Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/07/17

Area Forecast Discussion
National Weather Service La Crosse WI
948 PM CST Mon Mar 6 2017 .UPDATE... Issued at 947 PM CST Mon Mar 6 2017 Will allow Tornado Watch to expire at 10 pm as the strongest portion of the convective line has moved into Wisconsin. Will also cancel the Severe Thunderstorm Watch for Trempealeau and La Crosse Counties. UPDATE Issued at 830 PM CST Mon Mar 6 2017 As line of storms continue to move eastward late this evening, will be able to drop Tornado Watch. For now, cancelled Wabasha, Dodge, Olmsted, Mower, and Fillmore Counties in southeast MN, and Mitchell, Howard, Floyd, and Chickasaw Counties in northeast IA. UPDATE Issued at 813 PM CST Mon Mar 6 2017 Although the environment should become less favorable for severe convection into the late evening east of the Mississippi River, issued Severe Thunderstorm Watch until 08Z for remaining WI counties (sans Taylor/Clark) given mature line of thunderstorms moving into the area over the next several hours. Primary threats will be damaging wind and hail. && .SHORT TERM...(This evening through Tuesday) Issued at 334 PM CST Mon Mar 6 2017 Severe weather threat for tonight has increased across the area. Satellite imagery and surface observations show incredible clearing across much of IA/MN this afternoon under a mid-level dry slot. Low-level scouring now into the western forecast area east of I-35 and further destabilization is occurring. Currently, TSRA starting on the dry line near Omaha NE on the western gradient in CAPE. Per SPC mesoa...MLCAPES in western IA in the 1500 J/Kg and the 06.19Z RAP bring this to the I-35 corridor at 22Z before a massive hourly decline with only 800-1000 J/Kg by 00Z in Dodge MN-Floyd County IA counties. Decline and stabilization of the CAPE further occurs as the warm sector shifts east in the late evening into WI. Wind shear is the big story. Current 1km VWP from KMSP/KDMX radars showing 35-45 kts at 1km and 75 kts at KOAX at 6 km. So, some excellent shear with directional shear in the lowest 1 km. 06.19z RAP indicates 0-1km SRH values in the 200-400 m^^2/s^^2 range will be present in NE IA and SERN MN, so plenty for low-level spinning. Overall...the severe weather threat has increased with a favorable upstream environment. Storms should continue to develop into a N-S line from MN into IA late this afternoon and move east and enter Dodge-Floyd county /western forecast area/ around 6-7 pm. Would expect a QLCS line of storms to enter with threats of damaging winds and isolated tornadoes...mainly near/due to mesovorticies on the leading edge. Being early March and per RAP guidance, this threat should rapidly diminish east with stabilization and loss of heating, with severe storms becoming less in coverage. Storms are expected to continue well into WI with strong dynamical forcing. By midnight, the storms/rain should be near/exiting central WI. Post frontal winds still look as previously forecast for later tonight and Tuesday. With 40-50 kts at the top of the mixed layer...a wind advisory is warranted. On Tuesday mixing will be enhanced in the afternoon and it appears we will tap 2km winds. The good thing is it appears these winds decrease 5-10 kts at 2km keeping wind gusts in the 35-50 mph range at the surface. .LONG TERM...(Tuesday night through Monday) Issued at 334 PM CST Mon Mar 6 2017 A wind advisory may be needed Wednesday with stronger winds continuing. Thursday night through Monday...Main forecast concerns are precipitation chances and temperatures Thursday night through Monday. The 06.12z GFS/ECMWF/GEM are in good agreement in developing west to northwest flow aloft through the period. The biggest differences is timing the shortwave troughs embedded in the flow into the Upper Great Lakes Region. This will have impacts on timing of precipitation chances/types across the forecast area. The 06.12z GFS/ECMWF/GEM are in good agreement in advecting cooler air aloft into the Great Lakes region through the period. The 06.12z GFS/ECMWF show 925mb temperatures in the minus 5 to minus 10 degree celsius range for much of the period. This will allow temperatures to be below normal with highs in the lower to middle 30s. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 534 PM CST Mon Mar 6 2017 All eyes on an impressive line of thunderstorms just moving into the I-35 corridor. Will impact both TAF airfields this evening with strong gusty southwest winds from 35-40kts or more. Some hail also possible, but not enough confidence to include in 00Z TAFs. For the most part, upstream observations impacted by storms have stayed VFR with ceilings, but could see reductions in visibility to 2SM in heavy rain/thunder. Once storms move through, strong west-southwest wind will continue through the night and into Tuesday with frequent gusts between 35 and 40 kts. Otherwise, VFR cloud cover will be the rule. Did not include low-level wind shear in 00Z TAFs due to frequent high surface gusts, but expect winds around 2000 ft agl to at least 50 kts through this evening. && .FIRE WEATHER...For Tuesday Issued at 334 PM CST Mon Mar 6 2017 Strong winds and low relative humidities will cause weather conditions that could enhance fire spread on Tuesday, mainly in grasses. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Wind Advisory from 6 AM to 6 PM CST Tuesday for WIZ017-029- 032>034-041>044-053>055-061. MN...Wind Advisory until 6 PM CST Tuesday for MNZ079-086-087-094-095. Wind Advisory from 6 AM to 6 PM CST Tuesday for MNZ088-096. IA...Wind Advisory until 6 PM CST Tuesday for IAZ008>010-018-019. Wind Advisory from 6 AM to 6 PM CST Tuesday for IAZ011-029-030. && $$ UPDATE...Rogers SHORT TERM...Baumgardt LONG TERM...Baumgardt/Jones AVIATION...Rogers
Area Forecast Discussion
National Weather Service Duluth MN
934 PM CST Mon Mar 6 2017 .UPDATE... Issued at 934 PM CST Mon Mar 6 2017 Scattered thunderstorms will continue over far eastern Minnesota into northwest Wisconsin for a couple more hours but the threat for severe storms has ended. MUCAPE values were around 500J/KG over northwest Wisconsin into the Arrowhead as of 03Z but that will be diminishing over the next 1 to 3 hours as cold air advection develops. Some additional showers have developed over central to east central Minnesota behind the main line and they will continue to move north to northeast. We still expect temperatures to cool enough to support snow showers at all areas later tonight. No changes were made to the Wind Advisory at this time. Gusty winds will develop tonight as the cold front passes but they should mostly be below Wind Chill Advisory thresholds. The strongest winds are expect on Tuesday. && .SHORT TERM...(This evening through Tuesday) Issued at 311 PM CST Mon Mar 6 2017 Rain with thunderstorms this evening, chances of snow overnight, and windy for Tuesday highlight the short-term forecast period. This evening starts off wet and stormy, with some thunderstorms potentially severe. The Storm Prediction Center has expanded their convective outlook, which now includes a Slight Risk south of a Leader to McGregor to Phillips line. The Marginal Risk has also expanded farther north and west, encompassing most of the southwestern one-half of our forecast area. Thunderstorms are expected to develop along a cold front boundary that is expected to sweep through the region this evening. Latest HRRR model is progging convective initiation to occur roughly by 00z this evening and progressing east and northeastward towards the Twin Ports area. The storm environment appears to be more of the low CAPE/high shear variety, with the latest RAP/NAM model soundings indicating SBCAPE values between 500-1000 J/kg from the Brainerd Lakes towards the Twin Ports area, but 0-6 km bulk shear values near 60+ knots, thanks to a strengthening low-level jet, with 850 mb wind magnitudes of 50 to 55 kts. The biggest threats in the Slight Risk area are damaging winds and large hail. Thunderstorm activity should exit the eastern forecast area by around midnight tonight. Cold air advection will increase behind the cold front boundary, which will transition any rain showers to snow showers during the overnight hours. Snow accumulation through the day Tuesday are expected to be between 1 to 3 inches along the Iron Range and points northwest. Sfc winds are expected to weaken behind the cold front before intensifying again during the day Tuesday. The sfc low pressure center will meander its way across southeast Manitoba and extreme western Ontario Canada. Both the NAM and GFS are progging very deep boundary layer mixing of strong 850 mb low- level jet winds on the southern end of the sfc low, with the models progging strong momentum transport to the sfc, indicating gusts capable of 40 to 50 kts. Made some adjustments to the previous Wind Advisory as the start time seemed to be too early, so delayed the start time of the advisory to 12z Tuesday, and trimmed back the end time to 00z Wednesday. Moreover, decided to expand the Wind Advisory east to encompass all of northwest Wisconsin due to model soundings at Phillips indicating sufficiently strong boundary layer mixing of strong flow from aloft. Models have continued boundary layer mixing up to the 700 mb level, which would be sufficient to tap into the strong 850 flow. Due to the region staying underneath the cyclonic flow from the sfc low, kept chance POPs going for the rest of the day Tuesday, especially over the northern half of the forecast area. Temperatures Tuesday are expected to be closer to seasonal averages, but still slightly above average, with highs ranging from the mid to upper 20s northwest to the lower 40s southeast. Lows tonight will range in the upper teens northwest to upper 20s southeast. .LONG TERM...(Tuesday night through Monday) Issued at 311 PM CST Mon Mar 6 2017 Main forecast concern for extended will be colder air and shortwaves bringing the possibility of light snow. Colder temperatures will continue to flow into the forecast region Tuesday night and will persist through the end of the week. A strong upper low over northern Ontario will pull down the air through mid-week. A shortwave will move through the region Tuesday night and Wednesday causing light snow to develop. Accumulations will be mainly around 1 to 2 inches along and north of the Iron Range and in the Arrowhead. The high winds will slowly drop Tuesday evening and should be below advisory criteria by midnight. With the cold north-NW flow across the lake Wednesday, there will be a possibility of lake effect snow showers along the south shore Wednesday and Wednesday night. A ridge builds into the region late Wednesday night and will dominate the weather through Friday reinforcing the colder air across the region. Unlike last night`s run, the ECMWF now has the main precip area south of the forecast area similar to the the GFS/Canadian. So will keep the area mostly dry with little snow. Models are still depicting a low possibility of light snow on Sunday mainly south of Highway 2 but confidence is low for this shortwave. A stronger shortwave will move through central Minnesota on Monday bringing a better shot for snow for the forecast area. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 558 PM CST Mon Mar 6 2017 A strong area of low pressure was located along the far northeast North Dakota and southern Manitoba border early this evening with a warm front extending southeast into central and southern Minnesota. A cold front was located through eastern North Dakota into western South Dakota. The low will lift north and the fronts will move through the region overnight with strong cold air advection developing. Showers and thunderstorms will be possible this evening across much of the Northland diminishing from west to east. Some of the storms could be strong this evening over southern parts of the Northland. As the colder air moves in later tonight, snow showers will be possible. There will be low level wind shear this evening, then the wind will veer to west to southwest overnight and become gusty. Strong west to southwest winds are expected on Tuesday. IFR ceilings will gradually improve to MVFR for most areas overnight and improve further on Tuesday. There were some VFR conditions in the Brainerd Lakes region already but we do expect MVFR ceilings to move back in over the next couple hours. && .PRELIMINARY POINT TEMPS/POPS... DLH 24 35 12 23 / 80 30 20 10 INL 19 24 7 18 / 50 60 60 20 BRD 25 38 14 27 / 40 20 20 10 HYR 28 41 17 28 / 80 20 20 10 ASX 30 42 18 27 / 80 20 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...Wind Advisory from 6 AM to 6 PM CST Tuesday for WIZ001>004- 006>009. MN...Wind Advisory from 6 AM to 6 PM CST Tuesday for MNZ018-019-025- 026-033>038. LS...None. && $$ UPDATE...Melde SHORT TERM...JTS LONG TERM...Stewart AVIATION...Melde
Area Forecast Discussion
National Weather Service Houston/Galveston TX
925 PM CST Mon Mar 6 2017 .UPDATE... The main update to the evening forecast was to add a mention of patchy fog to the bays and coastal waters where southeast winds continued to advect warm, moist air (platform observations reporting dew points in the upper 60s to mid 70s) across the somewhat cooler shelf waters. May also see some radiation fog development inland as winds decrease ahead of an approaching cold front tonight, particularly in more sheltered or low-lying areas. Increasing isentropic lift on the 305K surface ahead of the front should result in a few sprinkles or possible a shower through the night, with some of this activity possible able to tap into some of the instability (lapse rates around 6.5 C/km) over far eastern Texas to produce possibly an isolated thunderstorm or two closer to sunrise. Otherwise, expect overnight lows to fall into the mid 60s to low 70s under partly to mostly cloudy skies. Anticipate the cold front now pushing across the Panhandle and central Oklahoma to reach the northern counties of the forecast area 7-9 AM and reach the Houston metro midday to early afternoon. Preliminary evaluation of the 00Z model guidance shows quite a bit of discontinuity between the timing of the cold front as it approaches the Houston metro, with the 00Z NAM now almost 3-6 hours slower than the 12Z ARW and NMM as well as the 02Z RAP. As of now, continuing to advertise the cold front pushing off the coast but will have to see how much the post-frontal airmass modifies as the front may slow or stall near the coast. Forecast soundings show precipitable water values increasing to around 1.5 inches ahead of the front and this, combined with a decelerating frontal boundary, may produce some locally heavy rain across the southern two tiers of counties during the afternoon to early evening hours tomorrow. Huffman && .PREV DISCUSSION... /ISSUED 601 PM CST Mon Mar 6 2017/ AVIATION... MVFR cigs are expected to return early this evening and gradually lower overnight toward IFR. Winds will not relax until between 06-09z as a cold front nears the area. Once the winds decouple, would expect some patchy fog to develop. Sfc dew pts near KGLS are near 70 so can`t rule out some sea fog developing near the coast. The RAP and TT WRF also begin to produce some light streamer showers between 08-10z so added a VCSH for inland TAF sites but could really get a shower just about anywhere. The front will approach KCLL between 13-15z, Houston between 17-21z and Galveston between 20-23z. PW values ahead of the rise to between 1.5 and 1.6 inches with CAPE values between 1500-2500 J/kg. LI values are progged between -4 and -7 so can`t rule out getting some strong to possibly severe storms along the front. Have tempo for the fropa and associated convection and might need to beef up the wind gusts with the front. Fcst soundings keep some cloudiness behind the front so will slow clearing until after this TAF package ends. 43 PREV DISCUSSION... /ISSUED 356 PM CST Mon Mar 6 2017/ DISCUSSION... Coverage beginning to decrease this afternoon and expecting most of this activity to be gone by this evening. However, this break should be short lived as the strong onshore winds help to gin up more WAA-type showers along/near the coast toward sunrise. Further north, we will be seeing development along/just ahead of the cold front moving down from the Southern Plains. While the upper dynamics look more favorable for strong storms NE of the CWA, we should still see a fairly healthy line of SHRA/TSRAs develop and begin moving into the area Tues morning. Still a bit concerned with locations in/around SE TX that received some good rainfall Sun and with the rains/clouds today, not really getting much drying. However, do think that the storms we do get will be moving and not likely to train. A brief break in the weather expected behind this front for most of Weds as a flat upper ridge builds in from the west. Returning onshore winds on Thurs will begin setting the stage for increasing POPS through the latter part of the week. Models are still a tad disparate with the upcoming pattern but starting to see some consensus with the GFS idea of a more active southern stream jet by late Thur on through Sat. The next cold front is currently on track for a Sat night FROPA across SE TX. 41 Marine... SCEC across the Upper Texas Coast tonight and into Tuesday morning, as winds will remain between 15 to 20 knots. Seas will also remain elevated in the offshore waters, remaining between 6 to 7 feet with the occasional 8 foot seas. Expecting south southeast winds out ahead of the next cold front that is passing through SE Texas Tuesday afternoon. Showers and scattered thunderstorms will begin Tuesday morning and continue through the afternoon out ahead of the front. The front should push offshore late Tuesday, and winds will shift out of the east northeast for much of the day Wednesday. Winds will quickly return to onshore flow overnight Wednesday and into Thursday. Still expecting moderate seas for the rest of the week. Hathaway && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 66 73 54 73 64 / 20 60 10 10 10 Houston (IAH) 70 76 54 72 62 / 20 60 20 20 10 Galveston (GLS) 67 72 62 68 65 / 10 60 30 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CST Tuesday for the following zones: Coastal waters from Freeport to the Matagorda Ship Channel out 20 NM...Coastal waters from High Island to Freeport out 20 NM...Waters from Freeport to the Matagorda Ship Channel from 20 to 60 NM...Waters from High Island to Freeport from 20 to 60 NM. && $$ Discussion...14
Area Forecast Discussion
National Weather Service Lincoln IL
829 PM CST Mon Mar 6 2017 .UPDATE... Issued at 829 PM CST Mon Mar 6 2017 Updated the forecast to increase wind speeds tonight with gusts of 35-45 mph and locally higher gusts especially with thunderstorms by overnight. Bloomington already gusting to 46 mph at 8 pm. Southerly sustained winds range from 20-35 mph over central IL at mid evening and have been gradually increasing during the evening. KILX 00Z sounding had 2k ft wind of 55 kts and some of this higher wind is mixing down toward the surface. Will continue to monitor to see if a wind advisory is needed, but for now have issued a special weather statement addressing these higher winds. A strong and deepening 980 mb surface low pressure was over south central Manitoba, with its cold front extending southward through eastern MN, central IA and nw MO. A line of strong to severe thunderstorms was along the cold front and quickly moving east. HRRR model has the squall line reaching areas nw of the IL river between 05-06Z (11 pm- midnight), nearing I-55 by 07Z/2 am, just east of I-57 by 09Z/3 am and to the IN border around 10Z (4 am). This line is still projected to weaken as it moves east across IL overnight, with slight risk west of I-57 and enhanced risk west of Peoria and Springfield. Main severe wx threat is damaging wind gusts with 15-30% risk, with 5-15% risk of large hail in western CWA and 2-5% risk of tornadoes over western half of CWA. Lows overnight to range from lower 40s over the IL river valley where skies clear late tonight, to the lower 50s over southeast IL. && .SHORT TERM...(This evening through Tuesday) ISSUED AT 243 PM CST Mon Mar 6 2017 Main concern in the short term is with the convection expected this evening. Pre-frontal line of showers and embedded storms is edging eastward across central western Illinois early this afternoon. Further west, radar imagery and GOES-16 1-minute visible imagery is showing a line of storms beginning to fire from northwest Iowa into south central Nebraska, along a dry line. High-resolution model guidance continues to show this filling in and marching eastward this evening, with decent agreement in the line reaching the Illinois River toward midnight and marching through the CWA through about 4-5 am. Latest SPC Day1 outlook has brought the enhanced risk as far east as a Peoria-Springfield line, focused on the wind potential as the line focuses into a QLCS, though in a weakening state as it pushes east across Illinois. A very sharp cutoff on the back edge of the rain shield will occur, but the rain will linger over the far southeast CWA into early Tuesday. Secondary concern will be the winds through Tuesday. Gusts of 25-35 mph are occurring this afternoon, but are expected to increase a bit this evening ahead of the line, with some 40-45 mph gusts likely. Conditions are a bit borderline for a wind advisory, but will need to monitor this closely over the next few hours. After the convection passes, there will be a short window when winds subside, but they should become gusty again by late morning as deep mixing takes place on Tuesday. Gusts of 30-35 mph appear more likely at this time for Tuesday afternoon. .LONG TERM...(Tuesday night through Monday) ISSUED AT 243 PM CST Mon Mar 6 2017 Central and southeast Illinois can expect an active weather period through the extended range of the forecast, with a system passing through or near the area about every other day. Model guidance continues to struggle with the details within this fast flow regime, which has required notable forecast adjustments from day-to-day. Despite the model variation/disagreement, the most consistent trend has been a further south/colder track to the weather systems. The first wave to impact the area is the weakest, and is currently forecast to brush by the area later Thursday into Thursday night. Initially, conditions would be warm enough for rain across the entire area. However, It will likely cool enough in the north Thursday night for a change over to snow, although no accumulation is anticipated. If the models continue to trend south with this wave, there is still the potential that it will miss us entirely. The second wave is the most significant, and is forecast to impact the area late Friday night into Saturday evening. This timing has been pretty consistent of late, but again this system has been trending more southerly in its track. If these trends hold, at least some light snow accumulation appears possible across the northern half of the forecast area into midday Saturday. A final wave arrives around Monday, but model agreement with respect to its timing is not as good as with the first two waves. This system also seems poised to produce snow and/or rain across the forecast area, with the snow more likely in the north and early in the day before temperatures warm. Above normal temperatures to start the period will trend below normal by the end of the week. The passage of each disturbance will deepen the upper-level troffing over eastern North America and advect cold low-level air into the area. I guess winter wasn`t quite done with us yet. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 555 PM CST Mon Mar 6 2017 MVFR ceilings (as low as 1k ft at BMI and CMI) could lift to VFR next few hours as SPI recently did. Continued VCSH in central IL TAFs this evening in warm sector. Strong southerly winds around 20 kts with gusts of 23-33 kts early this evening will increase during this evening as cold front in nw IA and eastern KS approaches IL/MS river by late evening. KILX 00Z sounding showed 2k ft southerly winds of 55 kts and supports these stronger winds. Latest HRRR model shows squall line pushing quickly east from western IA toward the IL river by PIA around 06Z, to I-55 by 07Z and to DEC and CMI by 08 or 09Z. Carried 2 hour period of TS with MVFR ceilings and vsbys along with SW wind gusts of 35-40 kts. Clearing to occur a few hours behind cold front with fair amount of sunshine expected Tue. Winds veer westerly behind cold front Tue and gust to 25-30 kts during day Tue, then diminish to 10-15 kts by 22 or 23Z Tue. && .FIRE WEATHER... Issued at 243 PM CST Mon Mar 6 2017 Some concerns for Tuesday with borderline red flag conditions in parts of the area. Deep mixing to take place from around 5000 feet, as forecast soundings show 50 knot winds mixing down to the surface. Very dry in the lower levels, and there is some concern that dew points could get lower than the low-mid 20s already in the grids for afternoon. Minimum humidity levels forecast to reach the upper 20s over the southwest CWA. That area currently has 10-hour dead fuel levels of 11-15%, but could dry out quickly despite the rain tonight as 30-35 mph wind gusts occur. No fire headlines planned at the present time due to the uncertainty. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...07 SHORT TERM...Geelhart LONG TERM...Bak AVIATION...07 FIRE WEATHER...Geelhart
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
754 PM CST Mon Mar 6 2017 .UPDATE... 754 PM CST Extensive N-S squall line extending from NW WI south through IA south into NW MO and then into eastern KS is moving fairly quickly eastward at about 35 kt. Line has a history of producing damaging winds with a couple supercells over NW MO and intense embedded mesovortices/mesocyclones in IA as well, some potentially tornadic. SPC mesoanalysis suggests the instability axis ahead of the line is fairly narrow, which was confirmed with the 00z soundings from ILX and DVN which both shower very little instability and strong CINH. Some destabilization may continue to occur east of the instability axis, however the rate of eastward expansion of the instability axis is being outpaced by the fast movement of the line. The result will likely be the line eventually outrunning the instability and weakening as it moves across our CWA. While the storms are expected to out run the instability and essentially begin to run out of gas, there could be a lingering damaging wind threat into portions of our CWA given the extreme wind fields and how little it`d take for this line to mix some of that momentum to the surface, even if the line is in a weakening phase. The DVN sounding sampled 52kt winds at 1km AGL, but RAP is forecasting the low level jet to strengthen this evening with 1km winds increasing to over 80kt. In fact, KDVN WSR-88D is already picking up 80kt winds at 1.7km AGL. Difficult to say how far east this line will be able to continue to run on fumes and pose a severe threat, but given the extremely powerful winds just off the deck, hard to rule out even a shower producing near severe gusts even over our eastern CWA. Other than the convective threat, we will continue to monitor synoptic winds this evening. As the low level flow continues to increase just off the deck, concerned we could see gusts in the 35-40kt range this evening, as very little stabilization of the boundary layer is taking place this evening. Have seen an ob or two approach wind advisory criteria, but plan at this point is to hold off on an NPW for winds unless there is a more substantial increase soon. Have tweaked timing of pops in the grids tonight, otherwise no big changes planned to going forecast. Izzi && .SHORT TERM... 112 PM CST Through tonight... Cloudy, mild, and breezy conditions will give way to windy conditions and a round of thunderstorms late this evening/early overnight hours. There is a batch of showers along the Mississippi River that will likely dissipate as they move farther east, though we may see some light showers or sprinkles from this espeically across north central Illinois. We do expect winds to ramp up more considerably this evening as the pressure gradient increases ahead strong low pressure across the upper Midwest. The low level jet will ramp up this evening, and there could be some lifting of cloud bases that will allow these higher winds to mix down in the evening. 40-45 mph will likely be reached, and in the thunderstorms it is possible that some of the stronger/near severe winds may get mixed down, as 45-47 kt winds are depicted on RAP forecast soundings at just over 1000 ft, and 60 kt winds at 2000 ft. We will need to monitor this potential for wind advisory level winds (sustained > 30 mph or sustained gusts > 45 mph) and if this may just be a convectively handled event, as there will probably be a few stronger gusts. Guidance is also a tad slower with the arrival of the cold front, with the main line of storms expected mainly after midnight across most of the area. Again more isolated/scattered activity is possible later this evening. KMD && .LONG TERM... 319 PM CST Tuesday through Monday... Main forecast concerns at the beginning of the period are with windy conditions expected both Tuesday and Wednesday, and then concerns for the weekend are with a return to a colder and potentially snowier pattern into early next week. Showers and thunderstorms which will move across the area tonight will shift east of the CWA by early Tuesday morning, as large scale ascent and front exit to the east. However, given a slower trend tonight and with some lingering forcing early in the morning, its possible that some light showers may still be situated over the eastern CWA, mainly in Indiana. Did leave some pops to account for this, but then expect dry conditions for the remainder of the day. Much drier air arrives on the backside of this system and anticipate skies to quickly clear Tuesday morning. Skies should remain sunny on Tuesday, despite expected pattern. However, some guidance showing some potential for diurnal cu and even light precip development over eastern Iowa and far northwest Illinois Tuesday afternoon. With the anticipated steep lapse rates and additional forcing per mid level energy and surface trough, this could be a possibility. Forecast soundings will be really dry though, and so have maintained a sunnier forecast with no chance of weather. Tight gradient will support sustained speeds around 20KT on Tuesday and with deep mixing/steep lapse rates especially in the afternoon, strong chance to mix down much higher gusts. Have kept gusts sub advisory, up to 40 MPH, but do think gusts of 40-45 KT will be possible over much of the CWA Tuesday afternoon. Gusty conditions will likely persist Tuesday night, but do anticipate a significant drop in speeds/gusts. Dry conditions continue Tuesday night into Wednesday, despite frontal boundary pushing through the area on Wednesday. Main concern on Wednesday will once again be with strong winds/gusts. Some variability among guidance on the strength of these winds. Will need to continue to monitor this period as advisory type winds of 45 MPH or higher appearing very possible, with some potential for higher gusts approaching warning criteria. By the end of the work week and especially this weekend into early next week, monitoring the potential for a more active pattern. With the arrival of much colder air, precip chances look to be for mainly snow. Low probability for precip Thursday night with a wave passing just to the south, but with guidance continuing to show southward moving system bringing snow chances across the area Friday night into Saturday. Have trended the forecast colder with more snow mention, with a chance for accumulating snow during this time. However, guidance still varying with exact evolution/track, so confidence is lower with exact trends. Will need to keep an eye on this system, as well as another possible snow producing system by early next week. Rodriguez && .AVIATION... For the 00Z TAFs... 545 pm...Main forecast concerns are winds through the period and thunderstorm potential late this evening/overnight. A cold front will move across the area after midnight. A line of thunderstorms currently over west/central IA will continue moving east into the rfd area by 06z and into the Chicago terminals centered around 07z. Exact timing will likely need tweaking and possible to go with a prevailing thunder time window as it approaches. Convective wind gusts with this line will likely be from the west/southwest and possibly 40kts or higher. A few showers will be possible this evening with lingering showers behind the thunderstorms for a few hours. Strong/gusty southerly winds will continue this evening with gusts increasing into the mid 30kt range. Winds will begin to shift more to the southwest ahead of the cold front and then shift more west/southwest overnight. Speeds/gusts should diminish some but still gusty overnight. Deep mixing of the low levels is possible Tuesday afternoon but there remains uncertainty regarding how deep the mixing may become. As a result...confidence for speeds/gusts Tuesday is only medium. Westerly winds gusting 25-30kts looks on track for most of Tuesday but there could be a period in the early/mid afternoon when wind gusts increase into the 35-40kt range. Speeds/gusts should diminish with sunset Tuesday evening but remain somewhat gusty into the early evening. A weak trough will move across the area Tuesday evening and while there is limited moisture available...its possible there could be some isolated showers or even a thunderstorm Tuesday evening but confidence is low. Trends will need to be monitored with later forecasts. cms && .MARINE... 319 PM CST Windy conditions will continue across the entire lake through Wednesday night into Thursday. In the near term...deepening surface low over the northern Plains will continue to strengthen as it moves into Ontario tonight into Wednesday. This will support stronger winds/gales over the nearshore and open waters for the remainder of the afternoon into Tonight. A brief lull in the stronger winds may occur by early Tuesday morning, but this should brief as stronger winds return by late in the morning and especially in the afternoon. However, it does appear that prevailing gales will continue over the north half into Tuesday. Further to the south, gales will be possible, especially in the afternoon. This will be for both the south half and the nearshore waters. At this time, it does appear that only occasional gusts will be possible, but will need to monitor this potential. Conditions favorable for stronger winds/gusts will persist Tuesday night into Wednesday and with high confidence of these higher winds, have extended the gale warning over the north half into Wednesday. Have lower confidence for these stronger winds over the south half and nearshore for Tuesday night, but confidence does rise for Wednesday. Wednesday will not only have the potential for gales, but even higher end gales. Will also need to monitor Wednesday as well. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Gale Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777- LMZ779 until 3 AM Tuesday. Dense Fog Advisory...LMZ777-LMZ779...3 AM Tuesday to 6 AM Tuesday. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion...Update
National Weather Service Little Rock AR
830 PM CST Mon Mar 6 2017 .Discussion... Overall forecast on track. Evening convection has been light over AR with a bit lack of upper lift, but are now seeing additional convection forming over northwest AR. But later this evening and into the overnight, better lift will be seen as the upper level low pressure trough swings closer to AR, and the cold front moves through AR overnight. All other factors are present in the atmosphere, good moisture, enough of instability, and speed and directional shear with the wind fields in the atmosphere. Still do expected isolated strong to severe storms before the cold front, while the better chance will be seen along the boundary. Damaging winds, large hail and isolated tornadoes are expected. Timing of the main storms with the cold front remain around 8 PM to midnight in northwest AR, midnight to 5 AM for central, and 4 AM to sunrise Tuesday for eastern to southeastern areas. Otherwise, lows tonight will be from the 40s to 50s north, the 50s to 60s central, to 60s south. Temperatures will quickly lower behind the cold front overnight. Winds will also be elevated from the northwest then become west later in the day. Clouds will break and partly to mostly sunny conditions will be seen later Tuesday, with highs in the 50s to 60s. Late evening update will mainly fine tune convection chances. (59) && .Prev Discussion.../ Issued 540 PM CST Mon Mar 6 2017/ .Aviation... Overall VFR ceilings with patchy MVFR conditions will start the forecast. An area of light rain and showers, with only isolated thunder, will initially move northeast over central to southern AR this early evening. Later this evening and especially overnight, additional convection, strong to severe in some locations, will be seen as an upper system and cold front move through the region. More MVFR and areas of IFR will be seen more after midnight and with the stronger convection. Winds will be south at 10 to 20 mph with some higher gusts, then switch to the west to northwest behind the front and be 10 to 20 mph. Low level wind shear will be seen as a low level jet has set up over AR this evening and into the overnight hours and affect most Taf sites. (59) && .Prev Discussion.../ Issued 256 PM CST Mon Mar 6 2017/ .SHORT TERM...Tonight Through Wednesday Light showers were in place around the state for much of the day today with overcast skies. Through the day today have continued to see temperatures warm across the state with breezy southerly winds. The main focus of the short term is the tonight period as a cold front approaches from the west. Strong warm advection win some locations, will be seen as an upper system and cold front move through the region.ill continue through the evening hours allowing temperatures to remain fairly steady after dark tonight...with dewpoints on the rise as well. Ahead of the cold front...a moderately unstable atmosphere and plenty of wind energy will be in place across the state. Nam and HRRR model soundings show over 1500 j/kg of CAPE and 400+ 0-1 helicity across portions of west central Arkansas. Equally concerning given these and other parameters, is that the HRRR has shown great run to run consistency in developing cells out ahead of the main line across portions of west central Arkansas. Coinciding with these parameters is that in the past few hours, have started to see some breaks in the clouds across portions of Yell, Logan, and Scott counties. Putting the pieces does appear that if enough forcing can be generated the locations where cells could develop ahead of the front would be north and west of an Arkadelphia to Conway to Mountain Home line. If these cells are able to develop...all modes of severe weather will be possible (hail, winds, tornado). This system will evolve very similar to what was seen last week as a cold front will move through the state during the overnight hours. Storms along this front will be linear in nature and lead to a straight line wind threat as it moves quickly through the state. Along these lines of storms, a brief tornado may spin up. Behind the front on Tuesday, dew points will plummet and breezy northwest winds will be seen. This will likely create a slightly elevated wildfire danger. But at this time, it does appear that a red flag warning will not be needed. && .LONG TERM...Wednesday Night Through Monday Night A few interesting events are shaping up during the extended term. First event will be a frontal boundary sagging down from the north into the state in the Thursday night into Friday time frame. Models generally push the front southward thru the CWA and bring it back north as a warm front later on Friday. Upper level flow will NWLY thru the period, and I am a bit concerned that the front may end up stalling and becoming quasi-stationary, which would lead to the potential for a heavier rain event. Will have to see how this evolves over the next day or two. The bigger focus right now will be on Saturday into Saturday night. Models are showing a vigorous shortwave dropping down, along with an associated cold front moving in from the northwest. At this time this certainly looks like it may have the potential to produce severe weather, although at this range it`s tough to make a judgement call on whether or not there will be enough instability. && .PRELIMINARY POINT TEMPS/POPS... Batesville AR 57 66 40 69 / 100 50 0 0 Camden AR 66 70 40 73 / 80 80 0 0 Harrison AR 46 63 38 70 / 90 10 0 0 Hot Springs AR 60 69 40 72 / 90 50 0 0 Little Rock AR 64 68 41 72 / 90 60 0 0 Monticello AR 65 69 41 72 / 80 90 10 0 Mount Ida AR 58 66 37 71 / 90 40 0 0 Mountain Home AR 49 64 38 70 / 90 10 0 0 Newport AR 59 66 40 69 / 90 60 0 0 Pine Bluff AR 66 70 41 70 / 80 90 0 0 Russellville AR 56 67 38 71 / 90 20 0 0 Searcy AR 60 68 39 71 / 90 60 0 0 Stuttgart AR 65 69 42 70 / 90 90 0 0 && .LZK Watches/Warnings/Advisories...NONE. && $$ Short Term...65 / Long Term...53
Area Forecast Discussion
National Weather Service Norman OK
936 PM CST Mon Mar 6 2017 .UPDATE... && .DISCUSSION... We have removed Kay and Noble counties from the Tornado Watch and added four more counties downstream. Latest radar/IR trends have indicated rapid cooling of CB southwestward over OKC metro. We have received reports of severe hail with the most intense updrafts and the thermodynamic/kinematic environment remains favorable for severe thunderstorms through much of the evening. The biggest uncertainty in the short term is southwestward extent of the convection given the proximity of the upper trough. Forcing/ascent and cooling aloft sufficient for convective initiation is more in question further west and south, but confidence is reasonably high for convection to impact east central and southeast portions of the area through the evening. Large hail and damaging winds are the main threat. Relatively wide positive area on 00z sounding in the hail growth zone and fairly low wet bulb zero heights support the severe hail potential. A relatively deep mixed layer that appears to have not decoupled significantly yet should support a continued wind threat as well. The tornado threat is low, this far west and should be more substantial further east in the state out of our area and into the Ozarks region where LCL heights are lower and low level winds are more backed contributing to higher 0-1km SRH values. Nevertheless, low level shear remains strong enough that a tornado cannot be ruled out. The bigger threat certainly is large hail and damaging winds though. Another concern is the ongoing wildfires across northwest Oklahoma. Several large hotspots are seen on 3.9um satellite imagery, and we have issued several fire warnings per the request of local officials. RH recovery will be very little overnight (-3F dew point at Buffalo mesonet currently), probably no higher than 30 percent so the fire threat will persist well into the night. Post-frontal northwesterly winds will decrease after midnight helping fire managers somewhat. We are growing increasingly concerned about the threat of fires once again tomorrow given very dry airmass and dry fuels, even though winds will be light. Winds may be strong enough for near critical to possibly critical fire weather conditions across northern Oklahoma near the Kansas border. BRB && .PREV DISCUSSION... /issued 558 PM CST Mon Mar 6 2017/ UPDATE... DISCUSSION... An early look at the Norman 00z sounding raw 1-second data reveals a pronounced capping inversion still in place with MLCIN of right around 100 joules. Convective initiation is not expected along the dryline/surface trough until later this evening when a cold front meets the warm moist air mass over eastern Oklahoma. Thunderstorms have already formed well to the north of the area along the front in Kansas and have quickly become linear. Convection is expected to continue to build southward along the front as 1.) cooling/ascent from approaching trough overspread the area, and 2.) frontal convergence lifts warm/moist conditionally unstable air mass. The western edge of the threat is difficult to forecast given the complicated nature and evolution synoptic and mesoscale features. Current thinking is that deeper convection will develop southward within the band of high-based cumulus collocated with the dryline/surface trough. As it moves east into higher low-level theta-e axis and is overtaken by the cold front, thunderstorms should develop into north-central Oklahoma. This may occur early enough that Ponca City and Perry has a higher threat than the current forecast indicates and an upward adjustment of probabilities may be needed. We also may need to raise probabilities for the Oklahoma City area given timing trends. Damaging wind and large hail is expected to be the primary hazards. Strong low-level shear is present with 0-1km bulk shear of 20 knots and 0-1km helicity of just over 200 m2/s2. A low tornado threat may exist, but the greater threat will be in eastern Oklahoma into the Ozarks. Storm mode (linear) and fairly high LCL heights (at least furtherest west) should preclude a more significant tornado threat. BRB PREV DISCUSSION... /issued 513 PM CST Mon Mar 6 2017/ DISCUSSION... AVIATION... /For the 00z TAFs/ Near term concerns for aviation are ongoing wildfires and wind trajectories that may result in reduced visibilities from smoke at Gage and Woodward. We have included MVFR smoke in that TAFs with 5 miles for now given the latest ob at Gage but it`s possible that lower visibilities may occur. We`ll monitor trends. Otherwise a cold front will move southeast across the area this evening resulting in a shift in wind direction to northwesterly. VFR conditions should prevail. Thunderstorms could back build southwestward along the front toward Oklahoma City and Norman, but probabilities of impact at either airport is low at the moment. Storms should develop southeast of Ponca City so an even lower probability of thunder at that site is expected. BRB PREV DISCUSSION... /issued 252 PM CST Mon Mar 6 2017/ DISCUSSION... Weather impacts today are fire weather (critical to extreme fire weather conditions), strong winds, and some potential for strong to severe thunderstorms late in the day into the evening. Early this afternoon, a moderately amplified but progressive upper flow pattern is seen in water vapor channel imagery. A strong upper level trough encroaching on the Rockies and an intense 100kt + 500 mb speed max at its base are already impacting our weather significantly. Isallobaric response to falling surface pressures in the lee of the Rockies have strengthened southerly low-level flow over the past 36-48 hours with moisture advection ongoing. Low stratus has been prevalent through the morning, with occasional drizzle where low level saturation is deepest, but has mostly eroded across most of the area. A sharpening dryline will move east and eventually intersect a southeastward moving cold front late today. A capping elevated mixed layer should suppress convective development along and ahead of the dryline through the afternoon. The main impetus for convective initiation should be combination of cooling/ascent with approaching trough and frontal forcing. Storms should build southwestward along advancing cold front possibly into our far northeast counties by late afternoon, and then expand and develop further across the eastern portion of our area through the evening. Moderate instability and strong effective bulk shear should support organized/persistent thunderstorms and a threat of severe weather with hail and damaging the wind the main through through the evening. A more detailed mesoanalysis will be conducted throughout the afternoon and evening and any pertinent information will be communicated through updates. A Wind Advisory is ongoing for much of the area, with a small High Wind Warning across northwest Oklahoma. Latest NAM and RAP Bufkit soundings suggest 40 knots near the top of the mixed layer across much of the area, and momentum transfer should support gusts near 50 mph. Observations have indicated a few locations approaching or reaching high wind criteria, mainly just west of our area and the threat of high wind criteria gusts for northwest Oklahoma will continue through the afternoon. Medium range guidance is in reasonable agreement for precipitation chances for the latter half of the week into the weekend. There is some uncertainty with timing/placement, and therefore extent of precipitation. Current thinking is warm/moist advection will be sufficient for at least some low stratus and drizzle Wednesday night ahead of a low- amplitude shortwave trough that will move through later in the day. Instability may become sufficient for at least isolated convection during the afternoon, particularly across the south and eastern portion of the area. Two more amplified/stronger shortwave troughs will pass through Saturday and early Monday. These will bring at least low probabilities of showers/storms. BRB Fire Weather: Conceptually, the ongoing conditions this afternoon in the northwest portion of our area are commiserate with some of the more active fire days given the position of a band of strong mid-level flow crossing a pronounced low level thermal ridge that is oriented north-northeast to south-southwest across western Oklahoma into western north Texas. Latest observations show RH values in the teens across northwest Oklahoma and frequent gusts around 50 mph. Several fires are ongoing across the Panhandles and southwest Kansas. Fuels are dry with latest ERC-G values approaching the 90th percentile. Critical to extreme fire weather conditions will persist through the afternoon before improving during the evening. RH recovery will be slow overnight in a post-dryline airmass with westerly/northwesterly flow. Most locations should only rise to around 30 percent by morning. Elevated to near critical fire weather conditions will develop across much of the area tomorrow. Minimum RH values are expected to be in the teens across the entire area. Limiting factor for a significant fire event will be winds given the position of the surface high pressure to our south. Nevertheless, initial attack fires may occur. Significant fire spread should be limited to north of the Kansas border where winds are expected to be higher. We will need to watch trends across northern Oklahoma where westerly winds could become strong enough for concern, albeit below critical wind speed values. Elevated to near critical fire weather conditions may develop Wednesday afternoon as southwesterly winds strengthen in a persistent dry air mass. BRB && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 77 39 64 39 / 20 30 0 0 Hobart OK 82 38 64 38 / 10 0 0 0 Wichita Falls TX 84 43 67 40 / 10 10 0 0 Gage OK 80 31 65 37 / 0 0 0 0 Ponca City OK 79 36 64 36 / 20 40 0 0 Durant OK 77 49 67 41 / 30 70 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Red Flag Warning until 11 PM CST this evening for OKZ004>007- 009>012-014>018-021>024-033>038. TX...Red Flag Warning until 11 PM CST this evening for TXZ083>085-087- 088. && $$ 12/17
Area Forecast Discussion
National Weather Service Paducah KY
606 PM CST Mon Mar 6 2017 .SHORT TERM...(Tonight through Wednesday night) Issued at 252 PM CST Mon Mar 6 2017 Strong/deepening transport of moist air is ongoing over the Quad State, well out ahead of a developing cold front, as evidenced by a surge of 60s surface dew points already nosing into SEMO. Gridded time/height cross sections show some dry air still between about 850- 600 mb, but fully saturating by late evening into the overnight hours. Soundings reveal PW`s on the order of 1.3", or near the 99th percentile for this time of year. As the column moistens, it also destabilizes. We don`t see it doing so enough to support prevalent thunder mention til after 00z, although this is marginal for the far western Ozark counties in the 21z-00z time frame. However, by midnight, we see 0-1KM MUCapes approach 4 digits in the western Ozarks, and maybe reach the 500- 1000 J/KG range perhaps across the remainder of SEMO. With the cold front extending northeast to southwest across the Show Me State at 06z, we`ll see pre frontal convection/including thunder start to develop best in our (western) counties in the 03z-06z time frame. A Slight Risk of Severe will exist (SWODY1) for damaging winds as wind fields/shear deepen upon the front`s approach, with an Enhanced Risk primarily (just) west of the CWA within the heart of the instability axis/peak wind shear. Surface gradient winds will likewise be increasing thru the teens/perhaps into the 20s mph, and may include gusts into the 30s mph, but should stop shy of advisory criteria. That then translates on eastward across the FA, as the front moves in, and bears down on the Ohio river by tmrw morning. As it does, the instability fields are sorta pinched off to the south/west, but bulk shear still exists and should maintain enough to support the mention of thunder, including the SLGT risk of svr, at least for about the western half of the FA for the first half of the night. Even so, it`ll be increasingly transitioning to a heavy rain event after midnight, particularly from 09z-15z. Anticipate good soaking rains given high spring-like seasonal PW`s and still good forcing even after max instability fields start to diminish. The front is a little slower than previous runs, so we carry the heavy rain along it thru our southeast counties thru tmrw morning. Afternoon hours is when we see the drier air start working further down the column in more earnest, and pcpn shutting off more completely as the front departs/finally fully exits to the east. .LONG TERM...(Thursday through Monday) Issued at 252 PM CST Mon Mar 6 2017 Confidence in the long term portion of this forecast is low. The 12Z model suite brings a stream of 3 storm systems through our region from Thursday through next Monday in a relatively fast west northwesterly flow aloft. Each of these systems start out as jet energy over the northern Rockies, that amplifies to some extent over the Plains/MS Valley. The models have not locked in very well, which is to be expected with this type of pattern. A 1040+ surface high will attempt to spill down out of the northern Plains Thursday, and a surface wave will develop along the leading edge over Missouri by 00Z Friday. The surface wave will move eastward over or near our area Thursday night. Elevated instability is generated in the models, so will keep a chance of thunderstorms in the forecast. Friday should be dry, but temperatures are iffy with the Arctic high trying to spill into our region. The models have trended cooler with the system arriving early Saturday morning, and that has led to an introduction of some snow mention in the far north early Saturday morning. If the 12Z models are correct, our temperature forecast is likely too warm, and there may be more of a concern for measurable snow Saturday. Will have to wait and see what the models do with that cold surface high before getting too excited about a brief bout of winter. On the flip side, if that cold air does not make it to our area, thunderstorms may be more of a concern than wintry weather. The final system will move into the area on Monday. In the progressive flow pattern, the surface high will push east of the area allowing for south winds and nice warm, moist advection ahead of/into this system. This should be an all liquid event, but there is a brief mention of snow with the rain in the north early Monday morning. The precipitation is not likely to begin until later in the morning, so no issues expected at this time. Of course if we are colder for the Saturday system and actually get some snow, that could have an impact on the Monday system. Lots to watch for in this is active week of weather. Stay tuned. && .AVIATION... Issued at 606 PM CST Mon Mar 6 2017 Main challenge with the 00z Tuesday WFO PAH TAF package will be addressing winds and timing of main convective line of thunderstorms. Following some of the trend from the day crew, kept non-thunderstorm winds elevated, both sustained winds and wind gusts through the evening and post convective line. The HRRR guidance had a reasonable solution for wind gusts through the evening, most of it due to surface pressure gradients. Though it is rarely used in the presence/proximity of convection, could not eliminate the use of wind shear outside of the main convective line during the first 3-15 hours of the forecast period. There is sufficient shear within the layer that could support significant wind concerns for flights traveling in these evening, even with gradient winds at the surface. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ SHORT TERM...DH LONG TERM...DRS AVIATION...Smith
Area Forecast Discussion
National Weather Service Pueblo CO
705 PM MST Mon Mar 6 2017 .UPDATE... Issued at 704 PM MST Mon Mar 6 2017 Have allowed Red Flag Warning to expire for this evening. UPDATE Issued at 603 PM MST Mon Mar 6 2017 Updated for expiration of winter weather and high wind highlights. Will let red flag warning run for another hour as still a few spots on the plains are below 15 percent rh as of 01z. && .SHORT TERM...(This evening through Wednesday) Issued at 346 PM MST Mon Mar 6 2017 Upper trof is pushing eastward and tight surface pressure gradient is expected to relax through the evening. We still have a window for high winds through 6 PM across the southeast mountains and plains though did trim the western areas a bit where high res models suggest main threat is done. Otherwise...critical fire weather conditions will continue until 7 PM after which time relative humidity values will come up above critical thresholds. It will remain windy all night across the higher mountains. In fact mountain top winds across northern sections of the forecast area (Pikes Peak...the Sawatch and Mosquito Ranges) may approach high wind criteria again by Tuesday morning. However cross-sections keep stronger winds aloft and do not look particularly favorable for mountain wave activity due to too much forward shear. Will have to watch this potential closely however as the latest hrrr run tries to spread some strong gusts down into the higher elevations of the rampart range towards 15z. For now it appears to stay below high wind criteria. On Tuesday...another round of critical fire weather conditions can be expected across the plains...mainly north of highway 50...though western parts of Pueblo county and eastern Fremont county will also hit criteria on the west side of the surface lee trof. Conditions do not look as volatile as today...with wind gusts in the 25-30 mph range. Also appears that the window for critical fire weather conditions will be shorter in duration. Have upgraded the Fire Weather Watch to a Red Flag warning with the addition of Fremont county...mainly for eastern portions. Temperatures on Tuesday will remain above average for most areas. Dry and warmer weather will return for Wednesday though winds should remain lighter and below critical fire weather thresholds. -KT .LONG TERM...(Tuesday night through Monday) Issued at 346 PM MST Mon Mar 6 2017 Wednesday night through Friday...Nearly zonal westerly flow across the region should keep dry and warm conditions in place through at least the first half of Friday. Expect max temps in the 50s and 60s for the high valleys, and in the 70s to near 80F for the eastern plains. Friday night through Monday...A couple of disturbances aloft will track across the Intermountain West and Northern Rockies over the weekend and into the start of the next work week. Look for isolated to low-end scattered pcpn chances along the ContDvd, with the best chance for new snow falling across the central mts. High temps are forecast to be in the 50s and 60s for most low to mid elevation locations each day, climbing to near 70F for the plains Sun and Mon. Moore && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 346 PM MST Mon Mar 6 2017 VFR conditions expected at the terminals through the next 24 hours. Main concern will be the winds with west winds gusting to around 35 to 40 kts at KCOS...KPUB...and KALS until 02z. Winds will gradually decrease through the evening...though will remain at around 10-15 kts through the night at both KCOS and KPUB. Winds will increase again on Tuesday with West to Northwest winds 15-25 kts affecting both KCOS and KPUB during the late morning/early afternoon. KALS should see light winds under 15 kts on Tuesday. Across the mountains IFR to LIFR conditions will persist across the continental divide due to snow and blowing snow through the evening with improving conditions expected towards morning. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 10 AM to 5 PM MST Tuesday for COZ222- 226>228-231-234-236. && $$ UPDATE...PETERSEN SHORT TERM...KT LONG TERM...MOORE AVIATION...KT
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday) Issued at 218 PM CST Mon Mar 6 2017 Intense upper trough working east across the Northern Rockies with a smaller-scale wave swinging southeast into the High Plains. Dryline had pushed through Concordia at 20Z with dewpoints in eastern Kansas still in the mid to upper 50s despite intense mixing. Deep west to southwest flow behind the dryline leading to some blowing dust to the west and northwest, but cold front was not far behind with northwest winds into Phillipsburg at 20Z. On the large scale, winds continue to be the main story. HRRR has been fairly close with trends over the past few hours and has been hitting at gusts topping 50kts in north central Kansas in the late afternoon. Latest runs backing off of the extent and coverage of this however, and given observations to the west, will continue with the Advisory into the early evening. Storm chances still looking rather good with CIN diminishing and dryline and front coming in. Obviously lots of deep shear is in place, with some veering for storm organization. Early storms should still be able to be discrete at least initially, but increasing forcing should bring a more linear mode toward evening. Enough low level shear for a tornado risk with the early storms too, and with a slightly slower dryline trend, the time for tornadogenesis in this area is increasing, though mitigated by right moving supercell motions around 45kt. The early evening will bear close watching for severe storms, with the front`s progression through the area by late evening ending storm chances. .LONG TERM...(Tuesday night through Monday) Issued at 218 PM CST Mon Mar 6 2017 By Tuesday, the mid-level trough axis will be shifting east of the area with northwesterly flow aloft still in place across the Northern and Central Plains. At the surface, low pressure will extend across the Northern Plains with high pressure tracking into Oklahoma and Texas. Models show a pressure gradient remaining in place over the region through the day, resulting in breezy westerly winds. These strong winds combined with dry conditions will lead to another day of extreme fire weather conditions for the entire outlook area. See the Fire Weather section below for further details. While these westerly winds will result in cooler conditions for Tuesday, high temperatures will still be above the seasonal normals in the upper 50s/low 60s. Dry conditions will continue through mid-week as northwest-to- southeast oriented zonal flow sets up over the central U.S. With surface high pressure advancing into the southeastern U.S., a warming trend is expected Wednesday and Thursday as winds shift to the south, pushing high temperatures back into the mid 60s to low 70s. There is a chance for some scattered showers and isolated thunderstorms Thursday afternoon into Thursday evening across east central KS as a front slides southward over the area. Cooler conditions are expected by Friday as expansive surface high pressure builds from the Northern Plains southward into the Central Plains behind the exiting front. This cooling trend will continue into the weekend as a mid-level trough dives into the Central Plains with northerly winds keeping high temperatures only in the mid 40s to low 50s. By early Saturday morning, models show two disturbances: one across the Northern Plains in association with the mid-level trough, and the second over Oklahoma as surface low pressure lifts northward. Models show these two disturbances converging over the CWA early Saturday morning with precipitation tracking eastward out of the area by the evening. With early morning temperatures Saturday morning near the freezing mark around the KS/NE border, there is the potential for a rain/snow mix across far northern KS before transitioning to all rain by mid/late morning. The next chance for precipitation may be Sunday night into Monday, however the ECMWF keeps this system further north of the CWA while the GFS/Canadian track it over the area. A rain/snow mix would be possible once again over far northern KS Monday morning as temperatures drop to near freezing. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 542 PM CST Mon Mar 6 2017 Broken line of TSRA to impact TOP and FOE in next 2 hours. Gusty winds and brief MVFR/IFR anticipated. Winds again become the main challenge with speeds picking up after 14Z. && .FIRE WEATHER... Issued at 218 PM CST Mon Mar 6 2017 Today: Very strong winds with falling RHs bring extreme fire danger to mainly western and central locations through sunset. Exact location of RH values falling below 20% is not certain, but any trimming of the Warning would lead to a poor message at this point. A tight pressure gradient will remain in place over the region on Tuesday, resulting in breezy westerly winds gusting upwards of 30- 40mph. Model soundings show very dry conditions in place over the entire region with dewpoints generally in the teens. Despite slightly cooler high temperatures (in the upper 50s to low 60s), these low dewpoints will be enough to cause RH values to plunge into the 14 to 18 percent range during the afternoon. The combination of these dry conditions and gusty winds will result in extreme fire danger conditions across the entire CWA. As a result, the Fire Weather Watch has been upgraded to a Red Flag Warning for the entire area. && .TOP WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 8 PM CST this evening for KSZ008>012- 020>024-034>038. Red Flag Warning from 11 AM to 6 PM CST Tuesday for KSZ008>012- 020>024-026-034>040-054>056-058-059. Wind Advisory until 8 PM CST this evening for KSZ008>012-020>024- 026-034>040-054>056-058-059. && $$ SHORT TERM...65 LONG TERM...Hennecke AVIATION...65 FIRE WEATHER...Hennecke/65