAY REACHING 80 DEGREES OVER A GOOD CHUNK OF SOUTHWEST KANSAS...AND HAVE INCREASED THE MAXT GRID AS A RESULT. THE HRRR AND RUC MODELS WERE USED AS THE PRIMARY GUIDANCE IN THE DEWPOINT/RH FORECAST FOR FIRE WEATHER CONCERNS. DEWPOINTS WILL BE VERY LOW ACROSS THE NORTHWESTERN 2/3RDS OF THE FORECAST AREA...IN THE 14 TO 20F RANGE...AS TEMPERATURES RISE INTO THE UPPER 70S/NEAR 80. THIS WILL RESULT IN RELATIVE HUMIDITY DOWN INTO THE 10 TO 15 PERCENT RANGE. THE MAIN QUESTION REGARDING SIGNIFICANCE OF THE CRITICAL FIRE WEATHER THREAT WILL BE WIND SPEED. HIGH RESOLUTION MODELS HAVE TRENDED DOWNWARD IN THE WIND SPEED ACROSS THE VERY LOW RH AREAS FOR THIS AFTERNOON...AND IT APPEARS THAT WIND SPEEDS WILL NOW BE RATHER MARGINAL FOR CRITICAL FIRE WX. THE LATEST FORECAST WILL REFLECT 15 TO 20 MPH WINDS FOR MOST OF THE DAY...WITH 20 TO 25 MPH FOR ONLY A COUPLE HOURS PROBABLY BY LATE AFTERNOON. GUSTS ARE STILL ANTICIPATED TO BE 25 TO 30 MPH. FARTHER EAST WHERE THE MSLP GRADIENT WILL BE TIGHTER...WINDS WILL BE FAIRLY STRONG AND APPROACH WIND ADVISORY CATEGORY. HAVE DECIDED TO NOT ISSUE A WIND ADVISORY IN THE SOUTH CENTRAL KANSAS COUNTIES GIVEN THE UNCERTAINTY IN DEEP MIXING...BUT THE REALLY DEEP MIXING MAY NOT REALLY MATTER MUCH AND WIND ADVISORY LEVEL WINDS (SUSTAINED 30 MPH) MAY STILL BE REACHED ACROSS PRATT-COMANCHE-BARBER COUNTIES. TONIGHT: AS THE UPPER TROUGH CONTINUES TO DIG SOUTHEAST LATE TODAY AND TONIGHT...THE FRONT (MENTIONED IN THE SYNOPSIS PARAGRAPH) WILL BEGIN ITS EQUATORWARD PUSH. THE FRONT IS EXPECTED TO REACH FAR NORTHWEST KANSAS AROUND 09Z TONIGHT. AHEAD OF THE FRONT IN SOUTHWEST KANSAS...WIND SPEEDS WILL STAY FAIRLY STRONG BY NOCTURNAL STANDARDS WITH SPEEDS AVERAGING 20 TO 30 MPH THROUGH MOST OF THE NIGHT...ESPECIALLY THE SOUTHEAST HALF OF THE FORECAST AREA. THIS WILL KEEP TEMPERATURES ABNORMALLY WARM THROUGH THE NIGHT WITH 06-12Z TEMPERATURES IN THE LOWER 50S FOR A GOOD PORTION OF THE FORECAST AREA. LOW LEVEL MOISTURE WILL ALSO BEGIN TO MOVE INTO THE SOUTHEASTERN COUNTIES WITH DEWPOINT TEMPERATURES RISING INTO THE UPPER 40S TO NEAR 50 (PARTICULARLY ACROSS BARBER COUNTY). THE DEVELOPMENT OF LOW STRATUS WILL HAVE TO BE WATCHED...BUT AT THIS TIME THE MAJORITY OF INITIAL LOW LEVEL CLOUD COVER TOWARD DAYBREAK WEDNESDAY WILL BE ACROSS OKLAHOMA AND AREAS OF SOUTH CENTRAL KANSAS JUST EAST OF BARBER COUNTY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 233 PM CST TUE MAR 6 2012 WARM AIR ADVECTION AND ISENTROPIC LIFT IMPROVES ACROSS SOUTH CENTRAL AND MUCH OF SOUTHWEST KANSAS WEDNESDAY NIGHT AS COLDER AIR NEAR THE SURFACE RETURNS BEHIND A COLD FRONT. MODEL SOUNDINGS ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS INDICATING A FAIRLY DEEP LAYER OF LOW LEVEL MOISTURE DEVELOPING BY 12Z THURSDAY...HOWEVER LITTLE MOISTURE IS PRESENT IN THE ICE CRYSTAL GROWTH ZONE. THIS WOULD SUPPORT MORE DRIZZLE/FREEZING DRIZZLE THAN SNOW SO THE MAIN QUESTION WILL BE THE TEMPERATURES NEAR THE SURFACE AS THIS PRECIPITATION FALLS. AT THIS TIME THE NAM WAS COLDER THAN ALL THE MODELS NEAR THE SURFACE AND THE 2 METER TEMPERATURE BETWEEN 18Z THURSDAY AND 00Z FRIDAY SUGGESTED AFTERNOON TEMPERATURES WILL BE AROUND 32 DEGREES FOR MUCH OF WESTERN KANSAS. AM CURRENTLY LEANING TOWARDS THESE COLDER TEMPERATURES THURSDAY AFTERNOON BASED ON EXPECTED CLOUD COVER, POSSIBLE PRECIPITATION AND COLD AIR ADVECTION ADVERTISED BY ALL THE MODELS ACROSS SOUTHWEST KANSAS. BASED ON THESE SURFACE TEMPERATURES LATE WEDNESDAY NIGHT AND THURSDAY THERE APPEARS TO BE CHANCE FOR A PROLONGED PERIOD LIGHT/VERY LIGHT FREEZING DRIZZLE ACROSS POTIONS OF SOUTHWEST KANSAS DURING THE DAY. CURRENTLY IT APPEARS THAT PRECIPITATION DURING THIS FREEZING DRIZZLE TIME FRAME WILL BE LIGHT (LESS THAN 0.05INCHES) SO WILL NOT BE ISSUING A WATCH OR ADVISORY. DO HOWEVER EXPECT THIS PROLONGED PERIOD OF LIGHT PRECIPITATION WILL PRODUCE SOME SLICK SPOTS ON SOME ELEVATED SURFACES. ON FRIDAY AND EARLY SATURDAY AN UPPER LOW WILL CONTINUE TO WOBBLE ACROSS NEW MEXICO AS A SERIES OF UPPER LEVEL DISTURBANCE ROTATES AROUND THIS SYSTEM. THE ECMWF, GEM, SREF MEAN, AND GFS ALL CONTINUE TO STRUGGLE WITH THE MOVEMENT OF THIS CUTOFF UPPER LOW AND CONFIDENCE IS NOT HIGH WITH WHICH ONE IS MORE CORRECT. AT THIS TIME GIVEN THAT THE GFS AT 12Z WEDNESDAY UNDERESTIMATED THE UPPER LEVEL JET STREAK WEST OF THIS SYSTEM AM CURRENTLY TRENDING TOWARD A SLOWER AND FURTHER SOUTH SOLUTION WHICH THE 00Z ECMWF,12Z GEM AND MEAN SREF INDICATED. WITH THIS IN MIND WILL HOLD ON TO THE PRECIPITATION CHANCES THROUGH THE WEEKEND AS MOISTURE AND WEAK LIFT PERSISTS ACROSS WESTERN KANSAS AHEAD OF THIS SLOW MOVING UPPER LEVEL SYSTEM. BY LATE THIS WEEKEND ALL THE MODELS BEGIN TO MOVE THIS SYSTEM EAST OF WESTERN KANSAS ALLOWING A UPPER LEVEL RIDGE TO BUILD INTO THE WESTERN HIGH PLAINS. MAGNITUDE AND TIMING OF THIS RIDGING STILL UNCLEAR BUT A WARMING TREND SHOULD BEGIN EARLY NEXT WEEK. 850MB TEMPERATURE TRENDS CONTINUE TO SUPPORT HIGHS REBOUNDING BACK INTO THE 60S BY AS EARLY AS MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1119 AM CST TUE MAR 6 2012 LOOK FOR STRONGER WINDS TO MIX TO THE SURFACE THIS AFTERNOON WITH SOUTH TO SOUTHWEST WINDS OF 20 TO 30KT AND ONLY A FEW CIRRUS. TONIGHT A LOW LEVEL JET OF 50 TO 55KTS AT H85 WILL DEVELOP WITH SURFACE WINDS STAYING IN THE 15 TO 25 MPH RANGE. A STRONG COLD FRONT WILL SWITCH WINDS TO THE NORTH AROUND DODGE CITY BY NOON TO 1 PM WEDNESDAY AND AROUND 9 TO 10 AM AT HAYS. WINDS WILL SHIFT ABRUPTLY NORTH AT 20 TO 30KTS WITH THE FROPA THEN SLACKEN DURING THE DAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 51 66 28 33 / 10 30 70 80 GCK 49 53 27 33 / 10 20 60 60 EHA 47 65 25 33 / 0 20 60 60 LBL 50 66 29 33 / 10 20 70 70 HYS 51 53 28 38 / 10 40 40 40 P28 55 68 35 36 / 20 70 80 80 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM CST /6 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>078-084>087. && $$ SHORT TERM...UMSCHEID LONG TERM....BURGERT AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1125 AM CST TUE MAR 6 2012 ...UPDATED FOR AVIATION... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 359 AM CST TUE MAR 6 2012 SYNOPSIS: WATER VAPOR LOOP AND LAST NIGHT`S RAOB ANALYSIS CONFIRMED THE DEVELOPMENT OF SIGNIFICANT MID LEVEL TROUGH OVER THE PACIFIC NORTHWEST REGION. 12-HR 500MB HEIGHT FALLS OF 130-170 METERS WERE OBSERVED OVER WESTERN OREGON AND WASHINGTON. THE BASE OF THIS TROUGH WAS CONTINUING TO DIG SOUTHEAST INTO NORTHERN CALIFORNIA AS OF 09Z THIS MORNING. STRONG WEST-SOUTHWESTERLY MID LEVEL FLOW WAS OCCURRING EAST OF THIS ACROSS THE GREAT BASIN REGION INTO THE ROCKIES. THIS WAS RESULTING IN A LARGE AREA OF LOWER TROPOSPHERIC WARMING WITH LOWER ELEVATION STATIONS ACROSS THE GREAT BASIN/ROCKIES SEEING 850MB TEMPS IN THE MID TO UPPER TEENS. 700MB TEMPERATURES WERE +4 TO +5C ACROSS ARIZONA AND NEW MEXICO. THE FRONT SEPARATING THE COLD, POLAR AIRMASS FROM THE WARM INTERMOUNTAIN WEST AIRMASS WAS POSITIONED FROM SOUTHWESTERN ALBERTA...EAST-SOUTHEASTWARD ALONG THE CANADA-US BORDER TO A WEAK CYCLONIC CENTER AT 850MB NEAR THE MANITOBA BORDER WITH MINNESOTA AND NORTH DAKOTA. STRONG SOUTHERLY FLOW WAS NOTED ACROSS THE SOUTHERN PLAINS BETWEEN THE LEE-SIDE TROUGH AND A GULF OF MEXICO HIGH. TODAY: THE VERY WARM AND DRY LOWER TROPOSPHERIC DOWNSLOPE AIRMASS WILL YIELD ANOTHER UNSEASONABLY WARM DAY ACROSS SOUTHWEST KANSAS. GIVEN THE RESULTS OF YESTERDAY AND AN EVEN WARMER THERMODYNAMIC ENVIRONMENT TODAY...THERE IS MUCH MORE CONFIDENCE IN HIGHS TODAY REACHING 80 DEGREES OVER A GOOD CHUNK OF SOUTHWEST KANSAS...AND HAVE INCREASED THE MAXT GRID AS A RESULT. THE HRRR AND RUC MODELS WERE USED AS THE PRIMARY GUIDANCE IN THE DEWPOINT/RH FORECAST FOR FIRE WEATHER CONCERNS. DEWPOINTS WILL BE VERY LOW ACROSS THE NORTHWESTERN 2/3RDS OF THE FORECAST AREA...IN THE 14 TO 20F RANGE...AS TEMPERATURES RISE INTO THE UPPER 70S/NEAR 80. THIS WILL RESULT IN RELATIVE HUMIDITY DOWN INTO THE 10 TO 15 PERCENT RANGE. THE MAIN QUESTION REGARDING SIGNIFICANCE OF THE CRITICAL FIRE WEATHER THREAT WILL BE WIND SPEED. HIGH RESOLUTION MODELS HAVE TRENDED DOWNWARD IN THE WIND SPEED ACROSS THE VERY LOW RH AREAS FOR THIS AFTERNOON...AND IT APPEARS THAT WIND SPEEDS WILL NOW BE RATHER MARGINAL FOR CRITICAL FIRE WX. THE LATEST FORECAST WILL REFLECT 15 TO 20 MPH WINDS FOR MOST OF THE DAY...WITH 20 TO 25 MPH FOR ONLY A COUPLE HOURS PROBABLY BY LATE AFTERNOON. GUSTS ARE STILL ANTICIPATED TO BE 25 TO 30 MPH. FARTHER EAST WHERE THE MSLP GRADIENT WILL BE TIGHTER...WINDS WILL BE FAIRLY STRONG AND APPROACH WIND ADVISORY CATEGORY. HAVE DECIDED TO NOT ISSUE A WIND ADVISORY IN THE SOUTH CENTRAL KANSAS COUNTIES GIVEN THE UNCERTAINTY IN DEEP MIXING...BUT THE REALLY DEEP MIXING MAY NOT REALLY MATTER MUCH AND WIND ADVISORY LEVEL WINDS (SUSTAINED 30 MPH) MAY STILL BE REACHED ACROSS PRATT-COMANCHE-BARBER COUNTIES. TONIGHT: AS THE UPPER TROUGH CONTINUES TO DIG SOUTHEAST LATE TODAY AND TONIGHT...THE FRONT (MENTIONED IN THE SYNOPSIS PARAGRAPH) WILL BEGIN ITS EQUATORWARD PUSH. THE FRONT IS EXPECTED TO REACH FAR NORTHWEST KANSAS AROUND 09Z TONIGHT. AHEAD OF THE FRONT IN SOUTHWEST KANSAS...WIND SPEEDS WILL STAY FAIRLY STRONG BY NOCTURNAL STANDARDS WITH SPEEDS AVERAGING 20 TO 30 MPH THROUGH MOST OF THE NIGHT...ESPECIALLY THE SOUTHEAST HALF OF THE FORECAST AREA. THIS WILL KEEP TEMPERATURES ABNORMALLY WARM THROUGH THE NIGHT WITH 06-12Z TEMPERATURES IN THE LOWER 50S FOR A GOOD PORTION OF THE FORECAST AREA. LOW LEVEL MOISTURE WILL ALSO BEGIN TO MOVE INTO THE SOUTHEASTERN COUNTIES WITH DEWPOINT TEMPERATURES RISING INTO THE UPPER 40S TO NEAR 50 (PARTICULARLY ACROSS BARBER COUNTY). THE DEVELOPMENT OF LOW STRATUS WILL HAVE TO BE WATCHED...BUT AT THIS TIME THE MAJORITY OF INITIAL LOW LEVEL CLOUD COVER TOWARD DAYBREAK WEDNESDAY WILL BE ACROSS OKLAHOMA AND AREAS OF SOUTH CENTRAL KANSAS JUST EAST OF BARBER COUNTY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CST TUE MAR 6 2012 THE EXTENDED PERIOD BEGINS 12Z WEDNESDAY. LOTS OF WEATHER TO CONSIDER, HOWEVER, THIS AFD SECTION WILL BE SLIGHTLY ABBREVIATED DUE TO MOST OF THE TIME WAS SPENT ON THE GRIDS MAKING NUMEROUS MODIFICATIONS. OVERALL, THE EXTENDED PERIOD RELIED HEAVILY ON THE 00Z ECMWF FOR THE SYNOPTIC PATTERN AND USED 00Z NAM FOR THERMODYNAMICS. THE 00Z GFS WAS COMPLETELY DISMISSED AS IT IS A CLEAR OUTLIER COMPARED TO THE ECMWF/NAM/GEM/UKMET. WEDNESDAY: ON WEDNESDAY, A SIGNIFICANT COLD FRONT WILL BE TRAVERSING ACROSS THE REGION. HAVE ADOPTED A NON DIURNAL TEMPERATURE CURVE WITH A FIRST GUESS FROM THE NAM AS PEAK HEATING WILL OCCUR NEAR THE NORMAL AFTERNOON HOURS TOWARDS MEDICINE LODGE, HOWEVER AT SCOTT CITY TO HAYS, MAX TEMPERATURES WILL BE REACHED EARLY AND THEN FALL LIKE A ROCK AS THE FRONT MOVES THROUGH. MOST OF THE DAY WEDNESDAY SHOULD REMAIN DRY, EXCEPT ACROSS SOUTH CENTRAL KANSAS WHERE WARM AIR ADVECTION AND ISENTROPIC LIFT COULD PROVIDE THIS REGION WITH DRIZZLE. BY WEDNESDAY EVENING INTO THURSDAY MORNING, A VORTMAX WILL SLIDE ACROSS THE REGION WITH SIGNIFICANT HEIGHT FALLS AND RELATED AGEOSTROPHIC MOTIONS (DYNAMIC LIFT) SPREADING ACROSS SOUTHWEST KANSAS. THIS DYNAMIC PROCESS WILL BE ENOUGH TO CAUSE RAIN AND ISOLATED THUNDERSTORMS ACROSS SOUTH CENTRAL KANSAS. ECMWF CAPE IS NOT PARTICULARLY IMPRESSIVE, HOWEVER, MID LEVEL LAPSE RATES WILL CONTINUE TO STEEPEN SO THINK THERE WILL BE ENOUGH INSTABILITY IN THE LOW TO MIDDLE PORTION OF THE ATMOSPHERE TO PRODUCE SOME LIGHTNING. SEVERE WEATHER IS NOT ANTICIPATED AS ANY CONVECTION WILL LIKE PEAK OVERNIGHT WITH SURFACE BASE INSTABILITY IS AT A MINIMUM. PLUS, THE CONVECTION WILL BE ELEVATED. PERHAPS SOME MARGINAL HAIL COULD OCCUR AT MEDICINE LODGE GIVEN THE AFOREMENTIONED STEEP LAPSE RATES BUT IT IS TOO EARLY TO TELL. MEANWHILE, THROUGH THE OVERNIGHT WEDNESDAY AND INTO THURSDAY, SIGNIFICANT COLD AIR ADVECTION WILL BE OCCURRING ON THE BACKSIDE OF OF 850-700 HPA TROUGH. RIGHT NOW, I HAVE EMPLOYED THE PROBABILITY OF WEATHER TYPE TOOL FROM THE ESTF SMART TOOL REPOSITORY AND HAVE USED THE NAM FOR A THERMODYNAMIC BACKGROUND. WOULD PREFER NOT TO USE THIS MESOSCALE MODEL AT THIS TIME RANGE, HOWEVER, THE ECMWF HAS LOW RESOLUTION IN THE VERTICAL AND CANNOT BE USED TO DETERMINE PRECIPITATION TYPE. THE POWT ACTUALLY PRODUCED FAIRLY REASONABLE LOOKING PRECIPITATION TYPE GRIDS AND I PARTICULARLY LIKE THE TRANSITION THROUGH THE OVERNIGHT HOURS. THERE WILL BE A ZONE ACROSS THE FORECAST AREA WHERE THE TOP DOWN METHOD AND FORECAST SOUNDINGS SHOW THAT FREEZING RAIN COULD BE HAPPEN. RIGHT NOW, I WAS CONSERVATIVE ON ICE ACCUMULATION AMOUNTS BUT IF THIS ZR AREA WERE TO EXPAND WITH ELEVATED SHOWERS/CONVECTION ON TOP OF A SHALLOW COLD AIR MASS...TREACHEROUS COMMUTING CONDITIONS WILL CERTAINLY BE A POSSIBILITY. IT IS TOO EARLY TO MENTION A WINTER STORM WATCH, BUT AN ICE STORM WARNING CANNOT BE COMPLETELY DISMISSED AT THIS POINT BASED OFF 00Z DATA THAT WAS ANALYZED. THURSDAY: FOR THURSDAY, THE COUNTY WARNING AREA WILL CONTINUE TO BE IN THE TRANSITION ZONE FOR PRECIPITATION TYPES. SNOW LOOKS LIKELY ACROSS MY NORTHWEST COUNTIES WHERE RAIN LOOKS LIKELY ACROSS SOUTH CENTRAL KANSAS. THE ECMWF IS MORE AGGRESSIVE WITH COLD AIR ADVECTION THROUGH THE 850-700 HPA LAYER COMPARED TO THE NAM WHICH WANTS TO KEEP THE WARM NOSE LINGERING AROUND, PARTICULARLY ACROSS SOUTH CENTRAL KANSAS. AS MENTIONED BEFORE, WENT AHEAD AND USED THE NAM THERMO FIELDS FOR PRECIPITATION TYPES ALTHOUGH THE ECMWF COULD BE MORE CORRECT IN CONTINUING TO DRIVE THE COLD AIR SOUTHWARD THROUGH THE DAY. ALL THESE DETAILS WILL BE HAMMERED OUT AS THE EVENT APPROACHES. FRIDAY AND BEYOND: DUE TO TIME CONSTRAINTS, DID NOT DEVIATE FROM THE ALLBLEND APPROACH. THERE IS TOO MUCH UNCERTAINTY IN WHAT WILL HAPPEN WITH THE UPPER LEVEL WAVE. THE ECMWF/GEM KEEPS THE WAVE CLOSER TO OUR AREA WHICH WOULD PROVIDE THE REGION WITH A CHANCE OF SHOWERS AND SNOW SHOWERS. THE GFS IS VERY PROGRESSIVE BUT AS MENTIONED ABOVE WAS DISCOUNTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1119 AM CST TUE MAR 6 2012 LOOK FOR STRONGER WINDS TO MIX TO THE SURFACE THIS AFTERNOON WITH SOUTH TO SOUTHWEST WINDS OF 20 TO 30KT AND ONLY A FEW CIRRUS. TONIGHT A LOW LEVEL JET OF 50 TO 55KTS AT H85 WILL DEVELOP WITH SURFACE WINDS STAYING IN THE 15 TO 25 MPH RANGE. A STRONG COLD FRONT WILL SWITCH WINDS TO THE NORTH AROUND DODGE CITY BY NOON TO 1 PM WEDNESDAY AND AROUND 9 TO 10 AM AT HAYS. WINDS WILL SHIFT ABRUPTLY NORTH AT 20 TO 30KTS WITH THE FROPA THEN SLACKEN DURING THE DAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 80 47 66 27 / 0 10 30 60 GCK 80 44 55 27 / 0 10 20 60 EHA 81 44 59 24 / 0 0 20 60 LBL 81 46 65 27 / 0 10 20 60 HYS 79 47 55 27 / 0 10 40 60 P28 75 52 69 34 / 0 20 70 80 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM CST /6 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>078-084>087. && $$ SHORT TERM...UMSCHEID LONG TERM....SUGDEN AVIATION...KRUSE
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
500 AM CST TUE MAR 6 2012 ...UPDATE TO AVIATION FOR 12Z TAFS... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 359 AM CST TUE MAR 6 2012 SYNOPSIS: WATER VAPOR LOOP AND LAST NIGHT`S RAOB ANALYSIS CONFIRMED THE DEVELOPMENT OF SIGNIFICANT MID LEVEL TROUGH OVER THE PACIFIC NORTHWEST REGION. 12-HR 500MB HEIGHT FALLS OF 130-170 METERS WERE OBSERVED OVER WESTERN OREGON AND WASHINGTON. THE BASE OF THIS TROUGH WAS CONTINUING TO DIG SOUTHEAST INTO NORTHERN CALIFORNIA AS OF 09Z THIS MORNING. STRONG WEST-SOUTHWESTERLY MID LEVEL FLOW WAS OCCURRING EAST OF THIS ACROSS THE GREAT BASIN REGION INTO THE ROCKIES. THIS WAS RESULTING IN A LARGE AREA OF LOWER TROPOSPHERIC WARMING WITH LOWER ELEVATION STATIONS ACROSS THE GREAT BASIN/ROCKIES SEEING 850MB TEMPS IN THE MID TO UPPER TEENS. 700MB TEMPERATURES WERE +4 TO +5C ACROSS ARIZONA AND NEW MEXICO. THE FRONT SEPARATING THE COLD, POLAR AIRMASS FROM THE WARM INTERMOUNTAIN WEST AIRMASS WAS POSITIONED FROM SOUTHWESTERN ALBERTA...EAST-SOUTHEASTWARD ALONG THE CANADA-US BORDER TO A WEAK CYCLONIC CENTER AT 850MB NEAR THE MANITOBA BORDER WITH MINNESOTA AND NORTH DAKOTA. STRONG SOUTHERLY FLOW WAS NOTED ACROSS THE SOUTHERN PLAINS BETWEEN THE LEE-SIDE TROUGH AND A GULF OF MEXICO HIGH. TODAY: THE VERY WARM AND DRY LOWER TROPOSPHERIC DOWNSLOPE AIRMASS WILL YIELD ANOTHER UNSEASONABLY WARM DAY ACROSS SOUTHWEST KANSAS. GIVEN THE RESULTS OF YESTERDAY AND AN EVEN WARMER THERMODYNAMIC ENVIRONMENT TODAY...THERE IS MUCH MORE CONFIDENCE IN HIGHS TODAY REACHING 80 DEGREES OVER A GOOD CHUNK OF SOUTHWEST KANSAS...AND HAVE INCREASED THE MAXT GRID AS A RESULT. THE HRRR AND RUC MODELS WERE USED AS THE PRIMARY GUIDANCE IN THE DEWPOINT/RH FORECAST FOR FIRE WEATHER CONCERNS. DEWPOINTS WILL BE VERY LOW ACROSS THE NORTHWESTERN 2/3RDS OF THE FORECAST AREA...IN THE 14 TO 20F RANGE...AS TEMPERATURES RISE INTO THE UPPER 70S/NEAR 80. THIS WILL RESULT IN RELATIVE HUMIDITY DOWN INTO THE 10 TO 15 PERCENT RANGE. THE MAIN QUESTION REGARDING SIGNIFICANCE OF THE CRITICAL FIRE WEATHER THREAT WILL BE WIND SPEED. HIGH RESOLUTION MODELS HAVE TRENDED DOWNWARD IN THE WIND SPEED ACROSS THE VERY LOW RH AREAS FOR THIS AFTERNOON...AND IT APPEARS THAT WIND SPEEDS WILL NOW BE RATHER MARGINAL FOR CRITICAL FIRE WX. THE LATEST FORECAST WILL REFLECT 15 TO 20 MPH WINDS FOR MOST OF THE DAY...WITH 20 TO 25 MPH FOR ONLY A COUPLE HOURS PROBABLY BY LATE AFTERNOON. GUSTS ARE STILL ANTICIPATED TO BE 25 TO 30 MPH. FARTHER EAST WHERE THE MSLP GRADIENT WILL BE TIGHTER...WINDS WILL BE FAIRLY STRONG AND APPROACH WIND ADVISORY CATEGORY. HAVE DECIDED TO NOT ISSUE A WIND ADVISORY IN THE SOUTH CENTRAL KANSAS COUNTIES GIVEN THE UNCERTAINTY IN DEEP MIXING...BUT THE REALLY DEEP MIXING MAY NOT REALLY MATTER MUCH AND WIND ADVISORY LEVEL WINDS (SUSTAINED 30 MPH) MAY STILL BE REACHED ACROSS PRATT-COMANCHE-BARBER COUNTIES. TONIGHT: AS THE UPPER TROUGH CONTINUES TO DIG SOUTHEAST LATE TODAY AND TONIGHT...THE FRONT (MENTIONED IN THE SYNOPSIS PARAGRAPH) WILL BEGIN ITS EQUATORWARD PUSH. THE FRONT IS EXPECTED TO REACH FAR NORTHWEST KANSAS AROUND 09Z TONIGHT. AHEAD OF THE FRONT IN SOUTHWEST KANSAS...WIND SPEEDS WILL STAY FAIRLY STRONG BY NOCTURNAL STANDARDS WITH SPEEDS AVERAGING 20 TO 30 MPH THROUGH MOST OF THE NIGHT...ESPECIALLY THE SOUTHEAST HALF OF THE FORECAST AREA. THIS WILL KEEP TEMPERATURES ABNORMALLY WARM THROUGH THE NIGHT WITH 06-12Z TEMPERATURES IN THE LOWER 50S FOR A GOOD PORTION OF THE FORECAST AREA. LOW LEVEL MOISTURE WILL ALSO BEGIN TO MOVE INTO THE SOUTHEASTERN COUNTIES WITH DEWPOINT TEMPERATURES RISING INTO THE UPPER 40S TO NEAR 50 (PARTICULARLY ACROSS BARBER COUNTY). THE DEVELOPMENT OF LOW STRATUS WILL HAVE TO BE WATCHED...BUT AT THIS TIME THE MAJORITY OF INITIAL LOW LEVEL CLOUD COVER TOWARD DAYBREAK WEDNESDAY WILL BE ACROSS OKLAHOMA AND AREAS OF SOUTH CENTRAL KANSAS JUST EAST OF BARBER COUNTY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CST TUE MAR 6 2012 THE EXTENDED PERIOD BEGINS 12Z WEDNESDAY. LOTS OF WEATHER TO CONSIDER, HOWEVER, THIS AFD SECTION WILL BE SLIGHTLY ABBREVIATED DUE TO MOST OF THE TIME WAS SPENT ON THE GRIDS MAKING NUMEROUS MODIFICATIONS. OVERALL, THE EXTENDED PERIOD RELIED HEAVILY ON THE 00Z ECMWF FOR THE SYNOPTIC PATTERN AND USED 00Z NAM FOR THERMODYNAMICS. THE 00Z GFS WAS COMPLETELY DISMISSED AS IT IS A CLEAR OUTLIER COMPARED TO THE ECMWF/NAM/GEM/UKMET. WEDNESDAY: ON WEDNESDAY, A SIGNIFICANT COLD FRONT WILL BE TRAVERSING ACROSS THE REGION. HAVE ADOPTED A NON DIURNAL TEMPERATURE CURVE WITH A FIRST GUESS FROM THE NAM AS PEAK HEATING WILL OCCUR NEAR THE NORMAL AFTERNOON HOURS TOWARDS MEDICINE LODGE, HOWEVER AT SCOTT CITY TO HAYS, MAX TEMPERATURES WILL BE REACHED EARLY AND THEN FALL LIKE A ROCK AS THE FRONT MOVES THROUGH. MOST OF THE DAY WEDNESDAY SHOULD REMAIN DRY, EXCEPT ACROSS SOUTH CENTRAL KANSAS WHERE WARM AIR ADVECTION AND ISENTROPIC LIFT COULD PROVIDE THIS REGION WITH DRIZZLE. BY WEDNESDAY EVENING INTO THURSDAY MORNING, A VORTMAX WILL SLIDE ACROSS THE REGION WITH SIGNIFICANT HEIGHT FALLS AND RELATED AGEOSTROPHIC MOTIONS (DYNAMIC LIFT) SPREADING ACROSS SOUTHWEST KANSAS. THIS DYNAMIC PROCESS WILL BE ENOUGH TO CAUSE RAIN AND ISOLATED THUNDERSTORMS ACROSS SOUTH CENTRAL KANSAS. ECMWF CAPE IS NOT PARTICULARLY IMPRESSIVE, HOWEVER, MID LEVEL LAPSE RATES WILL CONTINUE TO STEEPEN SO THINK THERE WILL BE ENOUGH INSTABILITY IN THE LOW TO MIDDLE PORTION OF THE ATMOSPHERE TO PRODUCE SOME LIGHTNING. SEVERE WEATHER IS NOT ANTICIPATED AS ANY CONVECTION WILL LIKE PEAK OVERNIGHT WITH SURFACE BASE INSTABILITY IS AT A MINIMUM. PLUS, THE CONVECTION WILL BE ELEVATED. PERHAPS SOME MARGINAL HAIL COULD OCCUR AT MEDICINE LODGE GIVEN THE AFOREMENTIONED STEEP LAPSE RATES BUT IT IS TOO EARLY TO TELL. MEANWHILE, THROUGH THE OVERNIGHT WEDNESDAY AND INTO THURSDAY, SIGNIFICANT COLD AIR ADVECTION WILL BE OCCURRING ON THE BACKSIDE OF OF 850-700 HPA TROUGH. RIGHT NOW, I HAVE EMPLOYED THE PROBABILITY OF WEATHER TYPE TOOL FROM THE ESTF SMART TOOL REPOSITORY AND HAVE USED THE NAM FOR A THERMODYNAMIC BACKGROUND. WOULD PREFER NOT TO USE THIS MESOSCALE MODEL AT THIS TIME RANGE, HOWEVER, THE ECMWF HAS LOW RESOLUTION IN THE VERTICAL AND CANNOT BE USED TO DETERMINE PRECIPITATION TYPE. THE POWT ACTUALLY PRODUCED FAIRLY REASONABLE LOOKING PRECIPITATION TYPE GRIDS AND I PARTICULARLY LIKE THE TRANSITION THROUGH THE OVERNIGHT HOURS. THERE WILL BE A ZONE ACROSS THE FORECAST AREA WHERE THE TOP DOWN METHOD AND FORECAST SOUNDINGS SHOW THAT FREEZING RAIN COULD BE HAPPEN. RIGHT NOW, I WAS CONSERVATIVE ON ICE ACCUMULATION AMOUNTS BUT IF THIS ZR AREA WERE TO EXPAND WITH ELEVATED SHOWERS/CONVECTION ON TOP OF A SHALLOW COLD AIR MASS...TREACHEROUS COMMUTING CONDITIONS WILL CERTAINLY BE A POSSIBILITY. IT IS TOO EARLY TO MENTION A WINTER STORM WATCH, BUT AN ICE STORM WARNING CANNOT BE COMPLETELY DISMISSED AT THIS POINT BASED OFF 00Z DATA THAT WAS ANALYZED. THURSDAY: FOR THURSDAY, THE COUNTY WARNING AREA WILL CONTINUE TO BE IN THE TRANSITION ZONE FOR PRECIPITATION TYPES. SNOW LOOKS LIKELY ACROSS MY NORTHWEST COUNTIES WHERE RAIN LOOKS LIKELY ACROSS SOUTH CENTRAL KANSAS. THE ECMWF IS MORE AGGRESSIVE WITH COLD AIR ADVECTION THROUGH THE 850-700 HPA LAYER COMPARED TO THE NAM WHICH WANTS TO KEEP THE WARM NOSE LINGERING AROUND, PARTICULARLY ACROSS SOUTH CENTRAL KANSAS. AS MENTIONED BEFORE, WENT AHEAD AND USED THE NAM THERMO FIELDS FOR PRECIPITATION TYPES ALTHOUGH THE ECMWF COULD BE MORE CORRECT IN CONTINUING TO DRIVE THE COLD AIR SOUTHWARD THROUGH THE DAY. ALL THESE DETAILS WILL BE HAMMERED OUT AS THE EVENT APPROACHES. FRIDAY AND BEYOND: DUE TO TIME CONSTRAINTS, DID NOT DEVIATE FROM THE ALLBLEND APPROACH. THERE IS TOO MUCH UNCERTAINTY IN WHAT WILL HAPPEN WITH THE UPPER LEVEL WAVE. THE ECMWF/GEM KEEPS THE WAVE CLOSER TO OUR AREA WHICH WOULD PROVIDE THE REGION WITH A CHANCE OF SHOWERS AND SNOW SHOWERS. THE GFS IS VERY PROGRESSIVE BUT AS MENTIONED ABOVE WAS DISCOUNTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 456 AM CST TUE MAR 6 2012 VFR CIGS WILL PREVAIL THROUGH THE TAF PERIOD. SOME HIGH LEVEL CIRRIFORM CLOUDS ARE LIKELY TODAY SPREADING IN DOWNSTREAM OF AN UPPER LEVEL DISTURBANCE LOCATED ACROSS THE DESERT SOUTHWEST. OTHERWISE, BREEZY S/SW WINDS AROUND 20 KT ARE EXPECTED TO PEAK THROUGH THIS AFTERNOON IN ASSOCIATION WITH ADIABATIC MIXING AND LEE TROUGHING. && .PRELIMINARY POINT TEMPS/POPS... DDC 80 47 66 27 / 0 10 30 60 GCK 80 44 55 27 / 0 10 20 60 EHA 81 44 59 24 / 0 0 20 60 LBL 81 46 65 27 / 0 10 20 60 HYS 79 47 55 27 / 0 10 40 60 P28 75 52 69 34 / 0 20 70 80 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CST /11 AM MST/ TODAY TO 7 PM CST /6 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>078- 084>087. && $$ SHORT TERM...UMSCHEID LONG TERM....SUGDEN AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
404 AM CST TUE MAR 6 2012 ...UPDATED SHORT TERM AND LONG TERM SECTIONS... .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 359 AM CST TUE MAR 6 2012 SYNOPSIS: WATER VAPOR LOOP AND LAST NIGHT`S RAOB ANALYSIS CONFIRMED THE DEVELOPMENT OF SIGNIFICANT MID LEVEL TROUGH OVER THE PACIFIC NORTHWEST REGION. 12-HR 500MB HEIGHT FALLS OF 130-170 METERS WERE OBSERVED OVER WESTERN OREGON AND WASHINGTON. THE BASE OF THIS TROUGH WAS CONTINUING TO DIG SOUTHEAST INTO NORTHERN CALIFORNIA AS OF 09Z THIS MORNING. STRONG WEST-SOUTHWESTERLY MID LEVEL FLOW WAS OCCURRING EAST OF THIS ACROSS THE GREAT BASIN REGION INTO THE ROCKIES. THIS WAS RESULTING IN A LARGE AREA OF LOWER TROPOSPHERIC WARMING WITH LOWER ELEVATION STATIONS ACROSS THE GREAT BASIN/ROCKIES SEEING 850MB TEMPS IN THE MID TO UPPER TEENS. 700MB TEMPERATURES WERE +4 TO +5C ACROSS ARIZONA AND NEW MEXICO. THE FRONT SEPARATING THE COLD, POLAR AIRMASS FROM THE WARM INTERMOUNTAIN WEST AIRMASS WAS POSITIONED FROM SOUTHWESTERN ALBERTA...EAST-SOUTHEASTWARD ALONG THE CANADA-US BORDER TO A WEAK CYCLONIC CENTER AT 850MB NEAR THE MANITOBA BORDER WITH MINNESOTA AND NORTH DAKOTA. STRONG SOUTHERLY FLOW WAS NOTED ACROSS THE SOUTHERN PLAINS BETWEEN THE LEESIDE TROUGH AND A GULF OF MEXICO HIGH. TODAY: THE VERY WARM AND DRY LOWER TROPOSPHERIC DOWNSLOPE AIRMASS WILL YIELD ANOTHER UNSEASONABLY WARM DAY ACROSS SOUTHWEST KANSAS. GIVEN THE RESULTS OF YESTERDAY AND AN EVEN WARMER THERMODYNAMIC ENVIRONMENT TODAY...THERE IS MUCH MORE CONFIDENCE IN HIGHS TODAY REACHING 80 DEGREES OVER A GOOD CHUNK OF SOUTHWEST KANSAS...AND HAVE INCREASED THE MAXT GRID AS A RESULT. THE HRRR AND RUC MODELS WERE USED AS THE PRIMARY GUIDANCE IN THE DEWPOINT/RH FORECAST FOR FIRE WEATHER CONCERNS. DEWPOINTS WILL BE VERY LOW ACROSS THE NORTHWESTERN 2/3RDS OF THE FORECAST AREA...IN THE 14 TO 20F RANGE...AS TEMPERATURES RISE INTO THE UPPER 70S/NEAR 80. THIS WILL RESULT IN RELATIVE HUMIDITY DOWN INTO THE 10 TO 15 PERCENT RANGE. THE MAIN QUESTION REGARDING SIGNIFICANCE OF THE CRITICAL FIRE WEATHER THREAT WILL BE WIND SPEED. HIGH RESOLUTION MODELS HAVE TRENDED DOWNWARD IN THE WIND SPEED ACROSS THE VERY LOW RH AREAS FOR THIS AFTERNOON...AND IT APPEARS THAT WIND SPEEDS WILL NOW BE RATHER MARGINAL FOR CRITICAL FIRE WX. THE LATEST FORECAST WILL REFLECT 15 TO 20 MPH WINDS FOR MOST OF THE DAY...WITH 20 TO 25 MPH FOR ONLY A COUPLE HOURS PROBABLY BY LATE AFTERNOON. GUSTS ARE STILL ANTICIPATED TO BE 25 TO 30 MPH. FARTHER EAST WHERE THE MSLP GRADIENT WILL BE TIGHTER...WINDS WILL BE FAIRLY STRONG AND APPROACH WIND ADVISORY CATEGORY. HAVE DECIDED TO NOT ISSUE A WIND ADVISORY IN THE SOUTH CENTRAL KANSAS COUNTIES GIVEN THE UNCERTAINTY IN DEEP MIXING...BUT THE REALLY DEEP MIXING MAY NOT REALLY MATTER MUCH AND WIND ADVISORY LEVEL WINDS (SUSTAINED 30 MPH) MAY STILL BE REACHED ACROSS PRATT-COMANCHE-BARBER COUNTIES. TONIGHT: AS THE UPPER TROUGH CONTINUES TO DIG SOUTHEAST LATE TODAY AND TONIGHT...THE FRONT (MENTIONED IN THE SYNOPSIS PARAGRAPH) WILL BEGIN ITS EQUATORWARD PUSH. THE FRONT IS EXPECTED TO REACH FAR NORTHWEST KANSAS AROUND 09Z TONIGHT. AHEAD OF THE FRONT IN SOUTHWEST KANSAS...WIND SPEEDS WILL STAY FAIRLY STRONG BY NOCTURNAL STANDARDS WITH SPEEDS AVERAGING 20 TO 30 MPH THROUGH MOST OF THE NIGHT...ESPECIALLY THE SOUTHEAST HALF OF THE FORECAST AREA. THIS WILL KEEP TEMPERATURES ABNORMALLY WARM THROUGH THE NIGHT WITH 06-12Z TEMPERATURES IN THE LOWER 50S FOR A GOOD PORTION OF THE FORECAST AREA. LOW LEVEL MOISTURE WILL ALSO BEGIN TO MOVE INTO THE SOUTHEASTERN COUNTIES WITH DEWPOINT TEMPERATURES RISING INTO THE UPPER 40S TO NEAR 50 (PARTICULARLY ACROSS BARBER COUNTY). THE DEVELOPMENT OF LOW STRATUS WILL HAVE TO BE WATCHED...BUT AT THIS TIME THE MAJORITY OF INITIAL LOW LEVEL CLOUD COVER TOWARD DAYBREAK WEDNESDAY WILL BE ACROSS OKLAHOMA AND AREAS OF SOUTH CENTRAL KANSAS JUST EAST OF BARBER COUNTY. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 359 AM CST TUE MAR 6 2012 THE EXTENDED PERIOD BEGINS 12Z WEDNESDAY. LOTS OF WEATHER TO CONSIDER, HOWEVER, THIS AFD SECTION WILL BE SLIGHTLY ABBREVIATED DUE TO MOST OF THE TIME WAS SPENT ON THE GRIDS MAKING NUMEROUS MODIFICATIONS. OVERALL, THE EXTENDED PERIOD RELIED HEAVILY ON THE 00Z ECMWF FOR THE SYNOPTIC PATTERN AND USED 00Z NAM FOR THERMODYNAMICS. THE 00Z GFS WAS COMPLETELY DISMISSED AS IT IS A CLEAR OUTLIER COMPARED TO THE ECMWF/NAM/GEM/UKMET. WEDNESDAY: ON WEDNESDAY, A SIGNIFICANT COLD FRONT WILL BE TRAVERSING ACROSS THE REGION. HAVE ADOPTED A NON DIURNAL TEMPERATURE CURVE WITH A FIRST GUESS FROM THE NAM AS PEAK HEATING WILL OCCUR NEAR THE NORMAL AFTERNOON HOURS TOWARDS MEDICINE LODGE, HOWEVER AT SCOTT CITY TO HAYS, MAX TEMPERATURES WILL BE REACHED EARLY AND THEN FALL LIKE A ROCK AS THE FRONT MOVES THROUGH. MOST OF THE DAY WEDNESDAY SHOULD REMAIN DRY, EXPECT ACROSS SOUTH CENTRAL KANSAS WHERE WARM AIR ADVECTION AND ISENTROPIC LIFT COULD PROVIDE THIS REGION WITH DRIZZLE. BY WEDNESDAY EVENING INTO THURSDAY MORNING, A VORTMAX WILL SLIDE ACROSS THE REGION WITH SIGNIFICANT HEIGHT FALLS AND RELATED AGEOSTROPHIC MOTIONS (DYNAMIC LIFT) SPREADING ACROSS SOUTHWEST KANSAS. THIS DYNAMIC PROCESS WILL BE ENOUGH TO CAUSE RAIN AND ISOLATED THUNDERSTORMS ACROSS SOUTH CENTRAL KANSAS. ECMWF CAPE IS NOT PARTICULARLY IMPRESSIVE, HOWEVER, MID LEVEL LAPSE RATES WILL CONTINUE TO STEEPEN SO THINK THERE WILL BE ENOUGH INSTABILITY IN THE LOW TO MIDDLE PORTION OF THE ATMOSPHERE TO PRODUCE SOME LIGHTNING. SEVERE WEATHER IS NOT ANTICIPATED AS ANY CONVECTION WILL LIKE PEAK OVERNIGHT WITH SURFACE BASE INSTABILITY IS AT A MINIMUM. PLUS, THE CONVECTION WILL BE ELEVATED. PERHAPS SOME MARGINAL HAIL COULD OCCUR AT MEDICINE LODGE GIVEN THE AFOREMENTIONED STEEP LAPSE RATES BUT IT IS TOO EARLY TO TELL. MEANWHILE, THROUGH THE OVERNIGHT WEDNESDAY AND INTO THURSDAY, SIGNIFICANT COLD AIR ADVECTION WILL BE OCCURRING ON THE BACKSIDE OF OF 850-700 HPA TROUGH. RIGHT NOW, I HAVE EMPLOYED THE PROBABILITY OF WEATHER TYPE TOOL FROM THE ESTF SMART TOOL REPOSITORY AND HAVE USED THE NAM FOR A THERMODYNAMIC BACKGROUND. WOULD PREFER NOT TO USE THIS MESOSCALE MODEL AT THIS TIME RANGE, HOWEVER, THE ECMWF HAS LOW RESOLUTION IN THE VERTICAL AND CANNOT BE USED TO DETERMINE PRECIPITATION TYPE. THE POWT ACTUALLY PRODUCED FAIRLY REASONABLE LOOKING PRECIPITATION TYPE GRIDS AND I PARTICULARLY LIKE THE TRANSITION THROUGH THE OVERNIGHT HOURS. THERE WILL BE A ZONE ACROSS THE FORECAST AREA WHERE THE TOP DOWN METHOD AND FORECAST SOUNDINGS SHOW THAT FREEZING RAIN COULD BE HAPPEN. RIGHT NOW, I WAS CONSERVATIVE ON ICE ACCUMULATION AMOUNTS BUT IF THIS ZR AREA WERE TO EXPAND WITH ELEVATED SHOWERS/CONVECTION ON TOP OF A SHALLOW COLD AIR MASS...TREACHEROUS COMMUTING CONDITIONS WILL CERTAINLY BE A POSSIBILITY. IT IS TOO EARLY TO MENTION A WINTER STORM WATCH, BUT AN ICE STORM WARNING CANNOT BE COMPLETELY DISMISSED AT THIS POINT BASED OFF 00Z DATA THAT WAS ANALYZED. THURSDAY: FOR THURSDAY, THE COUNTY WARNING AREA WILL CONTINUE TO BE IN THE TRANSITION ZONE FOR PRECIPITATION TYPES. SNOW LOOKS LIKELY ACROSS MY NORTHWEST COUNTIES WHERE RAIN LOOKS LIKELY ACROSS SOUTH CENTRAL KANSAS. THE ECMWF IS MORE AGGRESSIVE WITH COLD AIR ADVECTION THROUGH THE 850-700 HPA LAYER COMPARED TO THE NAM WHICH WANTS TO KEEP THE WARM NOSE LINGERING AROUND, PARTICULARLY ACROSS SOUTH CENTRAL KANSAS. AS MENTIONED BEFORE, WENT AHEAD AND USED THE NAM THERMO FIELDS FOR PRECIPITATION TYPES ALTHOUGH THE ECMWF COULD BE MORE CORRECT IN CONTINUING TO DRIVE THE COLD AIR SOUTHWARD THROUGH THE DAY. ALL THESE DETAILS WILL BE HAMMERED OUT AS THE EVENT APPROACHES. FRIDAY AND BEYOND: DUE TO TIME CONSTRAINTS, DID NOT DEVIATE FROM THE ALLBLEND APPROACH. THERE IS TOO MUCH UNCERTAINTY IN WHAT WILL HAPPEN WITH THE UPPER LEVEL WAVE. THE ECMWF/GEM KEEPS THE WAVE CLOSER TO OUR AREA WHICH WOULD PROVIDE THE REGION WITH A CHANCE OF SHOWERS AND SNOW SHOWERS. THE GFS IS VERY PROGRESSIVE BUT AS MENTIONED ABOVE WAS DISCOUNTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1132 PM CST MON MAR 5 2012 LEE TROUGHING WILL INCREASE ON TUESDAY AS AN UPPER LEVEL STORM SYSTEM DEVELOPS ACROSS THE WESTERN UNITED STATES. WINDS WILL INCREASE FROM THE SOUTH AT 20 TO 25 KTS BY 18-20Z. BY 03Z, A 65KT LOW LEVEL JET WILL DEVELOP AT DDC/GCK/HYS. LOW-LEVEL WIND SHEAR COULD BE A CONCERN, BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE 06Z TAF. && .PRELIMINARY POINT TEMPS/POPS... DDC 80 47 66 27 / 0 10 30 60 GCK 80 44 55 27 / 0 10 20 60 EHA 81 44 59 24 / 0 0 20 60 LBL 81 46 65 27 / 0 10 20 60 HYS 79 47 55 27 / 0 10 40 60 P28 75 52 69 34 / 0 20 70 80 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING FROM NOON CST /11 AM MST/ TODAY TO 7 PM CST /6 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>078- 084>087. && $$ SHORT TERM...UMSCHEID LONG TERM....SUGDEN AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1010 PM MST MON MAR 5 2012 .UPDATE... ISSUED AT 922 PM MST MON MAR 5 2012 TONIGHT THROUGH TUESDAY NIGHT...CIRRUS WILL MOVE ACROSS THE AREA TUESDAY AND TUESDAY NIGHT FROM THE SOUTHWEST AHEAD OF AN APPROACHING AND DEVELOPING UPPER LOW THAT BY 12Z WEDNESDAY WILL BE NEAR SOUTHWEST UTAH. HIGH TEMPERATURES TUESDAY MID 70S TO LOW 80S PER GFS/NAM/UKMET 850 TEMPS WHICH ARE 2-5 DEGREES F WARMER THAN THIS AFTERNOONS OBSERVED 850 TEMPS. RECORDS IN MCCOOK AND COLBY SHOULD BE TIED OR BROKEN. WINDS WILL BECOME S/SW AND INCREASE INTO THE BREEZY TO WINDY CATEGORY TUESDAY AFTERNOON DECREASING AFTER DARK. RH VALUES TUESDAY AFTERNOON WILL DROP DOWN INTO THE 10 PERCENT RANGE...POSSIBLY LOWER IN SPOTS. RED FLAG WARNING WAS ISSUED EARLIER THIS AFTERNOON. COLD FRONT TO MOVE IN BEFORE SUNRISE WEDNESDAY MORNING BRINGING MUCH COLDER TEMPERATURES TO THE AREA FOR THE AFTERNOON HOURS. UPDATE ISSUED AT 515 PM MST MON MAR 5 2012 ALLOWED RED FLAG WARNING AND WIND ADVISORY TO EXPIRE ON TIME. HAVE UPGRADED FIRE WEATHER WATCH TUESDAY TO A RED FLAG WARNING AND STARTED IT AN HOUR EARLIER PER CURRENT GRID RH VALUES AT OR BELOW 20 PERCENT FOR MUCH OF THE AREA. NO OTHER CHANGES MADE AT PRESENT TIME. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 214 PM MST MON MAR 5 2012 EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW WESTERLY FLOW ACROSS THE INTER-MOUNTAIN WEST AND CENTRAL HIGH PLAINS. AT THE SURFACE A LEE TROUGH HAS SHIFTED EAST TO BE NEAR THE COLORADO/KANSAS STATE LINE. THE TIGHTEST SURFACE GRADIENT REMAINS ALONG THE SE BORDER OF THE CWA...WHERE THE WIND ADVISORY IS STILL IN EFFECT. WINDS HAVE JUST STARTED TO REACH ADVISORY CRITERIA AT A FEW LOCATIONS EARLY THIS AFTERNOON. WINDS WILL BEGIN TO DECREASE AS DAYTIME MIXING COMES TO AN END. LOCATIONS CLOSER TO THE TROUGH AXIS MAY SEE WINDS DIMINISH SOONER. FOR NOW THE WIND ADVISORY AND RED FLAG WARNING WILL BE ALLOWED TO CONTINUE THROUGH 00Z...THOUGH WESTERN COUNTIES MAY BE ALLOWED TO END EARLIER. OVERNIGHT LOWS ARE TRICKY TONIGHT WITH WINDS AROUND 10 MPH POSSIBLE EAST AND WEST OF SURFACE TROUGH...WITH EXACT LOCATION OF TROUGH AXIS STILL IN QUESTION. IN ADDITION TO WINDS POSSIBLY ALLOWING FOR BETTER OVERNIGHT MIXING...WAA WILL CONTINUE THROUGH THE NIGHT WITH H85 TEMPS 14-17C. CURRENT FORECAST CALLS FOR LOW TO MID 30S AND UPPER 30S IN THE EAST NEAR HILL CITY. THIS STILL MAY BE TOO COOL CONSIDERING THE AIRMASS ALOFT. NEAR RECORD HIGHS ARE STILL FORECAST FOR TUESDAY WITH SW FLOW AND A VERY WARM AIRMASS IN PLACE ACROSS THE CWA. WITH AFTERNOON TEMPERATURES TODAY REACHING THE MID 70S AT WESTERN LOCATIONS...THERE SHOULD BE NO PROBLEMS REACHING THE UPPER 70S ON TUESDAY WHEN H85 TEMPS ARE FORECAST TO BE ABOUT 5C WARMER THAN TODAY. MANY LOCATIONS WILL PROBABLY REACH 80F. RED FLAG CONDITIONS WILL ALSO BE POSSIBLE TUESDAY WITH GUSTY WINDS VERY LOW RH VALUES EXPECTED ACROSS THE AREA. A FIRE WEATHER WATCH REMAINS IN EFFECT FOR THE ENTIRE CWA TUESDAY AFTERNOON AND EVENING. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 214 PM MST MON MAR 5 2012 TUESDAY NIGHT AND WEDNESDAY A TROUGH OF DIGS INTO THE WESTERN UNITED STATES AND FORMS A CLOSED LOW IN THE VICINITY OF THE 4-CORNERS REGION. CLOUDS WILL BEGIN TO INCREASE AHEAD OF THIS SYSTEM AND THE SURFACE LOW PRESSURE AREA IS SEEMINGLY SPLIT INTO TWO PARTS...WITH THE LEADING PORTION DEEPENING IN THE LEE OF THE ROCKIES AND MOVING SOUTHWARD INTO THE CENTRAL HIGH PLAINS EARLY WEDNESDAY MORNING AND THE TRAILING PORTION DEEPENING IN CLOSER PROXIMITY TO THE UPPER LOW CENTER NEAR THE 4-CORNERS AREA. A COLD FRONT ASSOCIATED WITH THE LEAD LOW PUSHES THROUGH THE FORECAST AREA DURING THE DAY ON WEDNESDAY AND KEEPS HIGH TEMPERATURES 30 DEGREES COOLER OR MORE FROM TUESDAY/S HIGHS. VERY LITTLE IF ANY PRECIPITATION IS EXPECTED WITH THIS FRONT AS IT SWEEPS THROUGH THE REGION AS THE AIRMASS STILL REMAINS RELATIVELY DRY ALOFT AND THE MAIN DYNAMICS WITH THE UPPER LOW CENTER ARE STILL OFF TO THE WEST. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WILL BRING THE POSSIBILITY OF A WINTRY MIX OF PRECIPITATION AS THE NORTHERN BRANCH OF THE UPPER PATTERN SWEEPS A TROUGH ACROSS THE NORTHERN PLAINS AND THE UPPER LOW NEAR THE 4-CORNERS REGION CUTS OFF AND DRIFTS SLOWLY OVER NEW MEXICO. THE SURFACE AREA OF LOWER PRESSURE CONSOLIDATES INTO A SINGLE LOW IN THE VICINITY OF FAR WESTERN TEXAS ON THURSDAY AND BEGINS TO ELONGATE ALONG THE SURFACE FRONTAL BOUNDARY STRETCHING FROM WESTERN TEXAS INTO THE MID-MISSISSIPPI VALLEY REGION. THE BEST CHANCES OF PRECIPITATION WILL BE ALONG THIS FRONTAL BOUNDARY...WITH DIMINISHING CHANCES THE FURTHER NORTH ONE TRAVELS AWAY FROM THE BOUNDARY. HAVE PLACED A MIX OF MAINLY LIGHT RAIN AND SNOW ACROSS THE FORECAST AREA WITH GREATER PRECIPITATION ACCUMULATIONS ACROSS THE SOUTHERN AREAS. THE CUT OFF UPPER LOW LINGERS OVER NEW MEXICO FRIDAY AND FRIDAY NIGHT AND THEN BEGINS TO LIFT OUT ACROSS THE CENTRAL AND SOUTHERN PLAINS ON SATURDAY THROUGH SUNDAY NIGHT. MODEL SOLUTIONS OFFER A VARIETY OF SOLUTIONS OF NOW AND WHEN THE UPPER LOW EVENTUALLY TRACKS EAST OF THE ROCKIES...SO CONFIDENCE IN ANY ONE SOLUTION IS MINIMAL AT THIS TIME. HAVE KEPT A SLIGHT CHANCE OF RAIN AND RAIN AND SNOW ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA DURING THIS TIME WITH A GENERAL RETURN OF TEMPERATURES TO NEAR NORMAL. WITH A SHORT WAVE RIDGE MOVING OVER THE AREA IN THE WAKE OF THE UPPER LOW LIFTING THROUGH...HAVE KEPT THE EARLY PART OF NEXT WEEK DRY WITH SLIGHTLY WARMER CONDITIONS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1004 PM MST MON MAR 5 2012 VFR CONDITIONS FOR BOTH KGLD AND KMCK. WEST WINDS AROUND 11KTS AT PRESENT TIME WILL SHIFT TO THE SOUTH/SOUTHWEST AND INCREASE INTO THE 15-20G30KT RANGE BY LATE TUESDAY MORNING/EARLY AFTERNOON AHEAD OF AN APPROACHING COLD FRONT...DECREASING SHORTLY AFTER SUNSET JUST A FEW CIRRUS CLOUDS EXPECTED...MAINLY TOWARD TUESDAY MORNING. && .FIRE WEATHER... ISSUED AT 515 PM MST MON MAR 5 2012 RED FLAG WARNING IN EFFECT FOR THE ENTIRE TRI-STATE AREA. RH VALUES AS LOW AS 8 PERCENT AND SOUTHWEST WINDS GUSTING 35 MPH WILL PRODUCE CRITICAL FIRE WEATHER CONDITIONS. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...RED FLAG WARNING FROM 10 AM TO 7 PM MST TUESDAY FOR COZ252>254. KS...RED FLAG WARNING FROM 10 AM MST /11 AM CST/ TO 7 PM MST /8 PM CST/ TUESDAY FOR KSZ001>004-013>016-027>029-041-042. NE...RED FLAG WARNING FROM 10 AM MST /11 AM CST/ TO 7 PM MST /8 PM CST/ TUESDAY FOR NEZ079>081. && $$ UPDATE...007 SHORT TERM...DR LONG TERM....LOCKHART AVIATION...007
AREA FORECAST DISCUSSION
NWS GOODLAND KS
930 PM MST MON MAR 5 2012 .UPDATE... ISSUED AT 922 PM MST MON MAR 5 2012 TONIGHT THROUGH TUESDAY NIGHT...CIRRUS WILL MOVE ACROSS THE AREA TUESDAY AND TUESDAY NIGHT FROM THE SOUTHWEST AHEAD OF AN APPROACHING AND DEVELOPING UPPER LOW THAT BY 12Z WEDNESDAY WILL BE NEAR SOUTHWEST UTAH. HIGH TEMPERATURES TUESDAY MID 70S TO LOW 80S PER GFS/NAM/UKMET 850 TEMPS WHICH ARE 2-5 DEGREES F WARMER THAN THIS AFTERNOONS OBSERVED 850 TEMPS. RECORDS IN MCCOOK AND COLBY SHOULD BE TIED OR BROKEN. WINDS WILL BECOME S/SW AND INCREASE INTO THE BREEZY TO WINDY CATEGORY TUESDAY AFTERNOON DECREASING AFTER DARK. RH VALUES TUESDAY AFTERNOON WILL DROP DOWN INTO THE 10 PERCENT RANGE...POSSIBLY LOWER IN SPOTS. RED FLAG WARNING WAS ISSUED EARLIER THIS AFTERNOON. COLD FRONT TO MOVE IN BEFORE SUNRISE WEDNESDAY MORNING BRINGING MUCH COLDER TEMPERATURES TO THE AREA FOR THE AFTERNOON HOURS. UPDATE ISSUED AT 515 PM MST MON MAR 5 2012 ALLOWED RED FLAG WARNING AND WIND ADVISORY TO EXPIRE ON TIME. HAVE UPGRADED FIRE WEATHER WATCH TUESDAY TO A RED FLAG WARNING AND STARTED IT AN HOUR EARLIER PER CURRENT GRID RH VALUES AT OR BELOW 20 PERCENT FOR MUCH OF THE AREA. NO OTHER CHANGES MADE AT PRESENT TIME. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 214 PM MST MON MAR 5 2012 EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOW WESTERLY FLOW ACROSS THE INTER-MOUNTAIN WEST AND CENTRAL HIGH PLAINS. AT THE SURFACE A LEE TROUGH HAS SHIFTED EAST TO BE NEAR THE COLORADO/KANSAS STATE LINE. THE TIGHTEST SURFACE GRADIENT REMAINS ALONG THE SE BORDER OF THE CWA...WHERE THE WIND ADVISORY IS STILL IN EFFECT. WINDS HAVE JUST STARTED TO REACH ADVISORY CRITERIA AT A FEW LOCATIONS EARLY THIS AFTERNOON. WINDS WILL BEGIN TO DECREASE AS DAYTIME MIXING COMES TO AN END. LOCATIONS CLOSER TO THE TROUGH AXIS MAY SEE WINDS DIMINISH SOONER. FOR NOW THE WIND ADVISORY AND RED FLAG WARNING WILL BE ALLOWED TO CONTINUE THROUGH 00Z...THOUGH WESTERN COUNTIES MAY BE ALLOWED TO END EARLIER. OVERNIGHT LOWS ARE TRICKY TONIGHT WITH WINDS AROUND 10 MPH POSSIBLE EAST AND WEST OF SURFACE TROUGH...WITH EXACT LOCATION OF TROUGH AXIS STILL IN QUESTION. IN ADDITION TO WINDS POSSIBLY ALLOWING FOR BETTER OVERNIGHT MIXING...WAA WILL CONTINUE THROUGH THE NIGHT WITH H85 TEMPS 14-17C. CURRENT FORECAST CALLS FOR LOW TO MID 30S AND UPPER 30S IN THE EAST NEAR HILL CITY. THIS STILL MAY BE TOO COOL CONSIDERING THE AIRMASS ALOFT. NEAR RECORD HIGHS ARE STILL FORECAST FOR TUESDAY WITH SW FLOW AND A VERY WARM AIRMASS IN PLACE ACROSS THE CWA. WITH AFTERNOON TEMPERATURES TODAY REACHING THE MID 70S AT WESTERN LOCATIONS...THERE SHOULD BE NO PROBLEMS REACHING THE UPPER 70S ON TUESDAY WHEN H85 TEMPS ARE FORECAST TO BE ABOUT 5C WARMER THAN TODAY. MANY LOCATIONS WILL PROBABLY REACH 80F. RED FLAG CONDITIONS WILL ALSO BE POSSIBLE TUESDAY WITH GUSTY WINDS VERY LOW RH VALUES EXPECTED ACROSS THE AREA. A FIRE WEATHER WATCH REMAINS IN EFFECT FOR THE ENTIRE CWA TUESDAY AFTERNOON AND EVENING. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 214 PM MST MON MAR 5 2012 TUESDAY NIGHT AND WEDNESDAY A TROUGH OF DIGS INTO THE WESTERN UNITED STATES AND FORMS A CLOSED LOW IN THE VICINITY OF THE 4-CORNERS REGION. CLOUDS WILL BEGIN TO INCREASE AHEAD OF THIS SYSTEM AND THE SURFACE LOW PRESSURE AREA IS SEEMINGLY SPLIT INTO TWO PARTS...WITH THE LEADING PORTION DEEPENING IN THE LEE OF THE ROCKIES AND MOVING SOUTHWARD INTO THE CENTRAL HIGH PLAINS EARLY WEDNESDAY MORNING AND THE TRAILING PORTION DEEPENING IN CLOSER PROXIMITY TO THE UPPER LOW CENTER NEAR THE 4-CORNERS AREA. A COLD FRONT ASSOCIATED WITH THE LEAD LOW PUSHES THROUGH THE FORECAST AREA DURING THE DAY ON WEDNESDAY AND KEEPS HIGH TEMPERATURES 30 DEGREES COOLER OR MORE FROM TUESDAY/S HIGHS. VERY LITTLE IF ANY PRECIPITATION IS EXPECTED WITH THIS FRONT AS IT SWEEPS THROUGH THE REGION AS THE AIRMASS STILL REMAINS RELATIVELY DRY ALOFT AND THE MAIN DYNAMICS WITH THE UPPER LOW CENTER ARE STILL OFF TO THE WEST. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WILL BRING THE POSSIBILITY OF A WINTRY MIX OF PRECIPITATION AS THE NORTHERN BRANCH OF THE UPPER PATTERN SWEEPS A TROUGH ACROSS THE NORTHERN PLAINS AND THE UPPER LOW NEAR THE 4-CORNERS REGION CUTS OFF AND DRIFTS SLOWLY OVER NEW MEXICO. THE SURFACE AREA OF LOWER PRESSURE CONSOLIDATES INTO A SINGLE LOW IN THE VICINITY OF FAR WESTERN TEXAS ON THURSDAY AND BEGINS TO ELONGATE ALONG THE SURFACE FRONTAL BOUNDARY STRETCHING FROM WESTERN TEXAS INTO THE MID-MISSISSIPPI VALLEY REGION. THE BEST CHANCES OF PRECIPITATION WILL BE ALONG THIS FRONTAL BOUNDARY...WITH DIMINISHING CHANCES THE FURTHER NORTH ONE TRAVELS AWAY FROM THE BOUNDARY. HAVE PLACED A MIX OF MAINLY LIGHT RAIN AND SNOW ACROSS THE FORECAST AREA WITH GREATER PRECIPITATION ACCUMULATIONS ACROSS THE SOUTHERN AREAS. THE CUT OFF UPPER LOW LINGERS OVER NEW MEXICO FRIDAY AND FRIDAY NIGHT AND THEN BEGINS TO LIFT OUT ACROSS THE CENTRAL AND SOUTHERN PLAINS ON SATURDAY THROUGH SUNDAY NIGHT. MODEL SOLUTIONS OFFER A VARIETY OF SOLUTIONS OF NOW AND WHEN THE UPPER LOW EVENTUALLY TRACKS EAST OF THE ROCKIES...SO CONFIDENCE IN ANY ONE SOLUTION IS MINIMAL AT THIS TIME. HAVE KEPT A SLIGHT CHANCE OF RAIN AND RAIN AND SNOW ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE FORECAST AREA DURING THIS TIME WITH A GENERAL RETURN OF TEMPERATURES TO NEAR NORMAL. WITH A SHORT WAVE RIDGE MOVING OVER THE AREA IN THE WAKE OF THE UPPER LOW LIFTING THROUGH...HAVE KEPT THE EARLY PART OF NEXT WEEK DRY WITH SLIGHTLY WARMER CONDITIONS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 515 PM MST MON MAR 5 2012 VFR CONDITIONS FOR BOTH KGLD AND KMCK. SOUTHWEST WINDS AT PRESENT TIME WILL BECOME WESTERLY EARLY TONIGHT THEN SHIFT TO THE SOUTH/SOUTHWEST AND INCREASE INTO THE 15-20G30KT RANGE BY LATE TUESDAY MORNING/EARLY AFTERNOON AHEAD OF AN APPROACHING COLD FRONT. JUST A FEW CIRRUS EXPECTED...MAINLY TOWARD MORNING. && .FIRE WEATHER... ISSUED AT 515 PM MST MON MAR 5 2012 RED FLAG WARNING IN EFFECT FOR THE ENTIRE TRI-STATE AREA. RH VALUES AS LOW AS 8 PERCENT AND SOUTHWEST WINDS GUSTING 35 MPH WILL PRODUCE CRITICAL FIRE WEATHER CONDITIONS. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...RED FLAG WARNING FROM 10 AM TO 7 PM MST TUESDAY FOR COZ252>254. KS...RED FLAG WARNING FROM 10 AM MST /11 AM CST/ TO 7 PM MST /8 PM CST/ TUESDAY FOR KSZ001>004-013>016-027>029-041-042. NE...RED FLAG WARNING FROM 10 AM MST /11 AM CST/ TO 7 PM MST /8 PM CST/ TUESDAY FOR NEZ079>081. && $$ UPDATE...007 SHORT TERM...DR LONG TERM....LOCKHART AVIATION...007
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EST TUE MAR 6 2012 .SYNOPSIS... ISSUED AT 405 PM EST TUE MAR 6 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF MOVING INTO THE ROCKIES WITH A BROAD DOWNSTREAM RIDGE EXPANDING FROM THE CNTRL TO ERN CONUS. MAIN PORTION OF THIS TROF WILL SHIFT ACROSS THE NRN CONUS/GREAT LAKES AND NEW ENGLAND OVER THE NEXT SEVERAL DAYS WHILE ENERGY IN THE SRN PORTION OF THE TROF BREAKS OUT AND CLOSES OFF OVER THE SW STATES. TROF WILL BRING A PERIOD OF PCPN WED THRU THU. EVENTUALLY...THE SW LOW WILL EJECT OUT TO THE NE OVER THE WEEKEND/EARLY NEXT WEEK. WHAT AFFECTS THE LOW WILL HAVE OVER THE UPPER LAKES REMAINS TO BE SEEN. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 405 PM EST TUE MAR 6 2012 IN THE SHORT TERM...CONCERNS REVOLVE AROUND TEMP TRENDS...FOG DEVELOPMENT AND THEN PCPN WED ASSOCIATED WITH COLD FRONT/TROF MOVING INTO THE UPPER LAKES. DWPTS ARE RISING INTO THE MID 30S TO LWR 40S AS FAR NE SE MN/SW WI THIS AFTN WITH TRAJECTORIES BRINGING THAT MOISTURE INTO UPPER MI DURING THE NIGHT AND WED MORNING. WITH THE LOW-LEVEL MOISTURE ADVECTION OVER THE SNOW COVER...STRATUS/FOG SHOULD EVENTUALLY DEVELOP TONIGHT. DENSE FOG MAY DEVELOP...ESPECIALLY OVER UPSLOPE HIGHER TERRAIN LATE TONIGHT INTO WED. IF THERE WAS SOME ADDITIONAL MOISTURE FROM RAIN/DRIZZLE...WOULD GO WITH MORE OF A DENSE FOG WORDING. FOR NOW...GOING FCST OF AN INCREASE IN LOWER CLOUDS AND FOG DEVELOPMENT...MAINLY LATER TONIGHT...LOOKS ON TRACK. TEMPS SHOULDN`T FALL MUCH IF AT ALL UNDER MOISTURE ADVECTION AND FAIRLY TIGHT PRES GRADIENT/STIRRING WINDS. MINS SHOULD BE IN THE MID 30S TO LWR 40S... WARMEST IN THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR. COLD FRONT IS STILL ON TRACK TO MOVE THRU THE AREA LATER WED AFTN/EVENING AS SFC LOW MOVES ACROSS NORTHERN PORTIONS OF ONTARIO. EVEN WITH CLOUDS/FOG (POSSIBLY DENSE) AHEAD OF THE FRONT...WARM START TO THE DAY SHOULD ALLOW TEMPS TO RISE WELL INTO THE 40S AHEAD OF THE FRONT WED. FCST SOUNDINGS FROM NAM/GFS INDICATE RAIN WILL BE PTYPE. EXCEPTION WILL BE THE FAR W LATE IN THE DAY. SOUNDINGS THERE INITIALLY SHOW COOLING WORKING IN BLO 850MB...THEN SHOW ALL OF THE PROFILE NEAR OR BLO 0C LATE AFTN...RESULTING IN CHANGE TO SNOW... WITH SLEET POSSIBLE AT LEAST BRIEFLY AS WELL. WITH SLOWER COOLING NOTED BY GEM/UKMET...OPTED TO SLOW CHANGEOVER BY A FEW HRS. NOT EXPECTING ANY SNOW/SLEET ACCUMULATION WED WITH TEMPS WELL INTO THE 30S THRU LATE AFTN OVER THE W. OTHERWISE...WITH ASSISTANCE OF RIGHT ENTRANCE OF UPPER JET...EXPECT AN AREA OF -RA TO DEVELOP (LIKELY/CATEGORICAL POPS)...MOSTLY ALONG/JUST BEHIND COLD FRONT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 405 PM EST TUE MAR 6 2012 COLD FRONT WILL BE STRETCHED FROM NE TO SW ACROSS THE CNTRL/ERN CWA AT THE START OF THE PERIOD...WHILE THE UPPER TROUGH IS STARTING TO PUSH INTO THE UPPER GREAT LKS. THIS FRONT WILL CONTINUE TO SLIDE SE INTO NRN LOWER MI DURING THE EARLY OVERNIGHT HRS. PCPN DEVELOPING ALONG THE FRONT TOMORROW AFTN WILL LARGELY BE FOCUSED OVER THE ERN CWA AT THE START OF THE PERIOD. THIS SHOULD BE FALLING AS RAIN...DUE TO THE ABUNDANT WAA FROM H925-800 LEADING TO TEMPS AT OR ABOVE 3C. FARTHER W IN CNTRL AND WRN UPPER MI...LLVL COLD AIR SURGING IN BEHIND THE FRONT WILL BRING IN A COLD LAYER FOR THE PCPN TO FALL INTO. THE MAIN QUESTION IS HOW QUICKLY THAT COLD AIR WILL SURGE IN BEHIND THE PCPN SHIFTING TO THE SE. MAY NOT BE ENOUGH COLD AIR TO ALLOW SLEET TO OCCUR...BUT DID MENTION A SLIGHT CHANCE OF IT ON THE BACK SIDE OF THE MAIN PCPN. IN ADDITION...SOME CONCERNS ON ICE CRYSTAL PRESENCE IN THE CLOUDS ON THE BACK EDGE OF THE PCPN. EVEN AS TEMPS START TO COOL BEHIND THE FRONT...THEY REALLY DON/T FALL MUCH BELOW -5C UNTIL THE BULK OF THE PCPN HAS MOVED TO THE EAST. THINKING IT WILL LARGELY BE A RAIN...THEN A QUICK PERIOD OF SLEET AND EITHER END OR BE A SLIGHT DZ/FLURRIES. THINK BEST CHANCES FOR SNOW WILL BE OVER THE W IN THE EVENING...AS THE COLD AIR ALLOWS FOR LK ENHANCEMENT WITH H900-875 TEMPS FALLING TO -8C. CLOUD DEPTH SHOULD BE LIMITED WITH THE INVERSION AROUND H850 OR 3KFT. THUS...WILL MAINLY BE FLURRIES OR LIGHT SNOW SHOWERS AND LINGERED CHANCES/SLIGHTS OVER THE NW FAVORED LOCATIONS IN THE W THROUGH THE EARLY OVERNIGHT HRS. DRY LLVL AIR WILL THEN QUICKLY WORK IN OVERNIGHT...SO HAVE DIMINISHED THE LINGERING POPS QUICKLY FROM W TO E NEAR LK SUPERIOR. THERE IS SOME POTENTIAL FOR CLEARING OVER THE INTERIOR W LATE IN THE NIGHT...WHICH COULD ALLOW TEMPS TO FALL BELOW GUIDANCE WITH PWAT VALUES AROUND 55 PERCENT OF NORMAL. WINDS WILL BE DIMINISHING WITH THE APPROACHING SFC RIDGE...BUT MAY NOT ARRIVE EARLY ENOUGH TO MAXIMIZE THE RADIATIONAL COOLING. WILL HIGHLIGHT THE COLDEST VALUES NEAR WATERSMEET WITH LOWS IN THE UPPER TEENS. UPPER TROUGH WILL BE MOVING OVER THE UPPER GREAT LAKES THROUGH THE DAY ON THURS...ALLOWING SFC LOW TO DEVELOP OVER SRN ONTARIO THURS AFTN AND INTENSIFY AS IT MOVES SE ON THURS NIGHT. DRY AIR ABOVE H850 BEHIND THE FRONT WILL BE PUSHING FROM NW TO SE ACROSS THE AREA THURS MORN AHEAD OF SECONDARY TROUGH BRINGING DEEPER MOISTURE AND COLDER AIR. THINK THIS WILL LEAD TO A PERIOD OF PARTLY CLOUDY TO MOSTLY SUNNY SKY OVER MUCH OF THE CWA IN THE MORNING. THEN...AS THE TROUGH MOVES INTO THE AREA AND BRINGS DEEPER MOISTURE AND H850-700 Q-VECTOR CONV...HAVE INCREASED CLOUDS AND BRING SLIGHT/CHANCES OF SNOW BACK IN THE AFTN NEAR LK SUPERIOR. UPPER TROUGH WILL START TO PUSH E ON THURS NIGHT AND CONTINUE E ON FRI...AS RIDGING STARTS TO MOVE OVER THE AREA AND SFC HIGH PUSHES INTO THE WRN GREAT LKS. WITH SECONDARY COLD FRONT DROPPING SE ACROSS LK SUPERIOR...EXPECT ADDITIONAL LLVL MOISTURE AND FALLING H850 TEMPS TOWARDS -13C TO LEAD TO INCREASING LAKE EFFECT/ENHANCEMENT FOR AREAS NEAR LK SUPERIOR. WITH THE STRONG NW AND THEN NNW WINDS...EXPECT CLOUD COVER TO SPREAD ACROSS MUCH OF THE AREA THURS NIGHT AND CONTINUE INTO FRI MORNING. WITH THE COLD AIR SPILLING IN...EXPECT GUSTY WINDS AS H925 WINDS TO 35KTS OVER THE NE HALF OF THE CWA TO MIX TO THE SFC AND PRODUCE 25-35KT GUSTS NEAR LK SUPERIOR E OF MARQUETTE. OVERALL...DON/T EXPECT TOO MUCH SNOW ACCUM AS THE PERIOD OF FAVORABLE CONDITIONS IT FAIRLY LIMITED ON THURS NIGHT...BEFORE DRIER AIR ARRIVES AND LOWERING INVERSION HEADING THROUGH THE DAY ON FRI. IN ADDITION...WITH THE INCREASING H850 WAA ON FRI AFTN OVER THE WRN LK WILL ALSO AID TO END THE LINGERING LES FROM W TO E THROUGH THE DAY FRI. ALL IN ALL...THURS AND FRI LOOK TO BE A PERIOD OF NORMAL TO BELOW NORMAL TEMPS ACROSS THE AREA AHEAD OF THE POTENTIAL WARM-UP FOR THE WEEKEND INTO NEXT WEEK. DAYS 4 THROUGH 7 /FRI NIGHT THROUGH TUESDAY/... UPPER LOW SPINNING OVER THE FOUR CORNERS REGION ON FRI NIGHT WILL BEGIN TO GET CAUGHT UP WITH THE FLOW AND DRIFT NNE. MEANWHILE...NEARLY ZONAL FLOW NRN STREAM LOOKS TO BE SETUP OVER SRN CANADA...KEEPING THE COLD AIR WELL N OF THE UPPER GREAT LKS. 12Z RUNS CONTINUE THE DIFFERENCES WITH THE TRACK OF THE UPPER LOW. HPC PREFERS A CONSENSUS SOLN NOT INCLUDING THE GFS...WHICH TRACKS THE LOW MUCH FASTER AND FARTHER SE. 12Z RUN IS THE SAME AND REMAINS VERY CONSISTENT OVER THE LAST SEVERAL RUNS...WHICH COULD LEAD SOME CREDIT TO THE THAT SOLN. ENS MEAN ON ECMWF/GEM IS A LITTLE SLOWER THAN THE DETERMINISTIC RUN...BUT FOLLOWS A SIMILAR TRACK. OVERALL CONSENSUS PULLS THE UPPER LOW THROUGH THE GREAT LKS REGION SUN INTO MON. WILL CONTINUE TO MENTION CHANCE POPS ACROSS THE AREA...WHICH SHOULD FALL AS RAIN DUE TO THE WARM AIR ALREADY IN PLACE. EXTENDED MODELS CONTINUE TO SHOW THE POTENTIAL FOR A BIG WARM UP BEHIND THE UPPER LOW THAT MOVES THROUGH THE GREAT LKS. AMPLIFYING AND NEARLY STATIONARY TROUGH OFF THE W COAST OF THE CONUS WILL LEAD TO AMPLIFYING RIDGE OVER THE CANADIAN PRAIRIES. THIS WILL ALLOW SFC HIGH TO BE STATIONED OVER THE ERN CONUS AND WITH THE MAIN LOWS TRACKING WELL TO THE N THROUGH CANADA...EXPECT SRLY FLOW TO BE SETUP OVER THE CWA. CONSENSUS OF THE MODELS GIVES VALUES IN THE 40S AND NEAR 50 ALONG THE WI BORDER FOR HIGHS ON TUES. THIS IS USUALLY UNDER DONE IN WELL ABOVE NORMAL SITUATIONS AND THE ECMWF /WHICH ALMOST ALWAYS VERIFIES THE BEST IN THESE ABOVE NORMAL SITUATIONS/ HAS VALUES ABOUT 7-10 DEGREES WARMER THAN THE CONSENSUS. THE TEMPS LOOK TO GET EVEN WARMER HEADING INTO WED/THURS. ECMWF HAS TEMPS FOR WED/THURS OF NEXT WEEK OVER THE W HALF IN THE 60S WITH COOLER TEMPS NEAR LK MI WITH THE SSW FLOW. ECMWF EVEN ATTEMPTS TO TRY AN PUSH A FEW 70S ALONG THE WI BORDER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1238 PM EST TUE MAR 6 2012 VFR CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW INTO EARLY EVENING. INCREASING LOW-LEVEL MOISTURE OVER SNOWPACK SHOULD RESULT IN LOW CLOUDS/FOG DEVELOPING TONIGHT...WITH BEST CHC OF LOW MVFR/POSSIBLE IFR CIG AT KSAW DUE TO UPSLOPE COMPONENT TO SOUTHERLY WIND. DOWNSLOPE NATURE OF SOUTHERLY WIND AT KIWD/KCMX SHOULD HELP TO MAINTAIN VFR CONDITIONS AT THOSE SITES. WITH FAIRLY STRONG WINDS ABOVE LOW-LEVEL INVERSION...EXPECT LLWS TONIGHT. IFR CIGS ARE LIKELY TO SETTLE IN AT ALL SITES WED MORNING AS LOW-LEVEL MOISTURE CONTINUES TO INCREASE AHEAD OF APPROACHING COLD FRONT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 405 PM EST TUE MAR 6 2012 SOUTHERLY WINDS OF 20-30KT OVER ERN LAKE SUPERIOR (LIGHTER OVER THE W) AHEAD OF AN APPROACHING COLD FRONT WILL SLOWLY DIMINISH TONIGHT. WINDS SHOULD MOSTLY DROP OFF BLO 20KT FOR MUCH OF WED AS THE COLD FRONT ARRIVES. WITH THE PASSAGE OF COLD FRONT...NW WINDS WILL BE ON THE INCREASE WED EVENING AND THEN THRU THU AS A FOLLOWING LOW PRES CENTER PASSES SE ACROSS NRN ONTARIO. UNDER CAA/INCREASING OVERWATER INSTABILITY...NW WINDS WILL INCREASE TO 20-30KT...ESPECIALLY THU/THU NIGHT. GALES ARE A POSSIBILITY. WINDS WILL DIMINISH TO UNDER 20KT BY LATE FRIDAY AFTN AS HIGH PRESSURE BUILDS INTO THE REGION. ON THE BACKSIDE OF THE HIGH...SW WINDS WILL RAMP BACK UP TO 20-30KT SAT. && .HYDROLOGY... ISSUED AT 405 PM EST TUE MAR 6 2012 EVEN WITH THE WARM TEMPS OVER THE NEXT 24-36 HOURS...DON/T EXPECT MUCH IF ANY MELTING TO OCCUR DUE TO THE UN-RIPE CONDITIONS OF THE SNOW PACK. LOOKING AT NOHRSC CURRENT AND FUTURE SNOWPACK TEMPERATURES...ONLY THE TOP AND MIDDLE LAYERS /TOP 2-10 INCHES DEPENDING ON LOCATION/ OF THE SNOWPACK BECOME RIPE OVER THE SW HALF OF THE CWA BY WED EVENING. THIS WILL LIKELY LEAD TO SOME COMPACTION/MELTING OF THE TOP OF THE EXISTING SNOWPACK...BUT IT SHOULD STILL RETAIN THE WATER AND KEEP MUCH OR ALL OF THE MOISTURE IN THE SNOWPACK THROUGH WED EVENING. WITH COOLER TEMPERATURES EXPECTED BEHIND THE COLD FRONT ON WED...DON/T EXPECT ANY MELTING TO OCCUR WED NIGHT INTO SAT. WITH THE WARMING TREND EXPECTED DURING THE WEEKEND AND INTO NEXT WEEK...WILL NEED TO KEEP AN EYE ON A SLOWLY RIPENING SNOWPACK. THE POTENTIAL FOR RAIN ON SUN/MON MAY ASSIST IN THIS RIPENING THROUGH THE FIRST PART OF NEXT WEEK. THE POTENTIAL FOR MELTING OF THE SNOWPACK COULD GREATLY INCREASE HEADING INTO THE MIDDLE OF NEXT WEEK...AS OVERNIGHT LOWS AND TD VALUES RISE ABOVE FREEZING. THE EXTENDED MODELS HAVE BEEN SHOWING WELL ABOVE NORMAL TEMPERATURES /10 PLUS DEGREES/ FOR THE MIDDLE OF NEXT WEEK. IF THE WARM TEMPS SHOWN ON THE ECMWF /HIGHS IN THE 60S FOR WED AND THURS/ COME TO FRUITION...THE MELT MAY BE FAIRLY FAST AND RUN OFF DIRECTLY INTO AREA RIVERS. THUS...WILL NEED TO KEEP AN EYE ON AREA RIVERS AND STREAMS NEXT WEEK FOR THE POTENTIAL OF RISING LEVELS DUE TO SNOWMELT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...ROLFSON SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...ROLFSON HYDROLOGY...SRF
AREA FORECAST DISCUSSION
NWS GLASGOW MT
950 AM MST TUE MAR 6 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY... UPDATE...SPLITTING UPPER TROUGH CONTINUES TO PUSH THROUGH NORTHEAST MONTANA. BAND OF LIGHT RAIN CURRENTLY LIES FROM PLENTYWOOD THROUGH JORDAN AND CONTINUES TO SLOWLY DRIFT TO THE SOUTH AND EAST. SURFACE COLD FRONT IS PUSHING IN BEHIND THIS BAND...WITH NORTHWEST WINDS INCREASING AND TEMPERAUTRES FALLING BEHIND THE FRONT. UPDATED TO ADJUST POPS CLOSER TO RADAR OBSERVATIONS THIS MORNING...AND IN LINE WITH THE HRRR MODEL THIS AFTERNOON WHICH IS CURRENTLY THE PERFORMER AMONG THE DIFFERENT MODELS. PRECIP WILL HAVE ENDED BY LATE AFTERNOON/EARLY EVENING...WITH COLDER TEMPERATURES EXPECTED TONIGHT. GILCHRIST PREVIOUS DISCUSSION...UPPER SPLITTING TROUGH IS MOVING IN FROM THE NORTHWEST AND AS MODELS HAVE BEEN SAYING OVER THE LAST SEVERAL DAYS. THE UPPER TROUGH WILL SPLIT WITH MOST OF THE ENERGY FOLLOWING THE SOUTHERN PART BECOMING A CLOSED CUT OFF SYSTEM OVER THE FOUR CORNERS AREA. THE NORTHERN PART HAS ALREADY COLLECTED THE QUASI STATIONARY FRONT ACROSS SOUTHERN CANADA AND WILL PUSH IT SOUTH AND EAST INTO EASTERN MONTANA AS WE GO THROUGH THE DAY. IT LOOKS LIKE THE REALLY BIG DROP IN TEMPERATURES WILL OCCUR THIS AFTERNOON AS THE CONTINENTAL POLAR AIR MASS MOVES IN FROM THE NORTHWEST. MOST HIGHS WILL OCCUR EARLY TUESDAY WITH MODERATELY STRONG COLD AIR ADVECTION DROPPING 850 MB TEMPS TO AS LOW AS -13C IN OUR N BY 5 PM TUESDAY. WINDS AT 850 MB ARE AROUND 30 KNOTS BEHIND THE FRONT IN THE AFTERNOON SO EXPECT A MODERATE NORTHWEST WIND MAKING TEMPERATURES FEEL MUCH COLDER AS THESE WIND MIX TO THE SURFACE. THE ONE THING ABOUT THIS SYSTEM IS THE MODELS ARE SLIGHTLY OFF ON PLACEMENT OF THE SURFACE FRONT AND SURFACE LOW THIS MORNING. THE LATEST 09Z RUC IS IN BETTER AGREEMENT WITH SURFACE OBSERVATIONS AND THE FRONT IS MUCH FARTHER SOUTH THEN THE 00Z MODELS WERE INDICATING. THIS IS INTERESTING SINCE THE LAST THREE CLIPPER SYSTEMS WE HAVE HAD MOVE THROUGH WERE FARTHER SOUTH THEN THE MODELS INDICATED. SO DECIDED TO RAISE POPS TO THE LIKELY CATEGORY AND EVEN THOUGHT ABOUT A WINTER HIGHLIGHT BUT DECIDE AGAINST IT. SINCE MOST OF THE PRECIP WILL BE RIGHT ALONG THE FRONT AND BEFORE 18Z AND THE SNOW WILL BE ELEVATION DEPENDENT IN THE MORNING. ANYTHING ABOVE 3000 FT IS LIKELY TO SEE SNOWFALL WHILE EVERY ELSE IT WILL BE A MIX OF RAIN AND SNOW. AFTER 18Z ONCE THE COLD AIR ADVECTION BECOMES STRONG THE WINTRY MIX WILL BECOME ALL SNOW ACROSS THE REGION FROM WEST TO EAST. ONCE THE PRECIPITATION TURNS OVER TO SNOW IT WILL NOT LAST VERY LONG SO EXPECT ANY SNOWFALL TOTALS TO BE LESS THE 1/2 AN INCH. A FEW OF THESE SPOTS ABOVE 3000 FT THAT WILL SEE LONGER PERIODS OF SNOW SHOWERS WHICH MEANS SLIGHTLY MORE IN THE WAY OF ACCUMULATION...BUT THE TOTAL WILL REMAIN BELOW 2 INCHES. THE STRONGER WINDS BEHIND THE FRONT WILL BLOW AROUND THE FALLING SNOW BUT THE NEW SNOWFALL SHOULD BE FAIRLY WET SO ONCE IT REACHES THE GROUND IT IS GOING TO BE HARD TO PICK UP. I DON`T EXPECT ANY FREEZING RAIN WITH THIS SYSTEM BUT SINCE IT WILL START OUT AS LIGHT RAIN IN MOST AREAS IT COULD PUT ENOUGH WATER ON THE SURFACE THAT WHEN THE FREEZING TEMPERATURES ARRIVE LATER IN THE AFTERNOON WE WILL SEE BLACK ICE FORMING ON SURFACES. ANOTHER THING TO BE LOOKING OUT FOR IN THE AFTERNOON. THE REST OF THE SHORT TERM FORECAST LOOKS THIS WAY. TUESDAY NIGHT WINDS DIE OUT AND THE SKIES WILL BECOME PARTLY CLOUDY WITH A MODIFIED POLAR SURFACE HIGH FROM THE NORTHWEST OVER THE AREA. 850 TEMPS OF -13C WILL MEAN LOWS 5 TO 15. WEAK RIDGING AND WARMING OF THE AIR MASS FOR WEDNESDAY AND THURSDAY WITH DRY WEATHER AND MOSTLY CLEAR SKIES. RSMITH .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE EXTENDED BEGINS WITH A POSITIVE TILT RIDGE OVER THE NORTHERN ROCKIES AND NORTHEAST MONTANA. AN UPPER LOW OVER THE SOUTH CENTRAL CONUS IS BLOCKING UP THE FLOW KEEPING THE NORTHERN BRANCH OF THE JET OVER NORTHERN CANADIAN PRAIRIES. THIS IS WELL AGREED UPON BY THE 00Z MODEL SUITE. THE MODELS THEN DIFFER GREATLY ON THE EJECTION OF THE UPPER LOW INTO THE GREAT LAKES REGION... HOWEVER FOR NORTHEAST MONTANA THE GFS AND EC EVOLVE INTO A SIMILAR PATTERN KEEPING THE REGION DRY AND MILD FOR THE REMAINDER OF THE EXTENDED PERIOD. THEREFORE THE CONFIDENCE IN MODEL PERFORMANCE IS LOW... THE OVERALL SOLUTION CONFIDENCE IN THE OPERATIONAL FORECAST IS HIGH. LOOK FOR AFTERNOON HIGHS IN THE 50S WITH VARIABLE HIGH CLOUDS THROUGH THE PERIOD. PROTON && .AVIATION... VFR. A COLD FRONT MOVING THROUGH SOUTHERN SASKATCHEWAN AND CENTRAL MONTANA THIS MORNING WILL CONTINUE TO MOVE TOWARDS NORTHEAST MONTANA. THE FRONT SHOULD MOVE THE GLASGOW AREA AROUND 17Z AND EXIT THE EASTERN AREAS BY 22Z. PRE-FRONTAL LOOK FOR AREAS OF RAIN SHOWERS AND LOW VFR CONDITIONS. POST FRONTAL MODERATE NORTHWEST WINDS AND SCATTERED SNOW SHOWERS MAY DROP FLIGHT LEVELS TO MVFR BRIEFLY. EXPECT VFR TO DOMINATE ALL AREAS BY 03Z. PROTON/AES && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
404 AM MST TUE MAR 6 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY... UPPER SPLITTING TROUGH IS MOVING IN FROM THE NORTHWEST AND AS MODELS HAVE BEEN SAYING OVER THE LAST SEVERAL DAYS. THE UPPER TROUGH WILL SPLIT WITH MOST OF THE ENERGY FOLLOWING THE SOUTHERN PART BECOMING A CLOSED CUT OFF SYSTEM OVER THE FOUR CORNERS AREA. THE NORTHERN PART HAS ALREADY COLLECTED THE QUASI STATIONARY FRONT ACROSS SOUTHERN CANADA AND WILL PUSH IT SOUTH AND EAST INTO EASTERN MONTANA AS WE GO THROUGH THE DAY. IT LOOKS LIKE THE REALLY BIG DROP IN TEMPERATURES WILL OCCUR THIS AFTERNOON AS THE CONTINENTAL POLAR AIR MASS MOVES IN FROM THE NORTHWEST. MOST HIGHS WILL OCCUR EARLY TUESDAY WITH MODERATELY STRONG COLD AIR ADVECTION DROPPING 850 MB TEMPS TO AS LOW AS -13C IN OUR N BY 5 PM TUESDAY. WINDS AT 850 MB ARE AROUND 30 KNOTS BEHIND THE FRONT IN THE AFTERNOON SO EXPECT A MODERATE NORTHWEST WIND MAKING TEMPERATURES FEEL MUCH COLDER AS THESE WIND MIX TO THE SURFACE. THE ONE THING ABOUT THIS SYSTEM IS THE MODELS ARE SLIGHTLY OFF ON PLACEMENT OF THE SURFACE FRONT AND SURFACE LOW THIS MORNING. THE LATEST 09Z RUC IS IN BETTER AGREEMENT WITH SURFACE OBSERVATIONS AND THE FRONT IS MUCH FARTHER SOUTH THEN THE 00Z MODELS WERE INDICATING. THIS IS INTERESTING SINCE THE LAST THREE CLIPPER SYSTEMS WE HAVE HAD MOVE THROUGH WERE FARTHER SOUTH THEN THE MODELS INDICATED. SO DECIDED TO RAISE POPS TO THE LIKELY CATEGORY AND EVEN THOUGHT ABOUT A WINTER HIGHLIGHT BUT DECIDE AGAINST IT. SINCE MOST OF THE PRECIP WILL BE RIGHT ALONG THE FRONT AND BEFORE 18Z AND THE SNOW WILL BE ELEVATION DEPENDENT IN THE MORNING. ANYTHING ABOVE 3000 FT IS LIKELY TO SEE SNOWFALL WHILE EVERY ELSE IT WILL BE A MIX OF RAIN AND SNOW. AFTER 18Z ONCE THE COLD AIR ADVECTION BECOMES STRONG THE WINTERY MIX WILL BECOME ALL SNOW ACROSS THE REGION FROM WEST TO EAST. ONCE THE PRECIPITATION TURNS OVER TO SNOW IT WILL NOT LAST VERY LONG SO EXPECT ANY SNOWFALL TOTALS TO BE LESS THE 1/2 AN INCH. A FEW OF THESE SPOTS ABOVE 3000 FT THAT WILL SEE LONGER PERIODS OF SNOW SHOWERS WHICH MEANS SLIGHTLY MORE IN THE WAY OF ACCUMULATION...BUT THE TOTAL WILL REMAIN BELOW 2 INCHES. THE STRONGER WINDS BEHIND THE FRONT WILL BLOW AROUND THE FALLING SNOW BUT THE NEW SNOWFALL SHOULD BE FAIRLY WET SO ONCE IT REACHES THE GROUND IT IS GOING TO BE HARD TO PICK UP. I DON`T EXPECT ANY FREEZING RAIN WITH THIS SYSTEM BUT SINCE IT WILL START OUT AS LIGHT RAIN IN MOST AREAS IT COULD PUT ENOUGH WATER ON THE SURFACE THAT WHEN THE FREEZING TEMPERATURES ARRIVE LATER IN THE AFTERNOON WE WILL SEE BLACK ICE FORMING ON SURFACES. ANOTHER THING TO BE LOOKING OUT FOR IN THE AFTERNOON. THE REST OF THE SHORT TERM FORECAST LOOKS THIS WAY. TUESDAY NIGHT WINDS DIE OUT AND THE SKIES WILL BECOME PARTLY CLOUDY WITH A MODIFIED POLAR SURFACE HIGH FROM THE NORTHWEST OVER THE AREA. 850 TEMPS OF -13C WILL MEAN LOWS 5 TO 15. WEAK RIDGING AND WARMING OF THE AIR MASS FOR WEDNESDAY AND THURSDAY WITH DRY WEATHER AND MOSTLY CLEAR SKIES. RSMITH .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE EXTENDED BEGINS WITH A POSITIVE TILT RIDGE OVER THE NORTHERN ROCKIES AND NORTHEAST MONTANA. AN UPPER LOW OVER THE SOUTH CENTRAL CONUS IS BLOCKING UP THE FLOW KEEPING THE NORTHERN BRANCH OF THE JET OVER NORTHERN CANADIAN PRAIRIES. THIS IS WELL AGREED UPON BY THE 00Z MODEL SUITE. THE MODELS THEN DIFFER GREATLY ON THE EJECTION OF THE UPPER LOW INTO THE GREAT LAKES REGION... HOWEVER FOR NORTHEAST MONTANA THE GFS AND EC EVOLVE INTO A SIMILAR PATTERN KEEPING THE REGION DRY AND MILD FOR THE REMAINDER OF THE EXTENDED PERIOD. THEREFORE THE CONFIDENCE IN MODEL PERFORMANCE IS LOW... THE OVERALL SOLUTION CONFIDENCE IN THE OPERATIONAL FORECAST IS HIGH. LOOK FOR AFTERNOON HIGHS IN THE 50S WITH VARIABLE HIGH CLOUDS THROUGH THE PERIOD. PROTON && .AVIATION... VFR. A COLD FRONT MOVING THROUGH SOUTHERN ALBERTA EARLY THIS MORNING WILL CONTINUE TO MOVE TOWARDS NORTHEAST MONTANA. THE FRONT SHOULD MOVE THE GLASGOW AREA AROUND 12Z AND EXIT THE EASTERN AREAS BY 16Z. PRE-FRONTAL LOOK FOR AREAS OF RAIN SHOWERS AND LOW VFR CONDITIONS. POST FRONTAL MODERATE NORTHWEST WINDS AND SCATTERED SNOW SHOWERS MAY DROP FLIGHT LEVELS TO MVFR BRIEFLY. EXPECT VFR TO DOMINATE ALL AREAS BY 03Z. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
752 PM CST WED MAR 7 2012 .DISCUSSION...MAIN CONCERN WILL BE BAND OF SNOW SHOWERS ACROSS CENTRAL NORTH DAKOTA ASSOCIATED WITH UPPER WAVE. HRRR INDICATES THESE SNOW SHOWERS WILL HOLD TOGETHER AS THE FORCING PROPAGATES THROUGH THE FA. TIMED 30 POPS AND SCATTERED SNOW SHOWERS FOR TONIGHT. ACCUMULATION WILL BE MINIMAL IF ANYTHING. ALSO ADJUSTED TEMPS ACCORDING TO HRRR...BUT THIS LED TO ONLY MINIMAL CHANGES. && .AVIATION...A MAJORITY OF THE OVERNIGHT AND MORNING HOURS WILL BE VFR. HOWEVER...THERE IS A PATCH OF IFR/MVFR CIGS THAT COULD BRIEFLY AFFECT KTVF AND KFAR THIS EVENING. THEN...THERE IS A NARROW BAND OF SNOW SHOWERS THAT WILL MOVE THROUGH THE REGION LATER IN THE NIGHT. WINDS ON THURSDAY WILL BE 20-30 KNOTS. && .PREV DISCUSSION... /ISSUED 309 PM CST WED MAR 7 2012/ SHORT TERM... CHALLENGES FOR THE FORECAST INCLUDE EXTENT OF WARM UP FOR THE END OF THE WEEK AND A CONCERN FOR LIGHT SNOW THURSDAY WITH THE PASSAGE OF A WEAK WAVE TO OUR NORTH. MODELS IN GOOD AGREEMENT AND WILL USE A BLEND FOR THE FORECAST. TONIGHT EXPECTING THE CLEAR SKIES UNDER THE WEAK SFC RIDGE AXIS CURRENTLY EXTENDING FROM NW ND NE ACROSS CENTRAL MANITOBA TO SLIDE EAST AND ALLOW SOME RADIATIONAL COOLING. HOWEVER THE NEXT TROUGH OF LOW PRESSURE WILL BRING SOME CLOUDS INTO THE FA QUICKLY SLOWING NIGHTTIME COOLING. WINDY TOMORROW BEHIND FROPA AND 850MB WINDS BETWEEN 30 AND 40KTS AND WITH A NEARLY ADIABATIC MIXED LAYER COULD SEE SOME OF THE GUSTS REALIZE THAT POTENTIAL ESPECIALLY IN THE HIGHER DVL BSN ELEVATIONS. THURSDAY EVENING WINDS QUICKLY DECOUPLE AS 1030MB SOMETHING SFC HIGH PRESSURE MOVES INTO THE REGION. CENTER OF THE HIGH WITH 850MB TEMPS IN THE -5 TO -10 C SHOULD BE OVER EASTERN ZONES FRI AM AND SO WENT MUCH COOLER WITH LOWS TOWARD THE GEM GUIDANCE BUT NOT AS COLD...SINGLE DIGITS NRRV AND EASTERN ZONES. WARM UP FOR THE WEEKEND BEGINS FRIDAY AS 500MB RIDGING AND THICKNESSES INCREASE WITH STRONG LOW LEVEL WAA AS 850MB TEMPS INCREASE TO 8 TO 12 C BY SATURDAY AFTERNOON. HIGHS FRIDAY WILL STRUGGLE AS SSE VALLEY WINDS NOT FAVORABLE FOR EFFICIENT WARMING...MUCH LIKE THIS PAST MONDAY. WINDS TO SHIFT TO THE WEST FOR SATURDAY WITH AFOREMENTIONED 850MB TEMPS AND GOOD MIXING WILL SEE HIGHS IN THE UPPER 40S TO LOW 50S WHERE SNOW PACK IS NONEXISTENT. LONG TERM... MODEL PROGS LIFT AN UPPER LOW NEWD ACROSS THE CENTRAL PLAINS ON SUN THEN INTO THE GTLKS REGION ON MON. TIMING AND PLACEMENT OF THIS SYSTEM IS IN DISAGREEMENT AMONGST THE MODELS WITH THE ECMWF THE QUICKEST AND THE GEM KEEPING THE LOW MUCH FURTHER SOUTH. THE NET RESULT IS A SLIGHT CHC OF RAIN FOR THE FAR SW ZONES SUN/SUN NIGHT...THOUGH LOOKING LESS PROBABLE WITH EACH MODEL RUN. WITH THE UPPER LOW OFF TO THE EAST BUILDING HEIGHTS AND WARMING 8H TEMPS SHOULD BRING OUR FIRST OPPORTUNITY FOR EXCEEDING 50 DEGREES BY MON FOLLOWED BY NEAR 60 DEGREE TEMPS IN THE FAR SOUTHERN ZONES ON WED. THE QUESTION WILL BE HOW FAST THE SNOW PACK MELTS AND THE AMOUNT OF MIXING FOR NEXT WEEK...THOUGH A WESTERLY WINDS SHOULD HELP. THE WARMTH SHOULD CONTINUE THRU NEXT WEEK BEFORE THE NEXT SYSTEM APPROACHES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
208 AM MST THU MAR 8 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 200 AM MST THU MAR 8 2012 THE UPPER LEVEL LOW WAS SAGGING SOUTH ALONG THE AZ-NM BORDER THIS MORNING THEN WILL EJECT SLOWLY EAST ACROSS SOUTHERN NM THIS AFTERNOON. ASSOCIATED DYNAMICAL LIFT IS SOUTH OF THE CWA AND WRAP- AROUND MOISTURE IS LIMITED. THIS WOULD PRODUCE SOME LIGHT ACCUMULATION IN THE VICINITY OF MONARCH...SLUMGULLION...AND WOLF CREEK PASSES TODAY. THE HRRR AND NAM12 ALSO PRODUCE LIGHT ACCUMULATION OVER THE MANCOS RIDGE THROUGH THIS AFTERNOON. OTHERWISE MOSTLY SUNNY SKIES WILL PREVAIL. AT THE SURFACE LOW PRESSURE NEAR THE FOUR CORNERS AND COLD HIGH PRESSURE PUSHING DOWN THE FRONT RANGE IS PRODUCING NE GRADIENT WINDS. MTN TOP NE WINDS ARE GUSTING 20-30 OVER EXPOSED TERRAIN. THE GRADIENT RELAXES THROUGH THE AFTERNOON. TONIGHT THE UPPER LOW SETTLES ONTO THE EASTERN NM PLAINS WHERE IT WILL LANGUISH INTO THE WEEKEND. THIS KEEPS THE FORECAST AREA IN A LIGHT EAST FLOW ALOFT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 256 PM MST WED MAR 7 2012 MEDIUM RANGE MODELS CONTINUE TO SHOW THE LOW SITTING OVER THE EASTERN NEW MEXICO AND WEST TEXAS REGIONS THROUGH FRIDAY...BEFORE IT EJECTS NORTH NORTHEAST INTO THE PLAINS THIS WEEKEND. NOT ANTICIPATING MUCH IN THE WAY OF IMPACT ON OUR FORECAST AREA...ALTHOUGH CANNOT RULE OUT A STRAY SHOWER OR TWO FOR THE EASTERN STRETCHES OF OUR SAN JUAN MOUNTAINS. HIGH PRESSURE WILL FINALLY PUSH ACROSS THE FORECAST AREA BY SUNDAY WITH TEMPS CLIMBING BACK TO ABOVE SEASONAL NORMS. THE RIDGE TRANSLATES EAST BY EARLY NEXT WEEK...WITH SOUTHWEST FLOW STRENGTHENING AS A NEW WAVE OF PACIFIC STORMS PLOWS INTO THE PAC NW. THIS WILL BRING A RETURN TO MORE SPRING LIKE WINDS OVER THE REGION...WITH BREEZY TO WINDY CONDITIONS EXPECTED MONDAY THROUGH WEDNESDAY. FEW WEAK DISTURBANCES WILL ALSO PASS THROUGH...ONE MONDAY NIGHT AND ANOTHER TUESDAY NIGHT...BRINGING A SLIGHT CHANCE OF MOUNTAINS SHOWERS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 200 AM MST THU MAR 8 2012 VFR CONDITIONS WILL DOMINATE INTO FRIDAY. THE EXCEPTION IS SCT SNOW SHOWERS IN THE SOUTHERN MTNS ALONG AND EAST OF HIGHWAY 550. EXPECT SCT MVFR CIGS AND VSBY THROUGH THE AFTERNOON THERE WITH MTN TOPS OCNLY OBSCURED. WIDESPREAD SNOW SHOWERS WILL OCCUR OVER AND EAST OF MONARCH...SLUMGULLION...AND WOLF CREEK PASSES THAT WILL PRODUCE MVFR/LOCAL IFR CIGS AND VSBY. ALL OF THESE SOUTHERN SHOWERS WILL DIMINISH QUICKLY AFTER 6 PM THIS EVENING WITH VFR CONDITIONS PREVAILING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JOE LONG TERM....JDC AVIATION...JOE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
344 AM CST THU MAR 8 2012 .DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 10Z... * WEST WINDS SHIFTING TO NORTHWEST THIS MORNING WITH OCNL GUSTS TO 20-25KT. * OCNL SHOWERS/SPRINKLES/DRIZZLE THROUGH ARND 14Z. * MVFR AND OCNL IFR CEILINGS THROUGH LATE MORNING. KREIN //DISCUSSION...UPDATED 06Z... SCATTERED SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF NORTHERN ILLINOIS THIS EVENING. THIS ACTIVITY IS ASSOCIATED WITH A COLD FRONT...WHICH IS CURRENTLY APPROACHING THE ROCKFORD AREA. THIS FRONT WILL QUICKLY MOVE ACROSS ALL OF NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA OVERNIGHT TONIGHT. THE FRONTAL PASSAGE WILL RESULT IN A WIND SWITCH OUT OF THE NORTHWEST OVER THE NEXT SEVERAL HOURS. SHOWERS AND POTENTIALLY A THUNDERSTORM WILL AFFECT THE TERMINALS FOR A BRIEF PERIOD ALONG AND AHEAD OF THE FRONTAL ZONE. IT APPEARS THAT THE BEST TIMING FOR CONVECTION WILL WITHIN THE NEXT HOUR OR TWO AT KRFD...06-09 UTC FOR KORD AND KMDW AND 07 TO 10 UTC AT KGYY. MUCH IF NOT ALL OF THE PRECIPITATION WILL END DURING THE PREDAWN HOURS ON THURSDAY MORNING. ASIDE FROM THE POTENTIAL FOR A BRIEF PERIOD OF LOW MVFR CIGS OR IFR CIGS AFTER THE FRONTAL PASSAGE LATE TONIGHT...CIGS SHOULD QUICKLY REBOUND DURING THE MORNING HOURS ON THURSDAY WITH VFR CONDITIONS EXPECTED TO QUICKLY RETURN. KJB //ORD AND MDW CONFIDENCE...UPDATED 10Z... * MODERATE-HIGH CONFIDENCE WITH WIND TRENDS FOR THE REMAINDER OF THE MORNING AND THROUGH TODAY. * MODERATE CONFIDENCE IN WIND TRENDS LATER TONIGHT. * MODERATE CONFIDENCE IN CEILING TRENDS THROUGH LATE THIS MORNING. * HIGH CONFIDENCE IN CIG/VIS TRENDS FROM LATE MORNING THROUGH TOMORROW MORNING. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... * FRIDAY AND SATURDAY...VFR. * SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. * TUESDAY...VFR. KJB && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 4 AM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
329 AM CST THU MAR 8 2012 .DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * WINDS SHIFTING TO WEST NORTHWEST BETWEEN 08 AND 09 UTC TONIGHT WITH FROPA. * PERIODS OF SHOWERS AND THE POTENTIAL FOR A RUMBLE OF THUNDER FOR A SHORT PERIOD THROUGH 09 UTC. * MVFR/IFR CEILINGS POSSIBLE FOLLOWING THE FROPA. KJB //DISCUSSION...UPDATED 06Z... SCATTERED SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF NORTHERN ILLINOIS THIS EVENING. THIS ACTIVITY IS ASSOCIATED WITH A COLD FRONT...WHICH IS CURRENTLY APPROACHING THE ROCKFORD AREA. THIS FRONT WILL QUICKLY MOVE ACROSS ALL OF NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA OVERNIGHT TONIGHT. THE FRONTAL PASSAGE WILL RESULT IN A WIND SWITCH OUT OF THE NORTHWEST OVER THE NEXT SEVERAL HOURS. SHOWERS AND POTENTIALLY A THUNDERSTORM WILL AFFECT THE TERMINALS FOR A BRIEF PERIOD ALONG AND AHEAD OF THE FRONTAL ZONE. IT APPEARS THAT THE BEST TIMING FOR CONVECTION WILL WITHIN THE NEXT HOUR OR TWO AT KRFD...06-09 UTC FOR KORD AND KMDW AND 07 TO 10 UTC AT KGYY. MUCH IF NOT ALL OF THE PRECIPITATION WILL END DURING THE PREDAWN HOURS ON THURSDAY MORNING. ASIDE FROM THE POTENTIAL FOR A BRIEF PERIOD OF LOW MVFR CIGS OR IFR CIGS AFTER THE FRONTAL PASSAGE LATE TONIGHT...CIGS SHOULD QUICKLY REBOUND DURING THE MORNING HOURS ON THURSDAY WITH VFR CONDITIONS EXPECTED TO QUICKLY RETURN. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH WIND SPEED/GUSTS AND DIRECTION...AND WITH WIND SHIFT WITH FROPA. * LOW TO MEDIUM CONFIDENCE WITH THUNDER TRENDS/TIMING. * HIGH CONFIDENCE WITH MVFR CEILINGS TONIGHT AND MEDIUM CONFIDENCE WITH A BRIEF PERIOD OF IFR CEILINGS LATER TONIGHT. KJB //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... * FRIDAY AND SATURDAY...VFR. * SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. * TUESDAY...VFR. KJB && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 4 AM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
308 AM CST THU MAR 8 2012 .DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * WINDS SHIFTING TO WEST NORTHWEST BETWEEN 08 AND 09 UTC TONIGHT WITH FROPA. * PERIODS OF SHOWERS AND THE POTENTIAL FOR A RUMBLE OF THUNDER FOR A SHORT PERIOD THROUGH 09 UTC. * MVFR/IFR CEILINGS POSSIBLE FOLLOWING THE FROPA. KJB //DISCUSSION...UPDATED 06Z... SCATTERED SHOWERS HAVE DEVELOPED ACROSS PORTIONS OF NORTHERN ILLINOIS THIS EVENING. THIS ACTIVITY IS ASSOCIATED WITH A COLD FRONT...WHICH IS CURRENTLY APPROACHING THE ROCKFORD AREA. THIS FRONT WILL QUICKLY MOVE ACROSS ALL OF NORTHEASTERN ILLINOIS AND NORTHWESTERN INDIANA OVERNIGHT TONIGHT. THE FRONTAL PASSAGE WILL RESULT IN A WIND SWITCH OUT OF THE NORTHWEST OVER THE NEXT SEVERAL HOURS. SHOWERS AND POTENTIALLY A THUNDERSTORM WILL AFFECT THE TERMINALS FOR A BRIEF PERIOD ALONG AND AHEAD OF THE FRONTAL ZONE. IT APPEARS THAT THE BEST TIMING FOR CONVECTION WILL WITHIN THE NEXT HOUR OR TWO AT KRFD...06-09 UTC FOR KORD AND KMDW AND 07 TO 10 UTC AT KGYY. MUCH IF NOT ALL OF THE PRECIPITATION WILL END DURING THE PREDAWN HOURS ON THURSDAY MORNING. ASIDE FROM THE POTENTIAL FOR A BRIEF PERIOD OF LOW MVFR CIGS OR IFR CIGS AFTER THE FRONTAL PASSAGE LATE TONIGHT...CIGS SHOULD QUICKLY REBOUND DURING THE MORNING HOURS ON THURSDAY WITH VFR CONDITIONS EXPECTED TO QUICKLY RETURN. KJB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE WITH WIND SPEED/GUSTS AND DIRECTION...AND WITH WIND SHIFT WITH FROPA. * LOW TO MEDIUM CONFIDENCE WITH THUNDER TRENDS/TIMING. * HIGH CONFIDENCE WITH MVFR CEILINGS TONIGHT AND MEDIUM CONFIDENCE WITH A BRIEF PERIOD OF IFR CEILINGS LATER TONIGHT. KJB //OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z... * FRIDAY AND SATURDAY...VFR. * SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. * TUESDAY...VFR. KJB && .MARINE... 150 PM CST LOW PRESSURE CONTINUES TO MOVE ACROSS NORTHERN LAKE SUPERIOR WITH ITS ASSOCIATED COLD FRONT EXTENDING SOUTHWARD INTO THE EASTERN U.P. OF MICHIGAN AND EASTERN WISCONSIN. THE PRESSURE GRADIENT REMAINS TIGHT ACROSS THE LAKE WITH SOUTHERLY GALES CONTINUING...ESPECIALLY CLOSER TO THE LEE SHORE WHERE BETTER MIXING IS BEING ADVECTED OFF THE LAND. THE LOW WILL DEEPEN THIS EVENING AS IT MOVES INTO WESTERN QUEBEC WHICH WILL HELP FURTHER TIGHTEN THE GRADIENT ACROSS THE NORTHERN PART OF THE LAKE AND AHEAD OF THE APPROACHING FRONT. THE GRADIENT MAY RELAX JUST SLIGHTLY AHEAD OF THE FRONTAL TROUGH ACROSS THE SOUTH HALF OF THE LAKE SO WINDS MAY EASE A BIT THIS EVENING BEFORE THE FRONT PASSES. ONCE THE FRONT PASSES TONIGHT WINDS WILL FLIP TO THE WEST THEN NORTHWEST WITH SPEEDS DIMINISHING AS THE LOW LEVEL FLOW WEAKENS. SPEEDS ARE EXPECTED TO DROP BELOW GALES BY LATE EVENING OR EARLY TONIGHT NORTH AND EARLY TONIGHT SOUTH THOUGH GUSTS WILL PROBABLY REMAIN IN THE 20-25 KT RANGE IF NOT CLOSE TO 30 KT AT TIMES. WINDS WILL SHIFT WESTERLY THURSDAY AS A WEAKER LOW DROPS SOUTHEASTWARD ACROSS CENTRAL ONTARIO AND HIGH PRESSURE SPREADS ACROSS THE NORTHERN PLAINS TOWARD THE UPPER MISSISSIPPI RIVER VALLEY. UNSTABLE CONDITIONS WILL BE IN PLACE OVER THE LAKE RESULTING IN DEEP MIXING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THESE TWO SYSTEMS THURSDAY EVENING. EXPECT GUSTS TO 30 KT WITH POTENTIAL FOR 35 KT GALES AS WELL FOR AT LEAST A FEW HOURS. WINDS WILL DIMINISH LATER FRIDAY AFTERNOON AS THE HIGH CRESTS THE LAKE BUT WINDS WILL FLIP TO THE SOUTH AND QUICKLY RAMP UP FRIDAY NIGHT...ESPECIALLY NORTH. WITH WARMER AIR MOVING BACK OVER THE LAKE STABILITY WILL BECOME A CONCERN IN TERMS OF GUST POTENTIAL BUT MID RANGE GALES LOOK POSSIBLE NORTH WITH SUB GALE FORCE WINDS EXPECTED SOUTH. SPEEDS SHOULD EASE LATER SATURDAY WHILE REMAINING SOUTHERLY. LOW PRESSURE WILL THEN LIFT ACROSS THE REGION SUNDAY NIGHT OR MONDAY MORNING BUT THE TRACK IS NOT YET CLEAR SO CONFIDENCE IN WIND DIRECTION AND SPEED IS LOW BY THIS TIME. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-LMZ741- LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ870-LMZ872- LMZ874-LMZ876-LMZ878 UNTIL 4 AM THURSDAY. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
453 AM EST THU MAR 8 2012 .SHORT TERM... STRONG COLD FRONT WAS JUST COMING INTO FAR NW CWA AT 09Z AND WILL QUICKLY MOVE ACROSS THE AREA TODAY. RADAR SHOWING AREA OF LIGHT TO MODERATE SHOWERS ALONG AND BEHIND FRONT WITH SCATTERED SHOWERS OUT AHEAD OF IT. SURFACE OBS SHOWING A GOOD 10 TO 15 DEGREE TEMP DROP BEHIND FRONT WITH COLD AIR ADVECTION EXPECTED TO CONTINUE THROUGH THE DAY WITH LITTLE RECOVERY IN TEMPS EXPECTED. HAVE TRIED TO TIME FRONT THROUGH THE AREA WITH TEMPERATURE DROP AND PCPN TRENDS. VERY DIFFICULT TO SAY THE LEAST AND ADJUSTMENTS WILL BE NECESSARY THROUGH THE MORNING. REGIONAL RADAR MOSAIC AND SATELLITE ALSO SHOWING AN AREA OF CONVECTION THAT HAS DEVELOPED OVERNIGHT IN OK AND KS AND IS MOVING NORTHEAST. HRRR SEEMS TO BE ONLY MODEL TO HAVE A DECENT HANDLE ON THIS WITH 04Z AND 05Z MODEL RUNS HAVING THIS WAVE COMING INTO NW INDIANA AROUND 14Z. DISCUSSION WITH HPC SUGGEST 06Z RUN TRENDING FARTHER EAST BUT GIVEN LOOKS OF RESPONSIBLE SHORT WAVE ON WATER VAPOR AND RECENT RADAR MOSAIC TRENDS HAVE CONCERNS THAT THIS MAY MOVE BACK INTO PART OF CENTRAL OR WEST CENTRAL CWA BY MID MORNING. FOR THIS REASON HAVE SLOWED THE TREND OF CLEARING POPS ACROSS THE AREA BY ABOUT 3 TO 5 HOURS TO ACCOUNT FOR THE POSSIBILITY OF THIS RAIN MOVING BACK IN. BY AFTERNOON THIS WAVE LOOKS TO CLEAR THE AREA AND RAPID DRYING BEGINS AND SHOULD SEE CLEARING SKIES. ANOTHER FAST MOVING SHORT WAVE PASSES TO THE NORTH TONIGHT BUT DRIVES SECONDARY COLD FRONT THROUGH. MAY SEE SOME INCREASE IN CLOUDS NORTH WITH THIS WAVE AND LAKE PLUME AS DELTA T VALUES CLIMB INTO THE TEENS. REMAINDER OF SHORT TERM FORECAST DRY WITH HIGH PRESSURE MOVING IN FRIDAY NIGHT. THIS SHOULD ALLOW WINDS TO DECOUPLE AND EXPECT GOOD RADIATIONAL COOLING BEFORE RETURN FLOW TRIES TO DEVELOP LATE. HAVE LOWERED TEMPS FRIDAY NIGHT. && .LONG TERM... SATURDAY THROUGH WEDNESDAY...A LONG WAVE TROF WILL BECOME ENTRENCHED ALONG THE WESTERN NORTH AMERICAN COAST WITH LARGE SCALE AMPLIFICATION DOWNSTREAM OVER THE CENTRAL AND EASTERN CONUS. MUCH WARMER AIR WILL RETURN TO THE AREA AND PERSIST THROUGH NEXT WEEK. SHORT WAVE ENERGY WILL EJECT NORTHEAST AND PROVIDE A CHANCE FOR SHOWERS THROUGH MOST OF THE PERIOD AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO RIVER. THE GFS ENSEMBLE MEMBERS HAVE FINALLY COME INTO REASONABLE AGREEMENT WITH ONE ANOTHER WITH MUCH SMALLER STANDARD DEVIATIONS REFLECTED IN THE MEX MOS. THERE IS POTENTIAL FOR HIGHS TO TOP 70 DEGREES DURING THE LATTER HALF OF THIS PERIOD. HOWEVER...GIVEN THE POTENTIAL FOR CLOUDS AND RAINFALL...KEPT HIGHS IN THE MID TO UPPER 60S TUESDAY/WEDNESDAY. ALSO...THERE IS AN OUTSIDE CHANCE ONE OF THE SHORTWAVES MAY BE ABLE TO TAP A LITTLE COOLER AIR AFTER THE SHORT WAVE PASSES. && .AVIATION... CONDITIONS TO DETERIORATE NEXT FEW HOURS AHEAD OF POTENT COLD FRONT. THETA E ADVECTION ONGOING WITH MOISTURE POOLED ALONG FRONT. RADAR SHOWING LARGE AREA OF SHOWERS MOVING TOWARD TAF SITES AND SATELLITE/OBS INDICATE MVFR AND OCCASIONAL IFR CONDITIONS. CANNOT RULE OUT VERY ISOLATED THUNDER SO LEFT CB MENTION IN. PCPN SHOULD END FROM WEST TO EAST THURSDAY BEGINNING AROUND 12 TO 14Z AT KSBN AND 15 TO 17Z AT KFWA. MVFR CLOUDS WILL LINGER AFTER FROPA BUT DRIER AIR IN THE AFTERNOON SHOULD SCOUR THINGS OUT. A WEAK SHORT WAVE TONIGHT COUPLED WITH FLOW DEVELOPING OFF LAKE MICHIGAN WITH DELTA T VALUES IN LOWER TEENS SUGGEST POSSIBLE LAKE CLOUD DEVELOPMENT LATE IN THE PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EST FRIDAY FOR LMZ043-046. && $$ SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS WICHITA KS
1210 AM CST THU MAR 8 2012 .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL AFFECT ALL TERMINALS FOR THE NEXT FEW HOURS. LOW LEVEL DRY AIR WILL ARRIVE FROM THE NORTH AND END PRECIPITATION BEFORE DAYBREAK IN CENTRAL KS...AND AROUND DAYBREAK AT KICT/KHUT. PRECIPITATION WILL LIKELY LINGER INTO THE MORNING AT KCNU. BRIEF PERIODS OF MVFR CEILINGS/VISIBILITY ARE EXPECTED IN/NEAR PRECIPITATION. GUSTY NORTH WINDS ARE EXPECTED DURING THE DAY GIVEN 45KTS AT 850MB AND 15-25KT IN BOUNDARY LAYER. -HOWERTON && .PREV DISCUSSION... /ISSUED 536 PM CST WED MAR 7 2012/ UPDATE... ADJUSTED THE SHORT TERM GRIDS TO BETTER REFLECT CURRENT OBSERVATIONS/ TRENDS. APPEARS THAT HRRR HAS BEST HANDLE ON FRONT/TIMING/TEMPERATURES IN THE VERY SHORT TERM...WITH A BLEND INTO THE NAM LATER TONIGHT. WILL LIKELY BE MAKING SOME TWEAKS TO POPS IN A BIT. AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU MAIN AVIATION CONCERNS ARE POTENTIAL THUNDERSTORMS THIS EVENING AND MVFR CEILINGS AT KCNU LATER TONIGHT. THERE APPEARS TO BE A NARROW WINDOW OF OPPORTUNITY FOR ELEVATED STORMS TO DEVELOP THIS EVENING AT KICT/KCNU AND POSSIBLY AS FAR NORTH AS KHUT. NAM/RUC MODEL FORECAST HAS 500+ J/G MUCAPE ACROSS SOUTH CENTRAL/SOUTHEAST KS ROUGHLY BETWEEN 03-08 UTC. CEILINGS WILL DECREASE IN THE RAIN AT KCNU WITH MVFR CEILINGS LOOKING LIKELY OVERNIGHT. SOME IMPROVEMENT IS ANTICIPATED ALL SITES DURING THE DAY. -HOWERTON PREV DISCUSSION... /ISSUED 317 PM CST WED MAR 7 2012/ DISCUSSION... MAIN FORECAST CONCERN IS THE PRECIPITATION CHANCES THIS EVENING AND LATER THIS WEEK. SYNOPSIS: A POTENT UPPER LEVEL TROUGH IS MOVING EASTWARD ACROSS THE INTER-MOUNTAIN WEST. AT THE SURFACE A COLD FRONT IS MAKING ITS WAY ACROSS KANSAS. AS OF 3PM THE FRONT IS APPROACHING WICHITA WHICH IS A LITTLE AHEAD OF WHAT WAS PREVIOUSLY THOUGHT. TEMPERATURES HAVE SURGED AHEAD OF THE FRONT AIDED BY THE GUSTY SOUTHERLY WINDS. TONIGHT - SATURDAY: THE UPPER TROUGH THAT ENTERED THE GREAT BASIN YESTERDAY HAS SPLIT...WITH THE CUT OFF PORTION LOCATED OVER NORTHERN ARIZONA/SOUTHERN UTAH...AND MOVING SLOWLY THROUGH THE FOUR CORNERS AREA. LEE CYCLOGENESIS HAS A SURFACE LOW CURRENTLY OVER NEW MEXICO WITH THE SURFACE TROUGH FOLLOWING THE COLD FRONT THROUGH KANSAS TO THE GREAT LAKES REGION. GUSTY SOUTH WINDS TODAY HAVE ADVECTED MID TO UPPER 50 DEWPOINTS TO THE SOUTHEASTERN TWO-THIRDS OF THE CWA. AS THIS COLD FRONT MOVES SOUTHEAST THROUGH THE AREA THIS EVENING...SHOWERS AND SCATTERED THUNDERSTORMS ARE LIKELY MAINLY ALONG AND BEHIND THE FRONT. THE LATEST GUIDANCE CONTINUES TO SHOW THAT PRECIPITATION WILL DEVELOP BEYOND 00Z THIS EVENING MAINLY OVER SOUTHEASTERN KANSAS. SUFFICIENT INSTABILITY AND SHEAR MAY SUPPORT A FEW STRONGER STORMS AND HAIL WITH THOSE CELLS...ESPECIALLY NEAR THE KANSAS/OKLAHOMA. NORTHERN EXTENT OF THE PRECIPITATION APPEARS TO BE GREATER WITH THE NAM THAN THE OTHER MODELS...THINK THE PRECIPITATION WILL RESIDE MAINLY OVER SOUTH CENTRAL AND SOUTHEASTERN KANSAS BUT THERE REMAINS A SLIGHT CHANCE OVER CENTRAL KANSAS. THE UPPER LEVEL LOW STALLS OVER THE TEXAS PANHANDLE FOR THURSDAY THROUGH SATURDAY...AND WILL PUSH ANOTHER SURGE OF MOISTURE NORTH THROUGHOUT THE DAY SATURDAY. ONCE AGAIN THE SOUTHEASTERN TWO-THIRDS ARE MORE FAVORED FOR THE PRECIPITATION SATURDAY...BUT THIS WILL HAVE TO BE MONITORED. PRECIP TYPE SHOULD STAY MOSTLY LIQUID FORM...BUT SLIGHT CHANCE THAT SOME COULD BE FREEZING DRIZZLE ON THE NORTHERN FRINGES. LAUGEMAN SUNDAY - WEDNESDAY: THE CUT OFF UPPER LOW WILL BE KICKED EASTWARD BY THE NEXT UPPER LEVEL WAVE MOVING INTO THE NORTHWEST. PRECIPITATION WILL BE POSSIBLE SUNDAY MORNING AS THE UPPER LOW LIFTS OVER THE AREA...BUT CHANCES DO NOT LOOK TO BE HIGH. THE SYSTEM WILL EXIT BY SUNDAY NIGHT AND WHILE ANOTHER DISTURBANCE WILL LIFT OVER US...IT LOOKS TO BE FAR ENOUGH EAST TO KEEP PRECIPITATION CHANCES AT BAY. WARM AIR ADVECTION THROUGH THE BEGINNING OF THE WEEK WILL HELP TEMPERATURES REACH WELL ABOVE NORMAL THROUGH THE PERIOD. BILLINGS FIRE WEATHER... THE GRASSLAND FIRE DANGER INDEX REMAINS VERY HIGH THROUGH THE REST OF THIS AFTERNOON WITH GUSTY SOUTHERLY WINDS AHEAD OF THE FRONT...BUT AS THE WINDS DECREASE THIS EVENING CONDITIONS WILL IMPROVE. BEHIND THE COLD FRONT WINDS WILL AGAIN BE GUSTY DURING THE DAY THURSDAY AND VERY HIGH FIRE DANGER WILL AGAIN BE POSSIBLE ACROSS PORTIONS OF CENTRAL KANSAS. OTHERWISE WITH THE CHANCES FOR PRECIPITATION AND LIGHTER WINDS DURING THE WEEKEND THE FIRE DANGER INDEX WILL MAX OUT IN THE HIGH CATEGORY. BILLINGS AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THE MAIN AVIATION CONCERN IS THE STRONG WINDS...COLD FRONT TIMING AND MVFR CONDITIONS POSSIBLE THIS AFTERNOON AND OVERNIGHT. THE COLD FRONT AS OF 18Z HAS JUST REACHED KSLN AND IT WILL CONTINUE A SLOW SOUTHWARD TREK THIS AFTERNOON/EVENING. EXPECT IT TO REACH KICT AFTER 00Z. AHEAD OF THE FRONT SOUTHERLY WINDS ARE VERY STRONG WITH SUSTAINED SPEEDS BETWEEN 25-30 KTS AND GUSTS UPWARDS TO 35-40 KTS. AS THE FRONT APPROACHES AND MOVES THROUGH WINDS WILL DECREASE AND BECOME NORTHERLY. NORTHERLY WINDS WILL BE GUSTY...BUT NOT AS STRONG AS AHEAD OF THE FRONT. CEILINGS ARE BOUNCING AROUND THE MVFR/VFR THRESHOLD IN THE 2500-3500 FT RANGE AHEAD AND BEHIND THE FRONT. HAVE REMAINED SOMEWHAT PESSIMISTIC WITH THE TAF FORECAST IN MVFR. PRECIPITATION CHANCES INCREASE AS THE FRONT MOVES INTO SOUTHERN KANSAS BETWEEN 02-06Z WHERE MOISTURE IS MORE PLENTIFUL. HAVE -SHRA AT KICT AND KCNU WHERE CONFIDENCE IS HIGHEST...WITH VCSH POSSIBLE AT ALL OTHER TERMINALS EXCEPT KRSL. COLDER AIR IS EXPECTED TO PUSH INTO CENTRAL KANSAS...BUT HAVE KEPT FREEZING PRECIPITATION OUT OF THE FORECAST AT THIS TIME AS THAT IS FURTHER OUT IN THE FORECAST AND CONFIDENCE ON THAT FEATURE IS LOW. BILLINGS && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 34 53 39 50 / 20 10 30 50 HUTCHINSON 32 53 39 50 / 20 10 30 40 NEWTON 33 53 39 49 / 10 10 30 50 ELDORADO 33 53 39 50 / 10 10 20 50 WINFIELD-KWLD 35 52 40 50 / 20 10 30 50 RUSSELL 29 54 39 51 / 10 10 20 20 GREAT BEND 29 53 39 50 / 20 10 30 30 SALINA 30 55 38 51 / 10 10 20 40 MCPHERSON 31 54 39 50 / 10 10 20 40 COFFEYVILLE 37 54 40 51 / 20 10 20 50 CHANUTE 34 55 38 51 / 10 10 20 50 IOLA 33 54 37 50 / 10 10 20 50 PARSONS-KPPF 35 54 39 51 / 20 10 20 50 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1030 PM MST WED MAR 7 2012 .UPDATE... ISSUED AT 1024 PM MST WED MAR 7 2012 CONVECTION HAS BROKEN OUT OVER THE PAST HOUR OR SO JUST SOUTHEAST OF THE FORECAST AREA WITHIN AXIS OF 700MB THETA-E AND RIGHT REAR QUAD OF UPPER JET. RUC SUGGESTING THAT MAIN ACTIVITY MAY CONTINUE TO DEVELOP NORTHWARD POSSIBLY INTO SOUTHEAST GOVE AND WICHITA COUNTIES FROM 06Z-08Z OR SO. RUC SOUNDINGS SUGGEST SNOW AS THE MAIN PRECIP TYPE. HAVE UPDATED FORECAST TO REFLECT THE CHANCE OF SNOW. UPDATE ISSUED AT 752 PM MST WED MAR 7 2012 TONIGHT-THURSDAY NIGHT...18Z GFS/NAM/ECWMF AND MOST RECENT 00Z NAM/RUC ALL SHOWING A MORE SOUTHERLY TRACK TO THE 500 LOW CURRENTLY OVER EAST CENTRAL ARIZONA. 850-500 MOISTURE RATHER LACKING TONIGHT EXCEPT ALONG THE HIGHER TERRAIN NEAR FLAGLER IN EASTERN COLORADO BUT THAT WILL BE BRIEF AS IT CONTINUES TO MOVE SOUTH AND OUT OF THE AREA. WILL NEED TO WATCH THE FAR EAST/SOUTHEAST/SOUTH LATE TONIGHT AS RUC ONLY MODEL TO GENERATE SOME LIGHT PRECIP AROUND 09Z DESPITE THE BETTER MOISTURE BEING FURTHER SOUTH. WITH THE MORE SOUTHERN TRACK MORE OF THE FORECAST AREA WILL SEE PLENTIFUL SUNSHINE. WINDS WILL AGAIN BE FROM THE NORTH AT 15 TO 25 MPH. LATEST NAM/SREF 2M TEMPS AND MAV/MET MOS GUIDANCE ALL IN AGREEMENT THAT AFTERNOON TEMPERATURES WILL PEAK GENERALLY IN THE 40S WITH A FEW 50S NEAR NORTON AND HILL CITY. THURSDAY NIGHT...STILL LOOKS DRY. 00Z NAM TRIES TO INCREASE THE LOW AND MID LEVEL MOISTURE ACROSS GREELEY AND WICHITA COUNTIES AS THE UPPER LOW STARTS TO ROTATE INTO NORTHEAST NEW MEXICO/TEXAS PANHANDLE. NOT MANY CHANGES MADE TO GRIDS DURING THIS PERIOD AT PRESENT TIME. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 212 PM MST WED MAR 7 2012 MAIN CONCERN WILL BE POSSIBILITY OF PRECIPITATION AND PRECIPITATION TYPE. IN THE PAST 24 HRS...THERE HAS BEEN MUCH UNCERTAINTY REGARDING PRECIP OVER THE AREA ASSOCIATED WITH THE UPPER TROUGH WEST OF THE REGION...BUT THE GENERAL TREND HAS MADE PRECIP LESS AND LESS LIKELY. BASED ON THIS TREND AND THE LATEST GUIDANCE...HAVE LOWERED PROBABILITIES FURTHER...AND KEPT THE HIGHEST CHANCES NEAREST TO THE TROUGH IN THE SOUTHWESTERN PART OF THE AREA. NAM MODEL SOUNDINGS INDICATE THAT THERE IS STILL POTENTIAL FOR A PERIOD OF FREEZING RAIN IN THE EARLY MORNING IF ANY PRECIP WERE TO FALL...BUT SNOW SHOULD QUICKLY BECOME THE PREDOMINANT PRECIP TYPE AS THE WESTERLY COMPONENT OF WINDS ALOFT MODIFIES THE AIR MASS. AS THE LOW MOVES FURTHER SOUTHEAST DURING THE DAYTIME ON THURSDAY...THE CHANCE FOR PRECIP SHOULD MINIMIZE DURING THE AFTERNOON HOURS. SKIES WILL CLEAR IN THE NORTHERN PORTION OF THE AREA...ALLOWING WARMER TEMPERATURES IN THE NORTH COMPARED TO FURTHER SOUTH. GUSTY NORTHERLY WINDS CAN BE EXPECTED DURING THE DAYTIME DUE TO THE MOVEMENT AND POSITION OF THE TROUGH. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 212 PM MST WED MAR 7 2012 THERE ARE STILL SOME MODEL DIFFERENCES WITH THE UPPER LOW DURING THIS TIMEFRAME. BOTH THE NAM/GFS BRING THE UPPER LOW INTO THE TEXAS PANHANDLE THURSDAY NIGHT/FRIDAY. THE GFS HOLDS THE LOW IN THE TEXAS PANHANDLE FRIDAY NIGHT WHILE THE NAM HAS IT POSITIONED A LITTLE FURTHER NORTH IN THE OKLAHOMA PANHANDLE. BOTH HAVE THE GFS/NAM HAVE THE UPPER LOW OVER THE OKLAHOMA PANHANDLE SATURDAY MORNING. THE GFS TAKES THE LOW INTO CENTRAL KANSAS SATURDAY NIGHT. OTHER THAN THURSDAY EVENING, LATE FRIDAY NIGHT AND SATURDAY BOTH MODELS KEEP THE DYNAMICS/MOISTURE OUTSIDE OF THE FA. FOR THE PERIODS JUST MENTIONED THERE IS SOME VERY MARGINAL MOISTURE OVER THE SOUTHEAST FRINGE OF THE FA. FORECAST SOUNDINGS NEAR THE BEST PLAN VIEW MOISTURE FIELD LOOK VERY DRY SO AM NOT OPTIMISTIC ABOUT ANY MEASURABLE PRECIPITATION. FOR THIS REASON HAVE INCLUDED ONLY SPRINKLES/FLURRIES THURSDAY EVENING AND LATE FRIDAY NIGHT. SOME LIGHT RAIN MAY BE POSSIBLE IN THE FAR EAST SATURDAY MORNING. OTHERWISE THE REMAINING PERIODS ARE DRY WITH NIL POPS. MIN TEMPERATURES WILL MODERATE FROM THE LOWER 20S THURSDAY NIGHT TO THE UPPER 20S/LOWER 30S FRIDAY/SATURDAY NIGHTS. MAX TEMPERATURES WILL GENERALLY REACH THE MID 50S FRIDAY/SATURDAY. FOR SUNDAY - WEDNESDAY...THE GFS SHOWS A RIDGE OVER THE FA SUNDAY FOLLOWED BY WEST SOUTHWESTERLY FLOW MONDAY THROUGH WEDNESDAY. LACK OF ANY SIGNIFICANT SHORTWAVE/FORCING WILL KEEP POPS NIL THROUGH THIS PART OF THE FORECAST. 850MB TEMPERATURES INDICATE THAT MAX TEMPERATURES SHOULD BE ABOUT 10 TO ALMOST 20 DEGREES ABOVE NORMAL IN THE 60S TO AROUND 70. MIN TEMPERATURES IN THE 30S/LOW 40S WILL BE ABOUT 10 TO 15 DEGREES ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1024 PM MST WED MAR 7 2012 VFR THROUGH THE PERIOD AT BOTH KGLD AND KMCK. RAPID CLEARING EXPECTED FROM NORTH TO SOUTH EARLY THURSDAY MORNING WITH ONLY A FEW CIRRUS CLOUDS EXPECTED SHORTLY THEREAFTER. N WINDS OF 10 KTS OR SO TO CONTINUE THROUGH 15Z THURSDAY THEN INCREASING INTO THE 15G25KT RANGE FROM 15Z-00Z AS HEATING/MIXING OCCUR. VRB06KTS EXPECTED BY 01Z THROUGH THE REMAINDER OF THE TAF PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...007 SHORT TERM...CJS LONG TERM....FS AVIATION...007
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
342 AM CST THU MAR 8 2012 .DISCUSSION... Showers with embedded thunderstorm early this morning are continuing to develop southwest of the area back into south central Kansas and back into the OK and TX Panhandles in an area of mid level frontogenetical forcing. These showers and thunderstorms have been lifting northeastward into the forecast area where even weak low-topped convection has been able to produce small hail with a freezing level at 2kft. These showers and thunderstorms will continue to be shunted to the south this morning as a upper level trough moves from the Upper Midwest into the Great Lakes region forcing the surface cold front, which was the focus of this precipitation, further south and east into the Ohio and Lower Mississippi River Valleys. Showers and perhaps a isolated thunderstorms will continue this morning occasionally mixing with sleet and snow perhaps evening changing over to all snow, mainly along and south of the Missouri River and will sink through the southern portion of the CWA by this afternoon. As this system sinks south of the area high pressure will build into the region from the Northern Plains tonight. This will allow for calm winds and clear skies providing for good radiational cooling and consequently dropped temperatures a degree or two for tonight. High pressure will remain in control over the area on the day on Saturday before shifting eastward into the Missouri River Valley on Saturday night. It is then we turn our attention to our next system of interest. This system is in the form of a closed low across the southwestern CONUS. Models are in good agreement that this system will pull out of the Southwest into the Southern Plains on Saturday night. Out ahead of the system Gulf moisture will be drawn northward under a good WAA regime. Model QPF fields spread showers across the area by Saturday night which continues into Sunday. Models differ on the timing the upper level system rotates through the area ranging anywhere from the faster GFS which brings it through on Sunday night to the slower GEM which brings it through Monday night so did not change much to the initialization to capture the myriad of timing scenarios. One caveat of interest in the model analysis is that the EC as it brings the system out of the Southwest into the Plains it open up the cut off low and begins to take on a negative tilt. If, this scenario does come to fruition it will provide for more unstable conditions than the other model solutions and thunderstorms possibly severe will be possible. However since the EC is the only model advertising this solution have opted to keep precipitation wording to just rain at the moment. Otherwise, for the beginning of the work week expect well above average conditions with downsloping westerly flow aloft and southern flow at the surface. Highs on Monday will be in the mid to upper 60s giving way to lower 70s on Tuesday and Wednesday. 73 && .AVIATION... For the 06Z TAFs...Have made significant changes to the first 6 hours of the TAFs to reflect the rapid development of elevated convection from southwest into north central KS since 04z. Latest short range model trends from the HRRR, RUC and NAM spread this convective activity northeastward and into the terminals shortly after midnight. A combination of isentropic ascent on the 300K surface, the right entrance region of a departing upper level jet streak and layered frontogenesis are working in concert to aid the convective development. Am expecting to see the rain and clod cover shift south after sunrise Thursday with VFR conditions quickly moving into the terminals. While thunder was not put into the forecast will need to monitor evolution of upstream convection and make any necessary short term adjustments. MJ && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
332 AM CST THU MAR 8 2012 .SHORT TERM... ISSUED AT 316 AM CST THU MAR 8 2012 (TODAY AND TONIGHT) COLD FRONT HAS MOVED ABOUT HALFWAY THROUGH THE CWA AND IS CURRENTLY ENTERING THE NORTHWESTERN PART OF THE ST. LOUIS METRO AREA. SHOWERS AND SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG AND AHEAD OF THE FRONT IN A BROAD AREA OF 950-850MB MOISTURE CONVERGENCE. THIS MOISTURE CONVERGENCE IS COINCIDENT WITH LARGE SCALE ASCENT FROM MID-LEVEL CURRENTLY PASSING THROUGH THE UPPER MIDWEST. A SECOND LARGER AREA OF PRECIPITATION IS MOVING ACROSS WESTERN MISSOURI WHICH IS BEING GENERATED BY THE LARGE SCALE ASCENT ON THE TAIL END OF THE TROUGH AND A LITTLE STRONGER LOW LEVEL CONVERGENCE ON THE NOSE OF A 50KT LOW LEVEL JET OVER THE PLAINS. THIS FORCING WILL CONSOLIDATE THROUGH THE MORNING PER THE RUC AS THE LOW LEVEL JET VEERS WITH TIME. THIS SHOULD BE ENOUGH TO KEEP LIKELY OR CATEGORICAL RAIN CHANCES GOING FOR ABOUT THE SOUTHERN TWO-THIRDS OF THE CWA EARLY THIS MORNING...WITH A GRADUAL DIMINISHING TREND THROUGH THE DAY AS THE FORCING PUSHES SOUTH AND EAST. THERE SHOULD BE ENOUGH INSTABILITY TO KEEP AT LEAST A MENTION OF SCATTERED THUNDERSTORMS THIS MORNING ALONG AND AHEAD OF THE 850MB COLD FRONT. CAN`T RULE OUT THE POTENTIAL FOR SOME SNOW OR SLEET ON THE NORTHERN FRINGE OF THE PRECIPITATION WHERE RUC SOUNDINGS ARE SHOWING THE LOW LEVEL THERMAL PROFILES COOLING NEAR 0C ABOUT THE TIME THAT THE PRECIPITATION ENDS. THINK THIS WILL BE A SHORT LIVED EVENT AND MAINLY FOUND WHERE CONVECTION IS MORE CONCENTRATED. TONIGHT SHOULD BE DRY AS SUBSIDENCE SETS IN BEHIND THE NORTHERN STREAM TROUGH. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY FALL THROUGH THE DAY OVER THE SOUTHERN HALF OF THE CWA EXTENSIVE CLOUD COVER AND DECENT COLD AIR ADVECTION BEHIND THE FRONT. GFS MOS TEMPERATURES LOOK A BIT TOO WARM TONIGHT GIVEN THE MAINLY CLEAR SKIES AND WINDS TURNING LIGHT AS THE SURFACE RIDGE SETTLES INTO THE AREA. BRITT && .LONG TERM... ISSUED AT 330 AM CST THU MAR 8 2012 (FRIDAY THROUGH NEXT WEDNESDAY) SFC HIGH BUILDS IN BEHIND THE DEPARTING CDFNT ON FRI WITH DRY WX EXPECTED ON FRI AND MOST OF SAT BEFORE ANOTHER ROUND OF PCPN DVLPS ON SAT NIGHT AS AN UPPER LOW OVER AZ/NM BEGINS LIFTING NEWD THROUGH THE CENTRAL CONUS. MODELS CONTINUE TO STRUGGLE WITH HOW AND WHEN THIS LOW LIFTS NEWD. THE PREVIOUS FOUR RUNS OF THE ECMWF WERE EVENLY SPLIT BETWEEN KEEPING THE VORT CENTER INTACT /00Z RUNS ON MARCH 7TH AND 8TH/ AND SPLITTING IT INTO TWO VORT MAXES /12Z RUNS ON MARCH 6TH AND 7TH...SIMILAR TO WHAT THE GFS HAS BEEN DEPICTING FOR THE LAST SEVERAL DAYS/. 08/00Z GEM REMAINS SIMILAR TO THE 07/00Z RUN AND SHOWS THE LOW RETROGRADING TO BAJA CA THEN MOVING THROUGH MEXICO BEFORE LIFTING THROUGH TX AND INTO NWRN MO. THESE LARGE DIFFERENCES BETWEEN THE 3 MODELS APPEAR TO STEM FROM DIFFERENT HANDLING OF THE INTERACTION BETWEEN THE CLOSED LOW AND A SUBTLE AREA OF ENHANCED VORTICITY THAT SHOULD BE MOVING THROUGH ID/NV AT 08/12Z. DESPITE THE DIFFERENT DETAILS...MODEL SOLUTIONS ALL SUGGEST ANOTHER ROUND OF PCPN SOMEWHERE BETWEEN SAT NIGHT AND MON AS THE CLOSED LOW /OR ITS REMNANTS/ FINALLY LIFTS NEWD. WAA SHRA EXPECTED TO DVLP FIRST FOLLOWED BY AN INCREASE IN PCPN COVERAGE AS LARGE SCALE LIFT INCREASES WITH THE APPROACHING VORT MAX. MODELS ARE OFTEN TOO QUICK TO BRING A CLOSED LOW BACK INTO THE PREVAILING FLOW THEREFORE I WOULD NOT BE SURPRISED IF THIS OVERALL FCST SCENARIO ENDS UP BEING DELAYED BY A DAY OR SO AS THE MODELS CATCH UP TO THE ATMOSPHERE. KANOFSKY && .AVIATION... ISSUED AT 1057 PM CST WED MAR 7 2012 COLD FRONT CONTINUES TO PUSH EAST AT A STEADY PACE AND JUST MOVED THROUGH UIN OVER THE LAST 30 MINUTES. LEADING EDGE OF NARROW BAND OF SHOWERS/ISOLATED THUNDERSTORMS DENOTES FRONT AND EXTRAPOLATION OF THIS ECHO MASS INDICATES IT SHOULD PUSH THROUGH COU BETWEEN 06-07Z. LONGER EXTRAPOLATION OF RADAR IMAGERY...AS WELL AS SURFACE COLD FRONTAL POSITIONS DURING THE EVENING...STILL INDICATE ARRIVAL OF COLD FRONT IN STL AREA 10-11Z TIME FRAME. THUNDERSTORMS HAVE BEEN INCREASING IN COVERAGE OVER THE PAST FEW HOURS IN THE BEST INSTABILITY AXIS OVER WESTERN MISSOURI...AND BASED ON 00Z GUIDANCE THAT SUGGESTS INSTABILITY WILL PERSIST INTO THE PREDAWN HOURS THINK THAT THIS NARROW LINE OF STORMS WILL BE ABLE TO HOLD TOGETHER AS IT WORKS EAST INTO EASTERN MO AND THE STL AREA. POST FRONTAL PRECIP HAS EXPANDED OVER IA BUT SO FAR AS REMAINED VERY LIMITED OVER MO...BUT THINK THIS WILL BE CHANGING OVERNIGHT AS SHORTWAVE DIGS INTO REGION AND ENHANCES LARGE SCALE UVV IN THE COLDER AIR. STILL LOOKS LIKE FROPA WILL BRING MVFR CIGS TO EACH TAF LOCATION...AND WHILE WE`RE NOT SEEING ANY WIDESPREAD IFR BEHIND THE FRONT ATTM WE`LL CERTAINLY HAVE TO CAREFULLY MONITOR CONDITIONS OVERNIGHT DUE TO THIS THREAT. SPECIFICS FOR KSTL... COLD FRONT STILL EXPECTED TO ARRIVE AROUND 10Z WITH A NARROW LINE OF THUNDERSTORMS. IMMEDIATELY BEHIND THE FRONT CONDITIONS SHOULD QUICKLY DROP TO MVFR WITH CIGS BTWN 1-3 KFT AND VSBYS 3-5SM IN LIGHT RAIN/FOG. 00Z DATA SUPPORTS EARLIER THINKING THAT DRIER AIR WELL BEHIND THE FRONT SHOULD BEGIN TO IMPROVE CONDITIONS DURING THE LATE MORNING...WITH MVFR CIGS MOVING OUT OF THE AREA AROUND MIDDAY. TRUETT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
319 AM CST THU MAR 8 2012 .SHORT TERM... ISSUED AT 316 AM CST THU MAR 8 2012 (TODAY AND TONIGHT) COLD FRONT HAS MOVED ABOUT HALFWAY THROUGH THE CWA AND IS CURRENTLY ENTERING THE NORTHWESTERN PART OF THE ST. LOUIS METRO AREA. SHOWERS AND SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG AND AHEAD OF THE FRONT IN A BROAD AREA OF 950-850MB MOISTURE CONVERGENCE. THIS MOISTURE CONVERGENCE IS COINCIDENT WITH LARGE SCALE ASCENT FROM MID-LEVEL CURRENTLY PASSING THROUGH THE UPPER MIDWEST. A SECOND LARGER AREA OF PRECIPITATION IS MOVING ACROSS WESTERN MISSOURI WHICH IS BEING GENERATED BY THE LARGE SCALE ASCENT ON THE TAIL END OF THE TROUGH AND A LITTLE STRONGER LOW LEVEL CONVERGENCE ON THE NOSE OF A 50KT LOW LEVEL JET OVER THE PLAINS. THIS FORCING WILL CONSOLIDATE THROUGH THE MORNING PER THE RUC AS THE LOW LEVEL JET VEERS WITH TIME. THIS SHOULD BE ENOUGH TO KEEP LIKELY OR CATEGORICAL RAIN CHANCES GOING FOR ABOUT THE SOUTHERN TWO-THIRDS OF THE CWA EARLY THIS MORNING...WITH A GRADUAL DIMINISHING TREND THROUGH THE DAY AS THE FORCING PUSHES SOUTH AND EAST. THERE SHOULD BE ENOUGH INSTABILITY TO KEEP AT LEAST A MENTION OF SCATTERED THUNDERSTORMS THIS MORNING ALONG AND AHEAD OF THE 850MB COLD FRONT. CAN`T RULE OUT THE POTENTIAL FOR SOME SNOW OR SLEET ON THE NORTHERN FRINGE OF THE PRECIPITATION WHERE RUC SOUNDINGS ARE SHOWING THE LOW LEVEL THERMAL PROFILES COOLING NEAR 0C ABOUT THE TIME THAT THE PRECIPITATION ENDS. THINK THIS WILL BE A SHORT LIVED EVENT AND MAINLY FOUND WHERE CONVECTION IS MORE CONCENTRATED. TONIGHT SHOULD BE DRY AS SUBSIDENCE SETS IN BEHIND THE NORTHERN STREAM TROUGH. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY FALL THROUGH THE DAY OVER THE SOUTHERN HALF OF THE CWA EXTENSIVE CLOUD COVER AND DECENT COLD AIR ADVECTION BEHIND THE FRONT. GFS MOS TEMPERATURES LOOK A BIT TOO WARM TONIGHT GIVEN THE MAINLY CLEAR SKIES AND WINDS TURNING LIGHT AS THE SURFACE RIDGE SETTLES INTO THE AREA. BRITT && .LONG TERM... ISSUED AT 300 PM CST WED MAR 7 2012 (THURSDAY THROUGH WEDNESDAY) COLD FRONT SHOULD MAKE IT TO THE STL METRO AREA BY 12Z THU WITH A BAND OF SHOWERS AND STORMS EXPECTED ALONG AND JUST BEHIND THE FRONT. THE BEST CHANCE OF RAIN ON THU WILL BE S AND E OF STL AS THE FRONT CONTINUES TO DROP SEWD THROUGH THE AREA. A SURFACE RIDGE WILL BUILD SEWD INTO OUR AREA BEHIND THE FRONT WITH COLDER AND DRIER AIR FILTERING INTO THE REGION. WITH RELATIVELY STRONG CAA BEHIND THE SFC/850 MB FRONT AREAS WHICH REMAIN CLOUDY ON THU MAY SEE LITTLE IF ANY DIURNAL RISE IN TEMPERATURES. MOST OF THIS RAIN SHOULD PUSH SOUTH OF OUR AREA BY THU EVNG WITH CLEARING FROM N-NW TO S-SE AND COLDER TEMPERATURES THU NGT. TRANQUIL...DRY WEATHER WITH NEAR NORMAL TEMPERATURES FOR FRI AND FRI NGT...THEN INCREASING CLOUDINESS ON SAT AS A SLOW MOVING CLOSED...UPPER LEVEL LOW NOW OVER NRN AZ MOVES THROUGH THE PLAINS AND APPROACHES MO. THE NAM MODEL IS A LITTLE QUICKER BRINGING SHOWERS INTO OUR AREA THIS WEEKEND AHEAD OF THIS UPPER LOW. FOR NOW WILL FOLLOW CLOSER TO THE GFS AND ECMWF MODELS SOLUTION WHICH BRING MOST OF THE RAIN THROUGH OUR FORECAST AREA SAT NGT AND SUN. MOST OF THE RAIN SHOULD SHIFT E OF OUR AREA BY SUN NGT...ALTHOUGH COULD NOT RULE OUT SOME LIGHT RAIN MAINLY OVER W CNTRL IL UNDERNEATH OR NEAR THE UPPER LOW CENTER. AFTER A BRIEF BREAK IN THE RAIN BOTH THE GFS AND ECMWF MODELS ARE BRINGING ANOTHER SHOT OF RAIN...MAINLY TO THE SRN AND ERN PORTIONS OF OUR AREA MON AFTN AND MON NGT AHEAD OF A SRN STREAM UPPER LEVEL TROUGH WHICH WILL MOVE NEWD INTO SERN MO BY MON EVNG. ALTHOUGH THE GFS MODEL TRIES TO BRING A WEAK COLD FRONT SEWD INTO OUR AREA TUE NGT...THE ECMWF MODEL IS WARMER WITH CONTINUING S-SWLY LOW LEVEL FLOW BRINGING THE 16 DEGREE C 850 MB ISOTHERM NEWD INTO MO ON WED WITH HIGH TEMPERATURES IN THE 70S LIKELY IF THIS SCENERIO VERIFIES. GKS && .AVIATION... ISSUED AT 1057 PM CST WED MAR 7 2012 COLD FRONT CONTINUES TO PUSH EAST AT A STEADY PACE AND JUST MOVED THROUGH UIN OVER THE LAST 30 MINUTES. LEADING EDGE OF NARROW BAND OF SHOWERS/ISOLATED THUNDERSTORMS DENOTES FRONT AND EXTRAPOLATION OF THIS ECHO MASS INDICATES IT SHOULD PUSH THROUGH COU BETWEEN 06-07Z. LONGER EXTRAPOLATION OF RADAR IMAGERY...AS WELL AS SURFACE COLD FRONTAL POSITIONS DURING THE EVENING...STILL INDICATE ARRIVAL OF COLD FRONT IN STL AREA 10-11Z TIME FRAME. THUNDERSTORMS HAVE BEEN INCREASING IN COVERAGE OVER THE PAST FEW HOURS IN THE BEST INSTABILITY AXIS OVER WESTERN MISSOURI...AND BASED ON 00Z GUIDANCE THAT SUGGESTS INSTABILITY WILL PERSIST INTO THE PREDAWN HOURS THINK THAT THIS NARROW LINE OF STORMS WILL BE ABLE TO HOLD TOGETHER AS IT WORKS EAST INTO EASTERN MO AND THE STL AREA. POST FRONTAL PRECIP HAS EXPANDED OVER IA BUT SO FAR AS REMAINED VERY LIMITED OVER MO...BUT THINK THIS WILL BE CHANGING OVERNIGHT AS SHORTWAVE DIGS INTO REGION AND ENHANCES LARGE SCALE UVV IN THE COLDER AIR. STILL LOOKS LIKE FROPA WILL BRING MVFR CIGS TO EACH TAF LOCATION...AND WHILE WE`RE NOT SEEING ANY WIDESPREAD IFR BEHIND THE FRONT ATTM WE`LL CERTAINLY HAVE TO CAREFULLY MONITOR CONDITIONS OVERNIGHT DUE TO THIS THREAT. SPECIFICS FOR KSTL... COLD FRONT STILL EXPECTED TO ARRIVE AROUND 10Z WITH A NARROW LINE OF THUNDERSTORMS. IMMEDIATELY BEHIND THE FRONT CONDITIONS SHOULD QUICKLY DROP TO MVFR WITH CIGS BTWN 1-3 KFT AND VSBYS 3-5SM IN LIGHT RAIN/FOG. 00Z DATA SUPPORTS EARLIER THINKING THAT DRIER AIR WELL BEHIND THE FRONT SHOULD BEGIN TO IMPROVE CONDITIONS DURING THE LATE MORNING...WITH MVFR CIGS MOVING OUT OF THE AREA AROUND MIDDAY. TRUETT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1154 PM CST WED MAR 7 2012 ...UPDATED AVIATION DISCUSSION... .DISCUSSION... Convection finally got going along the cold front. However, the activity is rather narrow, but intense. Not expecting any severe. Cold front with the attendant convection will spread gradually east across the sern 1/4 of the CWA. In the post frontal regime a number of short range models including the latest runs from the HRRR, RUC and NAM all blossom convection across south central into east central KS after 06z, spreading into west central MO and the southern half of the CWA after 09z. This appears to be a reflection of the right rear entrance region of the 250mb jet segment interacting with layered frontogenesis from 850mb to 650mb. Given the model consensus on spreading rain further north have increased and adjusted pops further north after midnight. MJ && .PREV DISCUSSION... /342 PM CST Wed Mar 7 2012/ An advancing cold front pushed into far northwest Missouri, and adjacent areas of extreme northeast Kansas, early this afternoon. This has brought some relief to those areas from the strong and gusty winds that persisted overnight and into today. Cloud cover in advance of the front has decreased the wind gusts farther south and east also, so while there is no grantee that any break in the clouds would not result in quick round of momentum transfer in the boundary layer, it looks unlikely at this time. So, have opted to drop the remainder of the wind advisory from west central Kansas through central Missouri under a a little early. After the frontal passage this evening, winds will turn to the northwest, remaining a bit gusty through the overnight hours into Thursday. Focusing on the front for tonight, radar returns and occasional surface observations indicate that showers are beginning to develop along and just behind it, across northwest Missouri and eastern Kansas. This expected activity will continue to ramp up as we move through the later afternoon and evening hours as modest isentropic assent is supplemented, and then supplanted, with moderate to strong frontogenic forcing in the post frontal environment. This, coupled with some moderate lapse rates that will still be present aloft as the front shifts through, should allow some embedded thunderstorm activity just behind the front this evening. Severe thunderstorm activity is not expected as there looks to be insufficient instability to fuel anything more than your average embedded thunderstorm. Showers, and some isolated thunder, may still be lingering across areas from east central Kansas into central Missouri Thursday morning and into the afternoon hours. With the passage of the cold front tonight, a modest dome of cool air will slide across the Lower Missouri River Valley Thursday into Friday, knocking our temperatures back down from the mid spring like temperatures we have enjoyed over the past few days. Thursday will be the coolest day with highs in the 40s to near 50, with Friday warming into the 50s across the whole forecast areas. Cutter Medium Range (Saturday-Tuesday)... Model consistency continues to be the primary forecast concern as we head through the initial stages of the medium range. Some progress has been made with GFS/ECMWF solutions in the depth of upper low trapped under broad ridging as it crosses the region. However the exact track of this low remains in doubt and will have significant implications on local conditions especially on Sunday. GEFS signals this disagreement well with two clusters of solutions. One clusters the more westerly ECMWF and the other cluster favors the progressive easterly solution of the GFS. Nevertheless, it does appear that broad warm advection will spread northward and into the area late Saturday and into Sunday. Currently favored areas for more widespread rain are focused on the eastern half of Missouri, with uncertainty on positioning of dry slot leading to lower certainty in western zones. Given the degree of warm advection, wouldn`t be surprised to see a bit of thunder, but confidence too low to introduce at this time. Have not trimmed much off the populated POPs for Sunday night given uncertainty of where cold core of upper low may pass. Heading into next week, rising mid-level heights will give credence to another substantial warm up looks in store for the area as we move into Tuesday and Wednesday. Southwesterly low level flow combined with 850mb temps +12 to +16 would feature lower to middle 70s. Have bumped overnight lows and max temps. Just food for thought beyond the medium range as we look for additional chances of snow this winter, continual NAEFS ensemble runs as well as guidance from CPC place very high probabilities of above normal temperatures continuing through the 8-14 day period with a continuation of westerly to southwesterly flow aloft. Dux && .AVIATION... For the 06Z TAFs...Have made significant changes to the first 6 hours of the TAFs to reflect the rapid development of elevated convection from southwest into north central KS since 04z. Latest short range model trends from the HRRR, RUC and NAM spread this convective activity northeastward and into the terminals shortly after midnight. A combination of isentropic ascent on the 300K surface, the right entrance region of a departing upper level jet streak and layered frontogenesis are working in concert to aid the convective development. Am expecting to see the rain and clod cover shift south after sunrise Thursday with VFR conditions quickly moving into the terminals. While thunder was not put into the forecast will need to monitor evolution of upstream convection and make any necessary short term adjustments. MJ && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1148 PM CST WED MAR 7 2012 .UPDATE...RADAR DATA FROM KUEX...AS WELL AS MULTIPLE SITES ACROSS KANSAS...INDICATE ELEVATED CONVECTION RAPIDLY SPREADING IN AERIAL COVERAGE ACROSS CENTRAL AND EASTERN KANSAS. RUC ANALYSIS AND LAPS DATA INDICATE AN AXIS OF ENHANCED THERMAL ADVECTION FROM JUST ABOVE 850MB TO NEAR 700MB...WITH RESULTANT ISENTROPIC UPGLIDE AND SATURATION EVIDENT ALONG THE 305K SURFACE. PROXIMITY SOUNDINGS...ALSO FROM RUC ANALYSIS AND LAPS DATA...ACROSS OUR SOUTHERN CWA AND POINTS FARTHER SOUTH ACROSS CENTRAL KANSAS INDICATE THIS CONVECTION IS ROOTED TO AROUND 700MB...WHERE MINIMAL CIN IS EVIDENT AND CAPE VALUES AS HIGH AS 300J/KG ALSO EXIST. SHORT TERM GUIDANCE SUGGESTS THIS AXIS OF MID LEVEL THERMAL ADVECTION WILL CONTINUE MOVING EAST THROUGH THE OVERNIGHT HOURS...THUS CARRYING CHANCES FOR CONVECTION WITH IT INTO EASTERN KANSAS AND WESTERN MISSOURI. THAT BEING SAID...BASED ON THE CURRENT TRAJECTORIES OF ONGOING CONVECTION ACROSS CENTRAL KANSAS...THERE IS A CHANCE SOME OF THIS ACTIVITY WILL CLIP EXTREME SOUTHEASTERN PORTIONS OF OUR CWA. WENT AHEAD AND UPDATED THE FORECAST AND HWO TO INCLUDE THUNDER MENTION FOR PORTIONS OF OSBORNE AND MITCHELL COUNTIES AS A RESULT. && .PREV DISCUSSION... /ISSUED 1044 PM CST WED MAR 7 2012/ AVIATION...06Z TAF. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. DRY AIR CONTINUES TO ADVECT SOUTH TONIGHT AND SKIES ARE GRADUALLY CLEARING. WINDS WILL BE FAIRLY LIGHT TONIGHT...BUT WILL INCREASE FM THE NORTHWEST THURSDAY MORNING...BEFORE TRANSITIONING WESTERLY AND DECREASING AGAIN THURS EVENING. PREV DISCUSSION... /ISSUED 335 PM CST WED MAR 7 2012/ SHORT TERM...THROUGH 00Z FRIDAY...THE FRONTAL BOUNDARY THAT BROUGHT BREEZY NORTHERLY WINDS AND MUCH COLDER TEMPERATURES TO THE REGION TODAY IS PRESENTLY DRAPED FROM SOUTHEASTERN NEBRASKA TO THE PANHANDLE OF OKLAHOMA/TEXAS. WHILE SOME MODERATE INSTABILITY AND POTENTIAL FOR SHOWER DEVELOPMENT IS EVIDENT ALONG AND JUST AHEAD OF THIS BOUNDARY...LATEST MODEL GUIDANCE CONTINUES TO SUGGEST THE BOUNDARY WILL SLOWLY SINK SOUTHEASTWARD OVERNIGHT... DIMINISHING ANY CHANCES FOR MEASURABLE PRECIPITATION ACROSS THE LOCAL AREA. AS A RESULT...WENT AHEAD AND TRIMMED BACK ANY MENTION OF PRECIP OVERNIGHT. ADDITIONALLY....WITH SLOWLY CLEARING SKIES APPROACHING FROM THE NORTHWEST AND DIMINISHING WINDS EXPECTED OVERNIGHT AS AN AREA OF SURFACE HIGH PRESSURE TRANSITIONS CLOSER TOWARDS THE LOCAL AREA FROM THE HIGH PLAINS...WENT AHEAD AND TWEAKED OVERNIGHT TEMPERATURES DOWN A BIT...ALBEIT THEY REMAIN RIGHT AROUND CLIMATOLOGY FOR THIS TIME OF YEAR. FOR THURSDAY...LIGHT NORTHERLY WINDS WILL BE PREVALENT ACROSS THE REGION AS THE AFOREMENTIONED AREA OF SURFACE HIGH PRESSURE SETTLES IN ACROSS THE STATE OF NEBRASKA. THIS WILL ALLOW FOR CLEARING SKIES AS A GENERALLY PLEASANT DAY ACROSS THE REGION...WITH AFTERNOON TEMPERATURES REBOUNDING A FEW DEGREES FROM THIS AFTERNOONS READINGS...WITH EXPECTED HIGH TEMPERATURES IN THE LOWER 50S MOST LOCATIONS...WHICH REMAINS APPROXIMATELY 5 DEGREES ABOVE SEASONAL NORMALS FOR THIS TIME OF YEAR. LONG TERM...00Z FRIDAY THROUGH WEDNESDAY. PRIMARY FORECAST CONCERNS ARE WITH TEMPERATURES...AND WEEKEND PRECIPITATION CHANCES. MODELS IN PRETTY GOOD AGREEMENT AT THE START OF THE LONG TERM PERIOD...THROUGH FRIDAY NIGHT...AND THE FORECAST REMAINS DRY. UPPER LEVEL PATTERN SHOWS NORTHWESTERLY FLOW ACROSS THE REGION...SITTING BETWEEN A TROUGH AXIS SWINGING THROUGH THE GREAT LAKES/MIDWEST...AND A SLOW MOVING CLOSED OFF UPPER LEVEL LOW PRESSURE SYSTEMS OVER NEW MEXICO. THROUGH THE DAYTIME ON FRIDAY AND EVEN FRIDAY NIGHT...NOT A LOW OF PROGRESS IS MADE BY THE LOW...WITH MODELS REMAINING IN PRETTY GOOD AGREEMENT SHOWING A SECOND LOW DEVELOPING TO THE SOUTHWEST /NRN BAJA/ OF THE ORIGINAL...WHICH BY 12Z SATURDAY IS NEAR THE PANHANDLES OF TX/OK. EVEN WITH THIS FIRST LOW CREEPING CLOSER TO THE CWA...PRECIPITATION IS EXPECTED TO REMAIN OFF TO THE SOUTH OF THE CWA. NOT A LOT OF SWEEPING CHANGES LOOKING AT THE SURFACE PATTERN EITHER...WHICH STARTS THE PERIOD OFF WITH THE CWA UNDER THE INFLUENCE OF A HIGH PRESSURE AXIS EXTENDING FROM NM...AND LIGHT NORTHERLY WINDS. THROUGH FRIDAY NIGHT...HIGH PRESSURE CONTINUES TO BE A PRIMARY PLAYER ACROSS THE CWA...WITH THE MAIN AXIS DRAPED ACROSS SRN PORTIONS OF THE CWA...BETWEEN HIGH PRESSURE CENTERS OVER THE SRN PLAINS AND ANOTHER DRIFTING SE INTO THE GREAT LAKES/MIDWEST. THIS WILL BRING A RETURN TO MORE SOUTHERLY FLOW...WITH LIGHTER SPEEDS ACROSS THE SRN CWA AND GUSTIER WINDS TO ACROSS THE NORTH. ALSO NOT EXPECTING MUCH OF A CHANGE IN AIRMASS COMPARED TO THURSDAY...AND FORECAST HIGHS ARE WITHIN A FEW DEGREES IN THE MID 50S. A LITTLE BIT MORE UNCERTAINTY ARISES AS WE GET INTO THE UPCOMING WEEKEND...WHICH WILL BE INFLUENCED BY THE MAIN UPPER LEVEL LOW PRESSURE SYSTEM. THROUGH THE DAYTIME HOURS ON SATURDAY...AGAIN NOT MUCH PROGRESS IS MADE LOOKING AT THE MODELS...WITH SOLUTIONS VARYING FROM A MORE ERN PATH LIKE THE GFS/NAM /ENDING UP OVER SCENT KS BY 00Z SUNDAY/...VS A MORE NRN PATH FROM THE EC /UP TOWARD NWRN KS/. LIFT OUT AHEAD OF THE LOW LOOKS TO BRING SOME SLIGHT CHANCES FOR PRECIPITATION DURING THE DAY ON SATURDAY...MAINLY ACROSS THE SRN/SERN THIRD OF THE CWA. SLIGHT PRECIPITATION CHANCES CONTINUE ON SATURDAY NIGHT AND EVEN INTO SUNDAY...AND KEPT POPS ON THE LOW SIDE WITH MODELS KEEPING THE MAIN BRUNT OF THE PRECIPITATION OFF TO THE E/S OF THE CWA. THE DAYTIME HOURS ON SUNDAY HAVE THE MOST AREAL COVERAGE OF POPS...WITH THE ACTUAL CENTER OF THE UPPER LEVEL LOW LOOKING TO CROSS THE REGION...THOUGH SLIGHT LOCATION/TIMING DIFFERENCE CONTINUE BETWEEN MODELS. KEPT THE EVENING/OVERNIGHT HOURS SUNDAY DRY FOR NOW WITH MORE SUPPORT GETTING THINGS OUT OF HERE...BUT IT WOULDNT TAKE MUCH OF A SLOW DOWN FOR SOME POPS TO BE NEEDED IN THE ERN PORTIONS OF THE CWA. TEMP PROFILES AT THIS POINT KEEP THINGS AS ALL LIQUID...WITH LITTLE/NO INSTABILITY PRESENT...KEPT ANY THUNDER MENTION OUT AS WELL. TEMPERATURES THROUGH THE WEEKEND ARE TRICKY...AND WILL BE DEPENDENT ON THE LOCATION/TIMING OF THE SYSTEM AND ACCOMPANYING CLOUDS/PRECIP. FORECAST HIGHS CURRENTLY ARE SITTING GENERALLY IN THE MID 50S. LOOKING TOWARD MONDAY THROUGH WEDNESDAY...THE DRY FORECAST RETURNS TO THE ENTIRE CWA. IN THE WAKE OF THIS UPPER LEVEL LOW PRESSURE SYSTEM PASSING THROUGH ON SUNDAY...EXPECTING TO SEE ZONAL/SLIGHTLY SWRLY FLOW SET UP ACROSS THE REGION...WITH NO NOTABLE SYSTEMS PUSHING THROUGH. KEPT HIGHS NEAR THE ALLBLEND...WITH MODELS VARYING WITH THE TIMING/MAGNITUDE OF COOLER AIR OF A FRONTAL BOUNDARY PUSHING THROUGH EARLY/MIDWEEK. THE GFS IS FASTER/COOLER THAN THE EC...ALREADY TRYING TO PUSH A FRONT THROUGH ON TUESDAY...WITH THE EC SHOWING A MORE MILD/WEAKER PASSAGE. FORECAST HIGHS MON THRU WED SIT MAINLY IN THE MID/UPPER 60S...WITH LOWER 70S POSSIBLE AS WELL ACROSS THE SOUTH. PREV DISCUSSION... /ISSUED 1217 PM CST WED MAR 7 2012/ AVIATION...18Z KGRI TAF...MVFR CIGS ARE EXPECTED TO CONTINUE FOR A FEW MORE HOURS AT KGRI...WITH CEILINGS SLOWLY IMPROVING THROUGH THE LATE AFTERNOON HOURS...AS THIS MORNINGS COLD FRONT CONTINUES TO PUSH FURTHER SOUTHEAST. IN ADDITION...STRONG NORTHERLY WINDS ARE EXPECTED TO RELAX AND BECOME LESS GUSTY AFTER AROUND 08/02Z AS SUN SETS AND PRESSURE GRADIENT SLACKENS...WITH PREVAILING VFR CONDITIONS EXPECTED THEREAFTER. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...BRYANT SHORT TERM...ROSSI LONG TERM...ADO
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1111 PM CST WED MAR 7 2012 .UPDATE... LATEST RUC DATA INDICATE SHOWERS AND THUNDERSTORMS NOT AS LIKELY FOR THE REMAINDER OF TONIGHT AS WE WERE THINKING. WITH SOUTHWEST FLOW ALOFT CONTINUING TONIGHT...I DECIDED NOT TO REMOVE SHOWERS AND THUNDERSTORMS COMPLETELY FROM THE TONIGHT GRIDS. I JUST DECREASED POPS TO 20 PERCENT MAX WITH MAINLY SHOWERS AND ISOLATED THUNDERSTORMS. I ALSO ADJUSTED SKY GRIDS FOR THE REMAINDER OF TONIGHT TO BRING THEM IN LINE WITH SATELLITE TRENDS AND THE LATEST RUC DATA. THE LATEST ZONE PRODUCT REFLECTS THESE CHANGES. OTHERWISE...ALL LOOKS ON TRACK. HUBER && .PREV DISCUSSION... /ISSUED 528 PM CST WED MAR 7 2012/ AVIATION... /00Z UPDATE/ VFR CONDITIONS WILL CONTINUE OVER ALL TAF SITES THROUGH THE REMAINDER OF THE EVENING WITH SOUTHERLY WINDS GUSTING TO AROUND 20KT. AS A COLD FRONT PUSHES SOUTH INTO WEST CENTRAL TEXAS AFTER MIDNIGHT...CEILINGS WILL DEGRADE TO MVFR AND SHOULD REMAIN MVFR AT ALL TAF SITES THROUGH THE END OF THE TAF PERIOD. WINDS WILL VEER TO THE NORTH AFTER FRONTAL PASSAGE...AROUND 15Z AT THE NORTHERN TERMINALS...AROUND 19Z AT THE SOUTHERN TERMINALS. NORTHERLY WINDS WILL GUST TO AROUND 25KT IN THE WAKE OF FRONTAL PASSAGE. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 60 67 38 50 40 / 20 30 40 30 30 SAN ANGELO 63 74 40 52 38 / 20 20 40 30 30 JUNCTION 62 74 45 54 41 / 10 20 50 40 40 && .SJT WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUBER
AREA FORECAST DISCUSSION
NWS PUEBLO CO
718 AM MST THU MAR 8 2012 .UPDATE... LAST SEVERAL RUNS OF THE HRRR MODEL CONTINUE TO INDICATE THAT THE SNOW OVER THE SOUTHERN MOUNTAINS WILL END LATER THIS MORNING AS DRIER AIR ADVECTS INTO THE REGION. FOR THIS REASON WILL LET THE WINTER STORM HILITES END LATER THIS MORNING. && .PREV DISCUSSION... /ISSUED 414 AM MST THU MAR 8 2012/ SHORT TERM... (TODAY AND TONIGHT) ..SNOW FINALLY MATERIALIZING ACROSS THE SANGRES/WETS AND SURROUNDING AREAS... CURRENTLY... DURING THE LAST FEW HOURS...RADAR RETURNS HAVE INCREASED SIGNIFICANTLY OVER THE SOUTHERN MTNS AND ADJACENT PLAINS. SNOW...LIKELY HEAVY...WAS INDICATED ON THE EAST SLOPES OF THE WETS AND IN THE VICINITY OF THE SPANISH PEAKS. COMPOSITE RADAR IS CLEARLY INDICATING THE CIRCULATION ASSOCIATED WITH THE WELL DEFINED...ALBEIT COMPACT...UPPER LOW...WHICH WAS LOCATED NEAR THE 4 CORNERS. THE SNOW HAS EXTENDED AS FAR NORTH AND EAST AS PUEBLO...WHERE A TRACE OF SNOW HAS OCCURRED DURING THE LAST HOUR OR SO. TODAY... MAIN CHANGE TO THE FCST WAS TO EXTEND THE WINTER STORM WARNING UNTIL 6 PM FOR A SMALL PART OF THE REGION. THIS REGION ENCOMPASSES THE SOUTHERN SANGRE DE CRISTO MOUNTAINS. FOR ALL OTHER AREAS...THE WINTER STORM WARNING WILL EXPIRE AT NOON. ALL MODELS CONTINUE TO INDICATE THE HEAVIEST SNOW WILL OCCUR WHERE IT IS OCCURRING NOW...THAT IS...ALONG THE EAST SLOPES OF THE S MTNS AND ADJACENT I-25 CORRIDOR. SNOW IS LIKELY OCCURRING ALONG THE E SLOPES OF THE SAN JUANS BASED ON SAT PIX IMGY AND MEAGER RADAR RETURNS AS SEEN BY NWS RADARS. UPPER LOW...WHICH IS LACKING SIGNIFICANTLY IN MOISTURE...IS FCST TO TRACK E-SE TODAY ACROSS NM. THIS WILL KEEP THE REGION IN DEEP UPSLOPE FLOW. BEST FORCING WILL BE OVER THE S TIER WHERE I HAVE KEPT THE POPS THE HIGHEST. TONIGHT... ALTHOUGH THE LOW IS FCST TO TRACK BACK NWD AND ACTUALLY RETROGRADE WWD ACROSS FAR N NM TONIGHT INTO TOMORROW...ALL GUIDANCE IS SHOWING VERY LITTLE...IF ANY...QPF OVER THE REGION. THE ONLY QPF BEING PRINTED OUT IS ACROSS THE FAR S TIER...ALONG THE IMMEDIATE CO/NM BORDER. ALTHOUGH UPSLOPE FLOW IS RATHER STRONG AND DEEP...THIS SYSTEM IS LACKING (DRAMATICALLY) WRT MOISTURE. SOUNDINGS ACROSS THE PLAINS SHOW VERY DRY AIR THROUGHOUT THE COLUMN ADVECTING INTO THIS SYSTEM FROM THE CENTRAL HIGH PLAINS. LIKEWISE...MOST AREAS TONIGHT WILL SEE MOSTLY CLEAR SKIES...WITH THE EXCEPTION BEING ALONG THE CO/NM BORDER. /34 LONG TERM... (FRIDAY THROUGH WEDNESDAY) FRIDAY AND SATURDAY...THE LOW PRESSURE SYSTEM IS EXPECTED TO SIT IN THE VICINITY OF THE OK AND TX PANHANDLES ON FRI...BUT HOW IT MOVES FROM THERE IS REALLY IN QUESTION NOW. MULTIPLE MODELS AND MODEL RUNS ARE SHOWING DIFFERING SOLUTIONS ON WHERE THE LOW CENTER WILL TRACK...FROM RETROGRADING BACK TO THE WEST ACROSS NM...TO EJECTING NORTH...TO SITTING IN PLACE. THE ONE THING MODELS SEEMED TO AGREE UPON WAS THAT THERE IS NOT A LOT OF MOISTURE ASSOCIATED WITH THIS SYSTEM...SO WILL FORECAST MEAGER QPF. GIVEN THE UNCERTAINTY OF THE TRACK...KEPT THE BEST PCPN CHANCES ALONG THE SOUTHERN PORTIONS OF THE CWA WITH FLOW BANKING UP AGAINST THE SOUTHERN FOOTHILLS AND S SANGRES. ON SAT...MODELS INDICATE THAT THE LOW WILL FINALLY MAKE SOME SORT OF MOVE OUT OF THE AREA...AND TAPERED POPS OFF THROUGH THE DAY. TEMPS BOTH DAYS SHOULD WARM INTO THE 40S AND 50S...WITH THE COLDEST TEMPS ALONG THE SOUTHERN TIER. SUNDAY THROUGH WEDNESDAY...THE UPPER LOW EXITS THE REGION...SETTING UP WEST TO SOUTHWEST FLOW ACROSS THE 4 CORNERS AND ROCKIES INTO THE NEXT WORK WEEK FOR DRY CONDITIONS AND WARMING TEMPS. 27 AVIATION... FOR KCOS...MVFR CONDITIONS WILL CONTINUE UNTIL ABOUT 14Z AND THEN DRIER AIR SHOULD ADVECT IN DECREASING THE CLOUDS. VFR SHOULD LAST THROUGH THE REST OF THE PERIOD. FOR KPUB...SAME AS KCOS ALTHOUGH LOWER CIGS/LIGHT SNOW SHOULD LAST UNTIL ABOUT 16Z. FOR KALS...OCCNL MVFR CONDITIONS WILL BE POSSIBLE THROUGH ABOUT 15Z...AND THEN MVFR IS EXPECTED THE REST OF THE FCST PERIOD. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 10 AM MST THIS MORNING FOR COZ067-068- 072>075-078>080-087-088. WINTER WEATHER ADVISORY UNTIL 10 AM MST THIS MORNING FOR COZ066. && $$ 34/34
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
311 AM MST THU MAR 8 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 200 AM MST THU MAR 8 2012 THE UPPER LEVEL LOW WAS SAGGING SOUTH ALONG THE AZ-NM BORDER THIS MORNING THEN WILL EJECT SLOWLY EAST ACROSS SOUTHERN NM THIS AFTERNOON. ASSOCIATED DYNAMICAL LIFT IS SOUTH OF THE CWA AND WRAP- AROUND MOISTURE IS LIMITED. THIS WOULD PRODUCE SOME LIGHT ACCUMULATION IN THE VICINITY OF MONARCH...SLUMGULLION...AND WOLF CREEK PASSES TODAY. THE HRRR AND NAM12 ALSO PRODUCE LIGHT ACCUMULATION OVER THE MANCOS RIDGE THROUGH THIS AFTERNOON. OTHERWISE MOSTLY SUNNY SKIES WILL PREVAIL. AT THE SURFACE LOW PRESSURE NEAR THE FOUR CORNERS AND COLD HIGH PRESSURE PUSHING DOWN THE FRONT RANGE IS PRODUCING NE GRADIENT WINDS. MTN TOP NE WINDS ARE GUSTING 20-30 OVER EXPOSED TERRAIN. THE GRADIENT RELAXES THROUGH THE AFTERNOON. TONIGHT THE UPPER LOW SETTLES ONTO THE EASTERN NM PLAINS WHERE IT WILL LANGUISH INTO THE WEEKEND. THIS KEEPS THE FORECAST AREA IN A LIGHT EAST FLOW ALOFT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 311 AM MST THU MAR 8 2012 THE MIDRANGE MODELS SEEM TO BE STALLING THE CLOSED LOW OVER NEW MEXICO FRIDAY AND FRIDAY NIGHT. THE GFS KEEPS THE 500 MB CENTER OVER NE NM AND THE PANHANDLES OF TX AND OK FRI. THEN LIFTS IT NORTH INTO EXTREME SE CO SAT...AND TAKES THE LOW CENTER TO WESTERN KS SUN MORNING. THE ECMWF RETROGRADES THE LOW CENTER BACK TO WESTERN NM FRI THEN PUSHES IT EAST SAT AND INTO THE TX PANHANDLE ABOUT 18Z SUN. THE GFS SOLUTION SHOULD RESULT IN NEARLY CLOUDLESS SKIES NORTH OF THE SAN JUAN MOUNTAINS FRI THROUGH THE WEEKEND. THE ECMWF WITH ITS LOW CENTER FURTHER WEST MAY KEEP MORE CLOUD COVER OVER THE SOUTHERN HALF OF THE FORECAST AREA FRI AND SAT. BOTH SCENARIOS PROVIDE LITTLE CHANCE OF PRECIP OUTSIDE OF ISOLD SHOWERS IN THE SAN JUANS THRU THE WEEKEND. SUNDAY IN BOTH MODELS SHOULD BRING CONTINUED WARM ADVECTION AS THE FLOW ALOFT BECOMES SOUTHWESTERLY. MAX TEMPS SUN THRU WED SHOULD BE 5-10 DEGREES ABOVE NORMAL ACROSS THE FORECAST AREA. EXPECT LITTLE CLOUD COVER AND DRY CONDITIONS AS WELL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 200 AM MST THU MAR 8 2012 VFR CONDITIONS WILL DOMINATE INTO FRIDAY. THE EXCEPTION IS SCT SNOW SHOWERS IN THE SOUTHERN MTNS ALONG AND EAST OF HIGHWAY 550. EXPECT SCT MVFR CIGS AND VSBY THROUGH THE AFTERNOON THERE WITH MTN TOPS OCNLY OBSCURED. WIDESPREAD SNOW SHOWERS WILL OCCUR OVER AND EAST OF MONARCH...SLUMGULLION...AND WOLF CREEK PASSES THAT WILL PRODUCE MVFR/LOCAL IFR CIGS AND VSBY. ALL OF THESE SOUTHERN SHOWERS WILL DIMINISH QUICKLY AFTER 6 PM THIS EVENING WITH VFR CONDITIONS PREVAILING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JOE LONG TERM....CC AVIATION...JOE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
815 AM CST THU MAR 8 2012 .DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * OCCASIONAL W/NW GUSTS TO 25 KT. * LOW END MVFR CIGS UNTIL 16Z THEN STEADY IMPROVEMENT TO VFR. BEACHLER //DISCUSSION...UPDATED 12Z... A STRONG COLD FRONT HAS PUSHED EAST OF THE TERMINALS THIS MORNING. WITH THE FROPA...WINDS HAVE SHIFTED TO NWLY AND DIMINISHED SOMEWHAT...THOUGH GUSTS TO 25KT ARE LIKELY THROUGH THE DAY. MUCH OF THE ASSOCIATED PCPN HAS ENDED...BUT AN UPPER LEVEL IMPULSE MOVING THROUGH CNTRL IL HAS BROUGHT MORE RAIN AND SOME ISOLD THUNDER...BUT LATEST RADAR IMAGERY INDICATES A WEAKENING TREND AND IT IS LIKELY THAT ANY REMAINING PRECIP SHOULD REMAIN SOUTH OF THE TERMINALS...WITH THE POSSIBLE EXCEPTION OF KGYY WHICH MAY STILL GET CLIPPED WITH SOME SHRA. OTHERWISE...THE TREND FOR THE DAY SHOULD BE FOR IMPROVING CIGS AS COOLER...DRIER AIR FILTERS IN BEHIND THE COLD FRONT. EXPECT THAT CIGS SHOULD IMPROVE TO VFR BY LATE MORNING. THE REMAINDER OF THE PERIOD SHOULD SEE VFR CONDITIONS AS HIGH PRESSURE BUILDS ACROSS THE REGION. A WEAK LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES TONIGHT SHOULD DRAG A SECONDARY COLD FRONT ACROSS THE AREA...BRINGING A REINFORCING SHOT OF COLD AIR. THIS COLD ADVECTION SHOULD BRING ANOTHER ROUND OF GUSTINESS DURG THE OVERNIGHT HOURS...THOUGH DO NOT EXPECT GUSTS TO EXCEED 25KT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN TIMING OF CIGS IMPROVEMENT. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
603 AM CST THU MAR 8 2012 .DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * GUSTY WEST TO NORTHWEST WINDS WITH OCNL GUSTS TO 25KT. * LOWER END MVFR CIGS THROUGH LATE MORNING. KREIN //DISCUSSION...UPDATED 12Z... A STRONG COLD FRONT HAS PUSHED EAST OF THE TERMINALS THIS MORNING. WITH THE FROPA...WINDS HAVE SHIFTED TO NWLY AND DIMINISHED SOMEWHAT...THOUGH GUSTS TO 25KT ARE LIKELY THROUGH THE DAY. MUCH OF THE ASSOCIATED PCPN HAS ENDED...BUT AN UPPER LEVEL IMPULSE MOVING THROUGH CNTRL IL HAS BROUGHT MORE RAIN AND SOME ISOLD THUNDER...BUT LATEST RADAR IMAGERY INDICATES A WEAKENING TREND AND IT IS LIKELY THAT ANY REMAINING PRECIP SHOULD REMAIN SOUTH OF THE TERMINALS...WITH THE POSSIBLE EXCEPTION OF KGYY WHICH MAY STILL GET CLIPPED WITH SOME SHRA. OTHERWISE...THE TREND FOR THE DAY SHOULD BE FOR IMPROVING CIGS AS COOLER...DRIER AIR FILTERS IN BEHIND THE COLD FRONT. EXPECT THAT CIGS SHOULD IMPROVE TO VFR BY LATE MORNING. THE REMAINDER OF THE PERIOD SHOULD SEE VFR CONDITIONS AS HIGH PRESSURE BUILDS ACROSS THE REGION. A WEAK LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES TONIGHT SHOULD DRAG A SECONDARY COLD FRONT ACROSS THE AREA...BRINGING A REINFORCING SHOT OF COLD AIR. THIS COLD ADVECTION SHOULD BRING ANOTHER ROUND OF GUSTINESS DURG THE OVERNIGHT HOURS...THOUGH DO NOT EXPECT GUSTS TO EXCEED 25KT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 12Z... * MODERATE CONFIDENCE IN CEILING TRENDS. * MODERATE TO HIGH CONFIDENCE IN WIND TRENDS. * MODERATE TO HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
516 AM CST THU MAR 8 2012 .DISCUSSION... ISSUED 314 AM CST THU MAR 8 2012 COLD FRONT PUSHING THROUGH THE FORECAST AREA THIS MORNING WITH SOME SHOWERS OUT AHEAD AND ALONG. A SECOND ROUND OF SHOWERS AND OCCASIONAL THUNDER PUSHING UP JUST BEHIND THE SFC BOUNDARY AS A WAVE MOVES NE INTO THE REGION. MORNING PRECIP AND HOW LONG IT WILL IMPACT THE REGION IS THE FIRST ISSUE...ALONG WITH THE HOURLY TEMPS THIS MORNING AS COLDER AIR MOVES INTO THE AREA. BEYOND THAT...THE FORECAST HAS FEW CHANGES AS THE MODELS STILL WORK OUT HOW THE MAIN UPPER LOW OVER THE SWRN CONUS IS GOING TO MOVE OUT AND ACROSS THE ERN HALF OF THE COUNTRY. STILL MORE IN FAVOR OF THE ECMWF...AND HAVE TRIED TO MITIGATE THE GFS IMPACTS IN THE EXTENDED AS MUCH AS COLLABORATION AND CONSENSUS WOULD ALLOW. THAT BEING SAID...THE GFS SOLUTION OF SPLITTING THE WAVE INTO SEVERAL SMALLER WAVES IS SLOWLY TURNING INTO A MORE ECMWF/NAM SOLUTION. BIGGEST IMPACT FOR THIS PARTICULAR DISCREPANCY WILL BE ON MON NIGHT/TUESDAY WHERE THE CONFIDENCE IN THE GOING FORECAST DECREASES. SHORT TERM...TODAY AND TOMORROW... HIGH TEMPERATURES LIKELY TO BE MET EARLY AS THE REMAINDER OF THE DAY WILL BE COOLER WITH THE FRONT PASSING THROUGH THIS MORNING. PRECIP WILL CONTINUE WITH A CHANCE FOR SOME THUNDER THIS MORNING WITH SOME STEEPER MID LEVEL LAPSE RATES ASSOCIATED WITH THE WAVE MOVING THROUGH THE FLOW JUST BEHIND THE SFC BOUNDARY. POPS DECREASING NW TO SE AFTER 18Z. TEMPS A BIT COOLER TONIGHT. CONCERN THAT GUIDANCE AND GOING FORECAST ARE NOT QUITE COOL ENOUGH SHOULD THE SKIES CLEAR A BIT MORE QUICKLY THAN THE MODEL RH PROFILES ARE HINTING. RATHER DRY AIR AVAILABLE BEHIND THIS WAVE. TOMORROW...TEMPS COOLER THAN LAST COUPLE OF DAYS...BUT STILL A BIT WARMER THAN SEASONABLE...UPPER 40S/NEAR 50 WITH PLENTY OF SUNSHINE. LONG TERM...SATURDAY THROUGH WEDNESDAY... WINDS COME AROUND TO MORE SOUTHERLY SATURDAY MORNING...AND ASSISTS IN A WARM UP WITH PLENTY OF SUNSHINE EARLY. HOWEVER...SOME OF THIS WARM UP WILL BE SHORT LIVED AS A DEVELOPING SYSTEM MOVES OUT OF THE SRN PLAINS INTO THE MIDWEST. MODELS HAVE HAD QUITE THE HISTORY WITH THIS SYSTEM...AND MANY MANY DIFFERENT SOLUTIONS. FOR NOW...THE EC IS PUSHING THE SYSTEM THROUGH...RATHER DIFFUSE AS AN OPEN WAVE...AND WEAKENING AND LESSENING THE QPF TRENDS IN THE LAST COUPLE OF RUNS. THE GFS IS ALSO EASING A BIT...BUT DELIVERING THE PRECIP IN A ONE TWO PUNCH FOR SAT NIGHT/SUN AND MON NIGHT/TUES. FOR NOW...BEST CHANCES FOR POPS ARE IN THE FORECAST WITH SUNDAY AND SUNDAY NIGHT. FROM TUES NIGHT THROUGH WED...KEEPING THE FORECAST DRY AT THIS POINT AS THE MODELS ARE STRUGGLING WITH A BIT OF FEEDBACK IN WEAK SWRLY FLOW. HJS && .AVIATION... ISSUED 516 AM CST THU MAR 8 2012 COLD FRONT HAS PASSED THROUGH THE TAF SITES THIS MORNING...WITH A BRIEF LULL IN THE PRECIPITATION. SHOWERS WILL RAMP UP AGAIN EARLY AS A SHORTWAVE MOVES FROM NORTHERN MO ACROSS CENTRAL IL. SINCE LIGHTNING HAS DECREASED IN THE PAST COUPLE OF HOURS...WILL JUST HAVE SOME VCTS IN THE MORNING. PRECIPITATION MAY MIX WITH LIGHT SNOW OR LIGHT SLEET AT PIA AS TEMPERATURES FALL THROUGH THE 30S ON THE BACK EDGE OF THE RAIN SHIELD. THE LATEST RUN OF THE HRRR MODEL HAS A DECENT HANDLE ON THE CURRENT WEATHER...SO WILL FOLLOW THIS AND EXPECT PRECIPITATION TO END AT PIA 15Z-16Z...AND AT CMI AROUND 18Z. CEILINGS/FLIGHT RULES VARY WIDELY OVER THE AREA THIS MORNING...BUT EXPECT GENERAL MVFR CONDITIONS WITH POSSIBLY IFR IN HEAVIER SHOWERS. OVERALL EXPECT IMPROVEMENT TO VFR A COUPLE OF HOURS AFTER PRECIPITATION ENDS...THEN MAINLY CLEAR SKIES BY 00Z FRI. NORTHWEST WINDS WILL STILL BE ON THE STRONG SIDE TODAY WITH 18-22 KT SUSTAINED WITH GUSTS ABOVE 30 KT AT TIMES. WINDS WILL THEN DIMINISH AND BACK TO WESTERLY AFTER 00Z FRI. 04 && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
640 AM EST THU MAR 8 2012 .AVIATION... FRONT WORKING THROUGH AREA WITH WINDS BECOMING NORTHWEST IN ITS WAKE. AREA OF PRECIPITATION ALONG FRONT ALSO WORKING EAST. WILL HAVE TO WATCH AREA OF POST FRONTAL PCPN THAT HAS BEEN WORKING NORTHEAST OVERNIGHT AND WILL LIKELY MOVE INTO KFWA BY 14 TO 15Z WITH MVFR RESTRICTIONS. SKIES CLEAR LATER TODAY WITH DRIER AIR. SECONDARY WAVE DROPS INTO AREA LATER TONIGHT WITH INCREASE IN CLOUDS BUT SHOULD BE VFR. && .SHORT TERM... STRONG COLD FRONT WAS JUST COMING INTO FAR NW CWA AT 09Z AND WILL QUICKLY MOVE ACROSS THE AREA TODAY. RADAR SHOWING AREA OF LIGHT TO MODERATE SHOWERS ALONG AND BEHIND FRONT WITH SCATTERED SHOWERS OUT AHEAD OF IT. SURFACE OBS SHOWING A GOOD 10 TO 15 DEGREE TEMP DROP BEHIND FRONT WITH COLD AIR ADVECTION EXPECTED TO CONTINUE THROUGH THE DAY WITH LITTLE RECOVERY IN TEMPS EXPECTED. HAVE TRIED TO TIME FRONT THROUGH THE AREA WITH TEMPERATURE DROP AND PCPN TRENDS. VERY DIFFICULT TO SAY THE LEAST AND ADJUSTMENTS WILL BE NECESSARY THROUGH THE MORNING. REGIONAL RADAR MOSAIC AND SATELLITE ALSO SHOWING AN AREA OF CONVECTION THAT HAS DEVELOPED OVERNIGHT IN OK AND KS AND IS MOVING NORTHEAST. HRRR SEEMS TO BE ONLY MODEL TO HAVE A DECENT HANDLE ON THIS WITH 04Z AND 05Z MODEL RUNS HAVING THIS WAVE COMING INTO NW INDIANA AROUND 14Z. DISCUSSION WITH HPC SUGGEST 06Z RUN TRENDING FARTHER EAST BUT GIVEN LOOKS OF RESPONSIBLE SHORT WAVE ON WATER VAPOR AND RECENT RADAR MOSAIC TRENDS HAVE CONCERNS THAT THIS MAY MOVE BACK INTO PART OF CENTRAL OR WEST CENTRAL CWA BY MID MORNING. FOR THIS REASON HAVE SLOWED THE TREND OF CLEARING POPS ACROSS THE AREA BY ABOUT 3 TO 5 HOURS TO ACCOUNT FOR THE POSSIBILITY OF THIS RAIN MOVING BACK IN. BY AFTERNOON THIS WAVE LOOKS TO CLEAR THE AREA AND RAPID DRYING BEGINS AND SHOULD SEE CLEARING SKIES. ANOTHER FAST MOVING SHORT WAVE PASSES TO THE NORTH TONIGHT BUT DRIVES SECONDARY COLD FRONT THROUGH. MAY SEE SOME INCREASE IN CLOUDS NORTH WITH THIS WAVE AND LAKE PLUME AS DELTA T VALUES CLIMB INTO THE TEENS. REMAINDER OF SHORT TERM FORECAST DRY WITH HIGH PRESSURE MOVING IN FRIDAY NIGHT. THIS SHOULD ALLOW WINDS TO DECOUPLE AND EXPECT GOOD RADIATIONAL COOLING BEFORE RETURN FLOW TRIES TO DEVELOP LATE. HAVE LOWERED TEMPS FRIDAY NIGHT. && .LONG TERM... SATURDAY THROUGH WEDNESDAY...A LONG WAVE TROF WILL BECOME ENTRENCHED ALONG THE WESTERN NORTH AMERICAN COAST WITH LARGE SCALE AMPLIFICATION DOWNSTREAM OVER THE CENTRAL AND EASTERN CONUS. MUCH WARMER AIR WILL RETURN TO THE AREA AND PERSIST THROUGH NEXT WEEK. SHORT WAVE ENERGY WILL EJECT NORTHEAST AND PROVIDE A CHANCE FOR SHOWERS THROUGH MOST OF THE PERIOD AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO RIVER. THE GFS ENSEMBLE MEMBERS HAVE FINALLY COME INTO REASONABLE AGREEMENT WITH ONE ANOTHER WITH MUCH SMALLER STANDARD DEVIATIONS REFLECTED IN THE MEX MOS. THERE IS POTENTIAL FOR HIGHS TO TOP 70 DEGREES DURING THE LATTER HALF OF THIS PERIOD. HOWEVER...GIVEN THE POTENTIAL FOR CLOUDS AND RAINFALL...KEPT HIGHS IN THE MID TO UPPER 60S TUESDAY/WEDNESDAY. ALSO...THERE IS AN OUTSIDE CHANCE ONE OF THE SHORTWAVES MAY BE ABLE TO TAP A LITTLE COOLER AIR AFTER THE SHORT WAVE PASSES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EST FRIDAY FOR LMZ043-046. && $$ SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
532 AM MST THU MAR 8 2012 .UPDATE... ISSUED AT 522 AM MST THU MAR 8 2012 STARTING TO SEE 12Z RAOBS COME IN AND AS EXPECTED AIR MASS BUILDING IN FROM THE NORTH LOOKS MUCH DRIER THAN PREVIOUS DAY. ESTIMATED MIXED LAYER DEWPOINTS OFF OF KLBF SOUNDING WOULD SUPPORT SINGLE DIGIT DEWPOINTS WITH ANY DEEP MIXING. GOES SOUNDINGS ALSO SUPPORTING VERY DRY LAYER ALOFT...AND THINK WITH PLENTIFUL SUNSHINE MUCH OF THE AREA WILL TAP INTO THIS DRIER AIR THIS AFTERNOON. DROPPING TDS INTO SINGLE DIGITS ALONG THE LINES OF LATEST HRRR STILL KEEP AFTERNOON HUMIDITY VALUES JUST ABOVE CRITICAL VALUES. WITH STRONGEST WINDS LIKELY BEFORE 20Z...THE MARGINAL NATURE OF PARAMETERS AND UNCERTAINTY IF WINDS/RH WILL LINE UP FOR SEVERAL HOURS KEEPS CONFIDENCE TOO LOW TO ISSUE A RFW AT THIS TIME. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 155 AM MST THU MAR 8 2012 TODAY...AREA OF THUNDERSTORMS THAT DEVELOPED ALONG NOSE OF STRONG ISENTROPIC ASCENT SHOULD CONTINUE TO DIMINISH/SHIFT SOUTH OF THE AREA THROUGH THE MORNING HOURS AS COLD AND DRY AIR ADVECTION OVERSPREAD THE AREA BEHIND DEPARTING TROUGH MOVING ACROSS EASTERN NEBRASKA. WITH MUCH DRIER AIR MOVING INTO THE AREA AND FAIRLY DEEP DOWNWARD MOTION...DO NOT SEE MUCH IN THE WAY OF A PRECIPITATION THREAT ONCE OVERNIGHT CONVECTION BEGINS TO SHIFT SOUTH. SKIES WILL GRADUALLY CLEAR...ALTHOUGH PLACEMENT OF CUT OF LOW AND PERSISTENT DEFORMATION ZONE MAY PROMOTE A PERSISTENT AREA OF MID/HIGH CLOUDS ACROSS SOUTHERN CWA...BUT AM NOT EXPECTING MUCH OF AN IMPACT ON SENSIBLE WX AT THIS TIME. TEMPERATURES SHOULD REBOUND INTO THE LOWER 50S ACROSS MUCH OF THE AREA DESPITE THE CAA WITH GUSTY NORTHERLY WINDS EXPECTED BTWN 15 AND 20Z BEFORE THINGS BEGIN TO DIMINISH. WITH LOW TEENS/SINGLE DIGIT DEWPOINTS MOVING INTO THE AREA...EXPECT HUMIDITIES TO FALL TO AROUND 20 PERCENT RANGE AND WITH THE GUSTY WINDS MAY APPROACH CRITICAL FIRE WX CONDITIONS FOR AN HOUR OR SO. CURRENTLY HUMIDITIES LOOK TO BE ABOVE CRITERIA AND WINDS ARE EXPECTED TO DIMINISH WHILE HUMIDITIES ARE AT THEIR LOWEST VALUES. HAVE SEEN A FEW POST FRONTAL FIRE WEATHER EVENTS THOUGH WITH DEEP COLD AND DRY AIR ADVECTION AND MAY NEED TO REEVALUATE ONCE 12Z RAOBS ARE AVAILABLE. TONIGHT-FRIDAY...GENERAL CONSENSUS IS UPPER LOW WILL MOVE INTO THE TEXAS PANHANDLE...WELL REMOVED FROM THE FORECAST AREA...WITH GEM AND SREF MEAN CONTINUING TO INDICATE SOME RETROGRADE MOTION. BOTH OF THESE SOLUTIONS AND GENERAL MODEL CONSENSUS KEEPS CWA WELL TO THE NORTH OF ANY APPRECIABLE PRECIPITATION THREAT AS STABLE MID LEVELS...AND PERSISTENT DRY NORTHERLY FLOW OVERNIGHT THURSDAY WILL BE ENOUGH TO PREVENT PRECIP DEVELOPMENT...EVEN IF SOME LARGE SCALE FORCING FOR ASCENT MAY BE PRESENT. MID LEVEL FLOW EXPECTED TO BECOME A BIT MORE SOUTHERLY DURING THE DAY ALLOWING FOR SOME INCREASING CLOUDS...BUT WITH BULK OF LARGE SCALE FORCING FOR ASCENT TO THE SOUTH OF THE AREA AND OVERALL LOW CONFIDENCE IN LARGE SCALE FEATURES...THINK DRY CONDITIONS WILL PREVAIL. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 155 AM MST THU MAR 8 2012 FRIDAY NIGHT-SATURDAY NIGHT...WHILE NEAR TERM MODELS HAVE COME INTO A LITTLE BETTER AGREEMENT WITH HOW H5 TROUGH WILL GRADUALLY LIFT TO THE NORTH ACROSS THE AREA THROUGH THE PERIOD...THERE REMAINS CONSIDERABLE SPREAD WITH RESPECT TO THE TIMING DIFFERENCES GREATER THAN 12 HOURS NOTED IN THE GEFS SPAGHETTI PLOTS FOR THE PERIOD. GIVEN THE FAIRLY COLD TEMPS ALOFT LEADING TO SOME DESTABILIZATION AND PV ADVECTION...THINK THERE IS AT LEAST A SMALL THREAT FOR PRECIPITATION AS IT PASSES. HOWEVER WITH AFOREMENTIONED UNCERTAINTY WITH RESPECT TO TIMING...CAN NOT REALLY JUSTIFY ANY MORE THAN SLIGHT PROBABILITIES AT THIS POINT FOR SATURDAY AND SATURDAY NIGHT...ALTHOUGH SLIGHTLY PREFER A SLOWER SOLUTION WHICH WOULD IMPACT AREA MORE ON SATURDAY NIGHT. -JRM SUNDAY THROUGH WEDNESDAY...MODELS ARE CONTINUING TO COME INTO BETTER AGREEMENT WITH TRACK OF THE UPPER LEVEL CLOSED FOR THIS PERIOD. CURRENT GUIDANCE HAS THE CLOSED LOW MOVING OVER THE AREA SUNDAY. PLACED IN SLIGHT CHANCES FOR THE EASTERN PART OF THE AREA WHERE ISENTROPIC LIFT AND 5-7H FRONTOGENESIS DEVELOP AHEAD OF THE CLOSED LOW AS IT MOVES THROUGH. AN UPPER LEVEL TROUGH JUST BEHIND THE CLOSED LOW WILL ALSO LIFT NORTHEAST SUNDAY NIGHT INTO MONDAY...BUT WILL REMAIN WELL SOUTH OF THE AREA. MONDAY A SHORT WAVE RIDGE MOVES IN BEHIND THE CLOSED LOW. TUESDAY AND WEDNESDAY THE UPPER LEVEL FLOW TURNS TO THE SOUTHWEST...BRINGING DRY AIR OVER THE AREA WHILE A SHORTWAVE TROUGH MOVES ACROSS THE NORTHWEST CONUS. TEMPERATURES FOR THE PERIOD WILL BE ABOVE NORMAL...WITH HIGHS AROUND 70 AND LOWS AROUND 40 BY THE START OF THE WORK WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 410 AM MST THU MAR 8 2012 VFR CONDITIONS EXPECTED FOR ENTIRE PERIOD AS DRY SFC HIGH PRESSURE SETTLES OVER THE AREA. NORTHERLY WINDS WILL INCREASE TO 15 TO 20 KTS WITH HIGHER GUSTS BTWN 15 AND 17Z AND WILL BECOME LIGHT AND VARIABLE LATE THIS AFTERNOON AND EARLY THIS EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...JRM LONG TERM....JRM/JTL AVIATION...JRM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
559 AM EST THU MAR 8 2012 .SYNOPSIS... ISSUED AT 537 AM EST THU MAR 8 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS FROM NW ONTARIO THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF LIGHT SNOW MOVING QUICKLY THROUGH THE ERN CWA WAS SUPPORTED BY 700-600 MB FGEN BEHIND THE COLD FRONT THAT EXITED UPPER MI TO THE SE. OTHERWISE...JUST A FEW FLURRIES REMAINED OVER CNTRL UPPER MI. AN UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD SRN MANITOBA. AT THE SFC..NW WINDS PREVAILED BTWN A TROUGH FROM QUEBEC TO LAKE HURON AND A RIDGFROM THE NRN PLAINS INTO NW ONTARIO. THE CLIPPER LOW ASSOCIATED WITH THE CLIPPER SHRTWVWAS LOCATED OVER N CNTRL MANTIOBA WITH A TRAILING COLD FRONT TO THE SW. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 537 AM EST THU MAR 8 2012 TODAY...EXPECT THE MID LEVEL TROUGH MOVING INTO THE AREA BY AFTERNOON TO BE REINFORCED BY THE SASK SHRTWV BY LATE TODAY. THE COMBINATION OF INCREASING 700-500 MB QVECTOR CONV...DEEPER MOISTURE...DAYTIME HEATING AND STEEP 900-700 MB LAPSE RATES NEAR 8 C/KM WILL SUPPORT SCT SHSN DEVELOPMENT THIS AFTERNOON WHICH WILL INCREASE IN COVERAGE AND INTENSITY LATE. TONIGHT...SHSN WILL TRANSITION TO LES AS COLDER AIR ARRIVES (850 MB TEMPS ARE FCST TO DROP INTO THE -14C TO -18C RANGE) AND WINDS VEER TO THE NW. AS THE WINDS VEER THE STRONGER LOW LEVEL CONV WILL SHIFT FROM WRN UPPER MI INTO THE NE CWA E OF MARQUETTE. WITH FAVORABLE 850-700 MB MOISTURE AND INVERSION HEIGHTS TO NEAR 10K FT...SOME STRONGER SNOWBANDS MAY DEVELOP WITH BRIEF HEAVY SNOW. HOWEVER...GIVEN THE SHIFTING LOCATION OF THE BANDS...OVERALL ACCUMULATIONS SHOULD STILL REMAIN IN THE 1 TO 3 INCH RANGE. WITH THE LONGER FETCH INTO THE EAST...SOME ISOLATED HIGHER AMOUNTS TO AROUND 4 INCHES MAY BE POSSIBLE NEAR OR JUST INLAND FROM GRAND MARAIS. GUSTY NORTHWEST WINDS INTO THE 20 TO 30 MPH RANGE NEAR LAKE SUPERIOR WILL ALSO CAUSE AREA OF BLSN. FRIDAY...LES WILL DIMINISH FROM THE WEST AS DRIER AIR MOVES INTO THE REGION ALONG WITH ACYC FLOW AND LOWERING INVERSION HEIGHTS AND (AOB 4K FT). HOWEVER...ADDITIONAL AMOUNTS IN THE 1 TO 3 INCH RANGE MAY BE POSSIBLE OVER THE EAST AS THE 850 MB THERMAL TROUGH (850 MB TEMPS AROUND -18C) LINGERS INTO THE EARLY AFTERNOON. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 537 AM EST THU MAR 8 2012 ...RAIN FOLLOWED BY SIGNIFICANT WARM-UP EARLY-MID NEXT WEEK MAY RESULT IN HYDRO ISSUES... NOTE: SEE LATER PORTION OF THIS LONG TERM DISCUSSION FOR THOUGHTS ON POSSIBLE HYDROLOGY ISSUES. POP/WX WISE IT IS PRETTY QUIET FRIDAY NIGHT THROUGH SATURDAY NIGHT. WARM AIR ADVECTIONS RAMPING UP AGAIN COULD LEAD TO BATCH OF LGT SNOW OVR LK SUPERIOR AND PERHAPS THE FAR NORTHERN FRINGE OF THE CWA. OTHERWISE JUST A PERIOD OF MID CLOUDS. MAIN STORY FRIDAY NIGHT INTO SATURDAY WILL BE GUSTY SOUTH TO SOUTHWEST WINDS. TREND THAT BEGAN TO APPEAR IN MODELS YESTERDAY CONTINUES TODAY. AS HIGH PRESSURE RIDGE MOVES EAST FRIDAY NIGHT SFC TROUGH OVR CNTRL CANADA WILL STEAMROLL EAST BY SUNRISE SATURDAY. TIGHT PRESSURE GRADIENT ENSUES AND VERY STRONG PRESSURE FALLS /OVR 12MB IN 6 HR/ ARE FCST NORTH OF LK SUPERIOR. PATTERN SUGGESTS THAT DESPITE WARM AIR ADVECTION REGIME...SOUTH TO SOUTHWEST WINDS COULD BECOME QUITE GUSTY. FCST SOUNDINGS INDICATE A LOT OF WIND JUST ABOVE SFC /50+ KTS AT 925MB PER GFS/ECMWF/NAM/ BUT IT IS STABLE. BLYR WINDS USUALLY DO A GOOD JOB HIGHLIGHTING HOW STRONG WINDS COULD GET AND THIS OUTPUT POINTS TO SOLID 35-40 KTS. GALES OVR LK SUPERIOR AND PROBABLY NEARSHORE ZONES OF LK MICHIGAN GOOD BET. ALSO...GOING TO MENTION SOME NEAR ADVY GUSTS IN HAZARDOUS WEATHER OUTLOOK FOR SOUTH SHORE OF LK SUPERIOR. BASED ON SFC WIND DIRECTION AND WHERE CORE OF STRONGEST WINDS IS FCST...THE SHORELINE FM BARAGA TO MARQUETTE ALONG LK SUPERIOR WOULD SEE STRONGEST WINDS. ALSO COULD SEE STRONGER WINDS OVR KEWEENAW COUNTY AS THAT AREA IS EXPOSED TO SOUTHERLY FLOW...ESPECIALLY HIGHER TERRAIN AREAS. PRESSURE FALL MOVES STEADILY TO THE EAST THROUGH THE DAY...BUT SOUNDINGS POINT TO BREEZY CONDITIONS CONTINUING FOR MUCH OF SATURDAY AS MIXING WILL BE HIGHER DUE TO MAINLY SUNNY SKIES. AS SOUTH WINDS KICK UP LATER FRIDAY NIGHT TEMPS SHOULD BEGIN TO RISE OVR MUCH OF CWA. USED NON-DIURNAL TEMP CURVE INTO SATURDAY WITH LOWS FRIDAY EVENING IN THE TEENS AND TEMPS RISING TOWARD FREEZING BY SUNRISE SATURDAY. MIXING TO H9 ON SATURDAY SEEMS PRETTY GOOD CONSIDERING AMOUNT OF INSOLATION EXPECTED. MIXING THIS HIGH GAVE READINGS INTO THE 50S OVR MOST OF THE WEST HALF OF CWA. SW WINDS WILL KEEP LK MICHIGAN AND INLAND AREAS OF EAST CWA COOLER IN THE UPR 30S TO MID 40S. IN THE EXTENDED...COULD BE AN ACTIVE WEATHER PERIOD OVR MUCH OF UPR LAKES...BUT NOT NECESSARILY FM AMOUNT OF STORM SYSTEMS. RATHER...ONE SYSTEM LOOKS TO BRING LGT MAYBE MODERATE RAIN AMOUNTS TO AREA LATER SUNDAY THROUGH SUNDAY NIGHT THEN A VERY SIGNIFICANT WARM-UP IS IN STILL LOOKS TO BE IN THE OFFING INTO THE MIDDLE OF NEXT WEEK. IF ALL GOES AS PLANNED...MOST AREAS IN THE CWA BY THIS TIME NEXT WEEK WILL HAVE LOST A MAJORITY IF NOT ALL OF THE SNOWPACK. WILL BE SOMETHING TO MONITOR INTO NEXT WEEK AS THERE COULD BE SOME HYDRO ISSUES GIVEN POTENTIAL TO MELT THE SNOW RATHER QUICKLY. LOW PRESSURE STILL FCST TO LIFT FM THE PLAINS/MISSISSIPPI RIVER VALLEY INTO THE UPR LAKES LATE SUNDAY. IN A GENERAL SENSE...THREE MAIN MODELS USED FOR THE EXTENDED /GFS/ECMWF/CANADIAN/ ALL SHOW THIS SYSTEM IMPACTING UPR MI. TIMING IS NOT SET THOUGH...AS LATEST ECMWF NOW BRINGS THE LOW MORE ACROSS LATER SUNDAY NIGHT INTO MONDAY. THIS TIMING IS CLOSER TO CANADIAN BUT STRAYS SIGNIFICANTLY FM NCEP MODELS /GFS AND NAM/. NCEP PREFERRED SLOWER APPROACH AS THERE COULD BE SOME BLOCKING AHEAD OF THE FEATURE. TRENDED THIS WAY IN GRIDS. HIGHEST CHANCES SUNDAY NIGHT STILL LOOKED FINE. MAIN CHANGE TO CONSENSUS ALLBLEND APPROACH WAS TO KEEP CHANCE POPS IN FOR ALL DAY MONDAY. ONCE THE SYSTEM CLEARS THE AREA LATER MONDAY/MONDAY NIGHT...ATTN IS ON POTENTIAL WARM-UP. SEEMS LIKE MORE OFTEN THAN NOT IN RECENT YEARS WE HAVE LOST THE SNOWPACK IN THE SPRING WITH MORE OF A GRADUAL WARM UP IN A STEADY FREEZE-THAW CYCLE /RISING ABOVE FREEZING DURING THE DAYS BUT FALLING BLO AT NIGHT/. WE SEE HOW WHEN THIS DOES NOT WORK WHAT CAN HAPPEN AS YESTERDAY AT THE OFFICE IN NEGAUNEE TWP WITH HIGHS AROUND 50 DEGREES AND DWPNTS WELL INTO THE 40S...WE LOST 8 INCHES OF OUR SNOWPACK IN ONE DAY! AFTER OUR BREAK IN THE SNOWMELT THE NEXT COUPLE DAYS...SEEMS LIKE WE COULD BE HEADING FOR SIMILAR QUICK SNOWMELT LATE THIS WEEKEND THROUGH MID NEXT WEEK. MAIN CONCERN WOULD BE TUESDAY AND WEDNESDAY AS ECMWF /WHICH FOR MOST PART USUALLY LEADS WAY ON THESE TYPE OF WARM-UPS WELL OVER CLIMATOLOGY/ INDICATES MAX TEMPS PUSHING OVER 60 DEGREES OVR AT LEAST THE WEST HALF OF THE CWA. ALLBLEND GUIDANCE /BIASED TOWARD THE GFS/ WAS MUCH COOLER AND WAS ADJUSTED UPWARD FOR BOTH DAYS. ECMWF ALSO INDICATES DWPNTS RISING ABOVE 40...ESPECIALLY ON WEDNESDAY AHEAD OF WEAK TROUGH FCST TO COME THROUGH ON THURSDAY. A COUPLE OF CAUTIONS THOUGH. LATEST ECMWF NOW TRYING TO SHOW MORE OF A TYPICAL SPRING LIKE MSLP PATTERN ON TUESDAY WITH POSSIBLE LAKE BREEZES AS MAIN TROUGH REMAINS OVR PLAINS. TRIMMED TEMPS SLIGHTLY TOWARD LK SUPERIOR SHORE FOR TUESDAY...WITH BETTER SHOT OF THE REALLY WARM TEMPS STAYING INLAND TOWARD WI BORDER. TROUGH IS CLOSE ENOUGH ON WEDNESDAY TO RESULT IN MAINLY SW FLOW FOR ALL AREAS AND ALLOWING THE WARM TEMPS RIGHT TO PUSH TO THE LK SUPERIOR SHORE AS WELL ALONG WITH DWPNTS RISING WELL ABOVE 40F. OBVIOUSLY GIVEN THIS KIND OF MOISTURE ADVECTION AND THE MELING SNOWPACK ONGOING...SOME STRATUS/FOG IS NOT OUT OF QUESTION WHICH WOULD IMPACT TEMPS. STILL QUESTIONS IN SPECIFICS BUT THIS TIME FRAME COULD POSE SOME ISSUES WITH REGARD TO RISES ON RIVES/STREAMS AND SOME AREAL FLOODING CONCERNS IN LOW-LYING SPOTS AS WELL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 558 AM EST THU MAR 8 2012 EXPECT MAINLY MVFR CIGS TODAY WITH LOW LEVEL MOISTURE REMAINING OVER THE AREA. AN APPROACHING DISTURBANCE/STEEP LAPSE RATES/DAYTIME HEATING WILL LIKELY LEAD TO SCT/NMRS -SHSN LATER THIS AFTN INTO THE EVENING HRS. MVFR CONDITIONS SHOULD GENERALLY PREVAIL...THOUGH SOME BRIEF PERIODS OF IFR MAY OCCUR DEPENDING ON THE INTENSITY OF THE -SHSN. SHSN WILL TRANSITION TO LES AS COLDER AIR MOVES IN TONIGHT BUT SHOULD MAINLY AFFECT KCMX. NORTHWEST WINDS WILL ALSO INCREASE LATE THIS EVENING AND OVERNIGHT WITH BLSN ALSO DEVELOPING AT KCMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 537 AM EST THU MAR 8 2012 A COUPLE OF PERIODS OF GALES ON THE LAKE INTO THIS WEEKEND. FIRST GALE EVENT IS TONIGHT WITH COLD AND UNSTABLE PROFILE OVER THE LAKE. SHOULD SEE FREQUENT GUSTS 35-40 KTS AND HAVE ISSUED GALE WARNING FOR ALL OF LK SUPERIOR INTO EARLY FRIDAY. HAVE ALSO POSTED HEAVY FREEZING SPRAY WARNING FOR TONIGHT. NOT OUT OF QUESTION THAT THIS MAY BE LAST HEAVY FREEZING SPRAY EPISODE OF WINTER. SOUTH TO SOUTHWEST GALES THEN LOOK LIKELY LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS OVER LK SUPERIOR. WARM AIR ADVECTION REGIME KEEPS HIGHER STABILITY IN LOW-LEVELS...BUT THINK THIS WILL BE OFFSET BY VERY STRONG PRESSURE FALLS SLIDING JUST NORTH OF LK SUPERIOR. SETUP USUALLY RESULTS IN STRONGEST WINDS OVER EASTERN HALF OF LK SUPERIOR. WINDS SETTLE DOWN CONSIDERABLY BY LATER SATURDAY NIGHT INTO SUNDAY. WIND DIRECTION LATER SUNDAY INTO MONDAY WILL BE HIGHLY DEPENDANT ON TRACK OF APPROACHING LOW PRESSURE SYSTEM FM CENTRAL PLAINS. EXPECT WINDS TO REMAIN LESS THAN 30 KTS AS THE SYSTEM MOVES THROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 4 AM TO 11 AM EST FRIDAY FOR LSZ267. GALE WARNING FROM 1 AM TO 11 AM EST FRIDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-240>245- 248-263>265. GALE WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 6 AM EST /5 AM CST/ FRIDAY FOR LSZ162-263. GALE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EST FRIDAY FOR LSZ264- 265. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
539 AM EST THU MAR 8 2012 .SYNOPSIS... ISSUED AT 537 AM EST THU MAR 8 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS FROM NW ONTARIO THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF LIGHT SNOW MOVING QUICKLY THROUGH THE ERN CWA WAS SUPPORTED BY 700-600 MB FGEN BEHIND THE COLD FRONT THAT EXITED UPPER MI TO THE SE. OTHERWISE...JUST A FEW FLURRIES REMAINED OVER CNTRL UPPER MI. AN UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD SRN MANITOBA. AT THE SFC..NW WINDS PREVAILED BTWN A TROUGH FROM QUEBEC TO LAKE HURON AND A RIDGFROM THE NRN PLAINS INTO NW ONTARIO. THE CLIPPER LOW ASSOCIATED WITH THE CLIPPER SHRTWVWAS LOCATED OVER N CNTRL MANTIOBA WITH A TRAILING COLD FRONT TO THE SW. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 537 AM EST THU MAR 8 2012 TODAY...EXPECT THE MID LEVEL TROUGH MOVING INTO THE AREA BY AFTERNOON TO BE REINFORCED BY THE SASK SHRTWV BY LATE TODAY. THE COMBINATION OF INCREASING 700-500 MB QVECTOR CONV...DEEPER MOISTURE...DAYTIME HEATING AND STEEP 900-700 MB LAPSE RATES NEAR 8 C/KM WILL SUPPORT SCT SHSN DEVELOPMENT THIS AFTERNOON WHICH WILL INCREASE IN COVERAGE AND INTENSITY LATE. TONIGHT...SHSN WILL TRANSITION TO LES AS COLDER AIR ARRIVES (850 MB TEMPS ARE FCST TO DROP INTO THE -14C TO -18C RANGE) AND WINDS VEER TO THE NW. AS THE WINDS VEER THE STRONGER LOW LEVEL CONV WILL SHIFT FROM WRN UPPER MI INTO THE NE CWA E OF MARQUETTE. WITH FAVORABLE 850-700 MB MOISTURE AND INVERSION HEIGHTS TO NEAR 10K FT...SOME STRONGER SNOWBANDS MAY DEVELOP WITH BRIEF HEAVY SNOW. HOWEVER...GIVEN THE SHIFTING LOCATION OF THE BANDS...OVERALL ACCUMULATIONS SHOULD STILL REMAIN IN THE 1 TO 3 INCH RANGE. WITH THE LONGER FETCH INTO THE EAST...SOME ISOLATED HIGHER AMOUNTS TO AROUND 4 INCHES MAY BE POSSIBLE NEAR OR JUST INLAND FROM GRAND MARAIS. GUSTY NORTHWEST WINDS INTO THE 20 TO 30 MPH RANGE NEAR LAKE SUPERIOR WILL ALSO CAUSE AREA OF BLSN. FRIDAY...LES WILL DIMINISH FROM THE WEST AS DRIER AIR MOVES INTO THE REGION ALONG WITH ACYC FLOW AND LOWERING INVERSION HEIGHTS AND (AOB 4K FT). HOWEVER...ADDITIONAL AMOUNTS IN THE 1 TO 3 INCH RANGE MAY BE POSSIBLE OVER THE EAST AS THE 850 MB THERMAL TROUGH (850 MB TEMPS AROUND -18C) LINGERS INTO THE EARLY AFTERNOON. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 537 AM EST THU MAR 8 2012 ...RAIN FOLLOWED BY SIGNIFICANT WARM-UP EARLY-MID NEXT WEEK MAY RESULT IN HYDRO ISSUES... NOTE: SEE LATER PORTION OF THIS LONG TERM DISCUSSION FOR THOUGHTS ON POSSIBLE HYDROLOGY ISSUES. POP/WX WISE IT IS PRETTY QUIET FRIDAY NIGHT THROUGH SATURDAY NIGHT. WARM AIR ADVECTIONS RAMPING UP AGAIN COULD LEAD TO BATCH OF LGT SNOW OVR LK SUPERIOR AND PERHAPS THE FAR NORTHERN FRINGE OF THE CWA. OTHERWISE JUST A PERIOD OF MID CLOUDS. MAIN STORY FRIDAY NIGHT INTO SATURDAY WILL BE GUSTY SOUTH TO SOUTHWEST WINDS. TREND THAT BEGAN TO APPEAR IN MODELS YESTERDAY CONTINUES TODAY. AS HIGH PRESSURE RIDGE MOVES EAST FRIDAY NIGHT SFC TROUGH OVR CNTRL CANADA WILL STEAMROLL EAST BY SUNRISE SATURDAY. TIGHT PRESSURE GRADIENT ENSUES AND VERY STRONG PRESSURE FALLS /OVR 12MB IN 6 HR/ ARE FCST NORTH OF LK SUPERIOR. PATTERN SUGGESTS THAT DESPITE WARM AIR ADVECTION REGIME...SOUTH TO SOUTHWEST WINDS COULD BECOME QUITE GUSTY. FCST SOUNDINGS INDICATE A LOT OF WIND JUST ABOVE SFC /50+ KTS AT 925MB PER GFS/ECMWF/NAM/ BUT IT IS STABLE. BLYR WINDS USUALLY DO A GOOD JOB HIGHLIGHTING HOW STRONG WINDS COULD GET AND THIS OUTPUT POINTS TO SOLID 35-40 KTS. GALES OVR LK SUPERIOR AND PROBABLY NEARSHORE ZONES OF LK MICHIGAN GOOD BET. ALSO...GOING TO MENTION SOME NEAR ADVY GUSTS IN HAZARDOUS WEATHER OUTLOOK FOR SOUTH SHORE OF LK SUPERIOR. BASED ON SFC WIND DIRECTION AND WHERE CORE OF STRONGEST WINDS IS FCST...THE SHORELINE FM BARAGA TO MARQUETTE ALONG LK SUPERIOR WOULD SEE STRONGEST WINDS. ALSO COULD SEE STRONGER WINDS OVR KEWEENAW COUNTY AS THAT AREA IS EXPOSED TO SOUTHERLY FLOW...ESPECIALLY HIGHER TERRAIN AREAS. PRESSURE FALL MOVES STEADILY TO THE EAST THROUGH THE DAY...BUT SOUNDINGS POINT TO BREEZY CONDITIONS CONTINUING FOR MUCH OF SATURDAY AS MIXING WILL BE HIGHER DUE TO MAINLY SUNNY SKIES. AS SOUTH WINDS KICK UP LATER FRIDAY NIGHT TEMPS SHOULD BEGIN TO RISE OVR MUCH OF CWA. USED NON-DIURNAL TEMP CURVE INTO SATURDAY WITH LOWS FRIDAY EVENING IN THE TEENS AND TEMPS RISING TOWARD FREEZING BY SUNRISE SATURDAY. MIXING TO H9 ON SATURDAY SEEMS PRETTY GOOD CONSIDERING AMOUNT OF INSOLATION EXPECTED. MIXING THIS HIGH GAVE READINGS INTO THE 50S OVR MOST OF THE WEST HALF OF CWA. SW WINDS WILL KEEP LK MICHIGAN AND INLAND AREAS OF EAST CWA COOLER IN THE UPR 30S TO MID 40S. IN THE EXTENDED...COULD BE AN ACTIVE WEATHER PERIOD OVR MUCH OF UPR LAKES...BUT NOT NECESSARILY FM AMOUNT OF STORM SYSTEMS. RATHER...ONE SYSTEM LOOKS TO BRING LGT MAYBE MODERATE RAIN AMOUNTS TO AREA LATER SUNDAY THROUGH SUNDAY NIGHT THEN A VERY SIGNIFICANT WARM-UP IS IN STILL LOOKS TO BE IN THE OFFING INTO THE MIDDLE OF NEXT WEEK. IF ALL GOES AS PLANNED...MOST AREAS IN THE CWA BY THIS TIME NEXT WEEK WILL HAVE LOST A MAJORITY IF NOT ALL OF THE SNOWPACK. WILL BE SOMETHING TO MONITOR INTO NEXT WEEK AS THERE COULD BE SOME HYDRO ISSUES GIVEN POTENTIAL TO MELT THE SNOW RATHER QUICKLY. LOW PRESSURE STILL FCST TO LIFT FM THE PLAINS/MISSISSIPPI RIVER VALLEY INTO THE UPR LAKES LATE SUNDAY. IN A GENERAL SENSE...THREE MAIN MODELS USED FOR THE EXTENDED /GFS/ECMWF/CANADIAN/ ALL SHOW THIS SYSTEM IMPACTING UPR MI. TIMING IS NOT SET THOUGH...AS LATEST ECMWF NOW BRINGS THE LOW MORE ACROSS LATER SUNDAY NIGHT INTO MONDAY. THIS TIMING IS CLOSER TO CANADIAN BUT STRAYS SIGNIFICANTLY FM NCEP MODELS /GFS AND NAM/. NCEP PREFERRED SLOWER APPROACH AS THERE COULD BE SOME BLOCKING AHEAD OF THE FEATURE. TRENDED THIS WAY IN GRIDS. HIGHEST CHANCES SUNDAY NIGHT STILL LOOKED FINE. MAIN CHANGE TO CONSENSUS ALLBLEND APPROACH WAS TO KEEP CHANCE POPS IN FOR ALL DAY MONDAY. ONCE THE SYSTEM CLEARS THE AREA LATER MONDAY/MONDAY NIGHT...ATTN IS ON POTENTIAL WARM-UP. SEEMS LIKE MORE OFTEN THAN NOT IN RECENT YEARS WE HAVE LOST THE SNOWPACK IN THE SPRING WITH MORE OF A GRADUAL WARM UP IN A STEADY FREEZE-THAW CYCLE /RISING ABOVE FREEZING DURING THE DAYS BUT FALLING BLO AT NIGHT/. WE SEE HOW WHEN THIS DOES NOT WORK WHAT CAN HAPPEN AS YESTERDAY AT THE OFFICE IN NEGAUNEE TWP WITH HIGHS AROUND 50 DEGREES AND DWPNTS WELL INTO THE 40S...WE LOST 8 INCHES OF OUR SNOWPACK IN ONE DAY! AFTER OUR BREAK IN THE SNOWMELT THE NEXT COUPLE DAYS...SEEMS LIKE WE COULD BE HEADING FOR SIMILAR QUICK SNOWMELT LATE THIS WEEKEND THROUGH MID NEXT WEEK. MAIN CONCERN WOULD BE TUESDAY AND WEDNESDAY AS ECMWF /WHICH FOR MOST PART USUALLY LEADS WAY ON THESE TYPE OF WARM-UPS WELL OVER CLIMATOLOGY/ INDICATES MAX TEMPS PUSHING OVER 60 DEGREES OVR AT LEAST THE WEST HALF OF THE CWA. ALLBLEND GUIDANCE /BIASED TOWARD THE GFS/ WAS MUCH COOLER AND WAS ADJUSTED UPWARD FOR BOTH DAYS. ECMWF ALSO INDICATES DWPNTS RISING ABOVE 40...ESPECIALLY ON WEDNESDAY AHEAD OF WEAK TROUGH FCST TO COME THROUGH ON THURSDAY. A COUPLE OF CAUTIONS THOUGH. LATEST ECMWF NOW TRYING TO SHOW MORE OF A TYPICAL SPRING LIKE MSLP PATTERN ON TUESDAY WITH POSSIBLE LAKE BREEZES AS MAIN TROUGH REMAINS OVR PLAINS. TRIMMED TEMPS SLIGHTLY TOWARD LK SUPERIOR SHORE FOR TUESDAY...WITH BETTER SHOT OF THE REALLY WARM TEMPS STAYING INLAND TOWARD WI BORDER. TROUGH IS CLOSE ENOUGH ON WEDNESDAY TO RESULT IN MAINLY SW FLOW FOR ALL AREAS AND ALLOWING THE WARM TEMPS RIGHT TO PUSH TO THE LK SUPERIOR SHORE AS WELL ALONG WITH DWPNTS RISING WELL ABOVE 40F. OBVIOUSLY GIVEN THIS KIND OF MOISTURE ADVECTION AND THE MELING SNOWPACK ONGOING...SOME STRATUS/FOG IS NOT OUT OF QUESTION WHICH WOULD IMPACT TEMPS. STILL QUESTIONS IN SPECIFICS BUT THIS TIME FRAME COULD POSE SOME ISSUES WITH REGARD TO RISES ON RIVES/STREAMS AND SOME AREAL FLOODING CONCERNS IN LOW-LYING SPOTS AS WELL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 537 AM EST THU MAR 8 2012 WITH DRIER AIR WORKING INTO THE AREA BEHIND COLD FRONT...LOW MVFR/IFR CIGS AT KIWD/KCMX/KSAW SHOULD RISE TO THE UPPER MVFR RANGE OVER THE NEXT SEVERAL HRS...AND NOT OUT OF THE QUESTION THAT CIGS COULD RISE TO VFR LATER IN THE NIGHT. ONGOING -SN WILL DIMINISH AND SHOULD NOT POSE MUCH VIS RESTRICTION LATER IN THE NIGHT AS WELL. APPROACHING DISTURBANCE/STEEP LAPSE RATES/DAYTIME HEATING WILL LIKELY LEAD TO SCT/NMRS -SHSN LATER THIS AFTN INTO THE EVENING HRS. MVFR CONDITIONS SHOULD GENERALLY PREVAIL...THOUGH SOME BRIEF PERIODS OF IFR MAY OCCUR DEPENDING ON INTENSITY OF -SHSN. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 537 AM EST THU MAR 8 2012 SOUTH TO SOUTHWEST GALES LOOKING LIKELY LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS OVER LK SUPERIOR. WARM AIR ADVECTION REGIME KEEPS HIGHER STABILITY IN LOW-LEVELS...BUT THINK THIS WILL BE OFFSET BY VERY STRONG PRESSURE FALLS SLIDING JUST NORTH OF LK SUPERIOR. SETUP USUALLY RESULTS IN STRONGEST WINDS OVER EASTERN HALF OF LK SUPERIOR. WINDS SETTLE DOWN CONSIDERABLY BY LATER SATURDAY NIGHT INTO SUNDAY. WIND DIRECTION LATER SUNDAY INTO MONDAY WILL BE HIGHLY DEPENDANT ON TRACK OF APPROACHING LOW PRESSURE SYSTEM FM CENTRAL PLAINS. EXPECT WINDS TO REMAIN LESS THAN 30 KTS AS THE SYSTEM MOVES THROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 4 AM TO 11 AM EST FRIDAY FOR LSZ267. GALE WARNING FROM 1 AM TO 11 AM EST FRIDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-240>245- 248-263>265. GALE WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 6 AM EST /5 AM CST/ FRIDAY FOR LSZ162-263. GALE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EST FRIDAY FOR LSZ264- 265. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...JLA AVIATION...ROLFSON MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1000 AM CST THU MAR 8 2012 .UPDATE... ADDED SCATTERED SNOW SHOWERS ACROSS THE SRN COUNTIES THIS MORNING TO ACCOUNT FOR A SMALL CLUSTER OF SNOW SHOWERS MOVING FROM E-CNTRL MN INTO WI. STILL ANTICIPATING THE CONVECTIVE SNOW SHOWERS TO DEVELOP THIS AFTERNOON...AND AFTER LOOKING AT THE LATEST HIGH- RES SHORT TERM MODELS...LOOKS VERY UNSTABLE IN THE LOW AND MID LEVELS... WITH STEEP LAPSE RATES AND 50-80 J/KG OF LOW-LVL CAPE...AND ALSO VERY SUPPORTIVE ALOFT FOR A QUICK INCH OF SNOW ACCUMULATION. WINDS WILL INCREASE FROM THE NW THIS AFTERNOON...AND COMBINE WITH THE SNOW SHOWERS TO PRODUCE AREAS OF BLOWING SNOW. VISIBILITIES COULD BE REDUCED TO A MILE OR LESS AT TIMES IN THE BLOWING SNOW. A STRONG 140KT JET WILL PUSH IN FROM THE NW...WITH THE NORTHLAND IN THE LEFT EXIT REGION...ALSO A STRONG 500MB VORT MAX WILL ADVECT INTO THE REGION TO HELP WITH VERTICAL MOTION. SYSTEM SHOULD MOVE THROUGH VERY RAPIDLY AS HIGH PRESSURE BUILDS IN ON THE BACK SIDE. && .PREV DISCUSSION... /ISSUED 654 AM CST THU MAR 8 2012/ AVIATION.../12Z TAF ISSUANCE/ ANOTHER COLD FRONT WILL TRACK SEWD ACROSS THE NORTHLAND THIS AFTERNOON AND EVENING...BRINGING INCREASING CLOUD COVER AND AREAS OF LIGHT SNOW TO THE REGION. CIGS AND VSBYS ASSOCIATED WITH THE FROPA WILL BE IN THE MVFR/LOW VFR RANGE. THE SNOW SHOULD END LATE THIS EVENING OVER OVERNIGHT AND SKIES WILL SCTR OUT. PREV DISCUSSION... /ISSUED 403 AM CST THU MAR 8 2012/ SHORT TERM...THE SHORT TERM FOCUS IS ON WINDS AND SNOW SHOWER POTENTIAL ACROSS THE NORTHLAND. AT 330 AM...FAIRLY WIDESPREAD CLOUD COVER WAS MOVING ACROSS THE NORTHLAND ALTHOUGH THERE WERE SEVERAL AREAS OF THIN CLOUDS. TEMPERATURES RANGED FROM THE UPPER 20S IN PORTIONS OF NW WI...TO NEAR 10 ABOVE FAR NORTHWEST. NORTHWEST FLOW WILL PERSIST ACROSS THE NORTHLAND TODAY. STRONG CAA WILL BECOME FAIRLY NEUTRAL THROUGHOUT THE DAY. THE NAM INDICATES THAT AT LEAST A COUPLE SHORTWAVES WILL MOVE THROUGH THE REGION IN NW FLOW TODAY. EACH WILL BE CAPABLE OF GENERATING SOME SNOW SHOWERS...BUT THE BEST CHANCE SHOULD BE ACROSS THE NORTH IN THE AFTERNOON AND EARLY EVENING. WITH COLD AIR ALOFT AND SOME SURFACE HEATING BETWEEN SNOW SHOWERS...THINK SOME OF THE SNOW SHOWERS COULD BE FAIRLY STRONG THIS AFTERNOON...EVEN BRINGING SOME GUSTY WINDS WITH THE SNOW SHOWERS. THE BIGGER STORY FOR TODAY MAY BE THE STRONG WINDS EXPECTED TO MOVE INTO THE CWA DURING THE AFTERNOON AND EVENING. HAVE BROUGHT WINDS UP QUITE A BIT. THE RUC SHOWS STRONG WINDS ALOFT MIXING DOWN TO THE SURFACE. THE FORECAST SOUNDINGS FOR DULUTH INDICATE 40-50 KNOTS WORKING ITS WAY TO JUST ABOVE THE SURFACE. AS A RESULT...WE COULD EASILY SEE SOME 20 TO 30 MPH SUSTAINED WINDS THIS AFTERNOON WITH HIGHER GUSTS AS WELL. WINDS WILL THEN DECREASED OVERNIGHT AS SKIES CLEAR FROM THE WEST. HAVE DROPPED TEMPS CONSIDERABLY FOR TONIGHT...CLOSER TO THE MAV GUIDANCE. THIS SHOULD RESULT IN TEMPERATURES DROPPING BELOW ZERO IN THE NORTH. FRIDAY SHOULD BE A BIT WARMER...AS WAA PUSHES ACROSS THE REGION. SHOULD BE SOMEWHAT OF AN INCREASE IN CLOUDS...ESPECIALLY IN THE NORTH. THINK MOST OF THE PRECIPITATION SHOULD REMAIN IN CANADA. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. THE EXTENDED FORECAST PERIOD WILL START OUT DRY AND MILD UNDER WITH A UPPER RIDGE BUILDING OVER THE WRN GREAT LAKES DUE TO STRONG SWRLY FLOW IN THE LOW-LEVELS. HOWEVER THE RIDGE WILL GIVE WAY TO A LOW PRESSURE SYSTEM DEVELOPING OVER THE CNTL PLAINS WHICH IS PROGGED TO LIFT NEWD OVER THE GREAT LAKES SUNDAY INTO MONDAY. THERE ARE STILL SOME SIGNIFICANT DIFFERENCES BETWEEN THE VARIOUS NWP MODEL SOLUTIONS...WITH THE NAM/GFS TAKING THE LOW OFF TO THE SOUTH AND EAST OF OUR CWA...WHILE THE ECMWF/GEM BRING IT RIGHT OVER THE NORTHLAND. DUE TO THESE DIFFERENCES...WE WILL KEEP POPS IN THE CHANCE CATEGORY ATTM. PRECIP TYPE SHOULD BE MAINLY RAIN DUE TO THE WARM AIRMASS IN PLACE ACROSS THE UPPER MIDWEST. BUT IF THE DYNAMIC LIFT IS STRONG ENOUGH...THERE COULD BE A WINTRY MIX SUNDAY NIGHT AND MONDAY MORNING. AFTER THE LOW MOVES OFF TO THE EAST...AN UNSEASONABLY WARM AND DRY PATTERN WILL DEVELOP ACROSS THE NORTHLAND NEXT WEEK AS SOUTHWEST FLOW DOMINATES ACROSS THE CTRL PART OF THE COUNTRY THROUGH WEDNESDAY. AVIATION.../06Z TAF ISSUANCE/ MVFR AND ISOLATED IFR IN CLOUDS AND SNOW IN A FRONTAL BAND SHOULD MOVE OUT OF THE IWD AND GOGEBIC RANGE AREA LATE TONIGHT. MN NORTH SHORE AND REST OF NORTHWEST WISCONSIN...MVFR IN CLOUDS IMPROVING TO VFR SCATTERED WITH AREAS OF BROKEN CLOUDS BY DAY BREAK THURSDAY MORNING. THE REST OF NORTHEAST MN...VFR THROUGH EARLY MORNING. AREAS OF LOW-END VFR IN CLOUDS WILL DEVELOP MIDMORNING ACROSS COASTAL WI AND NORTH OF ROUTE 2 IN NORTHEAST MN AFTER MIDMORNING THURSDAY...AND PERSIST TILL LATE THURSDAY AFTERNOON. VFR CLEAR BEGINNING THURSDAY EVENING. BRISK NORTHWEST WINDS...GUSTING TO 30 MPH...WILL CONTINUE INTO LATE THURSDAY AFTERNOON...AND SUBSIDE DURING THURSDAY EVENING. && .POINT TEMPS/POPS... DLH 31 7 29 25 / 30 30 0 10 INL 31 -5 32 22 / 40 20 10 10 BRD 34 5 35 29 / 30 10 0 0 HYR 33 5 33 27 / 30 30 0 10 ASX 34 10 30 25 / 30 30 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
654 AM CST THU MAR 8 2012 .AVIATION.../12Z TAF ISSUANCE/ ANOTHER COLD FRONT WILL TRACK SEWD ACROSS THE NORTHLAND THIS AFTERNOON AND EVENING...BRINGING INCREASING CLOUD COVER AND AREAS OF LIGHT SNOW TO THE REGION. CIGS AND VSBYS ASSOCIATED WITH THE FROPA WILL BE IN THE MVFR/LOW VFR RANGE. THE SNOW SHOULD END LATE THIS EVENING OVER OVERNIGHT AND SKIES WILL SCTR OUT. && .PREV DISCUSSION... /ISSUED 403 AM CST THU MAR 8 2012/ SHORT TERM...THE SHORT TERM FOCUS IS ON WINDS AND SNOW SHOWER POTENTIAL ACROSS THE NORTHLAND. AT 330 AM...FAIRLY WIDESPREAD CLOUD COVER WAS MOVING ACROSS THE NORTHLAND ALTHOUGH THERE WERE SEVERAL AREAS OF THIN CLOUDS. TEMPERATURES RANGED FROM THE UPPER 20S IN PORTIONS OF NW WI...TO NEAR 10 ABOVE FAR NORTHWEST. NORTHWEST FLOW WILL PERSIST ACROSS THE NORTHLAND TODAY. STRONG CAA WILL BECOME FAIRLY NEUTRAL THROUGHOUT THE DAY. THE NAM INDICATES THAT AT LEAST A COUPLE SHORTWAVES WILL MOVE THROUGH THE REGION IN NW FLOW TODAY. EACH WILL BE CAPABLE OF GENERATING SOME SNOW SHOWERS...BUT THE BEST CHANCE SHOULD BE ACROSS THE NORTH IN THE AFTERNOON AND EARLY EVENING. WITH COLD AIR ALOFT AND SOME SURFACE HEATING BETWEEN SNOW SHOWERS...THINK SOME OF THE SNOW SHOWERS COULD BE FAIRLY STRONG THIS AFTERNOON...EVEN BRINGING SOME GUSTY WINDS WITH THE SNOW SHOWERS. THE BIGGER STORY FOR TODAY MAY BE THE STRONG WINDS EXPECTED TO MOVE INTO THE CWA DURING THE AFTERNOON AND EVENING. HAVE BROUGHT WINDS UP QUITE A BIT. THE RUC SHOWS STRONG WINDS ALOFT MIXING DOWN TO THE SURFACE. THE FORECAST SOUNDINGS FOR DULUTH INDICATE 40-50 KNOTS WORKING ITS WAY TO JUST ABOVE THE SURFACE. AS A RESULT...WE COULD EASILY SEE SOME 20 TO 30 MPH SUSTAINED WINDS THIS AFTERNOON WITH HIGHER GUSTS AS WELL. WINDS WILL THEN DECREASED OVERNIGHT AS SKIES CLEAR FROM THE WEST. HAVE DROPPED TEMPS CONSIDERABLY FOR TONIGHT...CLOSER TO THE MAV GUIDANCE. THIS SHOULD RESULT IN TEMPERATURES DROPPING BELOW ZERO IN THE NORTH. FRIDAY SHOULD BE A BIT WARMER...AS WAA PUSHES ACROSS THE REGION. SHOULD BE SOMEWHAT OF AN INCREASE IN CLOUDS...ESPECIALLY IN THE NORTH. THINK MOST OF THE PRECIPITATION SHOULD REMAIN IN CANADA. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. THE EXTENDED FORECAST PERIOD WILL START OUT DRY AND MILD UNDER WITH A UPPER RIDGE BUILDING OVER THE WRN GREAT LAKES DUE TO STRONG SWRLY FLOW IN THE LOW-LEVELS. HOWEVER THE RIDGE WILL GIVE WAY TO A LOW PRESSURE SYSTEM DEVELOPING OVER THE CNTL PLAINS WHICH IS PROGGED TO LIFT NEWD OVER THE GREAT LAKES SUNDAY INTO MONDAY. THERE ARE STILL SOME SIGNIFICANT DIFFERENCES BETWEEN THE VARIOUS NWP MODEL SOLUTIONS...WITH THE NAM/GFS TAKING THE LOW OFF TO THE SOUTH AND EAST OF OUR CWA...WHILE THE ECMWF/GEM BRING IT RIGHT OVER THE NORTHLAND. DUE TO THESE DIFFERENCES...WE WILL KEEP POPS IN THE CHANCE CATEGORY ATTM. PRECIP TYPE SHOULD BE MAINLY RAIN DUE TO THE WARM AIRMASS IN PLACE ACROSS THE UPPER MIDWEST. BUT IF THE DYNAMIC LIFT IS STRONG ENOUGH...THERE COULD BE A WINTRY MIX SUNDAY NIGHT AND MONDAY MORNING. AFTER THE LOW MOVES OFF TO THE EAST...AN UNSEASONABLY WARM AND DRY PATTERN WILL DEVELOP ACROSS THE NORTHLAND NEXT WEEK AS SOUTHWEST FLOW DOMINATES ACROSS THE CTRL PART OF THE COUNTRY THROUGH WEDNESDAY. AVIATION.../06Z TAF ISSUANCE/ MVFR AND ISOLATED IFR IN CLOUDS AND SNOW IN A FRONTAL BAND SHOULD MOVE OUT OF THE IWD AND GOGEBIC RANGE AREA LATE TONIGHT. MN NORTH SHORE AND REST OF NORTHWEST WISCONSIN...MVFR IN CLOUDS IMPROVING TO VFR SCATTERED WITH AREAS OF BROKEN CLOUDS BY DAY BREAK THURSDAY MORNING. THE REST OF NORTHEAST MN...VFR THROUGH EARLY MORNING. AREAS OF LOW-END VFR IN CLOUDS WILL DEVELOP MIDMORNING ACROSS COASTAL WI AND NORTH OF ROUTE 2 IN NORTHEAST MN AFTER MIDMORNING THURSDAY...AND PERSIST TILL LATE THURSDAY AFTERNOON. VFR CLEAR BEGINNING THURSDAY EVENING. BRISK NORTHWEST WINDS...GUSTING TO 30 MPH...WILL CONTINUE INTO LATE THURSDAY AFTERNOON...AND SUBSIDE DURING THURSDAY EVENING. && .POINT TEMPS/POPS... DLH 32 7 29 25 / 30 30 0 10 INL 28 -5 32 22 / 40 20 10 10 BRD 34 5 35 29 / 30 10 0 0 HYR 35 5 33 27 / 30 30 0 10 ASX 34 10 30 25 / 30 30 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ AVIATION...BERDES
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
620 AM CST THU MAR 8 2012 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .DISCUSSION... MAIN CONCERN WILL BE WINDS THURSDAY AFTERNOON AND EVENING WITH COLD AIR ADVECTION. THE NEXT POTENTIAL WEATHER MAKER IS THE EMERGENCE OF THE CUTOFF LOW EARLY NEXT WEEK. FINALLY...THERMAL RIDGING WILL ALLOW NEAR RECORD BREAKING HIGH TEMPERATURES THROUGH MID WEEK. TODAY THROUGH TONIGHT...LATEST WV IMAGERY SHOWS TWO SHORTWAVES ACROSS THE US/CANADA BORDER. THE FIRST ONE IS LOCATED OVER NORTH DAKOTA...AND IS SPAWNING A FEW LIGHT SNOW SHOWERS OVER THE RED RIVER VALLEY. THIS FEATURE WILL CONTINUE TO HEAD SOUTHEAST...SO HAVE FLURRIES ACROSS THE NORTHERN TIERS. THE SECOND MORE POTENT WAVE IS STREAMING DOWN FROM SASKATCHEWAN...AND THIS WILL CONTINUE TO STRENGTHEN AS IT HEADS TOWARD THE GREAT LAKES REGION. THE STRONGEST FORCING ASSOCIATED WITH PV ANOMALY WILL BE ACROSS NORTHERN MINNESOTA...BUT EXPECT A FEW SNOW SHOWERS BY THE AFTERNOON. SOUNDINGS SHOW DEEP MIXING WITH 35 TO 40KTS ATOP THE MIXED LAYER...SO HAVE A WIND ADVISORY FOR NORTHWESTERN CWA. THIS IS ALSO SUPPORTED BY THE ISALLOBARIC MAPS SHOWING THE PRESSURE RISES ASSOCIATED WITH THE SUBSIDENCE ON THE BACK SIDE OF THE PASSING SHORTWAVE. WINDS SHOULD REMAIN STRONG THROUGH THE EVENING HOURS...BEFORE TAPERING OFF THURSDAY NIGHT. FRIDAY THROUGH WEDNESDAY...UPPER LEVEL RIDGING WILL REMAIN IN PLACE ACROSS THE MIDWEST ALLOWING FOR SOUTHWEST FLOW AND LOW LEVEL WARM AIR ADVECTION. THE ONLY CAVEAT IS A CUT OFF LOW CURRENTLY LOCATED ACROSS THE 4CORNERS REGION THAT IS EXPECTED TO TRACK NORTHEAST FOR THE WEEKEND. THERE IS STILL SOME DISAGREEMENT ON WHEN AND WHERE THIS LOW GO...WITH THE ECMWF 08.00 CONSIDERABLY SLOWER THAN PREVIOUS RUN...AS WELL AS THE LATEST GFS AND GEM. THEREFORE TRENDED SLOWER WITH THE ONSET OF PRECIPITATION AND KEPT SUNDAY AND MONDAY HIGH TEMPS NEAR GUIDANCE WITH THE POSSIBILITY OF CLOUD COVER. ASIDE FROM THIS SOLE CHANCE OF WIDESPREAD PRECIP...THE EXTENDED WILL BE DRY AND WARM. HAVE INCREASED THE TEMPS FOR SATURDAY...AND TUESDAY THROUGH THURSDAY AS SOUTHWESTERLY WINDS AND CLEAR SKIES ALLOW H925 TEMPS OF 8-10C TO MIX DOWN TO THE SURFACE...WHICH SHOULD EQUATE TO MID 60S...ESPECIALLY AT THOSE LOCATION WITH NO SNOW PACK. && .AVIATION.../12Z TAF ISSUANCE/ WATCHING TWO UPPER WAVES WITH THE POTENTIAL FOR -SN TODAY...ALONG WITH THE POTENTIAL FOR SOME RATHER STRONG WINDS THIS EVENING. FIRST WAVE AND BOUT OF WAA OUT AHEAD OF IT SENDING QUICK BURST OF IFR VSBY SN ACROSS MN THIS MORNING. IN GENERAL...HAVE SEEN 1-2 HOURS OF AROUND 2SM SNOW IN WRN MN. RUC TAKES THIS SNOW EAST THIS MORNING...PUTTING STC/MSP/RNH AND POSSIBLE EAU IN LINE FOR SNOW...THOUGH THE RUC BREAKS THE SNOW DOWN BY THE TIME IT REACHES EAU. THERE WILL THEN BE ABOUT A 4 HOUR BREAK BEFORE NEXT WAVE CURRENTLY UP OVER SASK DROPS SE TOWARD NW WI THIS EVENING. BEST FORCING/MOISTURE LOOKS TO REMAIN NORTH OF THE AREA...THOUGH REFLECTIVITY FORECASTS AND SREF PROBS DO INDICATE THAT ANOTHER BRIEF BURST OF SNOW MAY BE POSSIBLE AT AXN/STC/RNH/EAU. MAY ALSO SEE A BRIEF RETURN TO MVFR CIGS WITH THIS FEATURE AS WELL...BUT KEPT CONDITIONS VFR GIVEN LOWER CONFIDENCE IN CIGS BEING THAT LOW THIS FAR SOUTH. FOR WINDS...PRESSURE RISES...COLD AIR ADVECTION AND MIXING POTENTIAL ALL LINE UP START MOVING INTO THE AXN AREA AROUND 21Z AND EAU BY 06Z. THIS MEANS BEST GUST POTENTIAL LIKELY NEAR TO A FEW HOURS AFTER 00Z. BASED ON NAM SOUNDINGS...COLD AIR ADVECTION LOOKS TO OFFSET LOSS OF MIXING WITH SUNSET...SO WENT SUBSTANTIALLY HIGHER THAN GFSLAMP WINDS FOR WHEN BEST FORCING FOR WINDS MOVES THROUGH. WILL SEE A RAPID DECREASE IN NW WINDS AFTER 06Z AS SFC RIDGE MOVES IN FROM THE DAKOTAS. KMSP...BASED ON FAIRLY WIDESPREAD -SN OBS TO THE WEST...ADDED A TEMPO GROUP FOR SNOW. RUC/NAM/GFS ALL SPIT OUT A LITTLE SNOW AROUND 15Z...HENCE THE 14Z TO 16Z TIMING. UPSTREAM OBS HAVE SHOW VIS DOWN IN THE 1-3SM RANGE WITH CIGS 012-025 IN THE -SN. SKIES WILL LIKELY BE MAINLY SKC FOR A TIME BEHIND THIS WAVE...BEFORE THINGS CLOUD BACK UP AHEAD OF THE SASK WAVE. ANY SNOW LOOKS TO REMAIN NORTH OF THE FIELD...BUT WINDS CERTAINLY LOOK TO BE ROCKING BETWEEN 00Z AND 06Z AND STRONG COLD AIR ADVECTION ARRIVES. MAY BE A BIT OVERDONE IN THE TAF...BUT NAM HAS BEEN PRETTY PERSISTENT IN MIXING DOWN SOME 30 TO 40 KT WINDS IN THIS TIME FRAME...SO ADDED QUITE A BIT TO THE WINDS. BY FRIDAY MORNING...WINDS WILL LIKELY BE LGT AND VRB. //OUTLOOK...FRIDAY THROUGH TUESDAY. .FRI-SUN...VFR. SAT MORNING...LLWS POSSIBLE WITH STRONG WSW WINDS DURING THE DAY...POSSIBLE CROSS WIND ISSUES. .SUN NIGHT-MON...MVFR POSSIBLE WITH CHANCE OF -RA. .TUE...VFR. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM CST THIS EVENING FOR BENTON-DOUGLAS-KANDIYOHI-MEEKER-MORRISON-POPE-STEARNS- STEVENS-SWIFT-TODD. WI...NONE. && $$ JRB/MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
403 AM CST THU MAR 8 2012 .SHORT TERM...THE SHORT TERM FOCUS IS ON WINDS AND SNOW SHOWER POTENTIAL ACROSS THE NORTHLAND. AT 330 AM...FAIRLY WIDESPREAD CLOUD COVER WAS MOVING ACROSS THE NORTHLAND ALTHOUGH THERE WERE SEVERAL AREAS OF THIN CLOUDS. TEMPERATURES RANGED FROM THE UPPER 20S IN PORTIONS OF NW WI...TO NEAR 10 ABOVE FAR NORTHWEST. NORTHWEST FLOW WILL PERSIST ACROSS THE NORTHLAND TODAY. STRONG CAA WILL BECOME FAIRLY NEUTRAL THROUGHOUT THE DAY. THE NAM INDICATES THAT AT LEAST A COUPLE SHORTWAVES WILL MOVE THROUGH THE REGION IN NW FLOW TODAY. EACH WILL BE CAPABLE OF GENERATING SOME SNOW SHOWERS...BUT THE BEST CHANCE SHOULD BE ACROSS THE NORTH IN THE AFTERNOON AND EARLY EVENING. WITH COLD AIR ALOFT AND SOME SURFACE HEATING BETWEEN SNOW SHOWERS...THINK SOME OF THE SNOW SHOWERS COULD BE FAIRLY STRONG THIS AFTERNOON...EVEN BRINGING SOME GUSTY WINDS WITH THE SNOW SHOWERS. THE BIGGER STORY FOR TODAY MAY BE THE STRONG WINDS EXPECTED TO MOVE INTO THE CWA DURING THE AFTERNOON AND EVENING. HAVE BROUGHT WINDS UP QUITE A BIT. THE RUC SHOWS STRONG WINDS ALOFT MIXING DOWN TO THE SURFACE. THE FORECAST SOUNDINGS FOR DULUTH INDICATE 40-50 KNOTS WORKING ITS WAY TO JUST ABOVE THE SURFACE. AS A RESULT...WE COULD EASILY SEE SOME 20 TO 30 MPH SUSTAINED WINDS THIS AFTERNOON WITH HIGHER GUSTS AS WELL. WINDS WILL THEN DECREASED OVERNIGHT AS SKIES CLEAR FROM THE WEST. HAVE DROPPED TEMPS CONSIDERABLY FOR TONIGHT...CLOSER TO THE MAV GUIDANCE. THIS SHOULD RESULT IN TEMPERATURES DROPPING BELOW ZERO IN THE NORTH. FRIDAY SHOULD BE A BIT WARMER...AS WAA PUSHES ACROSS THE REGION. SHOULD BE SOMEWHAT OF AN INCREASE IN CLOUDS...ESPECIALLY IN THE NORTH. THINK MOST OF THE PRECIPITATION SHOULD REMAIN IN CANADA. .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. THE EXTENDED FORECAST PERIOD WILL START OUT DRY AND MILD UNDER WITH A UPPER RIDGE BUILDING OVER THE WRN GREAT LAKES DUE TO STRONG SWRLY FLOW IN THE LOW-LEVELS. HOWEVER THE RIDGE WILL GIVE WAY TO A LOW PRESSURE SYSTEM DEVELOPING OVER THE CNTL PLAINS WHICH IS PROGGED TO LIFT NEWD OVER THE GREAT LAKES SUNDAY INTO MONDAY. THERE ARE STILL SOME SIGNIFICANT DIFFERENCES BETWEEN THE VARIOUS NWP MODEL SOLUTIONS...WITH THE NAM/GFS TAKING THE LOW OFF TO THE SOUTH AND EAST OF OUR CWA...WHILE THE ECMWF/GEM BRING IT RIGHT OVER THE NORTHLAND. DUE TO THESE DIFFERENCES...WE WILL KEEP POPS IN THE CHANCE CATEGORY ATTM. PRECIP TYPE SHOULD BE MAINLY RAIN DUE TO THE WARM AIRMASS IN PLACE ACROSS THE UPPER MIDWEST. BUT IF THE DYNAMIC LIFT IS STRONG ENOUGH...THERE COULD BE A WINTRY MIX SUNDAY NIGHT AND MONDAY MORNING. AFTER THE LOW MOVES OFF TO THE EAST...AN UNSEASONABLY WARM AND DRY PATTERN WILL DEVELOP ACROSS THE NORTHLAND NEXT WEEK AS SOUTHWEST FLOW DOMINATES ACROSS THE CTRL PART OF THE COUNTRY THROUGH WEDNESDAY. && .AVIATION.../06Z TAF ISSUANCE/ MVFR AND ISOLATED IFR IN CLOUDS AND SNOW IN A FRONTAL BAND SHOULD MOVE OUT OF THE IWD AND GOGEBIC RANGE AREA LATE TONIGHT. MN NORTH SHORE AND REST OF NORTHWEST WISCONSIN...MVFR IN CLOUDS IMPROVING TO VFR SCATTERED WITH AREAS OF BROKEN CLOUDS BY DAY BREAK THURSDAY MORNING. THE REST OF NORTHEAST MN...VFR THROUGH EARLY MORNING. AREAS OF LOW-END VFR IN CLOUDS WILL DEVELOP MIDMORNING ACROSS COASTAL WI AND NORTH OF ROUTE 2 IN NORTHEAST MN AFTER MIDMORNING THURSDAY...AND PERSIST TILL LATE THURSDAY AFTERNOON. VFR CLEAR BEGINNING THURSDAY EVENING. BRISK NORTHWEST WINDS...GUSTING TO 30 MPH...WILL CONTINUE INTO LATE THURSDAY AFTERNOON...AND SUBSIDE DURING THURSDAY EVENING. && .POINT TEMPS/POPS... DLH 32 7 29 25 / 30 30 0 10 INL 28 -5 32 22 / 40 20 10 10 BRD 34 5 35 29 / 30 10 0 0 HYR 35 5 33 27 / 30 30 0 10 ASX 34 10 30 25 / 30 30 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...DAP LONG TERM....BERDES AVIATION...EOM
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
709 AM CST THU MAR 8 2012 .UPDATE... ISSUED AT 707 AM CST THU MAR 8 2012 HAVE UPDATE SHORT TERM FORECAST TO REFLECT DRYING TREND OVER THE NORTHERN PART OF THE CWA. ALSO MENTIONED THE CHANCE FOR SNOW OR SLEET THIS MORNING IN CENTRAL MISSOURI AS THE CURRENT OB AT KSZL HAS -PL. OTHERWISE...REST OF FORECAST STILL HOLDS. BRITT && .SHORT TERM... ISSUED AT 316 AM CST THU MAR 8 2012 (TODAY AND TONIGHT) COLD FRONT HAS MOVED ABOUT HALFWAY THROUGH THE CWA AND IS CURRENTLY ENTERING THE NORTHWESTERN PART OF THE ST. LOUIS METRO AREA. SHOWERS AND SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG AND AHEAD OF THE FRONT IN A BROAD AREA OF 950-850MB MOISTURE CONVERGENCE. THIS MOISTURE CONVERGENCE IS COINCIDENT WITH LARGE SCALE ASCENT FROM MID-LEVEL CURRENTLY PASSING THROUGH THE UPPER MIDWEST. A SECOND LARGER AREA OF PRECIPITATION IS MOVING ACROSS WESTERN MISSOURI WHICH IS BEING GENERATED BY THE LARGE SCALE ASCENT ON THE TAIL END OF THE TROUGH AND A LITTLE STRONGER LOW LEVEL CONVERGENCE ON THE NOSE OF A 50KT LOW LEVEL JET OVER THE PLAINS. THIS FORCING WILL CONSOLIDATE THROUGH THE MORNING PER THE RUC AS THE LOW LEVEL JET VEERS WITH TIME. THIS SHOULD BE ENOUGH TO KEEP LIKELY OR CATEGORICAL RAIN CHANCES GOING FOR ABOUT THE SOUTHERN TWO-THIRDS OF THE CWA EARLY THIS MORNING...WITH A GRADUAL DIMINISHING TREND THROUGH THE DAY AS THE FORCING PUSHES SOUTH AND EAST. THERE SHOULD BE ENOUGH INSTABILITY TO KEEP AT LEAST A MENTION OF SCATTERED THUNDERSTORMS THIS MORNING ALONG AND AHEAD OF THE 850MB COLD FRONT. CAN`T RULE OUT THE POTENTIAL FOR SOME SNOW OR SLEET ON THE NORTHERN FRINGE OF THE PRECIPITATION WHERE RUC SOUNDINGS ARE SHOWING THE LOW LEVEL THERMAL PROFILES COOLING NEAR 0C ABOUT THE TIME THAT THE PRECIPITATION ENDS. THINK THIS WILL BE A SHORT LIVED EVENT AND MAINLY FOUND WHERE CONVECTION IS MORE CONCENTRATED. TONIGHT SHOULD BE DRY AS SUBSIDENCE SETS IN BEHIND THE NORTHERN STREAM TROUGH. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY FALL THROUGH THE DAY OVER THE SOUTHERN HALF OF THE CWA EXTENSIVE CLOUD COVER AND DECENT COLD AIR ADVECTION BEHIND THE FRONT. GFS MOS TEMPERATURES LOOK A BIT TOO WARM TONIGHT GIVEN THE MAINLY CLEAR SKIES AND WINDS TURNING LIGHT AS THE SURFACE RIDGE SETTLES INTO THE AREA. BRITT && .LONG TERM... ISSUED AT 330 AM CST THU MAR 8 2012 (FRIDAY THROUGH NEXT WEDNESDAY) SFC HIGH BUILDS IN BEHIND THE DEPARTING CDFNT ON FRI WITH DRY WX EXPECTED ON FRI AND MOST OF SAT BEFORE ANOTHER ROUND OF PCPN DVLPS ON SAT NIGHT AS AN UPPER LOW OVER AZ/NM BEGINS LIFTING NEWD THROUGH THE CENTRAL CONUS. MODELS CONTINUE TO STRUGGLE WITH HOW AND WHEN THIS LOW LIFTS NEWD. THE PREVIOUS FOUR RUNS OF THE ECMWF WERE EVENLY SPLIT BETWEEN KEEPING THE VORT CENTER INTACT /00Z RUNS ON MARCH 7TH AND 8TH/ AND SPLITTING IT INTO TWO VORT MAXES /12Z RUNS ON MARCH 6TH AND 7TH...SIMILAR TO WHAT THE GFS HAS BEEN DEPICTING FOR THE LAST SEVERAL DAYS/. 08/00Z GEM REMAINS SIMILAR TO THE 07/00Z RUN AND SHOWS THE LOW RETROGRADING TO BAJA CA THEN MOVING THROUGH MEXICO BEFORE LIFTING THROUGH TX AND INTO NWRN MO. THESE LARGE DIFFERENCES BETWEEN THE 3 MODELS APPEAR TO STEM FROM DIFFERENT HANDLING OF THE INTERACTION BETWEEN THE CLOSED LOW AND A SUBTLE AREA OF ENHANCED VORTICITY THAT SHOULD BE MOVING THROUGH ID/NV AT 08/12Z. DESPITE THE DIFFERENT DETAILS...MODEL SOLUTIONS ALL SUGGEST ANOTHER ROUND OF PCPN SOMEWHERE BETWEEN SAT NIGHT AND MON AS THE CLOSED LOW /OR ITS REMNANTS/ FINALLY LIFTS NEWD. WAA SHRA EXPECTED TO DVLP FIRST FOLLOWED BY AN INCREASE IN PCPN COVERAGE AS LARGE SCALE LIFT INCREASES WITH THE APPROACHING VORT MAX. MODELS ARE OFTEN TOO QUICK TO BRING A CLOSED LOW BACK INTO THE PREVAILING FLOW THEREFORE I WOULD NOT BE SURPRISED IF THIS OVERALL FCST SCENARIO ENDS UP BEING DELAYED BY A DAY OR SO AS THE MODELS CATCH UP TO THE ATMOSPHERE. KANOFSKY && .AVIATION... ISSUED AT 550 AM CST THU MAR 8 2012 AREA OF RAIN WITH MAINLY MVFR CIGS/VSBYS WILL AFFECT THE TAF SITES THIS MORNING...THOUGH IT WILL DIMINISH FROM NORTHWEST TO SOUTHEAST WITH TIME. LIGHTNING HAS DIMINISHED IN THE PAST HOUR WITH THIS AREA OF PRECIPITATION...SO HAVE NO MORE THAN A CB TO REFLECT THIS TREND. THERE WAS SOME REPORTS EARLIER OF SNOW AND SLEET OVER WESTERN MO...BUT THINK PRECIPITATION WILL BE ENDING ABOUT THE SAME TIME THAT IT WILL BE GETTING COLD ENOUGH FOR THE CHANGEOVER SO WILL HOLD OFF ON ANY MENTION IN THE UIN TAF FOR NOW. PRECIPITATION HAS BEEN INCREASING IN AREAL COVERAGE OVER ERN KANSAS...BUT THINK THIS MAY BE A TEMPORARY TREND...SO WILL HOLD ON TO PRECIPITATION AT COU AND STL METRO AREA TAF SITES UNTIL 14-16Z. THEREAFTER... EXPECT DRY CONDITIONS WITH IMPROVING CIGS AND NORTHWESTERLY WINDS BRING DRIER AIR INTO THE LOW LEVELS. SPECIFICS FOR KSTL...PRECIPITATION ACROSS MO AND ERN KANSAS IS MOVING RAPIDLY EASTWARD AND CURRENTLY THINK IT WILL END BY MID MORNING AT THE TERMINAL. UNTIL THEN...THINK THAT CIGS WILL VARY FROM HIGH IFR TO MVFR. BY LATE MORNING...NORTHWESTERLY WINDS WILL BRING DRIER AIR INTO THE LOW LEVELS WHICH SHOULD ALLOW FOR VFR FLIGHT CONDITIONS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
551 AM CST THU MAR 8 2012 .SHORT TERM... ISSUED AT 316 AM CST THU MAR 8 2012 (TODAY AND TONIGHT) COLD FRONT HAS MOVED ABOUT HALFWAY THROUGH THE CWA AND IS CURRENTLY ENTERING THE NORTHWESTERN PART OF THE ST. LOUIS METRO AREA. SHOWERS AND SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG AND AHEAD OF THE FRONT IN A BROAD AREA OF 950-850MB MOISTURE CONVERGENCE. THIS MOISTURE CONVERGENCE IS COINCIDENT WITH LARGE SCALE ASCENT FROM MID-LEVEL CURRENTLY PASSING THROUGH THE UPPER MIDWEST. A SECOND LARGER AREA OF PRECIPITATION IS MOVING ACROSS WESTERN MISSOURI WHICH IS BEING GENERATED BY THE LARGE SCALE ASCENT ON THE TAIL END OF THE TROUGH AND A LITTLE STRONGER LOW LEVEL CONVERGENCE ON THE NOSE OF A 50KT LOW LEVEL JET OVER THE PLAINS. THIS FORCING WILL CONSOLIDATE THROUGH THE MORNING PER THE RUC AS THE LOW LEVEL JET VEERS WITH TIME. THIS SHOULD BE ENOUGH TO KEEP LIKELY OR CATEGORICAL RAIN CHANCES GOING FOR ABOUT THE SOUTHERN TWO-THIRDS OF THE CWA EARLY THIS MORNING...WITH A GRADUAL DIMINISHING TREND THROUGH THE DAY AS THE FORCING PUSHES SOUTH AND EAST. THERE SHOULD BE ENOUGH INSTABILITY TO KEEP AT LEAST A MENTION OF SCATTERED THUNDERSTORMS THIS MORNING ALONG AND AHEAD OF THE 850MB COLD FRONT. CAN`T RULE OUT THE POTENTIAL FOR SOME SNOW OR SLEET ON THE NORTHERN FRINGE OF THE PRECIPITATION WHERE RUC SOUNDINGS ARE SHOWING THE LOW LEVEL THERMAL PROFILES COOLING NEAR 0C ABOUT THE TIME THAT THE PRECIPITATION ENDS. THINK THIS WILL BE A SHORT LIVED EVENT AND MAINLY FOUND WHERE CONVECTION IS MORE CONCENTRATED. TONIGHT SHOULD BE DRY AS SUBSIDENCE SETS IN BEHIND THE NORTHERN STREAM TROUGH. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY FALL THROUGH THE DAY OVER THE SOUTHERN HALF OF THE CWA EXTENSIVE CLOUD COVER AND DECENT COLD AIR ADVECTION BEHIND THE FRONT. GFS MOS TEMPERATURES LOOK A BIT TOO WARM TONIGHT GIVEN THE MAINLY CLEAR SKIES AND WINDS TURNING LIGHT AS THE SURFACE RIDGE SETTLES INTO THE AREA. BRITT && .LONG TERM... ISSUED AT 330 AM CST THU MAR 8 2012 (FRIDAY THROUGH NEXT WEDNESDAY) SFC HIGH BUILDS IN BEHIND THE DEPARTING CDFNT ON FRI WITH DRY WX EXPECTED ON FRI AND MOST OF SAT BEFORE ANOTHER ROUND OF PCPN DVLPS ON SAT NIGHT AS AN UPPER LOW OVER AZ/NM BEGINS LIFTING NEWD THROUGH THE CENTRAL CONUS. MODELS CONTINUE TO STRUGGLE WITH HOW AND WHEN THIS LOW LIFTS NEWD. THE PREVIOUS FOUR RUNS OF THE ECMWF WERE EVENLY SPLIT BETWEEN KEEPING THE VORT CENTER INTACT /00Z RUNS ON MARCH 7TH AND 8TH/ AND SPLITTING IT INTO TWO VORT MAXES /12Z RUNS ON MARCH 6TH AND 7TH...SIMILAR TO WHAT THE GFS HAS BEEN DEPICTING FOR THE LAST SEVERAL DAYS/. 08/00Z GEM REMAINS SIMILAR TO THE 07/00Z RUN AND SHOWS THE LOW RETROGRADING TO BAJA CA THEN MOVING THROUGH MEXICO BEFORE LIFTING THROUGH TX AND INTO NWRN MO. THESE LARGE DIFFERENCES BETWEEN THE 3 MODELS APPEAR TO STEM FROM DIFFERENT HANDLING OF THE INTERACTION BETWEEN THE CLOSED LOW AND A SUBTLE AREA OF ENHANCED VORTICITY THAT SHOULD BE MOVING THROUGH ID/NV AT 08/12Z. DESPITE THE DIFFERENT DETAILS...MODEL SOLUTIONS ALL SUGGEST ANOTHER ROUND OF PCPN SOMEWHERE BETWEEN SAT NIGHT AND MON AS THE CLOSED LOW /OR ITS REMNANTS/ FINALLY LIFTS NEWD. WAA SHRA EXPECTED TO DVLP FIRST FOLLOWED BY AN INCREASE IN PCPN COVERAGE AS LARGE SCALE LIFT INCREASES WITH THE APPROACHING VORT MAX. MODELS ARE OFTEN TOO QUICK TO BRING A CLOSED LOW BACK INTO THE PREVAILING FLOW THEREFORE I WOULD NOT BE SURPRISED IF THIS OVERALL FCST SCENARIO ENDS UP BEING DELAYED BY A DAY OR SO AS THE MODELS CATCH UP TO THE ATMOSPHERE. KANOFSKY && .AVIATION... ISSUED AT 550 AM CST THU MAR 8 2012 AREA OF RAIN WITH MAINLY MVFR CIGS/VSBYS WILL AFFECT THE TAF SITES THIS MORNING...THOUGH IT WILL DIMINISH FROM NORTHWEST TO SOUTHEAST WITH TIME. LIGHTNING HAS DIMINISHED IN THE PAST HOUR WITH THIS AREA OF PRECIPITATION...SO HAVE NO MORE THAN A CB TO REFLECT THIS TREND. THERE WAS SOME REPORTS EARLIER OF SNOW AND SLEET OVER WESTERN MO...BUT THINK PRECIPITATION WILL BE ENDING ABOUT THE SAME TIME THAT IT WILL BE GETTING COLD ENOUGH FOR THE CHANGEOVER SO WILL HOLD OFF ON ANY MENTION IN THE UIN TAF FOR NOW. PRECIPITATION HAS BEEN INCREASING IN AREAL COVERAGE OVER ERN KANSAS...BUT THINK THIS MAY BE A TEMPORARY TREND...SO WILL HOLD ON TO PRECIPITATION AT COU AND STL METRO AREA TAF SITES UNTIL 14-16Z. THEREAFTER... EXPECT DRY CONDITIONS WITH IMPROVING CIGS AND NORTHWESTERLY WINDS BRING DRIER AIR INTO THE LOW LEVELS. SPECIFICS FOR KSTL...PRECIPITATION ACROSS MO AND ERN KANSAS IS MOVING RAPIDLY EASTWARD AND CURRENTLY THINK IT WILL END BY MID MORNING AT THE TERMINAL. UNTIL THEN...THINK THAT CIGS WILL VARY FROM HIGH IFR TO MVFR. BY LATE MORNING...NORTHWESTERLY WINDS WILL BRING DRIER AIR INTO THE LOW LEVELS WHICH SHOULD ALLOW FOR VFR FLIGHT CONDITIONS. BRITT && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
402 AM CST THU MAR 8 2012 .DISCUSSION... THE MAIN CHALLENGES WILL BE WIND AND BLOWING SNOW POTENTIAL TODAY AND TEMPS THROUGHOUT. MODELS ARE NOT HANDLING THIS INITIAL SNOW BAND OVER THE REGION WELL AT ALL...WITH THE RUC DOING THE BEST IN THE NEAR TERM. SOME REPORTS AND RADAR INDICATING A NARROW BAND OF 1-2 INCHES FROM GRAFTON TO MINTO TO MANVEL INTO THE GRAND FORKS AREA. WILL USE A MODEL BLEND AND NOT WARM THINGS UP TOO QUICKLY WITH STILL A DECENT SNOW PACK OVER THE REGION. FOR TODAY...SEVERAL SHORTWAVES WILL ROTATE THROUGH THE REGION. A COLD FRONT WILL PASS THROUGH THE AREA THIS AFTERNOON...ALONG WITH ABOUT 40-50KT TO MIX THROUGHOUT THE ENTIRE FORECAST AREA. A STRONG PRESSURE RISE WILL ALSO COME DOWN THE VALLEY...SO EXPECT WINDY CONDITIONS THIS AFTERNOON WITH GUSTS TO 40 MPH LIKELY. WILL ISSUE A WINTER WEATHER ADVISORY FOR THE NORTHERN VALLEY WITH SOME SNOW THIS MORNING...AND SNOW SHOWERS WITH THE FRONT SO THERE IS FRESH SNOW TO BLOW AROUND. THE STRONG WINDS SHOULD CAUSE BLOWING SNOW AND OPEN COUNTRY VSBY ISSUES...ESPECIALLY WHEN SNOW SHOWERS COMBINE WITH INCREASING WINDS THIS AFTERNOON. WILL GO WITH A WIND ADVISORY FOR THE REST OF THE REGION FROM 18Z-00Z. TEMPS WON/T WARM TOO MUCH GIVEN COLD FRONT AND INCREASING CLOUDS AND ISOLATED SNOW SHOWERS. FOR TONIGHT...SFC HIGH SETTLES OVER THE REGION AND IT WILL GET COLD IN THE EAST...WHERE TEMPS SHOULD DIP BELOW ZERO. EXPECT WARMER TEMPS TO THE WEST WITH RETURN FLOW BEGINNING AFTER 06Z. ON FRI...SOUTHERLY WINDS WILL INCREASE...ALTHOUGH WITH A COLD START TEMPS WON/T GET TOO WARM IN THE VALLEY. HAVE LOWERED TEMPS SOME FROM PREVIOUS FORECAST ALTHOUGH WITH SUNSHINE EXPECT AT LEAST SOME MELTING. ON SAT/SUN...MORE OF A WESTERLY SFC FLOW AND WARMING THERMAL FIELDS AT ALL LEVELS WILL MEAN TEMPS WELL ABOVE NORMAL. EXPECT THE WARMEST READINGS IN THE WEST AND TREED AREAS IN THE EAST...WITH COLDER READINGS ON THE VALLEY FLOOR. ON MON...ANY PRECIP SHOULD REMAIN SOUTH OF THE AREA AND WILL KEEP IT DRY WITH WARM WEATHER CONTINUING NEXT WEEK. && .AVIATION... MVFR/IFR CONDITIONS EXPECTED WITH CURRENT SNOW BAND AS IT PUSHES EAST EARLY THIS MORNING. NW WINDS WILL INCREASE IN ALL AREAS THIS AFTERNOON AND GUSTS TO 35KT WILL BE POSSIBLE. THERE COULD BE SOME BLSN IN THE NORTH THIS AFTERNOON...AND VSBYS SHOULD BE REDUCED ALONG WITH SOME SNOW SHOWERS THIS AFTERNOON WITH COLD FRONT. WINDS SHOULD QUICKLY SUBSIDE AFTER SUNSET. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR NDZ028>030-038-039-049-052-053. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR NDZ006>008-014>016-024-026-027-054. MN...WIND ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR MNZ002-003-006-009-016-017-022>024-027>032-040. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR MNZ001-004-005-007-008-013>015. && $$ DK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1042 AM MST THU MAR 8 2012 .SHORT TERM... .AVIATION...SHOULD SEE VFR CONDITIONS AND GENERALLY LIGHT WINDS FOR THE NEXT 24 H. SHSN WILL BE CONFINED TO SE CO S OF HGWY 160. BKN COGS AT KPUB SHOULD DISSIPATE BY EARLY AFTERNOON. ROSE && .PREV DISCUSSION... /ISSUED 905 AM MST THU MAR 8 2012/ UPDATE... HAVE UPDATED THE FORECAST TO CUT BACK POPS OVER THE CWA AND TO CANCEL THE WINTER HEADLINES. COULD STILL SEE SOME LIGHT SNOW ACCUMS OVR THE SRN MTS AND ADJACENT PLAINS...BUT IMPACT SHOULD BE MINIMAL AT THIS POINT. 44 PREV DISCUSSION... /ISSUED 718 AM MST THU MAR 8 2012/ UPDATE... LAST SEVERAL RUNS OF THE HRRR MODEL CONTINUE TO INDICATE THAT THE SNOW OVER THE SOUTHERN MOUNTAINS WILL END LATER THIS MORNING AS DRIER AIR ADVECTS INTO THE REGION. FOR THIS REASON WILL LET THE WINTER STORM HILITES END LATER THIS MORNING. PREV DISCUSSION... /ISSUED 414 AM MST THU MAR 8 2012/ SHORT TERM... (TODAY AND TONIGHT) SNOW FINALLY MATERIALIZING ACROSS THE SANGRES/WETS AND SURROUNDING AREAS... CURRENTLY... DURING THE LAST FEW HOURS...RADAR RETURNS HAVE INCREASED SIGNIFICANTLY OVER THE SOUTHERN MTNS AND ADJACENT PLAINS. SNOW...LIKELY HEAVY...WAS INDICATED ON THE EAST SLOPES OF THE WETS AND IN THE VICINITY OF THE SPANISH PEAKS. COMPOSITE RADAR IS CLEARLY INDICATING THE CIRCULATION ASSOCIATED WITH THE WELL DEFINED...ALBEIT COMPACT...UPPER LOW...WHICH WAS LOCATED NEAR THE 4 CORNERS. THE SNOW HAS EXTENDED AS FAR NORTH AND EAST AS PUEBLO...WHERE A TRACE OF SNOW HAS OCCURRED DURING THE LAST HOUR OR SO. TODAY... MAIN CHANGE TO THE FCST WAS TO EXTEND THE WINTER STORM WARNING UNTIL 6 PM FOR A SMALL PART OF THE REGION. THIS REGION ENCOMPASSES THE SOUTHERN SANGRE DE CRISTO MOUNTAINS. FOR ALL OTHER AREAS...THE WINTER STORM WARNING WILL EXPIRE AT NOON. ALL MODELS CONTINUE TO INDICATE THE HEAVIEST SNOW WILL OCCUR WHERE IT IS OCCURRING NOW...THAT IS...ALONG THE EAST SLOPES OF THE S MTNS AND ADJACENT I-25 CORRIDOR. SNOW IS LIKELY OCCURRING ALONG THE E SLOPES OF THE SAN JUANS BASED ON SAT PIX IMGY AND MEAGER RADAR RETURNS AS SEEN BY NWS RADARS. UPPER LOW...WHICH IS LACKING SIGNIFICANTLY IN MOISTURE...IS FCST TO TRACK E-SE TODAY ACROSS NM. THIS WILL KEEP THE REGION IN DEEP UPSLOPE FLOW. BEST FORCING WILL BE OVER THE S TIER WHERE I HAVE KEPT THE POPS THE HIGHEST. TONIGHT... ALTHOUGH THE LOW IS FCST TO TRACK BACK NWD AND ACTUALLY RETROGRADE WWD ACROSS FAR N NM TONIGHT INTO TOMORROW...ALL GUIDANCE IS SHOWING VERY LITTLE...IF ANY...QPF OVER THE REGION. THE ONLY QPF BEING PRINTED OUT IS ACROSS THE FAR S TIER...ALONG THE IMMEDIATE CO/NM BORDER. ALTHOUGH UPSLOPE FLOW IS RATHER STRONG AND DEEP...THIS SYSTEM IS LACKING (DRAMATICALLY) WRT MOISTURE. SOUNDINGS ACROSS THE PLAINS SHOW VERY DRY AIR THROUGHOUT THE COLUMN ADVECTING INTO THIS SYSTEM FROM THE CENTRAL HIGH PLAINS. LIKEWISE...MOST AREAS TONIGHT WILL SEE MOSTLY CLEAR SKIES...WITH THE EXCEPTION BEING ALONG THE CO/NM BORDER. /34 LONG TERM... (FRIDAY THROUGH WEDNESDAY) FRIDAY AND SATURDAY...THE LOW PRESSURE SYSTEM IS EXPECTED TO SIT IN THE VICINITY OF THE OK AND TX PANHANDLES ON FRI...BUT HOW IT MOVES FROM THERE IS REALLY IN QUESTION NOW. MULTIPLE MODELS AND MODEL RUNS ARE SHOWING DIFFERING SOLUTIONS ON WHERE THE LOW CENTER WILL TRACK...FROM RETROGRADING BACK TO THE WEST ACROSS NM...TO EJECTING NORTH...TO SITTING IN PLACE. THE ONE THING MODELS SEEMED TO AGREE UPON WAS THAT THERE IS NOT A LOT OF MOISTURE ASSOCIATED WITH THIS SYSTEM...SO WILL FORECAST MEAGER QPF. GIVEN THE UNCERTAINTY OF THE TRACK...KEPT THE BEST PCPN CHANCES ALONG THE SOUTHERN PORTIONS OF THE CWA WITH FLOW BANKING UP AGAINST THE SOUTHERN FOOTHILLS AND S SANGRES. ON SAT...MODELS INDICATE THAT THE LOW WILL FINALLY MAKE SOME SORT OF MOVE OUT OF THE AREA...AND TAPERED POPS OFF THROUGH THE DAY. TEMPS BOTH DAYS SHOULD WARM INTO THE 40S AND 50S...WITH THE COLDEST TEMPS ALONG THE SOUTHERN TIER. SUNDAY THROUGH WEDNESDAY...THE UPPER LOW EXITS THE REGION...SETTING UP WEST TO SOUTHWEST FLOW ACROSS THE 4 CORNERS AND ROCKIES INTO THE NEXT WORK WEEK FOR DRY CONDITIONS AND WARMING TEMPS. 27 AVIATION... FOR KCOS...MVFR CONDITIONS WILL CONTINUE UNTIL ABOUT 14Z AND THEN DRIER AIR SHOULD ADVECT IN DECREASING THE CLOUDS. VFR SHOULD LAST THROUGH THE REST OF THE PERIOD. FOR KPUB...SAME AS KCOS ALTHOUGH LOWER CIGS/LIGHT SNOW SHOULD LAST UNTIL ABOUT 16Z. FOR KALS...OCCNL MVFR CONDITIONS WILL BE POSSIBLE THROUGH ABOUT 15Z...AND THEN MVFR IS EXPECTED THE REST OF THE FCST PERIOD. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 44/31
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1020 AM MST THU MAR 8 2012 .UPDATE... ISSUED AT 1020 AM MST THU MAR 8 2012 CUT-OFF UPPER LOW OVER SOUTHWEST NM WAS KEEPING E-NE FLOW ACROSS THE FORECAST AREA TODAY...WITH CLOUDS PERSISTING OVER A PORTION OF SW CO WHERE ISOLATED TO SCATTERED LIGHT SNOW SHOWERS ARE STILL POSSIBLE FROM DAYTIME HEATINGJ PRODUCING SHALLOW AFTERNOON INSTABILITY. SURFACE HIGH PRESSURE WAS BUILDING INTO NE UT/NW CO. EARLY LOOK AT THE NEW MODELS RUNS SHOWS THE CUT- OFF LOW SHIFTING TOWARDS EASTERN OR NORTHEASTERN NM TONIGHT AND FRIDAY AS A SHORTWAVE CURRENTLY ENTERING NORTHERN NV DROPS SOUTHWARD. THE CURRENT FORECAST LOOKS ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 200 AM MST THU MAR 8 2012 THE UPPER LEVEL LOW WAS SAGGING SOUTH ALONG THE AZ-NM BORDER THIS MORNING THEN WILL EJECT SLOWLY EAST ACROSS SOUTHERN NM THIS AFTERNOON. ASSOCIATED DYNAMICAL LIFT IS SOUTH OF THE CWA AND WRAP- AROUND MOISTURE IS LIMITED. THIS WOULD PRODUCE SOME LIGHT ACCUMULATION IN THE VICINITY OF MONARCH...SLUMGULLION...AND WOLF CREEK PASSES TODAY. THE HRRR AND NAM12 ALSO PRODUCE LIGHT ACCUMULATION OVER THE MANCOS RIDGE THROUGH THIS AFTERNOON. OTHERWISE MOSTLY SUNNY SKIES WILL PREVAIL. AT THE SURFACE LOW PRESSURE NEAR THE FOUR CORNERS AND COLD HIGH PRESSURE PUSHING DOWN THE FRONT RANGE IS PRODUCING NE GRADIENT WINDS. MTN TOP NE WINDS ARE GUSTING 20-30 OVER EXPOSED TERRAIN. THE GRADIENT RELAXES THROUGH THE AFTERNOON. TONIGHT THE UPPER LOW SETTLES ONTO THE EASTERN NM PLAINS WHERE IT WILL LANGUISH INTO THE WEEKEND. THIS KEEPS THE FORECAST AREA IN A LIGHT EAST FLOW ALOFT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 311 AM MST THU MAR 8 2012 THE MIDRANGE MODELS SEEM TO BE STALLING THE CLOSED LOW OVER NEW MEXICO FRIDAY AND FRIDAY NIGHT. THE GFS KEEPS THE 500 MB CENTER OVER NE NM AND THE PANHANDLES OF TX AND OK FRI. THEN LIFTS IT NORTH INTO EXTREME SE CO SAT...AND TAKES THE LOW CENTER TO WESTERN KS SUN MORNING. THE ECMWF RETROGRADES THE LOW CENTER BACK TO WESTERN NM FRI THEN PUSHES IT EAST SAT AND INTO THE TX PANHANDLE ABOUT 18Z SUN. THE GFS SOLUTION SHOULD RESULT IN NEARLY CLOUDLESS SKIES NORTH OF THE SAN JUAN MOUNTAINS FRI THROUGH THE WEEKEND. THE ECMWF WITH ITS LOW CENTER FURTHER WEST MAY KEEP MORE CLOUD COVER OVER THE SOUTHERN HALF OF THE FORECAST AREA FRI AND SAT. BOTH SCENARIOS PROVIDE LITTLE CHANCE OF PRECIP OUTSIDE OF ISOLD SHOWERS IN THE SAN JUANS THROUGH THE WEEKEND. SUNDAY IN BOTH MODELS SHOULD BRING CONTINUED WARM ADVECTION AS THE FLOW ALOFT BECOMES SOUTHWESTERLY. MAX TEMPS SUN THROUGH WED SHOULD BE 5-10 DEGREES ABOVE NORMAL ACROSS THE FORECAST AREA. EXPECT LITTLE CLOUD COVER AND DRY CONDITIONS AS WELL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1020 AM MST THU MAR 8 2012 VFR CONDITIONS EXPECTED AT ALL TAF SITES THROUGH 18Z FRI WITH NORTHEAST FLOW ALOFT. CLOUDS LINGERED OVER PORTIONS OF SW CO FROM KMYP TO KDRO LATE THIS MORNING. SOME LOW-TOPPED CONVECTION COULD PRODUCE ISOLD TO SCT LIGHT SNOW SHOWERS OVER THE SAN JUAN MOUNTAINS FROM AFTERNOON INSTABILITY. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...JAD SHORT TERM...JOE LONG TERM....CC AVIATION...JAD
AREA FORECAST DISCUSSION
NWS PUEBLO CO
905 AM MST THU MAR 8 2012 .UPDATE... HAVE UPDATED THE FORECAST TO CUT BACK POPS OVER THE CWA AND TO CANCEL THE WINTER HEADLINES. COULD STILL SEE SOME LIGHT SNOW ACCUMS OVR THE SRN MTS AND ADJACENT PLAINS...BUT IMPACT SHOULD BE MINIMAL AT THIS POINT. ROSE && .PREV DISCUSSION... /ISSUED 718 AM MST THU MAR 8 2012/ UPDATE... LAST SEVERAL RUNS OF THE HRRR MODEL CONTINUE TO INDICATE THAT THE SNOW OVER THE SOUTHERN MOUNTAINS WILL END LATER THIS MORNING AS DRIER AIR ADVECTS INTO THE REGION. FOR THIS REASON WILL LET THE WINTER STORM HILITES END LATER THIS MORNING. PREV DISCUSSION... /ISSUED 414 AM MST THU MAR 8 2012/ SHORT TERM... (TODAY AND TONIGHT) .SNOW FINALLY MATERIALIZING ACROSS THE SANGRES/WETS AND SURROUNDING AREAS... CURRENTLY... DURING THE LAST FEW HOURS...RADAR RETURNS HAVE INCREASED SIGNIFICANTLY OVER THE SOUTHERN MTNS AND ADJACENT PLAINS. SNOW...LIKELY HEAVY...WAS INDICATED ON THE EAST SLOPES OF THE WETS AND IN THE VICINITY OF THE SPANISH PEAKS. COMPOSITE RADAR IS CLEARLY INDICATING THE CIRCULATION ASSOCIATED WITH THE WELL DEFINED...ALBEIT COMPACT...UPPER LOW...WHICH WAS LOCATED NEAR THE 4 CORNERS. THE SNOW HAS EXTENDED AS FAR NORTH AND EAST AS PUEBLO...WHERE A TRACE OF SNOW HAS OCCURRED DURING THE LAST HOUR OR SO. TODAY... MAIN CHANGE TO THE FCST WAS TO EXTEND THE WINTER STORM WARNING UNTIL 6 PM FOR A SMALL PART OF THE REGION. THIS REGION ENCOMPASSES THE SOUTHERN SANGRE DE CRISTO MOUNTAINS. FOR ALL OTHER AREAS...THE WINTER STORM WARNING WILL EXPIRE AT NOON. ALL MODELS CONTINUE TO INDICATE THE HEAVIEST SNOW WILL OCCUR WHERE IT IS OCCURRING NOW...THAT IS...ALONG THE EAST SLOPES OF THE S MTNS AND ADJACENT I-25 CORRIDOR. SNOW IS LIKELY OCCURRING ALONG THE E SLOPES OF THE SAN JUANS BASED ON SAT PIX IMGY AND MEAGER RADAR RETURNS AS SEEN BY NWS RADARS. UPPER LOW...WHICH IS LACKING SIGNIFICANTLY IN MOISTURE...IS FCST TO TRACK E-SE TODAY ACROSS NM. THIS WILL KEEP THE REGION IN DEEP UPSLOPE FLOW. BEST FORCING WILL BE OVER THE S TIER WHERE I HAVE KEPT THE POPS THE HIGHEST. TONIGHT... ALTHOUGH THE LOW IS FCST TO TRACK BACK NWD AND ACTUALLY RETROGRADE WWD ACROSS FAR N NM TONIGHT INTO TOMORROW...ALL GUIDANCE IS SHOWING VERY LITTLE...IF ANY...QPF OVER THE REGION. THE ONLY QPF BEING PRINTED OUT IS ACROSS THE FAR S TIER...ALONG THE IMMEDIATE CO/NM BORDER. ALTHOUGH UPSLOPE FLOW IS RATHER STRONG AND DEEP...THIS SYSTEM IS LACKING (DRAMATICALLY) WRT MOISTURE. SOUNDINGS ACROSS THE PLAINS SHOW VERY DRY AIR THROUGHOUT THE COLUMN ADVECTING INTO THIS SYSTEM FROM THE CENTRAL HIGH PLAINS. LIKEWISE...MOST AREAS TONIGHT WILL SEE MOSTLY CLEAR SKIES...WITH THE EXCEPTION BEING ALONG THE CO/NM BORDER. /34 LONG TERM... (FRIDAY THROUGH WEDNESDAY) FRIDAY AND SATURDAY...THE LOW PRESSURE SYSTEM IS EXPECTED TO SIT IN THE VICINITY OF THE OK AND TX PANHANDLES ON FRI...BUT HOW IT MOVES FROM THERE IS REALLY IN QUESTION NOW. MULTIPLE MODELS AND MODEL RUNS ARE SHOWING DIFFERING SOLUTIONS ON WHERE THE LOW CENTER WILL TRACK...FROM RETROGRADING BACK TO THE WEST ACROSS NM...TO EJECTING NORTH...TO SITTING IN PLACE. THE ONE THING MODELS SEEMED TO AGREE UPON WAS THAT THERE IS NOT A LOT OF MOISTURE ASSOCIATED WITH THIS SYSTEM...SO WILL FORECAST MEAGER QPF. GIVEN THE UNCERTAINTY OF THE TRACK...KEPT THE BEST PCPN CHANCES ALONG THE SOUTHERN PORTIONS OF THE CWA WITH FLOW BANKING UP AGAINST THE SOUTHERN FOOTHILLS AND S SANGRES. ON SAT...MODELS INDICATE THAT THE LOW WILL FINALLY MAKE SOME SORT OF MOVE OUT OF THE AREA...AND TAPERED POPS OFF THROUGH THE DAY. TEMPS BOTH DAYS SHOULD WARM INTO THE 40S AND 50S...WITH THE COLDEST TEMPS ALONG THE SOUTHERN TIER. SUNDAY THROUGH WEDNESDAY...THE UPPER LOW EXITS THE REGION...SETTING UP WEST TO SOUTHWEST FLOW ACROSS THE 4 CORNERS AND ROCKIES INTO THE NEXT WORK WEEK FOR DRY CONDITIONS AND WARMING TEMPS. 27 AVIATION... FOR KCOS...MVFR CONDITIONS WILL CONTINUE UNTIL ABOUT 14Z AND THEN DRIER AIR SHOULD ADVECT IN DECREASING THE CLOUDS. VFR SHOULD LAST THROUGH THE REST OF THE PERIOD. FOR KPUB...SAME AS KCOS ALTHOUGH LOWER CIGS/LIGHT SNOW SHOULD LAST UNTIL ABOUT 16Z. FOR KALS...OCCNL MVFR CONDITIONS WILL BE POSSIBLE THROUGH ABOUT 15Z...AND THEN MVFR IS EXPECTED THE REST OF THE FCST PERIOD. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 44/31
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
236 PM CST THU MAR 8 2012 .DISCUSSION... 1008 AM CST NO REAL ISSUES LATE THIS MORNING OR GOING INTO THE AFTERNOON...WITH MINOR CHANGES TO POP/WX GRIDS AS RAIN HAS EXITED THE CWA...AND SOME ADJUSTMENTS TO CLOUD TRENDS TODAY. SURFACE TROUGH AND ASSOCIATED COLD FRONT HAVE SINCE SHIFTED EAST/SOUTHEAST OF THE CWA THIS MORNING...AS HIGHER PRESSURE BUILDS EAST WITH PRESSURE RISES NOTED ACROSS MUCH OF THE REGION THIS HOUR. ALTHOUGH...MAIN RIDGE AXIS REMAINS TO THE WEST OVER THE CENTRAL PLAINS AND APPEARS AS IF IT WILL REMAIN SITUATED TO THE WEST WITH A FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER THE CWA TODAY. THIS WILL OCCUR AS AN UPPER LEVEL TROUGH REMAINS OVERHEAD...WITH A MID LEVEL SHORT WAVE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER MIDWEST...WHICH WILL PLAY A FACTOR WITH CLOUD TRENDS TODAY. LOW LEVEL CLOUD COVER WILL CONTINUE TO SHIFT EAST THROUGH THE SOUTHEAST PORTION OF THE CWA THROUGH MID DAY WITH A PARTIAL CLEARING TREND EXPECTED THROUGH MID DAY. ALTHOUGH...WITH COOLER AIR MOVING THROUGH...STEEPENING LOW LEVEL LAPSE RATES...AND THE APPROACHING WAVE...A REDEVELOPMENT OF CU/STRATO CU WILL HELP TO PROVIDE WHATEVER CLEAR SKIES ARE IN PLACE TO BECOME MORE PARTLY SUNNY/CLOUDY THIS AFTERNOON. THIS DIURNAL CU WILL THEN DIMINISH WITH A CLEARING TREND EXPECTED ONCE AGAIN LATE THIS AFTERNOON AND EARLY EVENING. EVENING SKIES GRIDS MAY NEED TO BE ADJUSTED FOR THE AFTERNOON ISSUANCE...AS A QUICKLY APPROACHING COLD FRONTAL BOUNDARY MAY PROVIDE ADDITIONAL CLOUD COVER LATE THIS EVENING BEFORE HIGH PRESSURE MOVES OVERHEAD EARLY FRIDAY. RODRIGUEZ //PREV DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * OCCASIONAL W/NW GUSTS TO 27KT...DIMINISHING TO ARND 12KT AFT 23Z. * PSBL BKN CIGS AT 5KFT AGL BTWN 04-08Z. BEACHLER //DISCUSSION...UPDATED 20Z... VISIBLE IMAGERY CONTINUES TO INDICATE THE BULK OF THE CLOUD COVER HAS DRIFTED SOUTHEAST OF MOST NORTHERN IL/NORTHWEST IN AIRFIELDS...WITH JUST A FEW LOCATIONS STILL REPORTING BKN CIGS. HOWEVER...THIS WILL CONTINUE TO DIMINISH THROUGH THE AFTN. EXPECT BY 23Z CIGS TO BE APPROACH FEW COVERAGE BUT REMAIN VFR. GUSTY WINDS HAVE ALSO COME UP HIGHER TO ARND 25 TO 28 KT AT TIMES...DIMINISHING TO ARND 12 KT AFTER SUNSET. PREV DISCUSSION FROM 18Z... VISIBLE IMAGERY SHOWS ABUNDANT CLOUDS ACROSS SOUTHERN IL STRETCHING NORTHEAST THROUGH INDIANA AND LOWER MICHIGAN. NORTHERN IL/NORTHWEST IN ARE ON THE BACK SIDE OF THIS CLOUD COVER...WITH A FEW POCKETS OF SCT/BKN CIGS ARND 3KFT AGL NOTED. THE GENERAL TREND HAS BEEN FOR IMPROVING CONDS TO VFR...AND MOST SFC OBS SUPPORT THIS AS WELL. GUIDANCE CONTINUES TO SUGGEST CIGS WILL IMPROVE TO FEW/SCT CONDS LATER THIS EVENING WITH WINDS STEADILY DIMINISHING AS WELL TO NW/W WINDS ARND 10-12KT. ANOTHER UPPER LEVEL SYSTEM MAY BRING BKN CIGS BACK TO FAR NORTHEAST IL/NORTHWEST IN AIRFIELDS BTWN 04-08Z. THEN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST AND SHOULD PROVIDE VFR CONDS THRU MUCH OF FRI. A FEW POCKETS OF DIURNAL CUMULUS CLOUDS WILL BE POSSIBLE FRI MIDDAY...HOWEVER SHUD REMAIN VFR CONDS. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN CIGS FORECAST THRU 23Z. * HIGH CONFIDENCE IN CIGS AFT 23Z. * HIGH CONFIDENCE IN ALL OTHER ELEMENTS. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 227 PM CST A COLD FRONT THAT MOVED THROUGH THE LAKES OVERNIGHT HAS SINCE SLIPPED INTO THE THE OHIO VALLEY TODAY. CLEAR SKIES WITH NORTHWESTERLY FLOW AND GOOD COLD AIR ADVECTION HAVE ALLOWED WINDS TO INCREASE AND GUST THIS AFTERNOON. ORIGINALLY INHERITED A SMALL CRAFT ADVISORY FOR THE INDY SHORES STARTING TONIGHT...BUT WITH THE STRONG WINDS THIS AFTERNOON...DECIDED TO PULL THE START TIME UP AND ALSO INCLUDE THE ILLINOIS SHORES AS WHRI2 WAS GUSTING TO 27 KTS. DO EXPECT A LITTLE LULL IN THE WINDS LATE THIS AFTERNOON AND INTO THE EVENING HOURS...BUT WITH ANOTHER FRONT APPROACHING OVERNIGHT...EXPECT WINDS TO KICK BACK UP AND BRING ALL OF THE NEARSHORE WATERS TO CRITERIA JUST FROM WINDS ALONE THIS EVENING. WINDS WILL ALSO INCREASE TO GALE FORCE THIS EVENING AND INTO THE EARLY MORNING HOURS FOR THE NORTHERN HALF OF THE LAKE AS A DEEPENING LOW PRESSURE CORE SLIDES SOUTHEAST FROM WESTERN ONTARIO AND TO JUST EAST OF MICHIGAN. WINDS WILL LIKELY INCREASE TO ABOVE 35 KTS FOR MUCH OF THE NORTHERN HALF OF THE LAKE FROM THE 09Z TO ROUGHLY 12 TO 13Z HOUR. DUE TO THE INCREASED LIKELIHOOD OF GALES...DID HOIST A GALE WARNING FOR THE OVERNIGHT HOURS. AS THE LOW PULLS OFF TO THE SOUTHEAST...WINDS WILL DECREASE ACROSS THE ILLINOIS SHORES AND ALL ADVISORY CRITERIA SHOULD ABATE BY FRIDAY AFTERNOON...AND THEN INTO THE EARLY EVENING HOURS FOR INDIANA. HIGH PRESSURE WILL THEN SLIDE BACK ACROSS THE LAKES INTO THE START OF THE WEEKEND. STRONG SOUTH WINDS WILL AGAIN RETURN ACROSS THE LAKE SATURDAY...WITH THE NORTHERN TIER OF THE LAKE AGAIN APPROACHING GALES MID MORNING AND CONTINUING OVERNIGHT. SHEA && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ868...3 AM FRIDAY TO 10 AM FRIDAY. SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...6 PM THURSDAY TO 9 PM FRIDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...6 PM THURSDAY TO 4 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
226 PM CST THU MAR 8 2012 .DISCUSSION... 1008 AM CST NO REAL ISSUES LATE THIS MORNING OR GOING INTO THE AFTERNOON...WITH MINOR CHANGES TO POP/WX GRIDS AS RAIN HAS EXITED THE CWA...AND SOME ADJUSTMENTS TO CLOUD TRENDS TODAY. SURFACE TROUGH AND ASSOCIATED COLD FRONT HAVE SINCE SHIFTED EAST/SOUTHEAST OF THE CWA THIS MORNING...AS HIGHER PRESSURE BUILDS EAST WITH PRESSURE RISES NOTED ACROSS MUCH OF THE REGION THIS HOUR. ALTHOUGH...MAIN RIDGE AXIS REMAINS TO THE WEST OVER THE CENTRAL PLAINS AND APPEARS AS IF IT WILL REMAIN SITUATED TO THE WEST WITH A FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER THE CWA TODAY. THIS WILL OCCUR AS AN UPPER LEVEL TROUGH REMAINS OVERHEAD...WITH A MID LEVEL SHORT WAVE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER MIDWEST...WHICH WILL PLAY A FACTOR WITH CLOUD TRENDS TODAY. LOW LEVEL CLOUD COVER WILL CONTINUE TO SHIFT EAST THROUGH THE SOUTHEAST PORTION OF THE CWA THROUGH MID DAY WITH A PARTIAL CLEARING TREND EXPECTED THROUGH MID DAY. ALTHOUGH...WITH COOLER AIR MOVING THROUGH...STEEPENING LOW LEVEL LAPSE RATES...AND THE APPROACHING WAVE...A REDEVELOPMENT OF CU/STRATO CU WILL HELP TO PROVIDE WHATEVER CLEAR SKIES ARE IN PLACE TO BECOME MORE PARTLY SUNNY/CLOUDY THIS AFTERNOON. THIS DIURNAL CU WILL THEN DIMINISH WITH A CLEARING TREND EXPECTED ONCE AGAIN LATE THIS AFTERNOON AND EARLY EVENING. EVENING SKIES GRIDS MAY NEED TO BE ADJUSTED FOR THE AFTERNOON ISSUANCE...AS A QUICKLY APPROACHING COLD FRONTAL BOUNDARY MAY PROVIDE ADDITIONAL CLOUD COVER LATE THIS EVENING BEFORE HIGH PRESSURE MOVES OVERHEAD EARLY FRIDAY. RODRIGUEZ //PREV DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * OCCASIONAL W/NW GUSTS TO 27KT...DIMINISHING TO ARND 12KT AFT 23Z. * PSBL BKN CIGS AT 5KFT AGL BTWN 04-08Z. BEACHLER //DISCUSSION...UPDATED 20Z... VISIBLE IMAGERY CONTINUES TO INDICATE THE BULK OF THE CLOUD COVER HAS DRIFTED SOUTHEAST OF MOST NORTHERN IL/NORTHWEST IN AIRFIELDS...WITH JUST A FEW LOCATIONS STILL REPORTING BKN CIGS. HOWEVER...THIS WILL CONTINUE TO DIMINISH THROUGH THE AFTN. EXPECT BY 23Z CIGS TO BE APPROACH FEW COVERAGE BUT REMAIN VFR. GUSTY WINDS HAVE ALSO COME UP HIGHER TO ARND 25 TO 28 KT AT TIMES...DIMINISHING TO ARND 12 KT AFTER SUNSET. PREV DISCUSSION FROM 18Z... VISIBLE IMAGERY SHOWS ABUNDANT CLOUDS ACROSS SOUTHERN IL STRETCHING NORTHEAST THROUGH INDIANA AND LOWER MICHIGAN. NORTHERN IL/NORTHWEST IN ARE ON THE BACK SIDE OF THIS CLOUD COVER...WITH A FEW POCKETS OF SCT/BKN CIGS ARND 3KFT AGL NOTED. THE GENERAL TREND HAS BEEN FOR IMPROVING CONDS TO VFR...AND MOST SFC OBS SUPPORT THIS AS WELL. GUIDANCE CONTINUES TO SUGGEST CIGS WILL IMPROVE TO FEW/SCT CONDS LATER THIS EVENING WITH WINDS STEADILY DIMINISHING AS WELL TO NW/W WINDS ARND 10-12KT. ANOTHER UPPER LEVEL SYSTEM MAY BRING BKN CIGS BACK TO FAR NORTHEAST IL/NORTHWEST IN AIRFIELDS BTWN 04-08Z. THEN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST AND SHOULD PROVIDE VFR CONDS THRU MUCH OF FRI. A FEW POCKETS OF DIURNAL CUMULUS CLOUDS WILL BE POSSIBLE FRI MIDDAY...HOWEVER SHUD REMAIN VFR CONDS. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN CIGS FORECAST THRU 23Z. * HIGH CONFIDENCE IN CIGS AFT 23Z. * HIGH CONFIDENCE IN ALL OTHER ELEMENTS. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 AM CST THU MAR 8 2012 .DISCUSSION... 1008 AM CST NO REAL ISSUES LATE THIS MORNING OR GOING INTO THE AFTERNOON...WITH MINOR CHANGES TO POP/WX GRIDS AS RAIN HAS EXITED THE CWA...AND SOME ADJUSTMENTS TO CLOUD TRENDS TODAY. SURFACE TROUGH AND ASSOCIATED COLD FRONT HAVE SINCE SHIFTED EAST/SOUTHEAST OF THE CWA THIS MORNING...AS HIGHER PRESSURE BUILDS EAST WITH PRESSURE RISES NOTED ACROSS MUCH OF THE REGION THIS HOUR. ALTHOUGH...MAIN RIDGE AXIS REMAINS TO THE WEST OVER THE CENTRAL PLAINS AND APPEARS AS IF IT WILL REMAIN SITUATED TO THE WEST WITH A FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER THE CWA TODAY. THIS WILL OCCUR AS AN UPPER LEVEL TROUGH REMAINS OVERHEAD...WITH A MID LEVEL SHORT WAVE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER MIDWEST...WHICH WILL PLAY A FACTOR WITH CLOUD TRENDS TODAY. LOW LEVEL CLOUD COVER WILL CONTINUE TO SHIFT EAST THROUGH THE SOUTHEAST PORTION OF THE CWA THROUGH MID DAY WITH A PARTIAL CLEARING TREND EXPECTED THROUGH MID DAY. ALTHOUGH...WITH COOLER AIR MOVING THROUGH...STEEPENING LOW LEVEL LAPSE RATES...AND THE APPROACHING WAVE...A REDEVELOPMENT OF CU/STRATO CU WILL HELP TO PROVIDE WHATEVER CLEAR SKIES ARE IN PLACE TO BECOME MORE PARTLY SUNNY/CLOUDY THIS AFTERNOON. THIS DIURNAL CU WILL THEN DIMINISH WITH A CLEARING TREND EXPECTED ONCE AGAIN LATE THIS AFTERNOON AND EARLY EVENING. EVENING SKIES GRIDS MAY NEED TO BE ADJUSTED FOR THE AFTERNOON ISSUANCE...AS A QUICKLY APPROACHING COLD FRONTAL BOUNDARY MAY PROVIDE ADDITIONAL CLOUD COVER LATE THIS EVENING BEFORE HIGH PRESSURE MOVES OVERHEAD EARLY FRIDAY. RODRIGUEZ //PREV DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * PATCHY BKN CIGS ARND 3000-3400FT AGL...LIFTING BY 23Z. * OCCASIONAL W/NW GUSTS TO 24KT...DIMINISHING TO ARND 12KT AFT 23Z. * PSBL BKN CIGS AT 5KFT AGL BTWN 04-08Z. BEACHLER //DISCUSSION...UPDATED 18Z... VISIBLE IMAGERY SHOWS ABUNDANT CLOUDS ACROSS SOUTHERN IL STRETCHING NORTHEAST THROUGH INDIANA AND LOWER MICHIGAN. NORTHERN IL/NORTHWEST IN ARE ON THE BACK SIDE OF THIS CLOUD COVER...WITH A FEW POCKETS OF SCT/BKN CIGS ARND 3KFT AGL NOTED. THE GENERAL TREND HAS BEEN FOR IMPROVING CONDS TO VFR...AND MOST SFC OBS SUPPORT THIS AS WELL. GUIDANCE CONTINUES TO SUGGEST CIGS WILL IMPROVE TO FEW/SCT CONDS LATER THIS EVENING WITH WINDS STEADILY DIMINISHING AS WELL TO NW/W WINDS ARND 10-12KT. ANOTHER UPPER LEVEL SYSTEM MAY BRING BKN CIGS BACK TO FAR NORTHEAST IL/NORTHWEST IN AIRFIELDS BTWN 04-08Z. THEN HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST AND SHOULD PROVIDE VFR CONDS THRU MUCH OF FRI. A FEW POCKETS OF DIURNAL CUMULUS CLOUDS WILL BE POSSIBLE FRI MIDDAY...HOWEVER SHUD REMAIN VFR CONDS. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN CIGS FORECAST THRU 23Z. * HIGH CONFIDENCE IN CIGS AFT 23Z. * HIGH CONFIDENCE IN ALL OTHER ELEMENTS. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1040 AM CST THU MAR 8 2012 .DISCUSSION... ISSUED 1040 AM CST THU MAR 8 2012 COLD FRONT HAS SETTLED SOUTHWARD INTO THE OHIO RIVER VALLEY THIS MORNING...TAKING THE BULK OF THE RAIN WITH IT. A FEW LIGHT SHOWERS LINGER TO THE NORTH OF THE BOUNDARY...WITH THE LATEST RADAR MOSAIC SHOWING THE PRECIP MAINLY LOCATED ALONG AND SOUTH OF A LITCHFIELD TO PARIS LINE. MID-LEVEL SHORT-WAVE CURRENTLY EVIDENT ON WATER VAPOR IMAGERY OVER SOUTHERN MINNESOTA/NORTHERN IOWA WILL TRACK E/SE ACROSS NORTHERN ILLINOIS THIS AFTERNOON...GRADUALLY PUSHING THE FRONT AND PRECIP EVEN FURTHER SOUTH. HAVE UPDATED FORECAST TO CARRY SCATTERED SHOWERS SOUTH OF THE I-72 CORRIDOR THROUGH MID-AFTERNOON...THEN WENT DRY ACROSS THE BOARD AFTER 21Z. AS WAVE MOVES BY TO THE NORTH...DRIER AIR WILL BRING CLEARING SKIES TO THE CENTRAL AND NORTHERN KILX CWA AS THE DAY PROGRESSES...WITH OVERCAST CONDITIONS PERSISTING ALONG/SOUTH OF I-70. ZONE UPDATE WILL BE ISSUED SHORTLY. BARNES && .AVIATION... ISSUED 516 AM CST THU MAR 8 2012 COLD FRONT HAS PASSED THROUGH THE TAF SITES THIS MORNING...WITH A BRIEF LULL IN THE PRECIPITATION. SHOWERS WILL RAMP UP AGAIN EARLY AS A SHORTWAVE MOVES FROM NORTHERN MO ACROSS CENTRAL IL. SINCE LIGHTNING HAS DECREASED IN THE PAST COUPLE OF HOURS...WILL JUST HAVE SOME VCTS IN THE MORNING. PRECIPITATION MAY MIX WITH LIGHT SNOW OR LIGHT SLEET AT PIA AS TEMPERATURES FALL THROUGH THE 30S ON THE BACK EDGE OF THE RAIN SHIELD. THE LATEST RUN OF THE HRRR MODEL HAS A DECENT HANDLE ON THE CURRENT WEATHER...SO WILL FOLLOW THIS AND EXPECT PRECIPITATION TO END AT PIA 15Z-16Z...AND AT CMI AROUND 18Z. CEILINGS/FLIGHT RULES VARY WIDELY OVER THE AREA THIS MORNING...BUT EXPECT GENERAL MVFR CONDITIONS WITH POSSIBLY IFR IN HEAVIER SHOWERS. OVERALL EXPECT IMPROVEMENT TO VFR A COUPLE OF HOURS AFTER PRECIPITATION ENDS...THEN MAINLY CLEAR SKIES BY 00Z FRI. NORTHWEST WINDS WILL STILL BE ON THE STRONG SIDE TODAY WITH 18-22 KT SUSTAINED WITH GUSTS ABOVE 30 KT AT TIMES. WINDS WILL THEN DIMINISH AND BACK TO WESTERLY AFTER 00Z FRI. 04 && .PREV DISCUSSION... ISSUED 314 AM CST THU MAR 8 2012 COLD FRONT PUSHING THROUGH THE FORECAST AREA THIS MORNING WITH SOME SHOWERS OUT AHEAD AND ALONG. A SECOND ROUND OF SHOWERS AND OCCASIONAL THUNDER PUSHING UP JUST BEHIND THE SFC BOUNDARY AS A WAVE MOVES NE INTO THE REGION. MORNING PRECIP AND HOW LONG IT WILL IMPACT THE REGION IS THE FIRST ISSUE...ALONG WITH THE HOURLY TEMPS THIS MORNING AS COLDER AIR MOVES INTO THE AREA. BEYOND THAT...THE FORECAST HAS FEW CHANGES AS THE MODELS STILL WORK OUT HOW THE MAIN UPPER LOW OVER THE SWRN CONUS IS GOING TO MOVE OUT AND ACROSS THE ERN HALF OF THE COUNTRY. STILL MORE IN FAVOR OF THE ECMWF...AND HAVE TRIED TO MITIGATE THE GFS IMPACTS IN THE EXTENDED AS MUCH AS COLLABORATION AND CONSENSUS WOULD ALLOW. THAT BEING SAID...THE GFS SOLUTION OF SPLITTING THE WAVE INTO SEVERAL SMALLER WAVES IS SLOWLY TURNING INTO A MORE ECMWF/NAM SOLUTION. BIGGEST IMPACT FOR THIS PARTICULAR DISCREPANCY WILL BE ON MON NIGHT/TUESDAY WHERE THE CONFIDENCE IN THE GOING FORECAST DECREASES. SHORT TERM...TODAY AND TOMORROW... HIGH TEMPERATURES LIKELY TO BE MET EARLY AS THE REMAINDER OF THE DAY WILL BE COOLER WITH THE FRONT PASSING THROUGH THIS MORNING. PRECIP WILL CONTINUE WITH A CHANCE FOR SOME THUNDER THIS MORNING WITH SOME STEEPER MID LEVEL LAPSE RATES ASSOCIATED WITH THE WAVE MOVING THROUGH THE FLOW JUST BEHIND THE SFC BOUNDARY. POPS DECREASING NW TO SE AFTER 18Z. TEMPS A BIT COOLER TONIGHT. CONCERN THAT GUIDANCE AND GOING FORECAST ARE NOT QUITE COOL ENOUGH SHOULD THE SKIES CLEAR A BIT MORE QUICKLY THAN THE MODEL RH PROFILES ARE HINTING. RATHER DRY AIR AVAILABLE BEHIND THIS WAVE. TOMORROW...TEMPS COOLER THAN LAST COUPLE OF DAYS...BUT STILL A BIT WARMER THAN SEASONABLE...UPPER 40S/NEAR 50 WITH PLENTY OF SUNSHINE. LONG TERM...SATURDAY THROUGH WEDNESDAY... WINDS COME AROUND TO MORE SOUTHERLY SATURDAY MORNING...AND ASSISTS IN A WARM UP WITH PLENTY OF SUNSHINE EARLY. HOWEVER...SOME OF THIS WARM UP WILL BE SHORT LIVED AS A DEVELOPING SYSTEM MOVES OUT OF THE SRN PLAINS INTO THE MIDWEST. MODELS HAVE HAD QUITE THE HISTORY WITH THIS SYSTEM...AND MANY MANY DIFFERENT SOLUTIONS. FOR NOW...THE EC IS PUSHING THE SYSTEM THROUGH...RATHER DIFFUSE AS AN OPEN WAVE...AND WEAKENING AND LESSENING THE QPF TRENDS IN THE LAST COUPLE OF RUNS. THE GFS IS ALSO EASING A BIT...BUT DELIVERING THE PRECIP IN A ONE TWO PUNCH FOR SAT NIGHT/SUN AND MON NIGHT/TUES. FOR NOW...BEST CHANCES FOR POPS ARE IN THE FORECAST WITH SUNDAY AND SUNDAY NIGHT. FROM TUES NIGHT THROUGH WED...KEEPING THE FORECAST DRY AT THIS POINT AS THE MODELS ARE STRUGGLING WITH A BIT OF FEEDBACK IN WEAK SWRLY FLOW. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1014 AM CST THU MAR 8 2012 .DISCUSSION... 1008 AM CST NO REAL ISSUES LATE THIS MORNING OR GOING INTO THE AFTERNOON...WITH MINOR CHANGES TO POP/WX GRIDS AS RAIN HAS EXITED THE CWA...AND SOME ADJUSTMENTS TO CLOUD TRENDS TODAY. SURFACE TROUGH AND ASSOCIATED COLD FRONT HAVE SINCE SHIFTED EAST/SOUTHEAST OF THE CWA THIS MORNING...AS HIGHER PRESSURE BUILDS EAST WITH PRESSURE RISES NOTED ACROSS MUCH OF THE REGION THIS HOUR. ALTHOUGH...MAIN RIDGE AXIS REMAINS TO THE WEST OVER THE CENTRAL PLAINS AND APPEARS AS IF IT WILL REMAIN SITUATED TO THE WEST WITH A FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER THE CWA TODAY. THIS WILL OCCUR AS AN UPPER LEVEL TROUGH REMAINS OVERHEAD...WITH A MID LEVEL SHORT WAVE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER MIDWEST...WHICH WILL PLAY A FACTOR WITH CLOUD TRENDS TODAY. LOW LEVEL CLOUD COVER WILL CONTINUE TO SHIFT EAST THROUGH THE SOUTHEAST PORTION OF THE CWA THROUGH MID DAY WITH A PARTIAL CLEARING TREND EXPECTED THROUGH MID DAY. ALTHOUGH...WITH COOLER AIR MOVING THROUGH...STEEPENING LOW LEVEL LAPSE RATES...AND THE APPROACHING WAVE...A REDEVELOPMENT OF CU/STRATO CU WILL HELP TO PROVIDE WHATEVER CLEAR SKIES ARE IN PLACE TO BECOME MORE PARTLY SUNNY/CLOUDY THIS AFTERNOON. THIS DIURNAL CU WILL THEN DIMINISH WITH A CLEARING TREND EXPECTED ONCE AGAIN LATE THIS AFTERNOON AND EARLY EVENING. EVENING SKIES GRIDS MAY NEED TO BE ADJUSTED FOR THE AFTERNOON ISSUANCE...AS A QUICKLY APPROACHING COLD FRONTAL BOUNDARY MAY PROVIDE ADDITIONAL CLOUD COVER LATE THIS EVENING BEFORE HIGH PRESSURE MOVES OVERHEAD EARLY FRIDAY. RODRIGUEZ //PREV DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * MVFR CIGS LINGER...ALTHOUGH STEADILY LIFTING TOWARDS VFR CIGS BY THIS AFTN. * OCCASIONAL W/NW GUSTS TO 25KT THRU THIS AFTN...THEN DIMINISHING. BEACHLER //DISCUSSION...UPDATED 12Z... A STRONG COLD FRONT HAS PUSHED EAST OF THE TERMINALS THIS MORNING. WITH THE FROPA...WINDS HAVE SHIFTED TO NWLY AND DIMINISHED SOMEWHAT...THOUGH GUSTS TO 25KT ARE LIKELY THROUGH THE DAY. MUCH OF THE ASSOCIATED PCPN HAS ENDED...BUT AN UPPER LEVEL IMPULSE MOVING THROUGH CNTRL IL HAS BROUGHT MORE RAIN AND SOME ISOLD THUNDER...BUT LATEST RADAR IMAGERY INDICATES A WEAKENING TREND AND IT IS LIKELY THAT ANY REMAINING PRECIP SHOULD REMAIN SOUTH OF THE TERMINALS...WITH THE POSSIBLE EXCEPTION OF KGYY WHICH MAY STILL GET CLIPPED WITH SOME SHRA. OTHERWISE...THE TREND FOR THE DAY SHOULD BE FOR IMPROVING CIGS AS COOLER...DRIER AIR FILTERS IN BEHIND THE COLD FRONT. EXPECT THAT CIGS SHOULD IMPROVE TO VFR BY LATE MORNING. THE REMAINDER OF THE PERIOD SHOULD SEE VFR CONDITIONS AS HIGH PRESSURE BUILDS ACROSS THE REGION. A WEAK LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES TONIGHT SHOULD DRAG A SECONDARY COLD FRONT ACROSS THE AREA...BRINGING A REINFORCING SHOT OF COLD AIR. THIS COLD ADVECTION SHOULD BRING ANOTHER ROUND OF GUSTINESS DURG THE OVERNIGHT HOURS...THOUGH DO NOT EXPECT GUSTS TO EXCEED 25KT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN TIMING OF VFR CIGS DEVELOPING. * HIGH CONFIDENCE IN ALL ELEMENTS AFT 21Z. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1009 AM CST THU MAR 8 2012 .DISCUSSION... 1008 AM CST NO REAL ISSUES LATE THIS MORNING OR GOING INTO THE AFTERNOON...WITH MINOR CHANGES TO POP/WX GRIDS AS RAIN HAS EXITED THE CWA...AND SOME ADJUSTMENTS TO CLOUD TRENDS TODAY. SURFACE TROUGH AND ASSOCIATED COLD FRONT HAVE SINCE SHIFTED EAST/SOUTHEAST OF THE CWA THIS MORNING...AS HIGHER PRESSURE BUILDS EAST WITH PRESSURE RISES NOTED ACROSS MUCH OF THE REGION THIS HOUR. ALTHOUGH...MAIN RIDGE AXIS REMAINS TO THE WEST OVER THE CENTRAL PLAINS AND APPEARS AS IF IT WILL REMAIN SITUATED TO THE WEST WITH A FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER THE CWA TODAY. THIS WILL OCCUR AS AN UPPER LEVEL TROUGH REMAINS OVERHEAD...WITH A MID LEVEL SHORT WAVE TROUGH DROPPING SOUTHEAST THROUGH THE UPPER MIDWEST...WHICH WILL PLAY A FACTOR WITH CLOUD TRENDS TODAY. LOW LEVEL CLOUD COVER WILL CONTINUE TO SHIFT EAST THROUGH THE SOUTHEAST PORTION OF THE CWA THROUGH MID DAY WITH A PARTIAL CLEARING TREND EXPECTED THROUGH MID DAY. ALTHOUGH...WITH COOLER AIR MOVING THROUGH...STEEPENING LOW LEVEL LAPSE RATES...AND THE APPROACHING WAVE...A REDEVELOPMENT OF CU/STRATO CU WILL HELP TO PROVIDE WHATEVER CLEAR SKIES ARE IN PLACE TO BECOME MORE PARTLY SUNNY/CLOUDY THIS AFTERNOON. THIS DIURNAL CU WILL THEN DIMINISH WITH A CLEARING TREND EXPECTED ONCE AGAIN LATE THIS AFTERNOON AND EARLY EVENING. EVENING SKIES GRIDS MAY NEED TO BE ADJUSTED FOR THE AFTERNOON ISSUANCE...AS A QUICKLY APPROACHING COLD FRONTAL BOUNDARY MAY PROVIDE ADDITIONAL CLOUD COVER LATE THIS EVENING BEFORE HIGH PRESSURE MOVES OVERHEAD EARLY FRIDAY. RODRIGUEZ && .PREV DISCUSSION... 307 AM CST THE IMMEDIATE CONCERNS WITH THE FORECAST ARE WITH THE FALLING TEMPERATURES...AS WELL AS CONTINUED POST FRONTAL SHOWERS AND EVEN SOME THUNDER CHANCES THIS MORNING ACROSS THE SOUTHERN HALF OF THE AREA. THEN ATTENTION TURNS TO RAIN POTENTIAL SUNDAY...FOLLOWED BY THE TEMPERATURES NEXT WEEK AS A SIGNIFICANT WARM UP...OR RE-WARM UP WE SHOULD SAY...LOOKS LIKELY. FOR THE CURRENT SITUATION...A VERY WELL-DEFINED COLD FRONT IS CLEARING THE FORECAST AREA EARLY THIS MORNING. ROBUSTLY WARM AIR AHEAD OF THIS FEATURE HELPED CHICAGO BREAK THEIR RECORD WARM LOW FOR YESTERDAY /54 DEGREES/. THE COMBINATION OF THE FRONTAL PASSAGE AND RAIN TOOK TEMPERATURES DOWN AS MUCH AS 14 DEGREES IN ONE HOUR AT SOME LOCATIONS. A GOOD PART OF THE SHOWER ACTIVITY IS POST-FRONTAL...ASSOCIATED WITH ELEVATED MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE BOUNDARY. ITS A GOOD THING A LOT OF THIS IS POST FRONTAL...AS MORE SHOWER ACTIVITY AHEAD OF THE FRONT COULD HAVE POTENTIALLY STEERED DOWN SOME OF THE 55 KT FLOW AT 1500 FT SEEN ON THE KLOT DOPPLER VELOCITY FOR HOURS AHEAD OF THE FRONT. THE NORTHWEST WIND SPEEDS BEHIND THE FRONT ARE ACTUALLY QUITE A BIT LOWER...GUSTING AT TIMES TO NEAR 25 MPH. THIS SHOULD CONTINUE TO BE THE CASE INTO THIS AFTERNOON. AN INTERESTING AREA OF ELEVATED CONVECTION IS SEEN IN NORTHERN MO AS OF 300 AM HAVING ORIGINATED IN KS WITH A SHORT WAVE PER WATER VAPOR ANALYSIS. THIS AREA CONTINUES TO GROW UPSCALE EAST NORTHEAST...WELL BEHIND THE FRONT. RUC AND NAM CROSS SECTIONS THROUGH THIS AREA SHOW STRONG MID-LEVEL FRONTOGENESIS AND A VERY DEEP LAYER /AROUND 200 MB/ OF NEGATIVE EPV AND SLIGHTLY DECREASING THETA-E...INDICATING CONVECTIVE INSTABILITY PRESENT. THE RUC FORECAST FOR THE FORCING AND INSTABILITY...AND HRRR PROJECTION OF REFLECTIVITY...SEEMS TO HAVE A STRONG HANDLE ON THIS...WHILE MOST OTHER GUIDANCE DOES NOT. THIS AREA IS FORECAST BY THE RUC/HRRR TO COME ACROSS THE SOUTHERN HALF OF THE FORECAST AREA EARLY THIS MORNING. THE CONVECTIVE SIGNAL WEAKENS SOMEWHAT...BUT STILL THINK ISOLATED TO SCATTERED THUNDER SHOULD BE SEEN AT LEAST CLOSE IF NOT INTO THE SOUTHERN FORECAST AREA. THERE COULD BE SOME SMALL HAIL WITH THIS GIVEN THE LOW WET BULB ZERO VALUES. THIS SHOULD EXIT BY 10 AM TO NOON...WITH LINGERING CLOUDS BEHIND THE FRONT ACROSS THE SOUTHERN AREA INTO EARLY TO MID AFTERNOON. COLD AIR ADVECTION BEHIND THE FRONT WILL UNDERCUT THE MORNING CLOUDS AND SHOWERS IN THE SOUTH...HELPING TO KEEP TEMPERATURES NEARLY STEADY OR EVEN CONTINUING TO FALL THROUGH MID-MORNING. CLEARING BY LATE MORNING INTO AFTERNOON WILL ALLOW FOR SOME REBOUND...BUT PROBABLY ONLY INTO THE LOWER TO MID 40S. CONFIDENCE ON THE DEGREE OF RECOVERY IS SOMEWHAT LOW DUE TO WEIGHING THE COLD AIR ADVECTION/CLOUD IMPACT THIS MORNING. THE UPPER TROUGH OVER MN EARLY THIS MORNING WILL PASS OVER THE GREAT LAKES AND BE RE-ENFORCED BY A STRONG JET MAX TO THE NORTHWEST. THIS WILL HELP TO PUSH A SECONDARY COLD FRONT SOUTH THROUGH THE AREA LATE THIS EVENING INTO OVERNIGHT. THIS LOOKS TO REALLY SEND DEW POINTS DOWN AND POTENTIALLY TEMPERATURES FURTHER TOO. THE COLD POCKET ASSOCIATED WITH THIS SHOULD DEVELOP SOME STRATOCU TONIGHT ACROSS NORTHERN AND EASTERN AREAS THAT MAY POTENTIALLY LINGER INTO FRI MORNING. HIGH PRESSURE WILL THEN PREVAIL FRIDAY INTO EARLY SATURDAY...WITH RETURN FLOW THEN SETTING UP FOR SATURDAY...WHICH SHOULD BE A FAIRLY PLEASANT AND SUNNY DAY. THE WELL-ORGANIZED CLOSED UPPER LOW OVER THE DESERT SOUTHWEST WILL DRIFT GRADUALLY NORTHEAST ON SATURDAY...THEN BEGIN TO BECOME MORE NEUTRAL TO NEGATIVELY TILED AS IT LIFTS OVER OUR AREA ON SUNDAY INTO SUNDAY NIGHT. THE AMOUNT OF MOISTURE RETURN AHEAD OF THIS IS FAIRLY SHORT IN DURATION...BUT IT CERTAINLY LOOKS TO BE DEEP ENOUGH AND WITHIN STRONG ENOUGH ISENTROPIC LIFT FOR FAIRLY WIDESPREAD RAIN/SHOWERS ON SUNDAY. HAVE CONTINUED TO INCH UP POPS. WHILE THE SYSTEM DRY SLOT EVOLVES RIGHT INTO THE AREA...ELEVATED INSTABILITY IS VERY MARGINAL DUE TO THE LIMITED DEGREE OF THETA-E RETURN. SO CONTINUE WITH NO THUNDER MENTION...BUT COULD SEE SOME GUSTIER SHOWERS POTENTIALLY SUNDAY AFTERNOON AND EVE IF THE GFS/EC PAN OUT AS IS. SO HAVE MENTIONED MORE OF A SHOWER WORDING DURING THE AFTERNOON AND EVE BECAUSE OF THIS. TEMPERATURES ON SUNDAY COULD ENCOMPASS A FAIRLY LARGE RANGE THANKS TO THE IMPACTS OF THE LIKELY RAIN. WITH CONFIDENCE INCREASING IN RAIN...HAVE CONTINUED NOT TO INCREASE TEMPERATURES DESPITE SOME GUIDANCE INDICATING WARMER IN SUCCESSIVE RUNS. THE GFS REMAINS CONSISTENT WITH HAVING ANOTHER UPPER WAVE...ACTUALLY ALMOST A PART OF THE FIRST ONE...MOVE NORTHEAST ACROSS THE OHIO RIVER VALLEY ON MONDAY NIGHT INTO TUESDAY. THE 08.00 EC TRENDED BACK AWAY FROM THIS...BUT HAS BEEN THE LESS CONSISTENT MODEL. HAVE KEPT POPS ON TUE MAINLY IN SOUTHEAST AREAS TO ACCOUNT FOR THIS WAVE. WHILE THIS COULD HAVE IMPACTS ON TEMPERATURES ON TUE...A LOW-LEVEL THERMAL TONGUE IS PROJECTED TO BE KNOCKING ON OUR DOOR FROM THE WEST AND SHOULD PROVIDE FOR ABOVE TO WELL ABOVE NORMAL TEMPERATURES. THE STRONGEST SIGNAL FOR VERY MILD READINGS AND A DRY ATMOSPHERIC COLUMN IS ON WED AT THIS TIME. AS PREVIOUS SHIFT DID...LEAN THE FORECAST TOWARDS THE BETTER PERFORMING EC IN THOSE TYPE OF REGIMES. HIGHS IN THE UPPER 60S INTO THE 70S ARE CURRENTLY WHAT THIS BLENDED APPROACH PRODUCES AND SEEMS TO MAKE SENSE. WHILE A FRONT IS PRESENTLY FORECAST TO MOVE THROUGH SOMETIME LATER WED INTO THU OF NEXT WEEK...IT WOULD SEEM LIKELY WITH THE PATTERN THAT ABOVE NORMAL TEMPERATURES CONTINUE THROUGH THE LATTER PART OF NEXT WEEK. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * OCCASIONAL W/NW GUSTS TO 25 KT. * LOW END MVFR CIGS UNTIL 16Z THEN STEADY IMPROVEMENT TO VFR. BEACHLER //DISCUSSION...UPDATED 12Z... A STRONG COLD FRONT HAS PUSHED EAST OF THE TERMINALS THIS MORNING. WITH THE FROPA...WINDS HAVE SHIFTED TO NWLY AND DIMINISHED SOMEWHAT...THOUGH GUSTS TO 25KT ARE LIKELY THROUGH THE DAY. MUCH OF THE ASSOCIATED PCPN HAS ENDED...BUT AN UPPER LEVEL IMPULSE MOVING THROUGH CNTRL IL HAS BROUGHT MORE RAIN AND SOME ISOLD THUNDER...BUT LATEST RADAR IMAGERY INDICATES A WEAKENING TREND AND IT IS LIKELY THAT ANY REMAINING PRECIP SHOULD REMAIN SOUTH OF THE TERMINALS...WITH THE POSSIBLE EXCEPTION OF KGYY WHICH MAY STILL GET CLIPPED WITH SOME SHRA. OTHERWISE...THE TREND FOR THE DAY SHOULD BE FOR IMPROVING CIGS AS COOLER...DRIER AIR FILTERS IN BEHIND THE COLD FRONT. EXPECT THAT CIGS SHOULD IMPROVE TO VFR BY LATE MORNING. THE REMAINDER OF THE PERIOD SHOULD SEE VFR CONDITIONS AS HIGH PRESSURE BUILDS ACROSS THE REGION. A WEAK LOW PRESSURE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES TONIGHT SHOULD DRAG A SECONDARY COLD FRONT ACROSS THE AREA...BRINGING A REINFORCING SHOT OF COLD AIR. THIS COLD ADVECTION SHOULD BRING ANOTHER ROUND OF GUSTINESS DURG THE OVERNIGHT HOURS...THOUGH DO NOT EXPECT GUSTS TO EXCEED 25KT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN WIND DIR/SPEED FORECAST. * MEDIUM CONFIDENCE IN TIMING OF CIGS IMPROVEMENT. BEACHLER //OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z... FRIDAY NIGHT AND SATURDAY...VFR. SUNDAY AND MONDAY...CHANCE OF RAIN. MVFR POSSIBLE. TUESDAY...CHANCE OF RAIN AND MVFR EARLY...OTHERWISE VFR. WEDNESDAY...VFR. KREIN && .MARINE... 325 AM CST SOUTHWEST GALES ARE FINALLY COMING TO AN END OVER THE LAKE! THE COLD FRONT IS ALMOST THROUGH LAKE MICHIGAN...WITH THE SOUTHEASTERN THIRD OF THE LAKE STILL AWAITING ITS ARRIVAL. WINDS BEHIND THE COLD FRONT HAVE DIMINISHED AND TURNED WEST TO NORTHWEST. THE ABRUPT CHANGE IN WIND SPEED AND DIRECTION HAS HELPED WAVES QUICKLY DIMINISH IN THE NEAR SHORE ZONES...THEREFORE NOT ISSUING A SMALL CRAFT ADVISORY FOR THIS MORNING. WINDS MAY GUST TO 25 KT FOR THE NEXT COUPLE OF HOURS...BUT NOT LONG ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. A WEAKENING LOW MOVES SOUTH OVER THE EASTERN GREAT LAKES AS THE HIGH PRESSURE TO OUR WEST MOVES INTO SOUTHERN MINNESOTA. AS THE TWO SYSTEMS MOVE CLOSER TOGETHER THE PRESSURE GRADIENT TIGHTENS OVERHEAD. THAT COMBINED WITH STRONG PRESSURE RISES WILL CREATE NORTHWEST GALES OVER THE NORTHERN TWO THIRDS OF THE LAKE LATE TONIGHT. GALES WILL BEGIN TO DIMINISH FRIDAY MORNING AS THE HIGH PRESSURE MOVES INTO THE IMMEDIATE AREA. THE HIGH WILL PASS OVER THE LAKE LATE FRIDAY AFTERNOON INTO FRIDAY EVENING. YET ANOTHER ROUND OF GALES IS POSSIBLE ON THE BACKSIDE OF THE HIGH PRESSURE SATURDAY MORNING. LOW END GALES ARE EXPECTED OVER THE CENTRAL THIRD OF THE LAKE...WITH GALES UP TO 40 KT LIKELY OVER THE NORTHERN THIRD OF THE LAKE. NOT ANTICIPATING GALES OVER THE SOUTHERN THIRD OF THE LAKE. GALES BEGIN TO DIMINISH SATURDAY AFTERNOON AS THE HIGH PRESSURE PULLS AWAY TO THE EAST...HOWEVER GALES OVER THE NORTHERN END OF THE LAKE LOOK LIKE THEY WILL PERSIST INTO THE EVENING HOURS. MODELS HAVE SIGNIFICANT DISCREPANCIES IN TIMING AND THE OVERALL PATTERN FOR THE REMAINDER OF THE FORECAST...SO WHILE NO GALES ARE FORECAST FOR NEXT WEEK...FORECAST CONFIDENCE IS LOW. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...3 AM FRIDAY TO 9 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1213 PM EST THU MAR 8 2012 .AVIATION... / 18Z TAFS / POST-FRONTAL RESIDUAL LOW LEVEL MOISTURE WILL CONTINUE TO SUPPORT MVFR CIGS THROUGH 20/21Z. DRY SUBSIDENT AIR WILL ADVECT IN FROM THE WEST THIS AFTERNOON WHICH WILL LIKELY SCOUR OUT THIS MVFR CEILING LEAVING MAINLY CLEAR/VFR SKIES BY LATER THIS AFTERNOON AND EVENING. PARTIAL CLEARING AND RESULTING DEEPER MIXING WILL ALLOW WINDS TO PICK UP BY MID AFTN...WITH GUSTS OF 25-30 KNOTS POSSIBLE THROUGH APPX 00Z. A SECONDARY FRONTAL BOUNDARY WILL DROP THROUGH THE AREA LATER TONIGHT. LOW LEVEL CAA AND NORTHWESTERLY TRAJECTORIES BEHIND THIS FRONT WILL ALLOW A LAKE EFFECT STRATO CU DECK TO SET UP OVER THE TERMINALS TOMORROW MORNING. ATTM...MODEL FCST SOUNDINGS ARE HINTING AT LOW VFR CEILINGS BTW 3-5 KFT. && .PREV DISCUSSION... /ISSUED 640 AM EST THU MAR 8 2012/ SHORT TERM... STRONG COLD FRONT WAS JUST COMING INTO FAR NW CWA AT 09Z AND WILL QUICKLY MOVE ACROSS THE AREA TODAY. RADAR SHOWING AREA OF LIGHT TO MODERATE SHOWERS ALONG AND BEHIND FRONT WITH SCATTERED SHOWERS OUT AHEAD OF IT. SURFACE OBS SHOWING A GOOD 10 TO 15 DEGREE TEMP DROP BEHIND FRONT WITH COLD AIR ADVECTION EXPECTED TO CONTINUE THROUGH THE DAY WITH LITTLE RECOVERY IN TEMPS EXPECTED. HAVE TRIED TO TIME FRONT THROUGH THE AREA WITH TEMPERATURE DROP AND PCPN TRENDS. VERY DIFFICULT TO SAY THE LEAST AND ADJUSTMENTS WILL BE NECESSARY THROUGH THE MORNING. REGIONAL RADAR MOSAIC AND SATELLITE ALSO SHOWING AN AREA OF CONVECTION THAT HAS DEVELOPED OVERNIGHT IN OK AND KS AND IS MOVING NORTHEAST. HRRR SEEMS TO BE ONLY MODEL TO HAVE A DECENT HANDLE ON THIS WITH 04Z AND 05Z MODEL RUNS HAVING THIS WAVE COMING INTO NW INDIANA AROUND 14Z. DISCUSSION WITH HPC SUGGEST 06Z RUN TRENDING FARTHER EAST BUT GIVEN LOOKS OF RESPONSIBLE SHORT WAVE ON WATER VAPOR AND RECENT RADAR MOSAIC TRENDS HAVE CONCERNS THAT THIS MAY MOVE BACK INTO PART OF CENTRAL OR WEST CENTRAL CWA BY MID MORNING. FOR THIS REASON HAVE SLOWED THE TREND OF CLEARING POPS ACROSS THE AREA BY ABOUT 3 TO 5 HOURS TO ACCOUNT FOR THE POSSIBILITY OF THIS RAIN MOVING BACK IN. BY AFTERNOON THIS WAVE LOOKS TO CLEAR THE AREA AND RAPID DRYING BEGINS AND SHOULD SEE CLEARING SKIES. ANOTHER FAST MOVING SHORT WAVE PASSES TO THE NORTH TONIGHT BUT DRIVES SECONDARY COLD FRONT THROUGH. MAY SEE SOME INCREASE IN CLOUDS NORTH WITH THIS WAVE AND LAKE PLUME AS DELTA T VALUES CLIMB INTO THE TEENS. REMAINDER OF SHORT TERM FORECAST DRY WITH HIGH PRESSURE MOVING IN FRIDAY NIGHT. THIS SHOULD ALLOW WINDS TO DECOUPLE AND EXPECT GOOD RADIATIONAL COOLING BEFORE RETURN FLOW TRIES TO DEVELOP LATE. HAVE LOWERED TEMPS FRIDAY NIGHT. LONG TERM... SATURDAY THROUGH WEDNESDAY...A LONG WAVE TROF WILL BECOME ENTRENCHED ALONG THE WESTERN NORTH AMERICAN COAST WITH LARGE SCALE AMPLIFICATION DOWNSTREAM OVER THE CENTRAL AND EASTERN CONUS. MUCH WARMER AIR WILL RETURN TO THE AREA AND PERSIST THROUGH NEXT WEEK. SHORT WAVE ENERGY WILL EJECT NORTHEAST AND PROVIDE A CHANCE FOR SHOWERS THROUGH MOST OF THE PERIOD AS GULF MOISTURE SPREADS NORTH ACROSS THE OHIO RIVER. THE GFS ENSEMBLE MEMBERS HAVE FINALLY COME INTO REASONABLE AGREEMENT WITH ONE ANOTHER WITH MUCH SMALLER STANDARD DEVIATIONS REFLECTED IN THE MEX MOS. THERE IS POTENTIAL FOR HIGHS TO TOP 70 DEGREES DURING THE LATTER HALF OF THIS PERIOD. HOWEVER...GIVEN THE POTENTIAL FOR CLOUDS AND RAINFALL...KEPT HIGHS IN THE MID TO UPPER 60S TUESDAY/WEDNESDAY. ALSO...THERE IS AN OUTSIDE CHANCE ONE OF THE SHORTWAVES MAY BE ABLE TO TAP A LITTLE COOLER AIR AFTER THE SHORT WAVE PASSES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EST FRIDAY FOR LMZ043-046. && $$ SHORT TERM...LASHLEY LONG TERM...SKIPPER AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION...CORRECTED AVIATION DISCUSSION
NWS QUAD CITIES IA IL
310 PM CST THU MAR 8 2012 .SYNOPSIS... 12Z UA ANALYSIS HAS AN 850MB COLD FRONT FROM SOUTHERN LAKE HURON INTO SOUTHEAST NEW MEXICO. A BIT MORE IMPRESSIVE IS THE 700MB COLD FRONT FROM THE MACKINAC STRAITS INTO SOUTHEAST COLORADO. A STRONG LLJ WAS TRANSPORTING MOISTURE FROM THE GULF COAST INTO NEW ENGLAND. SATELLITE TRENDS HAVE MID AND HIGH LEVEL CLOUDS FROM THE CENTRAL PLAINS INTO THE OHIO VALLEY. LOW LEVEL SC/CU WERE ACROSS THE UPPER MIDWEST IN ASSOCIATION WITH A SHORTWAVE ROTATING ACROSS NORTHERN IOWA TOWARD WISCONSIN. 18Z SFC ANALYSIS HAS THE PRIMARY FRONT FROM TEXAS INTO THE OHIO VALLEY WITH SEVERAL WEAK TROFS FROM THE GREAT LAKES INTO THE NORTHERN PLAINS. A NEW COLD FRONT WAS DROPPING SOUTH FROM CANADA AND WAS INTO NORTH DAKOTA AND MINNESOTA. DEW POINTS WERE IN THE TEENS AND 20S ACROSS MUCH OF THE MIDWEST WHILE 40S AND GREATER DEW POINTS RAN FROM THE SOUTHERN PLAINS INTO THE OHIO VALLEY. && .SHORT TERM...TONIGHT AND FRIDAY... THE SHORTWAVE AND ASSOCIATED PV ANOMALY IS MOVING INTO SOUTHERN WISCONSIN. THESE FEATURES COMBINED WITH STEEP LOW LEVEL LAPSE RATES HELPED PRODUCE THE STRONG WINDS STARTING AROUND MID DAY. AS THE BOUNDARY LAYER STABILIZES WITH SUNSET THE WINDS WILL DECREASE. LATER TONIGHT A STORM SYSTEM WILL PASS NORTH OF THE AREA BUT WILL DRAG ANOTHER COLD FRONT/BOUNDARY THROUGH THE AREA. THUS CLOUDS WILL BE ON THE INCREASE LATER THIS EVENING. ONCE THE FRONT PASSES... STRONG SUBSIDENCE SHOULD START BREAKING UP THE CLOUDS PRIOR TO SUNRISE. THE RUC DOES INDICATE LOW LEVEL LAPSE RATES GETTING STEEPER LATE TONIGHT SO THE SUBSIDENCE SHOULD ALLOW WINDS TO PICK UP AGAIN BEFORE DECREASING AGAIN PRIOR TO SUNRISE. ON FRIDAY HIGH PRESSURE SETTLES ACROSS THE AREA RESULTING IN MUCH LIGHTER WINDS AND GENERALLY SUNNY SKIES. SUBSIDENCE WILL LIMIT THE AMOUNT OF MIXING THAT OCCURS BUT THE STRONG MARCH SUN SHOULD ALLOW TEMPERATURES TO BE SIMILAR TO THURSDAY. ..08.. .LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY... CONTINUED ABOVE NORMAL TO WELL ABOVE NORMAL WITH A LIGHT TO MODERATE RAIN EVENT LATE SUNDAY INTO MONDAY. OVERALL...INITIALIZATION AND VERIFICATION SLIGHTLY BELOW AVERAGE WITH SIGNFICANT DISCREPANCIES OF TEXAS CONVECTION. THIS WILL IMPACT THE TIMING...EVOLUTION AND TRACK OF UPPER LOW FOR LATE SUNDAY. THIS IS HANDLED ADEQUATELY BY A BLEND OF THE HI-RES ECMWF AND GFS BUT COLD FRONTAL EVOLUTION SUGGESTS A BIT FASTER TRACK AND QUICKER OCCLUSION THAT MAY BECOMEM EVIDENT THE NEXT 24 HOURS WITH FASTER STARTING OF RAIN ON SUNDAY AND IN NW SECTIONS...LIGHTER AMOUNTS OF PRECIPITION. FRIDAY NIGHT...TRIMMED LOWS A FEW DEGREES IN EASTERN SECTIONS DUE TO LIGHT SE WINDS ALLOWING FOR A BIT OF DECOUPLE UNDER A CLEAR SKY WITH MIDDLE 20S POSSIBLE FOR LATER SHIFTS AND A DECENTR FROST ALONGAND EAST OF THE MISSISSIPPI RIVER. SATURDAY...WARMING TREND WITH INCREASING SOUTH TO SOUTHWEST WINDS AND COPIOUS SUNSHINE. UPPED HIGHS TO AROUND 60F WESTERN SECTIONS AND MIDDLE 50S EAST. IF ENOUGH BL MIXING OCCURS AS SUGGESTED...MAX TEMPS MAY STILL BE A FEW DEGREES TOO COOL. MINS SATURDAY NIGHT MAY BE AROUND MIDNIGHT BEFORE HIGH CLOUDS ARRIVE WITH UPPER 30S NORTH AND LOWER TO POSSIBLY MIDDLE 40S SOUTH SECTIONS. SUNDAY...AREAS OF LIGHT TO MODERATE RAIN TO OVERSPREAD THE AREA WITH AMOUNTS MOSTLY A QUARTER TO LOCALLY AROUND A HALF INCH. CLOUDS AND EVAPORATIVE COOLING TO KEEP HIGHS IN THE 50S THAT MAY FALL INTO THE 40S WITH PERIODS OF RAIN. TIMING QUESTION PRECLUDES GOING MORE THAN LIKELY WITH BULK OF RAIN SUGGESTED BETWEEN 21-09Z ATTM. SUNDAY NIGHT MINS MILD MOSTLY IN THE MIDDLE 40S DUE TO HIGH DEWPOINTS AND RH VALUES WITH LIGHT FOG NOT OUT OF THE QUESTION FOR LATER SHIFTS. MONDAY...CLEARING SKIES WITH ANY RAIN ENDING EARLY. SOUTH WINDS TO USHER IN MILD GULF OF MEXICO AIR WITH HIGHS WELL INTO THE 60S...OR ABOUT 20 DEGREES ABOVE NORMAL. TUESDAY THROUGH THURSDAY...MILD AND DRY WITH MORE WELL ABOVE NORMAL TEMPERATURES. HIGHS 65-75F SUGGESTED WITH LOWS 45-55 DEGREES WITH LIGHT TO MODERATE WINDS. WITH ENOUGH BL MIXING...UPPER 70S MAXES SUGGESTED WHICH ARE RECORD HIGHS FOR THIS PERIOD. RECORD MILD MINS ARE AROUND 50 DEGREES WHICH MAY ALSO BE THREATENED. ..NICHOLS.. && .AVIATION... VFR WX IS EXPECTED THROUGH 12Z/10. SUNSET WILL ALLOW THE ATMOSPHERE TO STABILIZE AND ALLOW WINDS TO DIMINISH. ANOTHER FRONTAL BOUNDARY IN THE NORTHERN PLAINS WILL MOVE THROUGH IOWA AND ILLINOIS IN THE 03Z-09Z/09 TIME FRAME BUT WILL COME THROUGH DRY BUT WINDS ARE EXPECTED TO INCREASE AFTER FRONTAL PASSAGE. HIGH PRESSURE BUILDING INTO THE MIDWEST PRIOR TO SUNRISE AND FRIDAY WILL ALLOW WINDS TO AGAIN DIMINISH. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ 08/NICHOLS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1235 PM CST THU MAR 8 2012 .UPDATE... DEEP MIXING IS UNDERWAY WITH HIGHER MOMENTUM AIR MIXING DOWN TO THE SFC. RUC TRENDS INDICATE LOW LEVEL LAPSE RATES MAY APPROACH DRY ADIABATIC THIS AFTERNOON. THE APPROACHING SHORTWAVE HAS A STRONG PV ANOMALY ASSOCIATED WITH IT WHICH IS AIDING IN MIXING DOWN THE HIGHER MOMENTUM AIR. PER THE RUC THE PV ANOMALY SHOULD PASS JUST NORTH OF THE CWFA BUT THE TIGHT PV GRADIENT ON THE SOUTH SIDE WILL MOVE ACROSS THE NORTHERN CWFA PRODUCING THE STRONG WINDS. BASED ON MOVEMENT FROM WATER VAPOR...THE SHORTWAVE AND PV ANOMALY SHOULD BE ACROSS SOUTHEAST WISCONSIN BY SUNSET. AT THAT TIME LAPSE RATES WILL BEGIN TO STABILIZE AND WINDS SHOULD DIMINISH QUICKLY. ..08.. && .PREV DISCUSSION... /ISSUED 1046 AM CST THU MAR 8 2012/ UPDATE... DATA THROUGH 15Z HAS HIGH LEVEL CLOUDS ACROSS THE SOUTHERN PART OF THE CWFA WHICH IS ASSOCIATED WITH TWO SFC WAVES MOVING ALONG THE COLD FRONT IN ARKANSAS. WATER VAPOR HAS A NICE VORT MAX AND ASSOCIATED SHORT WAVE ROTATING SOUTHEAST INTO NORTHERN IOWA IN THE FLOW ALOFT. THERE ARE SOME SC/CU CLOUDS ASSOCIATED WITH THIS VORT MAX AND VISIBLE TRENDS THE PAST FEW HOURS SUGGEST A POTENTIAL FOR THOSE CLOUDS TO MOVE INTO THE NORTHERN CWFA. LOW LEVEL LAPSE RATES ARE STEEPENING FROM THE DIURNAL HEATING WHICH IS ALLOWING HIGHER MOMENTUM AIR ALOFT TO MIX DOWN. RUC TRENDS SUGGEST SUSTAINED WINDS SHOULD INCREASE A BIT MORE FROM LATE MORNING THROUGH MID AFTERNOON BUT NOT BY MUCH. HOWEVER...WIND GUSTS SHOULD INCREASE A BIT MORE AS THE SHORTWAVE MOVES THROUGH THE AREA. IF THE RUC TIMING IS CORRECT...SOME GUSTS TO 40 MPH MAY BE POSSIBLE DURING THE AFTERNOON IN THE NORTHEAST QUADRANT OF THE CWFA. .08.. AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH 00Z/10 AS HIGH PRESSURE SLOWLY BUILDS INTO THE MIDWEST. DAYTIME HEATING IS ALLOWING STRONGER WINDS ALOFT TO MIX DOWN AND A PASSING DISTURBANCE ALOFT MAY ALLOW A BRIEF PERIOD OF WIND GUSTS OF 30-35KTS A FEW HOURS EITHER SIDE OF 21Z/08. THE DAYTIME HEATING MAY ALSO ALLOW SOME DIURNAL CU/SC TO DEVELOP BUT ANY CIGS WILL BE ABV 3KFT AGL. AS HIGH PRESSURE SETTLES OVER THE AREA LATE TONIGHT WINDS WILL DIMINISH. .08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1046 AM CST THU MAR 8 2012 .UPDATE... DATA THROUGH 15Z HAS HIGH LEVEL CLOUDS ACROSS THE SOUTHERN PART OF THE CWFA WHICH IS ASSOCIATED WITH TWO SFC WAVES MOVING ALONG THE COLD FRONT IN ARKANSAS. WATER VAPOR HAS A NICE VORT MAX AND ASSOCIATED SHORT WAVE ROTATING SOUTHEAST INTO NORTHERN IOWA IN THE FLOW ALOFT. THERE ARE SOME SC/CU CLOUDS ASSOCIATED WITH THIS VORT MAX AND VISIBLE TRENDS THE PAST FEW HOURS SUGGEST A POTENTIAL FOR THOSE CLOUDS TO MOVE INTO THE NORTHERN CWFA. LOW LEVEL LAPSE RATES ARE STEEPENING FROM THE DIURNAL HEATING WHICH IS ALLOWING HIGHER MOMENTUM AIR ALOFT TO MIX DOWN. RUC TRENDS SUGGEST SUSTAINED WINDS SHOULD INCREASE A BIT MORE FROM LATE MORNING THROUGH MID AFTERNOON BUT NOT BY MUCH. HOWEVER...WIND GUSTS SHOULD INCREASE A BIT MORE AS THE SHORTWAVE MOVES THROUGH THE AREA. IF THE RUC TIMING IS CORRECT...SOME GUSTS TO 40 MPH MAY BE POSSIBLE DURING THE AFTERNOON IN THE NORTHEAST QUADRANT OF THE CWFA. ..08.. && .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH 00Z/10 AS HIGH PRESSURE SLOWLY BUILDS INTO THE MIDWEST. DAYTIME HEATING IS ALLOWING STRONGER WINDS ALOFT TO MIX DOWN AND A PASSING DISTURBANCE ALOFT MAY ALLOW A BRIEF PERIOD OF WIND GUSTS OF 30-35KTS A FEW HOURS EITHER SIDE OF 21Z/08. THE DAYTIME HEATING MAY ALSO ALLOW SOME DIURNAL CU/SC TO DEVELOP BUT ANY CIGS WILL BE ABV 3KFT AGL. AS HIGH PRESSURE SETTLES OVER THE AREA LATE TONIGHT WINDS WILL DIMINISH. ..08.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1245 PM MST THU MAR 8 2012 .UPDATE... ISSUED AT 522 AM MST THU MAR 8 2012 STARTING TO SEE 12Z RAOBS COME IN AND AS EXPECTED AIR MASS BUILDING IN FROM THE NORTH LOOKS MUCH DRIER THAN PREVIOUS DAY. ESTIMATED MIXED LAYER DEWPOINTS OFF OF KLBF SOUNDING WOULD SUPPORT SINGLE DIGIT DEWPOINTS WITH ANY DEEP MIXING. GOES SOUNDINGS ALSO SUPPORTING VERY DRY LAYER ALOFT...AND THINK WITH PLENTIFUL SUNSHINE MUCH OF THE AREA WILL TAP INTO THIS DRIER AIR THIS AFTERNOON. DROPPING TDS INTO SINGLE DIGITS ALONG THE LINES OF LATEST HRRR STILL KEEP AFTERNOON HUMIDITY VALUES JUST ABOVE CRITICAL VALUES. WITH STRONGEST WINDS LIKELY BEFORE 20Z...THE MARGINAL NATURE OF PARAMETERS AND UNCERTAINTY IF WINDS/RH WILL LINE UP FOR SEVERAL HOURS KEEPS CONFIDENCE TOO LOW TO ISSUE A RFW AT THIS TIME. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 155 AM MST THU MAR 8 2012 TODAY...AREA OF THUNDERSTORMS THAT DEVELOPED ALONG NOSE OF STRONG ISENTROPIC ASCENT SHOULD CONTINUE TO DIMINISH/SHIFT SOUTH OF THE AREA THROUGH THE MORNING HOURS AS COLD AND DRY AIR ADVECTION OVERSPREAD THE AREA BEHIND DEPARTING TROUGH MOVING ACROSS EASTERN NEBRASKA. WITH MUCH DRIER AIR MOVING INTO THE AREA AND FAIRLY DEEP DOWNWARD MOTION...DO NOT SEE MUCH IN THE WAY OF A PRECIPITATION THREAT ONCE OVERNIGHT CONVECTION BEGINS TO SHIFT SOUTH. SKIES WILL GRADUALLY CLEAR...ALTHOUGH PLACEMENT OF CUT OF LOW AND PERSISTENT DEFORMATION ZONE MAY PROMOTE A PERSISTENT AREA OF MID/HIGH CLOUDS ACROSS SOUTHERN CWA...BUT AM NOT EXPECTING MUCH OF AN IMPACT ON SENSIBLE WX AT THIS TIME. TEMPERATURES SHOULD REBOUND INTO THE LOWER 50S ACROSS MUCH OF THE AREA DESPITE THE CAA WITH GUSTY NORTHERLY WINDS EXPECTED BTWN 15 AND 20Z BEFORE THINGS BEGIN TO DIMINISH. WITH LOW TEENS/SINGLE DIGIT DEWPOINTS MOVING INTO THE AREA...EXPECT HUMIDITIES TO FALL TO AROUND 20 PERCENT RANGE AND WITH THE GUSTY WINDS MAY APPROACH CRITICAL FIRE WX CONDITIONS FOR AN HOUR OR SO. CURRENTLY HUMIDITIES LOOK TO BE ABOVE CRITERIA AND WINDS ARE EXPECTED TO DIMINISH WHILE HUMIDITIES ARE AT THEIR LOWEST VALUES. HAVE SEEN A FEW POST FRONTAL FIRE WEATHER EVENTS THOUGH WITH DEEP COLD AND DRY AIR ADVECTION AND MAY NEED TO REEVALUATE ONCE 12Z RAOBS ARE AVAILABLE. TONIGHT-FRIDAY...GENERAL CONSENSUS IS UPPER LOW WILL MOVE INTO THE TEXAS PANHANDLE...WELL REMOVED FROM THE FORECAST AREA...WITH GEM AND SREF MEAN CONTINUING TO INDICATE SOME RETROGRADE MOTION. BOTH OF THESE SOLUTIONS AND GENERAL MODEL CONSENSUS KEEPS CWA WELL TO THE NORTH OF ANY APPRECIABLE PRECIPITATION THREAT AS STABLE MID LEVELS...AND PERSISTENT DRY NORTHERLY FLOW OVERNIGHT THURSDAY WILL BE ENOUGH TO PREVENT PRECIP DEVELOPMENT...EVEN IF SOME LARGE SCALE FORCING FOR ASCENT MAY BE PRESENT. MID LEVEL FLOW EXPECTED TO BECOME A BIT MORE SOUTHERLY DURING THE DAY ALLOWING FOR SOME INCREASING CLOUDS...BUT WITH BULK OF LARGE SCALE FORCING FOR ASCENT TO THE SOUTH OF THE AREA AND OVERALL LOW CONFIDENCE IN LARGE SCALE FEATURES...THINK DRY CONDITIONS WILL PREVAIL. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 155 AM MST THU MAR 8 2012 FRIDAY NIGHT-SATURDAY NIGHT...WHILE NEAR TERM MODELS HAVE COME INTO A LITTLE BETTER AGREEMENT WITH HOW H5 TROUGH WILL GRADUALLY LIFT TO THE NORTH ACROSS THE AREA THROUGH THE PERIOD...THERE REMAINS CONSIDERABLE SPREAD WITH RESPECT TO THE TIMING DIFFERENCES GREATER THAN 12 HOURS NOTED IN THE GEFS SPAGHETTI PLOTS FOR THE PERIOD. GIVEN THE FAIRLY COLD TEMPS ALOFT LEADING TO SOME DESTABILIZATION AND PV ADVECTION...THINK THERE IS AT LEAST A SMALL THREAT FOR PRECIPITATION AS IT PASSES. HOWEVER WITH AFOREMENTIONED UNCERTAINTY WITH RESPECT TO TIMING...CAN NOT REALLY JUSTIFY ANY MORE THAN SLIGHT PROBABILITIES AT THIS POINT FOR SATURDAY AND SATURDAY NIGHT...ALTHOUGH SLIGHTLY PREFER A SLOWER SOLUTION WHICH WOULD IMPACT AREA MORE ON SATURDAY NIGHT. -JRM SUNDAY THROUGH WEDNESDAY...MODELS ARE CONTINUING TO COME INTO BETTER AGREEMENT WITH TRACK OF THE UPPER LEVEL CLOSED FOR THIS PERIOD. CURRENT GUIDANCE HAS THE CLOSED LOW MOVING OVER THE AREA SUNDAY. PLACED IN SLIGHT CHANCES FOR THE EASTERN PART OF THE AREA WHERE ISENTROPIC LIFT AND 5-7H FRONTOGENESIS DEVELOP AHEAD OF THE CLOSED LOW AS IT MOVES THROUGH. AN UPPER LEVEL TROUGH JUST BEHIND THE CLOSED LOW WILL ALSO LIFT NORTHEAST SUNDAY NIGHT INTO MONDAY...BUT WILL REMAIN WELL SOUTH OF THE AREA. MONDAY A SHORT WAVE RIDGE MOVES IN BEHIND THE CLOSED LOW. TUESDAY AND WEDNESDAY THE UPPER LEVEL FLOW TURNS TO THE SOUTHWEST...BRINGING DRY AIR OVER THE AREA WHILE A SHORTWAVE TROUGH MOVES ACROSS THE NORTHWEST CONUS. TEMPERATURES FOR THE PERIOD WILL BE ABOVE NORMAL...WITH HIGHS AROUND 70 AND LOWS AROUND 40 BY THE START OF THE WORK WEEK. && .AVIATION...(FOR THE 21Z TAFS THROUGH 21Z FRIDAY AFTERNOON) ISSUED AT 1243 PM MST THU MAR 8 2012 VFR CONDITIONS EXPECTED THROUGH THE PERIOD. NORTHERLY WINDS WILL CONTINUE TO GRADUALLY DIMINISH THROUGH SUNSET. A FEW HIGH CLOUDS ARE SPILLING NORTH FROM A SYSTEM IN THE FOUR CORNERS. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...NONE. KS...NONE. NE...NONE. && $$ UPDATE...JRM SHORT TERM...JRM LONG TERM....JRM/JTL AVIATION...024
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST THU MAR 8 2012 .SYNOPSIS... ISSUED AT 537 AM EST THU MAR 8 2012 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS FROM NW ONTARIO THROUGH WRN MN INTO ERN NEBRASKA. A BAND OF LIGHT SNOW MOVING QUICKLY THROUGH THE ERN CWA WAS SUPPORTED BY 700-600 MB FGEN BEHIND THE COLD FRONT THAT EXITED UPPER MI TO THE SE. OTHERWISE...JUST A FEW FLURRIES REMAINED OVER CNTRL UPPER MI. AN UPSTREAM SHRTWV WAS MOVING FROM SE SASK TOWARD SRN MANITOBA. AT THE SFC..NW WINDS PREVAILED BTWN A TROUGH FROM QUEBEC TO LAKE HURON AND A RIDGFROM THE NRN PLAINS INTO NW ONTARIO. THE CLIPPER LOW ASSOCIATED WITH THE CLIPPER SHRTWVWAS LOCATED OVER N CNTRL MANTIOBA WITH A TRAILING COLD FRONT TO THE SW. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 537 AM EST THU MAR 8 2012 TODAY...EXPECT THE MID LEVEL TROUGH MOVING INTO THE AREA BY AFTERNOON TO BE REINFORCED BY THE SASK SHRTWV BY LATE TODAY. THE COMBINATION OF INCREASING 700-500 MB QVECTOR CONV...DEEPER MOISTURE...DAYTIME HEATING AND STEEP 900-700 MB LAPSE RATES NEAR 8 C/KM WILL SUPPORT SCT SHSN DEVELOPMENT THIS AFTERNOON WHICH WILL INCREASE IN COVERAGE AND INTENSITY LATE. TONIGHT...SHSN WILL TRANSITION TO LES AS COLDER AIR ARRIVES (850 MB TEMPS ARE FCST TO DROP INTO THE -14C TO -18C RANGE) AND WINDS VEER TO THE NW. AS THE WINDS VEER THE STRONGER LOW LEVEL CONV WILL SHIFT FROM WRN UPPER MI INTO THE NE CWA E OF MARQUETTE. WITH FAVORABLE 850-700 MB MOISTURE AND INVERSION HEIGHTS TO NEAR 10K FT...SOME STRONGER SNOWBANDS MAY DEVELOP WITH BRIEF HEAVY SNOW. HOWEVER...GIVEN THE SHIFTING LOCATION OF THE BANDS...OVERALL ACCUMULATIONS SHOULD STILL REMAIN IN THE 1 TO 3 INCH RANGE. WITH THE LONGER FETCH INTO THE EAST...SOME ISOLATED HIGHER AMOUNTS TO AROUND 4 INCHES MAY BE POSSIBLE NEAR OR JUST INLAND FROM GRAND MARAIS. GUSTY NORTHWEST WINDS INTO THE 20 TO 30 MPH RANGE NEAR LAKE SUPERIOR WILL ALSO CAUSE AREA OF BLSN. FRIDAY...LES WILL DIMINISH FROM THE WEST AS DRIER AIR MOVES INTO THE REGION ALONG WITH ACYC FLOW AND LOWERING INVERSION HEIGHTS AND (AOB 4K FT). HOWEVER...ADDITIONAL AMOUNTS IN THE 1 TO 3 INCH RANGE MAY BE POSSIBLE OVER THE EAST AS THE 850 MB THERMAL TROUGH (850 MB TEMPS AROUND -18C) LINGERS INTO THE EARLY AFTERNOON. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 537 AM EST THU MAR 8 2012 ...RAIN FOLLOWED BY SIGNIFICANT WARM-UP EARLY-MID NEXT WEEK MAY RESULT IN HYDRO ISSUES... NOTE: SEE LATER PORTION OF THIS LONG TERM DISCUSSION FOR THOUGHTS ON POSSIBLE HYDROLOGY ISSUES. POP/WX WISE IT IS PRETTY QUIET FRIDAY NIGHT THROUGH SATURDAY NIGHT. WARM AIR ADVECTIONS RAMPING UP AGAIN COULD LEAD TO BATCH OF LGT SNOW OVR LK SUPERIOR AND PERHAPS THE FAR NORTHERN FRINGE OF THE CWA. OTHERWISE JUST A PERIOD OF MID CLOUDS. MAIN STORY FRIDAY NIGHT INTO SATURDAY WILL BE GUSTY SOUTH TO SOUTHWEST WINDS. TREND THAT BEGAN TO APPEAR IN MODELS YESTERDAY CONTINUES TODAY. AS HIGH PRESSURE RIDGE MOVES EAST FRIDAY NIGHT SFC TROUGH OVR CNTRL CANADA WILL STEAMROLL EAST BY SUNRISE SATURDAY. TIGHT PRESSURE GRADIENT ENSUES AND VERY STRONG PRESSURE FALLS /OVR 12MB IN 6 HR/ ARE FCST NORTH OF LK SUPERIOR. PATTERN SUGGESTS THAT DESPITE WARM AIR ADVECTION REGIME...SOUTH TO SOUTHWEST WINDS COULD BECOME QUITE GUSTY. FCST SOUNDINGS INDICATE A LOT OF WIND JUST ABOVE SFC /50+ KTS AT 925MB PER GFS/ECMWF/NAM/ BUT IT IS STABLE. BLYR WINDS USUALLY DO A GOOD JOB HIGHLIGHTING HOW STRONG WINDS COULD GET AND THIS OUTPUT POINTS TO SOLID 35-40 KTS. GALES OVR LK SUPERIOR AND PROBABLY NEARSHORE ZONES OF LK MICHIGAN GOOD BET. ALSO...GOING TO MENTION SOME NEAR ADVY GUSTS IN HAZARDOUS WEATHER OUTLOOK FOR SOUTH SHORE OF LK SUPERIOR. BASED ON SFC WIND DIRECTION AND WHERE CORE OF STRONGEST WINDS IS FCST...THE SHORELINE FM BARAGA TO MARQUETTE ALONG LK SUPERIOR WOULD SEE STRONGEST WINDS. ALSO COULD SEE STRONGER WINDS OVR KEWEENAW COUNTY AS THAT AREA IS EXPOSED TO SOUTHERLY FLOW...ESPECIALLY HIGHER TERRAIN AREAS. PRESSURE FALL MOVES STEADILY TO THE EAST THROUGH THE DAY...BUT SOUNDINGS POINT TO BREEZY CONDITIONS CONTINUING FOR MUCH OF SATURDAY AS MIXING WILL BE HIGHER DUE TO MAINLY SUNNY SKIES. AS SOUTH WINDS KICK UP LATER FRIDAY NIGHT TEMPS SHOULD BEGIN TO RISE OVR MUCH OF CWA. USED NON-DIURNAL TEMP CURVE INTO SATURDAY WITH LOWS FRIDAY EVENING IN THE TEENS AND TEMPS RISING TOWARD FREEZING BY SUNRISE SATURDAY. MIXING TO H9 ON SATURDAY SEEMS PRETTY GOOD CONSIDERING AMOUNT OF INSOLATION EXPECTED. MIXING THIS HIGH GAVE READINGS INTO THE 50S OVR MOST OF THE WEST HALF OF CWA. SW WINDS WILL KEEP LK MICHIGAN AND INLAND AREAS OF EAST CWA COOLER IN THE UPR 30S TO MID 40S. IN THE EXTENDED...COULD BE AN ACTIVE WEATHER PERIOD OVR MUCH OF UPR LAKES...BUT NOT NECESSARILY FM AMOUNT OF STORM SYSTEMS. RATHER...ONE SYSTEM LOOKS TO BRING LGT MAYBE MODERATE RAIN AMOUNTS TO AREA LATER SUNDAY THROUGH SUNDAY NIGHT THEN A VERY SIGNIFICANT WARM-UP IS IN STILL LOOKS TO BE IN THE OFFING INTO THE MIDDLE OF NEXT WEEK. IF ALL GOES AS PLANNED...MOST AREAS IN THE CWA BY THIS TIME NEXT WEEK WILL HAVE LOST A MAJORITY IF NOT ALL OF THE SNOWPACK. WILL BE SOMETHING TO MONITOR INTO NEXT WEEK AS THERE COULD BE SOME HYDRO ISSUES GIVEN POTENTIAL TO MELT THE SNOW RATHER QUICKLY. LOW PRESSURE STILL FCST TO LIFT FM THE PLAINS/MISSISSIPPI RIVER VALLEY INTO THE UPR LAKES LATE SUNDAY. IN A GENERAL SENSE...THREE MAIN MODELS USED FOR THE EXTENDED /GFS/ECMWF/CANADIAN/ ALL SHOW THIS SYSTEM IMPACTING UPR MI. TIMING IS NOT SET THOUGH...AS LATEST ECMWF NOW BRINGS THE LOW MORE ACROSS LATER SUNDAY NIGHT INTO MONDAY. THIS TIMING IS CLOSER TO CANADIAN BUT STRAYS SIGNIFICANTLY FM NCEP MODELS /GFS AND NAM/. NCEP PREFERRED SLOWER APPROACH AS THERE COULD BE SOME BLOCKING AHEAD OF THE FEATURE. TRENDED THIS WAY IN GRIDS. HIGHEST CHANCES SUNDAY NIGHT STILL LOOKED FINE. MAIN CHANGE TO CONSENSUS ALLBLEND APPROACH WAS TO KEEP CHANCE POPS IN FOR ALL DAY MONDAY. ONCE THE SYSTEM CLEARS THE AREA LATER MONDAY/MONDAY NIGHT...ATTN IS ON POTENTIAL WARM-UP. SEEMS LIKE MORE OFTEN THAN NOT IN RECENT YEARS WE HAVE LOST THE SNOWPACK IN THE SPRING WITH MORE OF A GRADUAL WARM UP IN A STEADY FREEZE-THAW CYCLE /RISING ABOVE FREEZING DURING THE DAYS BUT FALLING BLO AT NIGHT/. WE SEE HOW WHEN THIS DOES NOT WORK WHAT CAN HAPPEN AS YESTERDAY AT THE OFFICE IN NEGAUNEE TWP WITH HIGHS AROUND 50 DEGREES AND DWPNTS WELL INTO THE 40S...WE LOST 8 INCHES OF OUR SNOWPACK IN ONE DAY! AFTER OUR BREAK IN THE SNOWMELT THE NEXT COUPLE DAYS...SEEMS LIKE WE COULD BE HEADING FOR SIMILAR QUICK SNOWMELT LATE THIS WEEKEND THROUGH MID NEXT WEEK. MAIN CONCERN WOULD BE TUESDAY AND WEDNESDAY AS ECMWF /WHICH FOR MOST PART USUALLY LEADS WAY ON THESE TYPE OF WARM-UPS WELL OVER CLIMATOLOGY/ INDICATES MAX TEMPS PUSHING OVER 60 DEGREES OVR AT LEAST THE WEST HALF OF THE CWA. ALLBLEND GUIDANCE /BIASED TOWARD THE GFS/ WAS MUCH COOLER AND WAS ADJUSTED UPWARD FOR BOTH DAYS. ECMWF ALSO INDICATES DWPNTS RISING ABOVE 40...ESPECIALLY ON WEDNESDAY AHEAD OF WEAK TROUGH FCST TO COME THROUGH ON THURSDAY. A COUPLE OF CAUTIONS THOUGH. LATEST ECMWF NOW TRYING TO SHOW MORE OF A TYPICAL SPRING LIKE MSLP PATTERN ON TUESDAY WITH POSSIBLE LAKE BREEZES AS MAIN TROUGH REMAINS OVR PLAINS. TRIMMED TEMPS SLIGHTLY TOWARD LK SUPERIOR SHORE FOR TUESDAY...WITH BETTER SHOT OF THE REALLY WARM TEMPS STAYING INLAND TOWARD WI BORDER. TROUGH IS CLOSE ENOUGH ON WEDNESDAY TO RESULT IN MAINLY SW FLOW FOR ALL AREAS AND ALLOWING THE WARM TEMPS RIGHT TO PUSH TO THE LK SUPERIOR SHORE AS WELL ALONG WITH DWPNTS RISING WELL ABOVE 40F. OBVIOUSLY GIVEN THIS KIND OF MOISTURE ADVECTION AND THE MELING SNOWPACK ONGOING...SOME STRATUS/FOG IS NOT OUT OF QUESTION WHICH WOULD IMPACT TEMPS. STILL QUESTIONS IN SPECIFICS BUT THIS TIME FRAME COULD POSE SOME ISSUES WITH REGARD TO RISES ON RIVES/STREAMS AND SOME AREAL FLOODING CONCERNS IN LOW-LYING SPOTS AS WELL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1232 PM EST THU MAR 8 2012 AN APPROACHING DISTURBANCE/STEEP LAPSE RATES/DAYTIME HEATING WILL LIKELY LEAD TO SCT/NMRS -SHSN LATER THIS AFTN INTO THE EVENING HRS. MVFR CONDITIONS SHOULD GENERALLY PREVAIL...THOUGH SOME BRIEF PERIODS OF IFR MAY OCCUR DEPENDING ON INTENSITY OF -SHSN. SHSN WILL TRANSITION TO LES AS COLDER AIR MOVES IN TONIGHT BUT SHOULD MAINLY AFFECT KCMX. NORTHWEST WINDS WILL ALSO INCREASE LATE THIS EVENING AND OVERNIGHT WITH BLSN ALSO DEVELOPING AT KCMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 537 AM EST THU MAR 8 2012 A COUPLE OF PERIODS OF GALES ON THE LAKE INTO THIS WEEKEND. FIRST GALE EVENT IS TONIGHT WITH COLD AND UNSTABLE PROFILE OVER THE LAKE. SHOULD SEE FREQUENT GUSTS 35-40 KTS AND HAVE ISSUED GALE WARNING FOR ALL OF LK SUPERIOR INTO EARLY FRIDAY. HAVE ALSO POSTED HEAVY FREEZING SPRAY WARNING FOR TONIGHT. NOT OUT OF QUESTION THAT THIS MAY BE LAST HEAVY FREEZING SPRAY EPISODE OF WINTER. SOUTH TO SOUTHWEST GALES THEN LOOK LIKELY LATER FRIDAY NIGHT INTO SATURDAY AS PRESSURE GRADIENT TIGHTENS OVER LK SUPERIOR. WARM AIR ADVECTION REGIME KEEPS HIGHER STABILITY IN LOW-LEVELS...BUT THINK THIS WILL BE OFFSET BY VERY STRONG PRESSURE FALLS SLIDING JUST NORTH OF LK SUPERIOR. SETUP USUALLY RESULTS IN STRONGEST WINDS OVER EASTERN HALF OF LK SUPERIOR. WINDS SETTLE DOWN CONSIDERABLY BY LATER SATURDAY NIGHT INTO SUNDAY. WIND DIRECTION LATER SUNDAY INTO MONDAY WILL BE HIGHLY DEPENDANT ON TRACK OF APPROACHING LOW PRESSURE SYSTEM FM CENTRAL PLAINS. EXPECT WINDS TO REMAIN LESS THAN 30 KTS AS THE SYSTEM MOVES THROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 4 AM TO 11 AM EST FRIDAY FOR LSZ267. GALE WARNING FROM 1 AM TO 11 AM EST FRIDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ FRIDAY FOR LSZ162-240>245- 248-263>265. GALE WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 6 AM EST /5 AM CST/ FRIDAY FOR LSZ162-263. GALE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EST FRIDAY FOR LSZ264- 265. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB SHORT TERM...JLB LONG TERM...JLA AVIATION...TITUS MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1141 AM CST THU MAR 8 2012 .AVIATION...18Z TAF ISSUANCE... TEMPORARY RIDGING CROSSING CWA LATE THIS MORNING. VFR AT ALL TERMINALS EXCEPT KBRD WHERE EARLIER SYSTEM HAS LEFT MVFR CEILINGS. STRONG WINDS ALOFT BEGINNING TO MIX DOWN WITH DAYTIME WARMING OF BDRY LYR. VIGOROUS COLD FRONT/UPPER SYSTEM APPROACHING THE CWA QUICKLY AND EXPECT A BURST OF MDT/POSSIBLY HEAVY SNOW TO ACCOMPANY THIS SYSTEM THIS AFTN. USED TEMPO DUE TO FAST MOVING NATURE OF FEATURE AND EXPECT IFR DURING THE SNOW. RAPID CLEARING EXPECTED THIS EVENING FROM WEST TO EAST AS DEEP LAYER DRYING OCCURS BEHIND FRONT. && .PREV DISCUSSION... /ISSUED 1000 AM CST THU MAR 8 2012/ UPDATE... ADDED SCATTERED SNOW SHOWERS ACROSS THE SRN COUNTIES THIS MORNING TO ACCOUNT FOR A SMALL CLUSTER OF SNOW SHOWERS MOVING FROM E-CNTRL MN INTO WI. STILL ANTICIPATING THE CONVECTIVE SNOW SHOWERS TO DEVELOP THIS AFTERNOON...AND AFTER LOOKING AT THE LATEST HIGH- RES SHORT TERM MODELS...LOOKS VERY UNSTABLE IN THE LOW AND MID LEVELS... WITH STEEP LAPSE RATES AND 50-80 J/KG OF LOW-LVL CAPE...AND ALSO VERY SUPPORTIVE ALOFT FOR A QUICK INCH OF SNOW ACCUMULATION. WINDS WILL INCREASE FROM THE NW THIS AFTERNOON...AND COMBINE WITH THE SNOW SHOWERS TO PRODUCE AREAS OF BLOWING SNOW. VISIBILITIES COULD BE REDUCED TO A MILE OR LESS AT TIMES IN THE BLOWING SNOW. A STRONG 140KT JET WILL PUSH IN FROM THE NW...WITH THE NORTHLAND IN THE LEFT EXIT REGION...ALSO A STRONG 500MB VORT MAX WILL ADVECT INTO THE REGION TO HELP WITH VERTICAL MOTION. SYSTEM SHOULD MOVE THROUGH VERY RAPIDLY AS HIGH PRESSURE BUILDS IN ON THE BACK SIDE. PREV DISCUSSION... /ISSUED 654 AM CST THU MAR 8 2012/ AVIATION.../12Z TAF ISSUANCE/ ANOTHER COLD FRONT WILL TRACK SEWD ACROSS THE NORTHLAND THIS AFTERNOON AND EVENING...BRINGING INCREASING CLOUD COVER AND AREAS OF LIGHT SNOW TO THE REGION. CIGS AND VSBYS ASSOCIATED WITH THE FROPA WILL BE IN THE MVFR/LOW VFR RANGE. THE SNOW SHOULD END LATE THIS EVENING OVER OVERNIGHT AND SKIES WILL SCTR OUT. PREV DISCUSSION... /ISSUED 403 AM CST THU MAR 8 2012/ SHORT TERM...THE SHORT TERM FOCUS IS ON WINDS AND SNOW SHOWER POTENTIAL ACROSS THE NORTHLAND. AT 330 AM...FAIRLY WIDESPREAD CLOUD COVER WAS MOVING ACROSS THE NORTHLAND ALTHOUGH THERE WERE SEVERAL AREAS OF THIN CLOUDS. TEMPERATURES RANGED FROM THE UPPER 20S IN PORTIONS OF NW WI...TO NEAR 10 ABOVE FAR NORTHWEST. NORTHWEST FLOW WILL PERSIST ACROSS THE NORTHLAND TODAY. STRONG CAA WILL BECOME FAIRLY NEUTRAL THROUGHOUT THE DAY. THE NAM INDICATES THAT AT LEAST A COUPLE SHORTWAVES WILL MOVE THROUGH THE REGION IN NW FLOW TODAY. EACH WILL BE CAPABLE OF GENERATING SOME SNOW SHOWERS...BUT THE BEST CHANCE SHOULD BE ACROSS THE NORTH IN THE AFTERNOON AND EARLY EVENING. WITH COLD AIR ALOFT AND SOME SURFACE HEATING BETWEEN SNOW SHOWERS...THINK SOME OF THE SNOW SHOWERS COULD BE FAIRLY STRONG THIS AFTERNOON...EVEN BRINGING SOME GUSTY WINDS WITH THE SNOW SHOWERS. THE BIGGER STORY FOR TODAY MAY BE THE STRONG WINDS EXPECTED TO MOVE INTO THE CWA DURING THE AFTERNOON AND EVENING. HAVE BROUGHT WINDS UP QUITE A BIT. THE RUC SHOWS STRONG WINDS ALOFT MIXING DOWN TO THE SURFACE. THE FORECAST SOUNDINGS FOR DULUTH INDICATE 40-50 KNOTS WORKING ITS WAY TO JUST ABOVE THE SURFACE. AS A RESULT...WE COULD EASILY SEE SOME 20 TO 30 MPH SUSTAINED WINDS THIS AFTERNOON WITH HIGHER GUSTS AS WELL. WINDS WILL THEN DECREASED OVERNIGHT AS SKIES CLEAR FROM THE WEST. HAVE DROPPED TEMPS CONSIDERABLY FOR TONIGHT...CLOSER TO THE MAV GUIDANCE. THIS SHOULD RESULT IN TEMPERATURES DROPPING BELOW ZERO IN THE NORTH. FRIDAY SHOULD BE A BIT WARMER...AS WAA PUSHES ACROSS THE REGION. SHOULD BE SOMEWHAT OF AN INCREASE IN CLOUDS...ESPECIALLY IN THE NORTH. THINK MOST OF THE PRECIPITATION SHOULD REMAIN IN CANADA. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. THE EXTENDED FORECAST PERIOD WILL START OUT DRY AND MILD UNDER WITH A UPPER RIDGE BUILDING OVER THE WRN GREAT LAKES DUE TO STRONG SWRLY FLOW IN THE LOW-LEVELS. HOWEVER THE RIDGE WILL GIVE WAY TO A LOW PRESSURE SYSTEM DEVELOPING OVER THE CNTL PLAINS WHICH IS PROGGED TO LIFT NEWD OVER THE GREAT LAKES SUNDAY INTO MONDAY. THERE ARE STILL SOME SIGNIFICANT DIFFERENCES BETWEEN THE VARIOUS NWP MODEL SOLUTIONS...WITH THE NAM/GFS TAKING THE LOW OFF TO THE SOUTH AND EAST OF OUR CWA...WHILE THE ECMWF/GEM BRING IT RIGHT OVER THE NORTHLAND. DUE TO THESE DIFFERENCES...WE WILL KEEP POPS IN THE CHANCE CATEGORY ATTM. PRECIP TYPE SHOULD BE MAINLY RAIN DUE TO THE WARM AIRMASS IN PLACE ACROSS THE UPPER MIDWEST. BUT IF THE DYNAMIC LIFT IS STRONG ENOUGH...THERE COULD BE A WINTRY MIX SUNDAY NIGHT AND MONDAY MORNING. AFTER THE LOW MOVES OFF TO THE EAST...AN UNSEASONABLY WARM AND DRY PATTERN WILL DEVELOP ACROSS THE NORTHLAND NEXT WEEK AS SOUTHWEST FLOW DOMINATES ACROSS THE CTRL PART OF THE COUNTRY THROUGH WEDNESDAY. AVIATION.../06Z TAF ISSUANCE/ MVFR AND ISOLATED IFR IN CLOUDS AND SNOW IN A FRONTAL BAND SHOULD MOVE OUT OF THE IWD AND GOGEBIC RANGE AREA LATE TONIGHT. MN NORTH SHORE AND REST OF NORTHWEST WISCONSIN...MVFR IN CLOUDS IMPROVING TO VFR SCATTERED WITH AREAS OF BROKEN CLOUDS BY DAY BREAK THURSDAY MORNING. THE REST OF NORTHEAST MN...VFR THROUGH EARLY MORNING. AREAS OF LOW-END VFR IN CLOUDS WILL DEVELOP MIDMORNING ACROSS COASTAL WI AND NORTH OF ROUTE 2 IN NORTHEAST MN AFTER MIDMORNING THURSDAY...AND PERSIST TILL LATE THURSDAY AFTERNOON. VFR CLEAR BEGINNING THURSDAY EVENING. BRISK NORTHWEST WINDS...GUSTING TO 30 MPH...WILL CONTINUE INTO LATE THURSDAY AFTERNOON...AND SUBSIDE DURING THURSDAY EVENING. && .POINT TEMPS/POPS... DLH 31 7 29 25 / 30 30 0 10 INL 31 -5 32 22 / 40 20 10 10 BRD 34 5 35 29 / 30 10 0 0 HYR 33 5 33 27 / 30 30 0 10 ASX 34 10 30 25 / 30 30 0 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ AVIATION...CANNON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
ISSUED BY NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 1143 AM CST THU MAR 8 2012 .UPDATE... ISSUED AT 707 AM CST THU MAR 8 2012 HAVE UPDATE SHORT TERM FORECAST TO REFLECT DRYING TREND OVER THE NORTHERN PART OF THE CWA. ALSO MENTIONED THE CHANCE FOR SNOW OR SLEET THIS MORNING IN CENTRAL MISSOURI AS THE CURRENT OB AT KSZL HAS -PL. OTHERWISE...REST OF FORECAST STILL HOLDS. BRITT && .SHORT TERM... ISSUED AT 316 AM CST THU MAR 8 2012 (TODAY AND TONIGHT) COLD FRONT HAS MOVED ABOUT HALFWAY THROUGH THE CWA AND IS CURRENTLY ENTERING THE NORTHWESTERN PART OF THE ST. LOUIS METRO AREA. SHOWERS AND SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG AND AHEAD OF THE FRONT IN A BROAD AREA OF 950-850MB MOISTURE CONVERGENCE. THIS MOISTURE CONVERGENCE IS COINCIDENT WITH LARGE SCALE ASCENT FROM MID-LEVEL CURRENTLY PASSING THROUGH THE UPPER MIDWEST. A SECOND LARGER AREA OF PRECIPITATION IS MOVING ACROSS WESTERN MISSOURI WHICH IS BEING GENERATED BY THE LARGE SCALE ASCENT ON THE TAIL END OF THE TROUGH AND A LITTLE STRONGER LOW LEVEL CONVERGENCE ON THE NOSE OF A 50KT LOW LEVEL JET OVER THE PLAINS. THIS FORCING WILL CONSOLIDATE THROUGH THE MORNING PER THE RUC AS THE LOW LEVEL JET VEERS WITH TIME. THIS SHOULD BE ENOUGH TO KEEP LIKELY OR CATEGORICAL RAIN CHANCES GOING FOR ABOUT THE SOUTHERN TWO-THIRDS OF THE CWA EARLY THIS MORNING...WITH A GRADUAL DIMINISHING TREND THROUGH THE DAY AS THE FORCING PUSHES SOUTH AND EAST. THERE SHOULD BE ENOUGH INSTABILITY TO KEEP AT LEAST A MENTION OF SCATTERED THUNDERSTORMS THIS MORNING ALONG AND AHEAD OF THE 850MB COLD FRONT. CAN`T RULE OUT THE POTENTIAL FOR SOME SNOW OR SLEET ON THE NORTHERN FRINGE OF THE PRECIPITATION WHERE RUC SOUNDINGS ARE SHOWING THE LOW LEVEL THERMAL PROFILES COOLING NEAR 0C ABOUT THE TIME THAT THE PRECIPITATION ENDS. THINK THIS WILL BE A SHORT LIVED EVENT AND MAINLY FOUND WHERE CONVECTION IS MORE CONCENTRATED. TONIGHT SHOULD BE DRY AS SUBSIDENCE SETS IN BEHIND THE NORTHERN STREAM TROUGH. TEMPERATURES SHOULD REMAIN STEADY OR SLOWLY FALL THROUGH THE DAY OVER THE SOUTHERN HALF OF THE CWA EXTENSIVE CLOUD COVER AND DECENT COLD AIR ADVECTION BEHIND THE FRONT. GFS MOS TEMPERATURES LOOK A BIT TOO WARM TONIGHT GIVEN THE MAINLY CLEAR SKIES AND WINDS TURNING LIGHT AS THE SURFACE RIDGE SETTLES INTO THE AREA. BRITT && .LONG TERM... ISSUED AT 330 AM CST THU MAR 8 2012 (FRIDAY THROUGH NEXT WEDNESDAY) SFC HIGH BUILDS IN BEHIND THE DEPARTING CDFNT ON FRI WITH DRY WX EXPECTED ON FRI AND MOST OF SAT BEFORE ANOTHER ROUND OF PCPN DVLPS ON SAT NIGHT AS AN UPPER LOW OVER AZ/NM BEGINS LIFTING NEWD THROUGH THE CENTRAL CONUS. MODELS CONTINUE TO STRUGGLE WITH HOW AND WHEN THIS LOW LIFTS NEWD. THE PREVIOUS FOUR RUNS OF THE ECMWF WERE EVENLY SPLIT BETWEEN KEEPING THE VORT CENTER INTACT /00Z RUNS ON MARCH 7TH AND 8TH/ AND SPLITTING IT INTO TWO VORT MAXES /12Z RUNS ON MARCH 6TH AND 7TH...SIMILAR TO WHAT THE GFS HAS BEEN DEPICTING FOR THE LAST SEVERAL DAYS/. 08/00Z GEM REMAINS SIMILAR TO THE 07/00Z RUN AND SHOWS THE LOW RETROGRADING TO BAJA CA THEN MOVING THROUGH MEXICO BEFORE LIFTING THROUGH TX AND INTO NWRN MO. THESE LARGE DIFFERENCES BETWEEN THE 3 MODELS APPEAR TO STEM FROM DIFFERENT HANDLING OF THE INTERACTION BETWEEN THE CLOSED LOW AND A SUBTLE AREA OF ENHANCED VORTICITY THAT SHOULD BE MOVING THROUGH ID/NV AT 08/12Z. DESPITE THE DIFFERENT DETAILS...MODEL SOLUTIONS ALL SUGGEST ANOTHER ROUND OF PCPN SOMEWHERE BETWEEN SAT NIGHT AND MON AS THE CLOSED LOW /OR ITS REMNANTS/ FINALLY LIFTS NEWD. WAA SHRA EXPECTED TO DVLP FIRST FOLLOWED BY AN INCREASE IN PCPN COVERAGE AS LARGE SCALE LIFT INCREASES WITH THE APPROACHING VORT MAX. MODELS ARE OFTEN TOO QUICK TO BRING A CLOSED LOW BACK INTO THE PREVAILING FLOW THEREFORE I WOULD NOT BE SURPRISED IF THIS OVERALL FCST SCENARIO ENDS UP BEING DELAYED BY A DAY OR SO AS THE MODELS CATCH UP TO THE ATMOSPHERE. KANOFSKY && .AVIATION... ISSUED AT 1141 AM CST THU MAR 8 2012 AREAS OF RAIN SHIFTED SOUTH OF THE TERMINALS THIS MORNING AS DRY AIR WITHIN THE GREATS LAKES TROUGH SHIFTED INTO NORTHERN MISSOURI. THIS HAS ALSO BROUGHT HIGHER CEILINGS TO THE TERMINALS...WITH VFR CONDITIONS PREVAILING AT ALL THE TERMINALS NOW. EXPECT THE VFR CONDITIONS TO PREVAIL THROUGH THE NEXT 30 HOURS. TERMINALS IN THE VICINITY OF THE ILLINOIS-MISSOURI BORDER WILL CONTINUE TO EXPECT GUSTY WINDS THROUGH THE EARLY AFTERNOON HOURS...THOUGH TOWARDS THE MID TO LATE AFTERNOON HOURS WIND CONDITIONS SHOULD CALM TO AROUND 12 KNOTS AS THE COOL DOME OF HIGH PRESSURE OVERSPREADS THE REGION. OVERNIGHT...VFR CONDITIONS WILL PERSIST AND THE WIND WILL SETTLE TO AROUND 5 KNOTS FROM THE NORTHWEST. SPECIFICS FOR KSTL... VFR CONDITIONS EXPECTED TO PREVAIL AT THE KSTL TERMINAL THROUGH THE NEXT 30 HOURS. ONLY ITEM TO WATCH FOR WILL BE THE SHIFT IN WIND TOWARDS THE LATE PERIODS OF THE TAF CYCLE. OVERNIGHT WINDS WILL CALM TO AROUND 5 KNOTS FROM THE NORTHWEST...BUT DURING THE MID TO LATE MORNING HOURS FRIDAY EXPECT THE WIND TO PICK UP IN SPEED AND SHIFT CLOSER TO DUE NORTH. CUTTER && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1020 AM CST THU MAR 8 2012 .DISCUSSION... MAIN CHALLENGES REMAIN MAX TEMPS AND FRONTAL PASSAGE WITH -SN/BLSN. COLD FRONT NOW STARTING TO ENTER THE NW PORTION OF THE FORECAST AREA WITH -SN REDUCING VISIBILITIES. MODEL SOUNDINGS STILL SHOW AN ADIABATIC LAYER IN THE LOW LEVELS SO WIND FORECAST REMAINS GOOD. EXPECT TEMPS TO LEVEL OFF A BIT AFTER 18Z WHEN THE COLD ADVECTION IS EXPECTED TO BEGIN PUSHING IN TO THE NORTHERN AREAS. AVIATION... MAINLY VFR CONDS THIS MORNING WILL LOWER TO MVFR THIS AFTN WITH THE APPROACH OF THE COLD FRONT. NW WINDS WILL INCREASE IN ALL AREAS THIS AFTERNOON AND GUSTS TO 35KT WILL BE POSSIBLE. THERE COULD BE SOME BLSN IN THE NORTH THIS AFTERNOON...AND VSBYS SHOULD BE REDUCED ALONG WITH SOME SNOW SHOWERS THIS AFTERNOON. WINDS SHOULD QUICKLY SUBSIDE AFTER SUNSET. && .PREV DISCUSSION... /ISSUED 402 AM CST THU MAR 8 2012/ DISCUSSION... THE MAIN CHALLENGES WILL BE WIND AND BLOWING SNOW POTENTIAL TODAY AND TEMPS THROUGHOUT. MODELS ARE NOT HANDLING THIS INITIAL SNOW BAND OVER THE REGION WELL AT ALL...WITH THE RUC DOING THE BEST IN THE NEAR TERM. SOME REPORTS AND RADAR INDICATING A NARROW BAND OF 1-2 INCHES FROM GRAFTON TO MINTO TO MANVEL INTO THE GRAND FORKS AREA. WILL USE A MODEL BLEND AND NOT WARM THINGS UP TOO QUICKLY WITH STILL A DECENT SNOW PACK OVER THE REGION. FOR TODAY...SEVERAL SHORTWAVES WILL ROTATE THROUGH THE REGION. A COLD FRONT WILL PASS THROUGH THE AREA THIS AFTERNOON...ALONG WITH ABOUT 40-50KT TO MIX THROUGHOUT THE ENTIRE FORECAST AREA. A STRONG PRESSURE RISE WILL ALSO COME DOWN THE VALLEY...SO EXPECT WINDY CONDITIONS THIS AFTERNOON WITH GUSTS TO 40 MPH LIKELY. WILL ISSUE A WINTER WEATHER ADVISORY FOR THE NORTHERN VALLEY WITH SOME SNOW THIS MORNING...AND SNOW SHOWERS WITH THE FRONT SO THERE IS FRESH SNOW TO BLOW AROUND. THE STRONG WINDS SHOULD CAUSE BLOWING SNOW AND OPEN COUNTRY VSBY ISSUES...ESPECIALLY WHEN SNOW SHOWERS COMBINE WITH INCREASING WINDS THIS AFTERNOON. WILL GO WITH A WIND ADVISORY FOR THE REST OF THE REGION FROM 18Z-00Z. TEMPS WON/T WARM TOO MUCH GIVEN COLD FRONT AND INCREASING CLOUDS AND ISOLATED SNOW SHOWERS. FOR TONIGHT...SFC HIGH SETTLES OVER THE REGION AND IT WILL GET COLD IN THE EAST...WHERE TEMPS SHOULD DIP BELOW ZERO. EXPECT WARMER TEMPS TO THE WEST WITH RETURN FLOW BEGINNING AFTER 06Z. ON FRI...SOUTHERLY WINDS WILL INCREASE...ALTHOUGH WITH A COLD START TEMPS WON/T GET TOO WARM IN THE VALLEY. HAVE LOWERED TEMPS SOME FROM PREVIOUS FORECAST ALTHOUGH WITH SUNSHINE EXPECT AT LEAST SOME MELTING. ON SAT/SUN...MORE OF A WESTERLY SFC FLOW AND WARMING THERMAL FIELDS AT ALL LEVELS WILL MEAN TEMPS WELL ABOVE NORMAL. EXPECT THE WARMEST READINGS IN THE WEST AND TREED AREAS IN THE EAST...WITH COLDER READINGS ON THE VALLEY FLOOR. ON MON...ANY PRECIP SHOULD REMAIN SOUTH OF THE AREA AND WILL KEEP IT DRY WITH WARM WEATHER CONTINUING NEXT WEEK. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ028>030-038-039- 049-052-053. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ006>008-014>016-024-026-027-054. MN...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ002-003-006-009- 016-017-022>024-027>032-040. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ001- 004-005-007-008-013>015. && $$ HOPKINS
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
245 PM CST THU MAR 8 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT A COLD FRONT IS CURRENTLY MOVING SOUTHEAST OUT OF ND THIS AFTERNOON. COMBINED WITH MOSTLY CLEAR SKIES AS HIGH PRESSURE BUILDS INTO THE DAKOTAS TONIGHT AND SNOW COVER ON THE GROUND...TEMPS WILL FALL INTO THE SINGLE DIGITS TO LOWER TEENS IN THE EAST. WHERE GROUND IS BARE...EXPECT LOWS TO DROP INTO THE UPPER TEENS TO MID 20S. WINDS WILL DIMINISH BETWEEN 0Z AND 03Z AFTER THE FROPA. UNTIL THEN STRONGEST WINDS WILL BE BETWEEN 21Z AND 0Z. MOST AREAS WILL STAY BELOW ADVISORY CRITERIA..THOUGH THE 17Z RUC INDICATES THAT CORSON COUNTY AND LOCAL AREAS IN THE FAR NORTHEAST CORNER MAY BRIEFLY SEE SUSTAINED WINDS NEAR 30 MPH. DECIDED THE IMPACT WAS NOT SUFFICIENT ENOUGH TO MERIT AN ADVISORY. AT THIS POINT SNOW PACK IS WET AND HEAVY ENOUGH TO LIMIT ANY BLOWING SNOW. WITH DRY WEATHER AND A WARMING TREND CONTINUING THROUGH SATURDAY...WILL NEED TO KEEP AN EYE ON ANY FIRE WEATHER CONCERNS IN SNOW FREE AREAS ACROSS CENTRAL SD. EXPECT SURFACE TEMPS TO CLIMB INTO THE LOWER 50S IN THE EAST TO LOWER 70S IN SOUTHCENTRAL SD BY SATURDAY AS H85 TEMPS RISE TO NEAR +13. .LONG TERM...SUNDAY THROUGH THURSDAY AS THE PERIOD OPENS...THERE IS A LONGWAVE RIDGE OF HIGH PRESSURE POSITIONED OVER THE WESTERN CONUS /ESPECIALLY THE PAC NW/ AND A CUT-OFF LOW SPINNING/MEANDERING OVER THE DESERT SW. BY MONDAY...THIS CUT-OFF LOW IS FINALLY EJECTING OUT OF THE SWRN CONUS ACROSS THE CENTRAL AND NORTHERN PLAINS. TEMP-WISE...CURRENT SOLUTIONS SUGGEST IT WILL BE WARM ENOUGH THAT ANY PRECIPITATION COMING INTO THE FAR EASTERN CWA SUNDAY NIGHT OR MONDAY IN ASSOCIATION WITH THIS LOW WOULD BE RAIN. THE REMAINDER OF THE LONG TERM SEES THE UPPER RIDGE ACROSS THE WEST REPOSITION TO THE EASTERN GREAT LAKES/EASTERN CONUS...WHILE A BROAD LONGWAVE TROF DEVELOPS ACROSS THE WEST COAST WITH VARIOUS TRANSIENT S/WS PROGGED TO WORK INLAND ACROSS WASHINGTON..IDAHO AND MONTANA BEFORE BEING REDIRECTED NORTH AND EAST ACROSS NORTH DAKOTA...NORTHERN MN AND SC CANADA. LARGELY...THIS CWA IS NOT EXPECTED TO RECEIVE MEASURABLE PRECIPITATION BETWEEN MONDAY NIGHT AND THURSDAY. OTHER THAN A COLD FRONT PROGGED TO PASS THROUGH WEDNESDAY/WEDNESDAY NIGHT BRINGING A TEMPORARY COOL DOWN...THERE SEEMS TO BE NO END IN SIGHT TO MILD...UNSEASONABLY WARM /MUCH ABOVE NORMAL/ AIR OVER THE CWA NEXT WEEK. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE EXPECTED THRU THE TAF PERIOD WITH SCT MID AND HIGH LEVEL CLOUDS AROUND FROM THIS AFTERNOON THROUGH MID-EVENING. ACROSS FAR NORTHEAST SOUTH DAKOTA...THE KABR AND KATY TERMINALS MAY BE FLIRTING WITH SOME 3000FT AGL CIGS LATE THIS AFTERNOON/EARLY THIS EVENING. OTHERWISE...SKIES SHOULD CLEAR OFF BY LATE THIS EVENING. BREEZY WESTERLY SFC WINDS THIS AFTERNOON WILL SWITCH AROUND TO THE NORTH IN THE FAR NORTHEAST CORNER OF SOUTH DAKOTA LATE THIS AFTERNOON AND INCREASE TO 20 TO 30 KNOTS FOR A FEW HOURS. KABR AND KATY MAY GET INTO THESE STRONG NORTHERLY WINDS VERY BRIEFLY EARLY THIS EVENING. MORE LIKELY...THESE TWO TERMINALS...LIKE KPIR AND KMBG...WILL JUST GRADUALLY LOOSE THE GUST CHARACTER BY EARLY THIS EVENING AS WINDS SLOWLY SWING AROUND FROM WEST TO NORTH TO EAST BY LATE TONIGHT...AND FINALLY AROUND TO THE SOUTH-SOUTHEAST BY FRIDAY MORNING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...WISE LONG TERM...DORN AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1204 PM CST THU MAR 8 2012 .UPDATE... ADJUSTED TEMPERATURES ACROSS ROBERTS/BIG STONE/TRAVERSE COUNTIES AFTER 21Z. AS A WEAK COLD FRONT MOVES OUT OF ND LATER TODAY...IT WILL CAUSE A NON-DIURNAL TEMP TREND...COOLING THINGS OFF IN THE NE. 15Z RUC INDICATES ANY ASSOCIATED LIGHT PRECIP WILL REMAIN OFF TO THE EAST OF THIS CWA SO DID NOT ADD IN ANY FLURRIES...THOUGH THEY ARE NOT COMPLETELY OUT OF THE QUESTION IF THE WAVE FOLLOWS ITS CURRENT TRAJECTORY SO WILL NEED TO KEEP AN EYE ON THAT. OTHERWISE CURRENT FORECAST LOOKS TO BE ON TRACK AND NO FURTHER CHANGES WERE MADE. SEE UPDATED AVIATION DISCUSSION BELOW. && .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH SATURDAY THE MODELS CONTINUE TO SHOW A WARM UP THROUGH THE SHORT TERM. FOR TODAY...A COUPLE SHORT WAVES WILL AFFECT THE REGION ALONG WITH A COLD FRONT. THE FIRST SHORT WAVE WAS MOVING ACROSS NORTHERN SD THIS MORNING BRINGING SOME MID LEVEL CLOUDS ALONG WITH A FEW FLURRIES IN NORTHEAST SD AND WC MN EARLY THIS MORNING. THE OTHER STRONGER SHORT WAVE WILL DROP SOUTHEAST OUT OF CANADA AND ACROSS NORTHERN MN TODAY. THE PRECIPITATION WITH THIS WAVE WILL REMAIN TO OUR NORTHEAST. THE ISSUE WITH THIS WAVE WILL BE THE COLD FRONT DROPPING IN BEHIND IT THIS AFTERNOON AND SWEEPING ACROSS EASTERN SD. AS A RESULT...WEST WINDS THIS MORNING WILL TURN NORTHWEST INTO THE AFTERNOON AND INCREASE QUITE A BIT. AS THE CAA INCREASES AND THE MIXING LAYER DEEPENS THIS AFTERNOON...EXPECT IT TO BECOME WINDY ACROSS MUCH OF NORTHEAST SD AND WC MN THIS AFTERNOON. WILL BE CLOSE TO WIND ADVISORY WINDS. HIGH TEMPERATURES WILL LIKELY BE REACHED IN ADVANCE OR JUST BEHIND THE COLD FRONT THIS AFTERNOON. LOWERED AFTERNOON HIGHS SOME EAST IN THE CWA. THE SNOW COVER ALSO REMAINS PRETTY EXTENSIVE EAST IN THE CWA WITH AMOUNTS FROM 2 TO OVER 10 INCHES. THIS WILL CONTINUE TO HAVE AN AFFECT ON HIGH TEMPERATURES INTO FRIDAY. SURFACE HIGH PRESSURE WILL PUSH IN TONIGHT WITH WINDS FALLING OFF QUICKLY EARLY THIS EVENING. THIS WILL PUSH EAST ON FRIDAY WITH WINDS TURNING SOUTH TO SOUTHWEST AND INCREASING. EXPECT MOSTLY CLEAR SKIES TONIGHT WITH LIGHT WINDS. DROPPED TEMPERATURES SOME EAST IN THE CWA FOR TONIGHT. FOR FRIDAY AND SATURDAY...THE MODELS SHOW UPPER LEVEL RIDGING BUILDING AND REMAINING OVER THE REGION AS VERY WARM 85H AIR OF OVER +10C PUSHES IN ON FRIDAY AND REMAINS THROUGH SATURDAY. FRIDAY WILL BE WARMER WITH BREEZY/WINDY SOUTHWEST WINDS WITH A TIGHT SURFACE PRESSURE GRADIENT AND INCREASING MIXING LAYER. THE SNOW COVER SHOULD STILL KEEP HIGHS IN THE MID TO UPPER 40S EAST IN THE CWA. BY SATURDAY...MUCH OF THE SNOW COVER WILL BE DIMINISHED WITH HIGHS IN THE 50S AND 60S CWA WIDE. IT WILL BE DRY THROUGH SATURDAY WITH VERY LITTLE IF ANY CLOUD COVER. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY HIGH TEMPERATURE FORECASTING IS THE MAIN CHALLENGE THROUGH THE EXTENDED PERIOD...AND DETERMINING JUST HOW WARM IT WILL GET AS VERY MILD AIR MASS STREAMS ACROSS THE NORTHERN PLAINS. 850 MB AND EVEN 925 MB TEMPS SOAR INTO THE TEENS ABOVE CELSIUS DURING SEVERAL PERIODS FROM LATE THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK. LATE THIS WEEKEND INTO EARLY NEXT WEEK...PORTIONS OF THE NORTHEASTERN CWA COULD STILL BE DEALING WITH SNOW COVER BUT EXPECT THIS TO BE QUICKLY DIMINISHING THROUGH THE TIME PERIOD. MAY NEED TO TEMPER READINGS ON SUNDAY ACROSS THE FAR NORTHEAST BUT WILL HAVE TO SEE HOW SNOW COVER MELTS UNTIL THEN. 00Z GFS STILL SHOWING A COOLING FRONTAL PASSAGE FOR TUESDAY WHICH WOULD KNOCK TEMPS BACK SOME...BUT THIS HAS NO SUPPORT FROM 00Z RUNS OF THE EC OR CANADIAN MODELS. FOR RIGHT NOW CURRENT FORECAST HIGHS ON TUESDAY ARE A FEW TICKS LOWER THEN MONDAY...BUT STILL VERY MILD NONETHELESS WITH READINGS IN THE 50S AND 60S. IN FACT...THE ENTIRE EXTENDED PERIOD IS SHAPING UP VERY MILD WITH READINGS MOSTLY IN THE 50S AND 60S...POSSIBLY EVEN A FEW LOW 70S OVER THE SOUTHWEST CWA. AS FOR PRECIPITATION...IT LOOKS DRY THROUGHOUT THE PERIOD AT THIS TIME. WILL NEED TO WATCH A SHORTWAVE THAT TRAVELS NORTHWARD ACROSS THE CENTRAL PLAINS MONDAY INTO MONDAY NIGHT. FOR THE MOST PART...MODELS HAVE KEPT THIS SYSTEM TO THE EAST THE PAST COUPLE DAYS. THE MOST RECENT RUNS OF THE EC AND CANADIAN NUDGE THIS BACK WEST NOW AND BRING WESTERN EDGE OF PRECIP SHIELD NEAR I-29 CORRIDOR. GFS REMAINS FASTER AND FARTHER EAST WITH WAVE. SOMETHING TO WATCH AS POPS MAY NEED TO BE ADDED TO THE FAR EASTERN COUNTIES IF MODELS KEEP NUDGING THIS SYSTEM FURTHER WEST. && .AVIATION... 18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE EXPECTED THRU THE TAF PERIOD WITH SCT MID AND HIGH LEVEL CLOUDS AROUND FROM THIS AFTERNOON THROUGH MID-EVENING. ACROSS FAR NORTHEAST SOUTH DAKOTA...THE KABR AND KATY TERMINALS MAY BE FLIRTING WITH SOME 3000FT AGL CIGS LATE THIS AFTERNOON/EARLY THIS EVENING. OTHERWISE...SKIES SHOULD CLEAR OFF BY LATE THIS EVENING. BREEZY WESTERLY SFC WINDS THIS AFTERNOON WILL SWITCH AROUND TO THE NORTH IN THE FAR NORTHEAST CORNER OF SOUTH DAKOTA LATE THIS AFTERNOON AND INCREASE TO 20 TO 30 KNOTS FOR A FEW HOURS. KABR AND KATY MAY GET INTO THESE STRONG NORTHERLY WINDS VERY BRIEFLY EARLY THIS EVENING. MORE LIKELY...THESE TWO TERMINALS...LIKE KPIR AND KMBG...WILL JUST GRADUALLY LOOSE THE GUST CHARACTER BY EARLY THIS EVENING AS WINDS SLOWLY SWING AROUND FROM WEST TO NORTH TO EAST BY LATE TONIGHT...AND FINALLY AROUND TO THE SOUTH-SOUTHEAST BY FRIDAY MORNING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...WISE SHORT TERM...MOHR LONG TERM...TMT AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1029 AM CST THU MAR 8 2012 .UPDATE... ADJUSTED TEMPERATURES ACROSS ROBERTS/BIG STONE/TRAVERSE COUNTIES AFTER 21Z. AS A WEAK COLD FRONT MOVES OUT OF ND LATER TODAY...IT WILL CAUSE A NON-DIURNAL TEMP TREND...COOLING THINGS OFF IN THE NE. 15Z RUC INDICATES ANY ASSOCIATED LIGHT PRECIP WILL REMAIN OFF TO THE EAST OF THIS CWA SO DID NOT ADD IN ANY FLURRIES...THOUGH THEY ARE NOT COMPLETELY OUT OF THE QUESTION IF THE WAVE FOLLOWS ITS CURRENT TRAJECTORY SO WILL NEED TO KEEP AN EYE ON THAT. OTHERWISE CURRENT FORECAST LOOKS TO BE ON TRACK AND NO FURTHER CHANGES WERE MADE. && .PREVIOUS DISCUSSION... .SHORT TERM...TODAY THROUGH SATURDAY THE MODELS CONTINUE TO SHOW A WARM UP THROUGH THE SHORT TERM. FOR TODAY...A COUPLE SHORT WAVES WILL AFFECT THE REGION ALONG WITH A COLD FRONT. THE FIRST SHORT WAVE WAS MOVING ACROSS NORTHERN SD THIS MORNING BRINGING SOME MID LEVEL CLOUDS ALONG WITH A FEW FLURRIES IN NORTHEAST SD AND WC MN EARLY THIS MORNING. THE OTHER STRONGER SHORT WAVE WILL DROP SOUTHEAST OUT OF CANADA AND ACROSS NORTHERN MN TODAY. THE PRECIPITATION WITH THIS WAVE WILL REMAIN TO OUR NORTHEAST. THE ISSUE WITH THIS WAVE WILL BE THE COLD FRONT DROPPING IN BEHIND IT THIS AFTERNOON AND SWEEPING ACROSS EASTERN SD. AS A RESULT...WEST WINDS THIS MORNING WILL TURN NORTHWEST INTO THE AFTERNOON AND INCREASE QUITE A BIT. AS THE CAA INCREASES AND THE MIXING LAYER DEEPENS THIS AFTERNOON...EXPECT IT TO BECOME WINDY ACROSS MUCH OF NORTHEAST SD AND WC MN THIS AFTERNOON. WILL BE CLOSE TO WIND ADVISORY WINDS. HIGH TEMPERATURES WILL LIKELY BE REACHED IN ADVANCE OR JUST BEHIND THE COLD FRONT THIS AFTERNOON. LOWERED AFTERNOON HIGHS SOME EAST IN THE CWA. THE SNOW COVER ALSO REMAINS PRETTY EXTENSIVE EAST IN THE CWA WITH AMOUNTS FROM 2 TO OVER 10 INCHES. THIS WILL CONTINUE TO HAVE AN AFFECT ON HIGH TEMPERATURES INTO FRIDAY. SURFACE HIGH PRESSURE WILL PUSH IN TONIGHT WITH WINDS FALLING OFF QUICKLY EARLY THIS EVENING. THIS WILL PUSH EAST ON FRIDAY WITH WINDS TURNING SOUTH TO SOUTHWEST AND INCREASING. EXPECT MOSTLY CLEAR SKIES TONIGHT WITH LIGHT WINDS. DROPPED TEMPERATURES SOME EAST IN THE CWA FOR TONIGHT. FOR FRIDAY AND SATURDAY...THE MODELS SHOW UPPER LEVEL RIDGING BUILDING AND REMAINING OVER THE REGION AS VERY WARM 85H AIR OF OVER +10C PUSHES IN ON FRIDAY AND REMAINS THROUGH SATURDAY. FRIDAY WILL BE WARMER WITH BREEZY/WINDY SOUTHWEST WINDS WITH A TIGHT SURFACE PRESSURE GRADIENT AND INCREASING MIXING LAYER. THE SNOW COVER SHOULD STILL KEEP HIGHS IN THE MID TO UPPER 40S EAST IN THE CWA. BY SATURDAY...MUCH OF THE SNOW COVER WILL BE DIMINISHED WITH HIGHS IN THE 50S AND 60S CWA WIDE. IT WILL BE DRY THROUGH SATURDAY WITH VERY LITTLE IF ANY CLOUD COVER. .LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY HIGH TEMPERATURE FORECASTING IS THE MAIN CHALLENGE THROUGH THE EXTENDED PERIOD...AND DETERMINING JUST HOW WARM IT WILL GET AS VERY MILD AIR MASS STREAMS ACROSS THE NORTHERN PLAINS. 850 MB AND EVEN 925 MB TEMPS SOAR INTO THE TEENS ABOVE CELSIUS DURING SEVERAL PERIODS FROM LATE THIS WEEKEND INTO THE MIDDLE OF NEXT WEEK. LATE THIS WEEKEND INTO EARLY NEXT WEEK...PORTIONS OF THE NORTHEASTERN CWA COULD STILL BE DEALING WITH SNOW COVER BUT EXPECT THIS TO BE QUICKLY DIMINISHING THROUGH THE TIME PERIOD. MAY NEED TO TEMPER READINGS ON SUNDAY ACROSS THE FAR NORTHEAST BUT WILL HAVE TO SEE HOW SNOW COVER MELTS UNTIL THEN. 00Z GFS STILL SHOWING A COOLING FRONTAL PASSAGE FOR TUESDAY WHICH WOULD KNOCK TEMPS BACK SOME...BUT THIS HAS NO SUPPORT FROM 00Z RUNS OF THE EC OR CANADIAN MODELS. FOR RIGHT NOW CURRENT FORECAST HIGHS ON TUESDAY ARE A FEW TICKS LOWER THEN MONDAY...BUT STILL VERY MILD NONETHELESS WITH READINGS IN THE 50S AND 60S. IN FACT...THE ENTIRE EXTENDED PERIOD IS SHAPING UP VERY MILD WITH READINGS MOSTLY IN THE 50S AND 60S...POSSIBLY EVEN A FEW LOW 70S OVER THE SOUTHWEST CWA. AS FOR PRECIPITATION...IT LOOKS DRY THROUGHOUT THE PERIOD AT THIS TIME. WILL NEED TO WATCH A SHORTWAVE THAT TRAVELS NORTHWARD ACROSS THE CENTRAL PLAINS MONDAY INTO MONDAY NIGHT. FOR THE MOST PART...MODELS HAVE KEPT THIS SYSTEM TO THE EAST THE PAST COUPLE DAYS. THE MOST RECENT RUNS OF THE EC AND CANADIAN NUDGE THIS BACK WEST NOW AND BRING WESTERN EDGE OF PRECIP SHIELD NEAR I-29 CORRIDOR. GFS REMAINS FASTER AND FARTHER EAST WITH WAVE. SOMETHING TO WATCH AS POPS MAY NEED TO BE ADDED TO THE FAR EASTERN COUNTIES IF MODELS KEEP NUDGING THIS SYSTEM FURTHER WEST. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS EXPECTED THRU TAF PERIOD WITH SCT MID AND HIGH LEVEL CLOUDS. SFC WINDS WILL INCREASE FROM WEST/NORTHWEST BY LATE MORNING INTO THE 15 TO 25 KNOT RANGE. WINDS WILL SUBSIDE AROUND SUNSET. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...WISE SHORT TERM...MOHR LONG TERM...TMT AVIATION...DORN WEATHER.GOV/ABERDEEN