Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/20/21

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
603 PM MDT Mon Jul 19 2021 .AVIATION... 00Z TAF CYCLE Upper level north to south ridge axis is over NM this evening. The axis will remain over NM but will tilt to the northeast/southwest during the next 24 hrs with drier air aloft continuing to spread over ern NM. Isold showers and tstms will continue this evening with brief MVFR cigs/vsbys in precipitation. Activity to slowly dissipate through 06Z and mostly end after that. Similar convection scenario Tuesday afternoon into the night. && .PREV DISCUSSION...241 PM MDT Mon Jul 19 2021... .SYNOPSIS... A decrease in the coverage of showers and thunderstorms is expected to continue through Tuesday before greater chances return to the region beginning Wednesday. The focus for heavier rainfall will be over northern, central, and western New Mexico Wednesday through Sunday with localized flash flooding possible. Temperatures will remain near to slightly below normal for mid July. && .DISCUSSION... SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)... Upper ridge axis stretched along the AZ/NM border and northward today will slowly tilt in a clockwise direction during the next 24 to 36 hours. Some drier air at and above 500 mb has spread over eastern NM and into portions of central NM as well with the main moisture plume directed over AZ. The upper high circulation has apparently spread some elevated smoke into the region, resulting in hazy skies and which the HRRR indicates will persist in the short term and possibly become a bit more concentrated. Otherwise, southeast NM seems to be the focus area for storms this afternoon, but LAPS is indicating the southwest portion of NM may become more active later this afternoon or this evening, which the RAP13 and NAM12 are hinting at as well. Isolated activity would persist over southeast NM after midnight if the NAM12 is right. Northeast NM may see an uptick in activity Tuesday as the ridge axis shifts. Not confident the low clouds/fog observed this morning in far east central NM or in the Moreno Valley will reappear tonight, so left it out out the weather grids. Overnight lows will be a few degrees warmer than normal, while highs on Tuesday will be near to below average for mid July. LONG TERM...(WEDNESDAY THROUGH SUNDAY)... Wednesday will signal the beginning of a return to greater storm coverage across the region thru the weekend. The wedge of mid and upper level dry air sliding over the area Monday and Tuesday will be shunted into southern NM and northern Chihuahua Wednesday. An axis of 700-500mb layer deformation is expected to coincide w/ greater moist instability over the northwestern half of our area Wednesday and Thursday. This will increase the coverage of showers and storms w/ heavy rainfall once again. An easterly wave approaching from TX will increase subsidence over eastern NM where very little storm coverage is expected both days. Models continue to struggle w/ the progression of the easterly wave Friday thru the weekend. There are big differences amongst models with respect to the depth, location, and orientation of the wave which will have impacts on the coverage and location of the heavier rainfall across NM. At this time, a notable uptick in storm coverage is expected over the western half of NM from Friday thru Sunday but confidence remains very low east of the Cont Dvd. Either way, there will still be abundant moist instability in place w/ slow storm motion so locally heavy rainfall remains possible. Max temps will also be near to slightly below normal for mid July areawide. 99/Guyer && .FIRE WEATHER... The upper ridge axis stretched along the AZ/NM border and northward today will slowly tilt in a clockwise direction during the next 24 to 36 hours. Storm motion will generally be from northeast to southwest through tonight, then may become more north to south over eastern NM Tuesday while remaining northeast to southwest over western NM. Cells may move more slowly and erratically Wednesday with the upper high center becoming more elongated from west to east. In any event, the focus for showers and storms will be generally along and west of I-25 and along and north of I-40 through much of this week. Highs will be near to below normal and overnight lows will be a few degrees warmer than average. Winds will be light outside of convective activity and areas of fair to poor ventilation are forecast for portions of the north, west and central this week. 99 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service La Crosse WI
654 PM CDT Mon Jul 19 2021 .SHORT TERM...(This evening through Tuesday) Issued at 240 PM CDT Mon Jul 19 2021 Surface high pressure was in control over the area with thunderstorms continuing to roll southward out of northern MN. Just west of the ridge is a CAPE pool that may allow a bit of development westward toward/along the Red River. Current and forecast instability shows a bit of instability into northwest WI, but any forcing would have to be based on the system cold pool. Expected impacts are high clouds at this time. The MN thunderstorms initiated on an east-west cold frontal boundary shifting south through southwest Ontario. This front will travel south/west to about the Mississippi river by later Tuesday and with ~2500 J/Kg of MLCAPE on the convergent boundary, some storm chances exist. Wind shear does not look favorable for organized storms, but a pulse strong to severe storm could occur. With only shallow near-surface convergence the main forcing mechanism, would expect isolated to scattered coverage of showers or storms. Moisture will be pooling on the front which will increase the mugginess in the area on and west of the front. Smoke should increase Tuesday based on HRRR smoke guidance. .LONG TERM...(Tuesday night through Monday) Issued at 240 PM CDT Mon Jul 19 2021 A warm period with mid 80s to 90 expected depending on thickness of smoke. On Wednesday and Thursday, there is good large scale model consensus on more shortwave trough ripples in the northwest flow. The shortwaves emanate out of the western U.S. monsoonal airstream convection ongoing in NV/UT/ID. With the front in the area and better low-level southwest flow, isentropic lift will be increasing into the front. The NAM is most aggressive with the low-level moisture transport but there seems to be forcing across many models Thursday afternoon, especially in WI. With the front evolving northeast slowly in warm advection, the placement is still a question. If the front is still in the area, this again provides more shower/storm chances, but not severe storms, and mainly for WI. Low-level warmth and warm advection continues into the late week under the edge of the upper ridge and in northwest flow. Temperatures may need to be raised late week. Good signals still coming in about a Saturday convective complex mainly affecting WI and probably elevated...but we will need to keep an eye on this one. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 650 PM CDT Mon Jul 19 2021 VFR conditions expected through the TAF period. Not anticipating fog tonight at LSE given slightly stronger winds just above the surface. Guidance does not suggest much potential for patches of low stratus at LSE either; looking fairly dry near the surface compared to previous nights. Have left low stratus out of the TAFs for now but will monitor trends this evening. A cold front will drop in from the northeast Tuesday afternoon. Pretty low potential overall for showers and storms with this front, but isolated convection is possible in the afternoon. Due to low confidence/coverage, have left mention out of the TAFs for now. Generally light winds under 10 knots through the period, out of the west to southwest tonight, then shifting to the northwest to north Tuesday afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Baumgardt LONG TERM...Baumgardt AVIATION...Kurz
Area Forecast Discussion
National Weather Service Bismarck ND
1001 PM CDT Mon Jul 19 2021 .UPDATE... Issued at 957 PM CDT Mon Jul 19 2021 Thunderstorm activity has tamed down quite a bit, with only a few little cells floating through eastern parts of our area. With that said, will keep low chances in through the night as a variety of weak disturbances moving through the ridge could cause a few storms to develop. Have also spread areas of smoke through our whole area as have noticed some lowered visibility reports peppered through parts of western/central ND. In addition, models are hinting at some fog possibly developing later over the northern tier, where surface air is nearly saturated. So, have spread the patchy fog across the far north. UPDATE Issued at 708 PM CDT Mon Jul 19 2021 An area of thunderstorms, with one becoming significantly severe, has developed over north central North Dakota where a plethora of boundaries are noted. This is in an area of 40kt+ deep layer shear and strong instability of around 2-3 KJ/Kg. The most significant storm is now pushing south in southern McHenry County about to slide into Sheridan and possibly far eastern McLean. This storm has had a history of producing baseball hail and 70 mph wind gusts. For the next few hours, expect the severe threat to continue over north central North Dakota possibly nudging into the northern James River Valley, with current development off to the northeast of the significant storm. With that said, CIN expected to quickly increase as we close into sunset, therefore expect the severe threat to wane in a couple of hours. && .SHORT TERM...(This evening through Tonight) Issued at 229 PM CDT Mon Jul 19 2021 Fire weather, heat and thunderstorms (in no particular order) are the main threats late this afternoon and tonight. Fire Weather...We continue to hold in the near critical fire weather conditions range, and unless we see winds really pick-up, we`ll probably leave this as is. Current humidities are generally around 15 percent in the far southwest, although did see Beach drop down to 12 percent this hour. Other than the far southwest, readings are generally 15 to 30 percent. Wind speeds are around 15 knots in the far southwest, but under 10 knots elsewhere. Given the marginal area, and marginal thresholds will likely ride with the near critical fire conditions. Heat Advisory...The Heat Advisory continues through 9 PM CDT. So far we`ve seen heat index values to around 103 at Bismarck, with many stations in the 95 to 100 range as of 230 PM CDT. Maximum heat indices look to peak around 4-5PM CDT and then drop off thereafter. Thunderstorms...A very unstable airmass remains over central into eastern ND with MLCAPE values of 1500-3500 from north central into east central ND with little CIN indicated from the EMC RAP on the SPC mesoanalysis page. However shear remains weak. This would favor possibly a marginally severe hail or wind event with an updraft that can survive the cap. Recent convection that developed near Jamestown was briefly able to sustain an updraft, but as of 300 PM the cell was dissipating. It`s possible we could see a few more cells develop along the southward moving outflow boundary this afternoon. Whether they can sustain themselves remains to be seen. If so, a marginally severe wind or hail report can not be ruled out base in the strong instability. A baroclinic zone remains along the International Border and later tonight it`s possible we could see a few storms along this boundary and northward into Canada, but most will remain dry. .LONG TERM...(Tuesday through Monday) Issued at 229 PM CDT Mon Jul 19 2021 Hot and dry conditions continue through much of the work week. A weak cold front moves through the forecast area in the Tue-Wed timeframe with only slight chances for thunderstorms due to the strong capping. Temperatures Tuesday through Friday remain in the 90 to 100 degree range across western and central ND, with the warmest readings west and south central. Humidity values drop a bit, but we could still be flirting with Heat Advisory criteria. Most likely it will be a day to day call with marginal Heat Advisory criteria possible each afternoon. There does look to be an increase in surface based smoke tonight into Tuesday morning north of the frontal boundary that`s been lingering along the International Border. We kept a mention of smoke in the forecast far north central late tonight into Tuesday morning, as well as some patchy fog. The best chance of thunderstorms in the next several days looks to be on Friday as as stronger shortwave impulse tracks across southern Canada and flattens our upper level ridge. This should also cool us down a little through the upcoming weekend. At this time it`s looking like mid 80s north to mid 90s south through the weekend, so not a big drop in temperatures at all, but some relief. After the chance of thunderstorms Friday, the rest of the weekend looks mostly dry at this time, with indications of possibly warming up again early next week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 708 PM CDT Mon Jul 19 2021 Ongoing strong/severe thunderstorms over north central North Dakota will continue to settle southerly this evening, but at this time do not expect them to hit any of the TAF sites. With that said, additional development is possible, but will withhold from mentioning in any TAFs as confidence is quite low whether they would be affected. Otherwise, VFR conditions are expected. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JJS SHORT TERM...TWH LONG TERM...TWH AVIATION...JJS
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
805 PM CDT Mon Jul 19 2021 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...Surface obs indicate that VFR conditions are prevailing across the RGV this evening. The 00Z BRO sounding shows a relatively dry atms over the region with a PWAT of 1.86 inches. The latest HRRR guidance keeps the conv clear of the RGV throughout the night with more conv firing off in central TX closer to the cold front pushing into the region. The HRRR then brings this conv north of a line from LRD-CRP by tomorrow morning. This conv will likely take its time moving into the RGV due to the slow movement of the cold front to our north. Guidance does include a PROB30 group for the MFE are for tomorrow afternoon and do not have much of an argument against this. && .PREV DISCUSSION... /issued 259 PM CDT Mon Jul 19 2021/ SHORT TERM (Now through Tuesday Night): The mid level ridge will remain over the Four Corners region through the short term, but its affect on Deep South Texas will lessen as an elongated trough over the Southeast CONUS extends across Texas. At the surface, high pressure off the East Coast extending across the Gulf of Mexico will allow light to moderate southeast winds to persist through tomorrow morning. As the trough axis approaches Deep South Texas tomorrow, rain chances will increase with the upper level support, along with increased PWATs. WPC has included the northern ranchlands and part of Zapata and Starr counties in a Marginal Risk of Excessive Rainfall tomorrow through tomorrow night, so we will watch for the potential for flash flooding in these areas. Overall QPF amounts are expected to be in the 0.25 to 0.5 inch range, but locally higher amounts will be possible. Winds will decrease in response to an approaching cold front associated with the trough and shift northerly or northeasterly during the day tomorrow, but the south- southeasterly flow will return overnight Tuesday night. The front will stall north of our area, so even though there will be a weak wind shift, no CAA is expected. Temperatures will be near climatological normal for overnight lows, but will likely be a few degrees below normal for Tuesday`s high. However, heat indices will top out in the 100 to 107 degree range tomorrow afternoon, so it will still feel hot. Temperatures may not quite reach this high if the cloud cover/convection is more widespread, so this is a lower confidence forecast for tomorrow`s temperatures. LONG TERM (Wednesday through Monday): 500mb low/elongated trough across east and south Texas Wednesday will continued to provide unsettled weather across deep south Texas Wednesday into Thursday as low to mid level moisture remains high across the area and both the GFS and the ECMWF prog high rain chances Wednesday through Thursday. WPC currently has the entire CWA in a marginal threat of excessive rainfall for Wednesday. Will continue to mention showers and thunderstorms across the Rio Grande Valley and northern ranchlands Wednesday through Thursday before the 500mb low/inverted trough across Texas Thursday begins to nudge northwest as a 500mb subtropical ridge moves into the western Gulf of Mexico Friday. This will provide drier air across deep south Texas as well as an increase in subsidence across the lower Texas coast. Rain chances will remain limited through the rest of the week into the weekend as a result and temperatures in the afternoon will return to near normal with the decrease in cloud cover and rain chances through the rest of the forecast period. MARINE (Now through Tuesday Night): Generally favorable marine conditions are expected through mid week with wave heights in the 1 to 3 or 2 to 4 foot range and light to moderate winds expected. However, isolated to scattered showers and thunderstorms will be possible over the waters with heavy rain and occasional cloud to water lightning tomorrow and tomorrow night. Wednesday through Saturday...Light south to southwest winds will prevail across the coastal waters Wednesday with a trough of low pressure along the Texas coast. Winds will back to the south to southeast Thursday with surface high pressure across the eastern Gulf of Mexico. Light south to southeast winds will prevail Thursday before increasing slightly on Friday as the pressure gradient increases slightly across the western Gulf of Mexico. Moderate south to southeast winds will prevail across the coastal waters Friday with winds approaching SCEC conditions across the offshore waters Fri night. The pressure gradient will remain relatively strong across the western Gulf of Mexico Saturday with SCEC conditions possible across the offshore waters. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 78 92 78 89 / 10 20 30 50 BROWNSVILLE 78 95 78 92 / 0 20 30 50 HARLINGEN 77 95 76 90 / 10 20 30 50 MCALLEN 77 95 77 91 / 0 30 40 50 RIO GRANDE CITY 77 98 76 94 / 10 30 40 60 SOUTH PADRE ISLAND 81 87 80 86 / 10 20 30 50 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: Short Term/Aviation...60-Speece Long Term...55-Adams Upper Air...65-Soria
Area Forecast Discussion
National Weather Service Burlington VT
1033 PM EDT Mon Jul 19 2021 .SYNOPSIS... Hazy conditions will persist overnight and into tomorrow morning due to smoke overhead from upstream fires. A cold front will pass Tuesday afternoon, spawning showers and thunderstorms during the afternoon and evening. A few of which may produce gusty winds and locally heavy rain. Additional chances for showers exists Wednesday through Friday and again on Sunday, with generally cooler than normal weather persisting through the period. && .NEAR TERM /THROUGH TUESDAY NIGHT/... As of 1033 PM EDT Monday...After flaring up quite nicely across the Adirondacks, convection has begun to really diminish. Of course, as I type this, new cell development has begun in Franklin County, Vermont, but the trend should be weakening. Raised PoPs over parts of Essex County, New York for a semi- organized cluster of decaying thunderstorms. Fog can already also be seen on nighttime microphysics satellite RGB, and the haze will continue to persist overnight, and then worsen. Based on conditions, expanded fog and also made note of reduced visibilities from haze, as each new HRRR cycle continues to paint a picture of a slight increase in smoke presence across the lowest levels, which should be cleared as an oncoming front pushes it south in the afternoon. The air will likely be unhealthy for sensitive groups. The forecast is overall in great shape. Previous Discussion below. Overall, cloud cover should decrease overnight, though the skies will remain hazy due to smoke from upstream forest fires. In addition, patchy fog is likely to develop within favored locations across the Adirondacks and eastern Vermont. Overnight low temperatures will be in the low to mid 60s. Tuesday will feature a passing cold front, with showers and thunderstorms developing along and ahead of the front during the afternoon and evening. Plenty of instability (>1000 J/kg of CAPE) will be present ahead of the approaching front, owing to effective daytime heating and dewpoints in the 60s. However, skies will again look milky and hazy with smoke from upstream fires moving overhead. Ultimately, this could limit the amount of heating and instability available. On the other hand, synoptic lift will support the development of thunderstorms with lowering heights as an upper level trough approaches. Marginal wind shear and lapse rates will exist across the North Country as well. This means that storms are likely to develop along and ahead of the passing cold front, mainly between noon and 8 PM, passing from north to south. Few of the storms have the potential to become severe, producing strong, gusty winds. There also exists the potential for localized heavy rain with PWATs of 1.3 to 1.5 inches. High temperatures on Tuesday will be in the upper 70s to low 80s, with warmer temperatures to the south. Thunder potential will decrease overnight Tuesday into Wednesday in the wake of the cold front, though rain showers are likely to continue as the upper trough continues to move overhead. Overnight lows will be in the upper 50s to low 60s. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 255 PM EDT Monday... Upper trough lags surface frontal passage during Wednesday with continued cloudiness and a decent chance of showers and perhaps a few storms, especially across the eastern and southern portions of the forecast area. Shower activity then ends by Wednesday evening as the trough pulls east. Highs to remain seasonably mild in the 70s with overnight lows mainly in the 50s. Patchy fog also a good bet Wednesday night per low level moisture profiles. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 255 PM EDT Monday...As discussed yesterday, the Northeast remains in a northwesterly upper flow regime to the east of a pronounced western US ridge through the Thursday through Monday time frame. A weak feature embedded within this flow may spark a few showers, mainly north and east on Friday. Otherwise dry weather is expected through Saturday. By next Sunday into Monday there is better consensus on a more pronounced shortwave trough passage with a renewed threat for showers and perhaps a few storms. Temperatures remain seasonably mild through the entire period with daily highs in the 70s to around 80, and overnight lows mainly in the 50s to lower 60s. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... Through 00Z Wednesday...Mainly VFR at this time with southwest winds around 5 knots, except west at MSS. At MSS and SLK, haze is being observed at 4 to 6 SM due to smoke from upwind wildfires. This seems likely to continue overnight and reach PBG shortly, but as winds become light and terrain driven past 03Z, the progress of haze into Vermont will slow. Anticipate areas of fog to develop at MSS, SLK, and MPV, generally at 1 to 4 SM, and occasionally down to 1/4 SM visibility from roughly 06Z-12Z. Around 12Z, anticipate a transition to west to northwest winds around 5 knots, which will start to drive lower visibilities from haze/smoke into Vermont, and have mentioned 4 to 6 SM visibilities across the region as hourly smoke forecasts indicate spreading and thickening over our region. Around 15Z, scattered showers and isolated storms will begin to develop, with a more concentrate area moving from northwest to southeast beyond 18Z, which will also start to clear out remaining haze. This activity will continue beyond 00Z Wednesday. Outlook... Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Wednesday: Mainly VFR, with areas MVFR possible. Likely SHRA, Slight chance TSRA. Wednesday Night: VFR. Patchy BR. Thursday: VFR. Patchy BR. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. Chance SHRA. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Hammond NEAR TERM...Hammond/Haynes SHORT TERM...JMG LONG TERM...JMG AVIATION...Haynes
National Weather Service Sioux Falls SD
1050 PM CDT Mon Jul 19 2021 .SHORT TERM...(This Evening through Tuesday Night) Issued at 248 PM CDT Mon Jul 19 2021 With weak flow aloft, afternoon satellite shows mostly clear skies with surface observations climbing into the mid to upper 80s and isolated 90s west of the James River. The weak flow aloft is courtesy of a strong high pressure ridge which has set up across the central Rockies and is looking to remain in place throughout the work week. At the surface, a surface high pressure meanders a bit around the central US, leaving the region predominantly under southerly surface flow. For tonight, this will keep quiet weather continuing, with possibly some patchy fog in low lying areas into the early morning hours. One thing of note is the activity that is currently ongoing in eastern ND and western MN, which has a south/southeasterly trajectory. All the models point towards the group of storms dying out as instability wanes this evening, but it`s not out of the realm of possibility given the weak flow and cold-pool driven convection. On the backside of the ridge, the HRRR smoke trajectories indicate the area will be socked in all day Tuesday with rather thick smoke aloft. Good news is that the inversion above 800 mb should keep most of the smoke from reaching the surface layer, which agrees with low amounts of near-surface smoke that the HRRR is projecting. Otherwise, expect mostly a repeat of Monday for Tuesday, with slightly warmer temperatures as surface flow remains southerly, the inversion aloft strengthens, and ample sunshine blankets the region. Temperatures as a result will largely be in the upper 80s to lower 90s. Areas west of the James River will likely see winds pick up a bit during the afternoon hours as a surface low pressure tries to develop over WY, but gusts should remain under 20 mph. .LONG TERM...(Wednesday through Monday) Issued at 248 PM CDT Mon Jul 19 2021 As surface flow remains largely southerly thanks to that surface high, expect temperatures to continue increasing throughout the second half of the week. The aforementioned surface low continues to try to develop as it slowly drifts eastwards, keeping the region in an area of enhanced surface pressure gradient. With winds at the top of the mixed layer in the 25-30 knot range, gusts of 25-30 mph should be expected for areas along/west of I-29, with gusts in the 20-25 mph range elsewhere. With the stagnant pattern, temperatures on Wednesday will be quite similar to those on Tuesday, again in the upper 80s and lower 90s. RH`s look to remain above 30 percent, so critical fire thresholds aren`t being met but certainly something to keep in mind in case any burning is planned for Wednesday. The previously shift mentioned a Wednesday night wave moving towards the area, but the latest ensemble guidances (particularly the NBM probabilities) have come in primarily dry. So, while a couple deterministic models continue to hint at it being possible, have left the populated guidance untouched thus a dry overnight period into Thursday morning. The forecast becomes a bit more uncertain for the rest of the period, as the upper level heights remain fairly consistent and eventually bringing the low pressure near/through the region. When and how this occurs will certainly have effects on the temperature and rain forecast, but for now have left the extended forecast unchanged due to the uncertainty. This leaves temperatures to continue climbing into Friday, with widespread temperatures in the lower to upper 90s and heat indices approaching the triple digit mark. A jet max looks to finally flatten the upper level ridge a bit by the weekend, which should help get closer to more seasonably normal temperatures. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1050 PM CDT Mon Jul 19 2021 VFR conditions are forecast to prevail this TAF cycle. Much like the past few days, look for wildfire smoke to linger overhead tonight and tomorrow, with minimal impacts expected near the sfc. In addition to this, could also see some diurnally driven cu develop during the afternoon hours. Otherwise, expect light and variable winds overnight to become south-southeasterly by tomorrow afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...APT LONG TERM...APT AVIATION...SSC
Area Forecast Discussion
National Weather Service Glasgow MT
702 PM MDT Mon Jul 19 2021 .DISCUSSION... EVENING UPDATE: Minor changes were made to hourly Temp, RH, and Wind data sets to keep up with observations through tonight. Currently a boundary running from Opheim to just east of Saco to Winnett has sharpened up heavier than the HRRR was predicting and has gained a slight eastward component. It is unknown exactly where or if the boundary will stall out, but areas just to the west and north of it are experiencing a drop of 15 degrees compared to the southeast side. GAH AFTERNOON DISCUSSION: The current heatwave is reaching its crescendo this afternoon, with several records already falling as temps surge well above triple digits. Some monsoonal is currently approaching northeast Montana from the southwest, and could drive a few showers or thunderstorms this evening and overnight tonight. Current suite of hazard products including excessive heat warning and red flag warning (through midnight) look on track. Tuesday the thermal low will shift to the east, allowing for a bit cooler temps across northeast montana, however the lower yellowstone valley still looks to be near 100 degrees. Monsoonal moisture will remain in the mix, keeping some mention of showers and thunderstorms in the forecast. Wednesday into Thursday The upper ridge will flatten out a bit as an upper trough slides from British Columbia into Alberta, allowing for continued chances for precip, and continued hot temperatures. Friday and beyond flattened ridging will keep above average temps and dry conditions going for the foreseeable future. Gilchrist && .AVIATION... LAST UPDATED: 0100Z FLIGHT CAT: VFR. SMOKE AND HAZE: Will continue to push through the area over the next few days, lowering normal and slantwise visibility at times. Currently MVFR visibility is not anticipated. DENSITY ALTITUDE: With record highs across the area high density altitude will take more power and runway distance to take off. LLWS: Low level wind shear will be possible across the terminals from about 04/06Z to 15Z. WIND: Southeast at 10 to 20 kts this evening, reducing to 5 to 15 kts after midnight. Then increasing to 10 to 20 kts Tuesday with varying direction wrapping around a low as it passes through. DISCUSSION: Thanks to building monsoonal moisture thunderstorms are possible tonight at KGGW though confidence is very low. Isolated to scattered showers could expand to the other terminals by late Tuesday morning. /GAH && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 9 PM MDT Thursday for Central and Southeast Phillips...Central and Southern Valley...Daniels... Dawson...Eastern Roosevelt...Garfield...McCone...Northern Phillips...Northern Valley...Petroleum...Prairie...Richland... Sheridan...Southwest Phillips...Western Roosevelt...Wibaux. Red Flag Warning until midnight MDT tonight for MTZ120-122-134>137. && $$
Area Forecast Discussion
National Weather Service Grand Rapids MI
811 PM EDT Mon Jul 19 2021 LATEST UPDATE... Update/Aviation .SYNOPSIS... Issued at 330 PM EDT Mon Jul 19 2021 - Very small chance for a shower over Central Lower this evening - Better chances for showers/storms Tuesday afternoon/evening - Thursday into Saturday precipitation chances && .UPDATE... Issued at 810 PM EDT Mon Jul 19 2021 Updated to add Ottawa, Allegan and Van Buren counties and adjacent nearshore waters to the Beach Hazard Statement/Small Craft Advisory, but with a later start/end time than the counties to the north (issued earlier). The period of higher winds and waves in this area is more for Tuesday evening whereas location to the north will be seeing the increasing north flow and building waves in the afternoon. && .DISCUSSION...(This evening through next Monday) Issued at 330 PM EDT Mon Jul 19 2021 - Very small chance for a shower over Central Lower this evening Cannot rule out a small chance for a shower or a storm across Central Lower Michigan this evening. MUCAPE values are on the order of 1000-2000 j/kg across our eastern half of the forecast area, essentially from U.S. Highway 131 to the east. There is some convergence seen in the surface wind field across Central Lower Michigan where a cumulus field has recently developed. The chances are low 10-20 percent, so not zero this evening. Of the 5 models in the SPC HREF only one from the 12z run is really showing any precipitation. So, not out of the realm of possibilities, but the threat is small. - Better chances for showers/storms Tuesday afternoon/evening Better chances exist for showers and storms tomorrow (Tuesday). The chance of showers and storms will be forced by a cold front dropping south through the Lower Peninsula. The issue though is that the flow will be westerly ahead of the cold frontal passage and that may advect in slightly more stable air off of Lake Michigan. In looking at the SPC HREF there is definitely a better chance of showers and storms to our west over Wisconsin and to our east of Eastern Lower Michigan. Our chances for precipitation are certainly not zero, but better chances exist to our west and east. Right now we have a dry forecast towards Lake Michigan tomorrow and 20-40 pct chance pops in the east. Based on the 12z SPC HREF this looks good. - Thursday into Saturday precipitation chances Chances for showers and thunderstorms exist at times during the period of Thursday through Saturday. A warm front will be situated in the area during this time frame. Best chances will be when we have some upper support that coincident with the surface front in the area. That will be on Thursday and again Friday night into Saturday. The pattern will be dominated over the course of the next 7 days with northwest upper flow (smoke will be likely aloft) and occasional shortwaves rippling through the flow bringing us chances for showers and storms. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 810 PM EDT Mon Jul 19 2021 Smoke layer aloft is still present, likely located between 5K and 8K ft based on VAD wind profile and HRRR Smoke progs. 6 mile vsby in haze at LAN indicates that some of the smoke has made it down to the sfc. There`s also some high level cirrus cloud arriving from the north tonight. Can`t rule out some patchy shallow ground fog early Tuesday morning but was not confident enough to put in any of the TAFs. VFR continuing on Tuesday although winds increasing out of the west to 10 to 20 kts in the afternoon, then shifting more northerly later in the day with the passage of a cold front. Can`t rule out a shower or even a tstm at LAN and JXN after 21Z Tuesday, but best coverage expected to be farther east so have not included that low threat in the TAFs. && .MARINE... Issued at 330 PM EDT Mon Jul 19 2021 We have gone ahead and issued both a Beach Hazards Statement and Small Craft Advisory for Tuesday afternoon and Tuesday night from Grand Haven off to the north. Winds increase behind a cold front Tuesday afternoon with winds expected to reach 20+ knots at times. This should be enough to push waves into the 3 to 5 foot range. We feel these areas have the best chance at seeing larger waves. There are indications that the waves may push into areas south of Grand Haven as well Tuesday evening and Tuesday night, but at this point we will wait on those areas for higher confidence. High pressure builds in for Wednesday into Wednesday night with quiet mid summer conditions expected during that time. The surface pressure gradient is actually baggy into Thursday and Friday as well, so little to no waves expected from Wednesday through Friday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from Tuesday evening through Wednesday morning for MIZ056-064-071. Beach Hazards Statement from Tuesday afternoon through late Tuesday night for MIZ037-043-050. LM...Small Craft Advisory from noon Tuesday to 2 AM EDT Wednesday for LMZ847>849. Small Craft Advisory from 6 PM Tuesday to 8 AM EDT Wednesday for LMZ844>846. && $$ UPDATE...Meade SYNOPSIS...Duke DISCUSSION...Duke AVIATION...Meade MARINE...Duke
Area Forecast Discussion
National Weather Service Lincoln IL
931 PM CDT Mon Jul 19 2021 .SYNOPSIS... Issued at 232 PM CDT Mon Jul 19 2021 Dry and seasonable weather is expected through much of this week. Things turn hot and humid Friday into the weekend with heat indices climbing into the upper 90s to 100. The next chance for precipitation arrives for some later this week and for most this weekend. && .UPDATE... Issued at 925 PM CDT Mon Jul 19 2021 Expansive high pressure at the surface from the Central Plains to the central Great Lakes will keep our weather quiet tonight and likely tomorrow as well. Light northeast winds and clear skies will set the stage for light fog to develop late. The HRRR has started indicating some patchy dense fog from BMI to CMI to Taylorville. The GFS is broad brushing some light 4-5SM fog in a large portion of our forecast area. Dewpoint depressions are still on the high side for mid-evening, but ground fog will still be possible in low lying areas and near waterways. Lows should bottom out in the mid 60s, which is at or below the current dewpoints. Will add some patchy fog for late tonight. Otherwise, the forecast appears on track. && .SHORT TERM...(This evening) ISSUED AT 232 PM CDT Mon Jul 19 2021 Large-scale upper ridging remains in place over the western CONUS, with northwest flow positioned over the Upper Midwest into the eastern Great Lakes Region. At the surface high pressure is centered over IA, with a stationary front stretched from the Mid-Atlantic states to Texas slowly edging toward the Gulf as the surface high builds southward. High pressure will keep the weather rather benign here for the meantime with mostly dry and seasonable conditions expected. Scattered diurnal cumulus blanket the area as of 2 PM, with a hazy or milky look to the sky. This happens to be smoke from western US and Canadian wildfires riding over the top of the ridge and working it`s way into the Midwest states as it rounds the high. This smoke will remain positioned aloft with little impact to air quality. Instead, it will add an orange-pink hue to our sunsets over the next few days. Light winds and clear skies overnight may allow patchy fog to develop once again for some. Lows tonight will be similar to last night, with values in the middle to upper 60s. .LONG TERM...(Tuesday through Monday) ISSUED AT 232 PM CDT Mon Jul 19 2021 Northwest flow remains positioned aloft through the long term period. A few shortwave troughs look to ride the eastern edge of the large-scale ridge this week, though most of these will impact the Great Lakes Region through Thursday keeping any chances for precipitation northeast of our area. The pattern looks to hold steady until later this week as the ridge suppresses some and migrates eastward as a trough moves onshore the Pacific NW. This will act to move the surface high east of here, turning winds southwesterly by Thursday. Temperatures and humidity will increase going into the weekend with highs Friday into early next week looking to peak in the low 90s with dewpoints in the low to middle 70s. This will lead to uncomfortable heat indices of 95 to 100+ during this time as well. The next chance for precipitation looks to return across east-central IL Friday afternoon as a weak wave ripples through the flow aloft. Better chances for showers and storms for the entire area look possible later Saturday into Sunday as a cold front sags southward from a wave topping the western CONUS ridge. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 652 PM CDT Mon Jul 19 2021 VFR conditions are expected to prevail through tomorrow afternoon. Diurnal cumulus around 4k feet have nearly completely dissipated. A layer of smoke aloft will keep a milky appearance to the skies tonight, otherwise no clouds are expected overnight. Still seeing indications of brief MVFR fog near PIA and BMI, but confidence is low on that occurring. Another day of patchy VFR CU are expected on Tuesday, but limited BKN ceilings if any develop. Winds will remain light overnight, mostly out of the northeast. A wind shift to N-NW is forecast for Tuesday as the orientation of the surface ridge alters slightly. Prevailing speeds should remain less than 10kt. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SYNOPSIS...NMB SHORT TERM...NMB LONG TERM...NMB AVIATION...Shimon
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1040 PM CDT Mon Jul 19 2021 .SHORT TERM... (Through Late Tuesday Night) Issued at 246 PM CDT Mon Jul 19 2021 Currently aloft, a broad trough is positioned over the eastern U.S. with a series of shortwaves digging southward along its western periphery across the Midwest and Plains. One of these shortwaves is currently making its way out of the Middle Mississippi Valley and providing weak lift across portions of central and southern Missouri, where 2,500 J/kg of SBCAPE resides. This has allowed for showers to recently blossom in these areas, and I expect the chance for this isolated to scattered convection to continue in southwestern portions of the CWA over the next several hours before instability wanes and the shortwave continues southward. A mid-level warm nose seen in model soundings is expected to keep convection as mostly showers, but I can`t completely rule out a rumble of thunder. Additionally, several recent HRRR runs have wanted to produce brief, isolated showers in our Illinois counties this afternoon associated with a weak shortwave in northern Illinois. However, the cumulus through much of Illinois looks weak per visible satellite, and lapse rates are very poor in this area, so I find this solution unlikely at the moment. Tomorrow, the lack of any apparent upper-level disturbances, poor lapse rates, and capping are expected to keep the CWA rain-free. The surface high that is currently in place over the Midwest will hold, keeping temperatures similar to what they are today across the CWA. Elmore .LONG TERM... (Wednesday through Next Monday) Issued at 246 PM CDT Mon Jul 19 2021 On Wednesday, the ridge over the western U.S. will build eastward and broaden as the trough over the eastern portion of the country slowly pushes off over the Atlantic Ocean. In response to this upper- level pattern shift, the surface high responsible for our weather early this week will shift eastward, placing the Middle Mississippi Valley on its western periphery and returning southerly flow to the CWA. This flow will help advect warmer air and higher dew points into the region for the end of the week, pushing temperatures to and then above normal for the weekend. There are still subtle differences in the ridge`s eastward extent and positioning this weekend and the phasing of an eastern upper-level trough late weekend/early next week among ensemble guidance noted in WPC ensemble cluster analysis. Even with these differences in ridge placement, the recent run of the NAEFS and EPS have 850 mb temperatures that line up with each other a little better than previous runs for Friday and Saturday. Values at 850 mb are currently forecast to be around 18-19 degrees C Friday, with Saturday being the warmest at 20-21 degrees C. This correlates with surface temperatures at or just above 90 for Friday and in the low to mid 90s for Saturday. This aligns well with ensemble means during this timeframe, which is representative of the current forecast. If the ridge is able to shift a little further east, we could see afternoon highs climbing a degree or two warmer that currently forecast. With the return of the heat and humidity to the CWA, I can`t rule out isolated to scattered diurnal convection during peak heating in the extended period through Saturday over portions of the CWA, but my confidence is greater in a dry forecast. A leading shortwave ahead of an upper-level trough is forecast to pass through the upper Midwest Saturday and Sunday, sending a cold front through the Midwest late Saturday and Sunday. Understandably at this lead time, there is much spread among guidance on the placement and progression of the front, which decreases confidence in temperatures and rain chances for Sunday and beyond. Elmore && .AVIATION... (For the 06z TAFs through 06z Tuesday Night) Issued at 1039 PM CDT Mon Jul 19 2021 High pressure will continue to settle over the region, resulting in tranquil conditions through the TAF period. The only potential fly in the ointment is the potential for fog in the river vallies in the early morning hours on Tuesday. Guidance still shows very little in the way of fog development, but with dewpoint depressions dropping to near or below 5 degrees and light winds, at least patchy fog is possible. I`m not terribly confident that fog will develop, so I`ve stuck with just 6SM BR at JEF, SUS, and CPS. That said, if fog does indeed develop, I would not be surprised if visbys drop below 6 miles at times. BSH && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX