Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/11/24


Area Forecast Discussion
National Weather Service Des Moines IA
615 PM CDT Tue Sep 10 2024 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Low (<30%) chance of sprinkles in the north this afternoon and evening, mainly north of Highway 20. Rainfall amounts largely immeasurable. - Smoke overhead at least through Wednesday with above average temperatures continuing into Thursday. - Very low (<20%) chance for rain Friday in the southeast, otherwise cloudiness and northerly flow to temporarily cool temperatures over the weekend. && .DISCUSSION... Issued at 144 PM CDT Tue Sep 10 2024 As a weak wave moves across southern MN this afternoon, cloud cover and perhaps some light sprinkles will continue to fester across northern Iowa until late this evening. Another passing weak wave may keep some sprinkles going in northeast Iowa past midnight, but will largely be non-impactful. Southerly flow and efficient mixing will work to warm temperatures further into the 80s Wednesday. Looking at trends in the HRRR smoke model, the heaviest concentration of upper level smoke will park on the 300mb ridge axis across mostly northern Iowa. Have lowered temperatures in this area a few degrees below guidance as well as adjusted sky cover. Smoke is still not anticipated to reach the ground as the subsidence region remains northwest of the state. Smoke trends will be monitored for Thursday as the landfall of Francine may give a more southerly component to the upper air flow, pushing smoke away from the state. Despite the smoke overhead, temperatures will remain above average into Thursday and may push close to 90 degrees. Remnants of Francine will proceed northward up the Mississippi channel and eventually succumb to the upper level pattern, keeping rain chances largely out of the state save for the far southeast in the deformation zone. What can be said is there will be an abundance of cloud cover for the southeast and northerly winds will hold temperatures closer to 80 on Friday and Saturday. Highs in the 80s are expected into early next week. Ensemble guidance hints at a longwave trough that will move inland and deepening over the western CONUS Tuesday into Wednesday of next week, a large enough feature worth monitoring for any sort of pattern change next week. && .AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/... Issued at 615 PM CDT Tue Sep 10 2024 VFR conditions will prevail through the period. There are mid and high level clouds that are passing over central Iowa this evening and into tonight, which may have sprinkles or a fleeting shower. Otherwise, there will be high level smoke and breezy surface winds from the south at 5 to 10 knots tonight will increase to around 10 knots during the day Wednesday. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Jimenez AVIATION...Ansorge
Area Forecast Discussion
National Weather Service Grand Forks ND
1017 PM CDT Tue Sep 10 2024 .KEY MESSAGES... - Varying thicknesses of upper level smoke will limit the amount of sun and affect temperatures and humidity levels tonight into Wednesday (and potentially beyond), and the smoke may briefly reach the surface tonight. && .UPDATE... Issued at 1017 PM CDT Tue Sep 10 2024 Smoke continues to impacts eastern ND and is spreading east into northwest as the cold front continues south, and with the diurnal inversion forming it it seems to be getting trapped near the surface (particularly in the Red River Valley). Visibilities in smoke have generally ranged from 3-6sm and air quality sensors have been reporting in the orange category (unhealthy for sensitive groups). Trends support the negative side of smoke models and we will likely see impacts continue into the morning. I went ahead and expanded the mention of smoke and timing through 15Z (10am) Wednesday. UPDATE Issued at 657 PM CDT Tue Sep 10 2024 Wildfire smoke has mixed to the surface as a front has started to push into eastern ND where vis has ranged from 3 to 6 miles near the frontal zone. This is well reflected by multiple runs of the RAP near surface smoke field which on more recent runs show smoke lingering longer and a little farther east. Some adjustments to smoke were made, otherwise the forecast is on track. && .DISCUSSION... Issued at 224 PM CDT Tue Sep 10 2024 ...Synopsis... 500mb heights rebound slightly tonight behind today`s departing shortwave, but as the next closed 500mb low pushes into the Pacific Northwest, the flow turns more south or southwest for Wednesday through Friday. The main 500mb system eventually tracks northeast into central Manitoba, but another shortwave may still push through the Northern Plains. For this FA, this looks to be late Friday into early Saturday (although at this point, any precipitation looks to be minimal). Behind this wave, heights rebound again for the weekend into early next week. ...Smoke... The upper level smoke has been tricky to deal with. Sunday and Monday had some around, but it still remained nearly totally sunny. Today, the smoke has been pretty thick, making it seem more cloudy than sunny. It has slowed the daily temperature rise, which has also led to humidity levels staying higher for longer. This has led to challenges with the fire weather forecast, which contains hour by hour forecasts of sky cover, temperature, and humidity. The upper level smoke is thinning now across the Devils Lake region down toward Bismarck, where temperatures have risen into the mid to upper 80s. Within the Red River Valley and adjacent areas of Minnesota, temperatures were still in the mid to upper 70s. As some thinning of the upper level smoke occurs during the mid to late afternoon, temperatures should jump up more. Models show lower levels of high level smoke tonight, but then higher levels again on Wednesday. As for surface level smoke, there may be a few hours tonight where there is some, especially along the surface front. This front is currently along a Langdon to Devils Lake to Bismarck line, and Bismarck is reporting a 6 mile visibility in haze. Minot is also reporting 4 miles visibility in haze. This isn`t really bad, but noticeable. The Minnesota Pollution Control Agency continues to monitor levels of surface smoke across Minnesota, and if concentrations get higher than anticipated, may issue an alert. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 657 PM CDT Tue Sep 10 2024 Wildfire smoke has mixed to the surface over parts of eastern ND, with MVFR vis being reported and this may continue to progress south through the evening as a from moves south (and winds shift to the northeast. There is a chance for it to linger near the surface into the night, but current guidance favors improving trends late as the front passes. Wildfire smoke will continue to stream into the region (eastern ND/northwest MN) aloft over the next several days, but additional surface impacts are much less certain. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...DJR DISCUSSION...Godon AVIATION...DJR
Area Forecast Discussion
National Weather Service Grand Rapids MI
948 PM EDT Tue Sep 10 2024 .KEY MESSAGES... - Sprinkles or light rain showers tonight in Central MI - Warm and dry pattern, only a chance of weekend showers && .UPDATE... Issued at 948 PM EDT Tue Sep 10 2024 Upstream precip reports have been only Trace to 0.02 and dry air continues to chew up most of the precip attempting to move into nrn sections of the area. No changes needed to earlier fcst of sprinkles mainly north of a Whitehall to Mt Pleasant line. && .DISCUSSION... Issued at 333 PM EDT Tue Sep 10 2024 - Sprinkles or light rain showers tonight in Central MI A couple subtle 700-500 mb shortwave troughs / vorticity maxima are rippling through this broad ridge and weak flow regime. A moist layer 700-600 mb (above 10,000 feet) with lapse rates supportive of weak instability for moist parcels is producing altocumulus, showers, and a few thunderstorms in Central Wisconsin and back toward Minn/Iowa. The first wave of showers are on track to arrive in the Ludington area after 8 PM. Dry air will be present beneath the clouds toward the surface, which should evaporate most of the precip. Some of the convection-allowing models do produce narrow swaths of measurable rainfall (0.01 inch or more) north of M-20 overnight into tomorrow morning. For what it`s worth, the ones that are bearish on rain reaching the surface have also been underrepresenting the ongoing showers in Wisconsin. Will mention a chance of sprinkles in the forecast north of a New Era to Mount Pleasant line, though there`s a possibility of isolated bona fide rain showers overcoming the dry air. Farther south, patchy fog may develop early Wed morning in the Irish Hills vicinity and east, including the Jackson area. - Warm and dry pattern, only a chance of weekend showers Broad scale upper-level ridging will amplify over the Great Lakes later in the week, supporting a stretch of warmer-than-normal temperatures with highs in the 80s. At least the dew points should be more comfortable than they were during the heat a few weeks ago. HRRR-Smoke is indicating smoke from western North American fires will be present over Michigan Wed and Thu, so skies may be hazy. Most of the smoke should stay in the 2 km to 6 km layer (7,000 to 20,000 feet). The northward progression of the remnants of Tropical Storm or Hurricane Francine may be blocked by a strengthening anticyclone over the Great Lakes late in the week. There is a chance of showers over the weekend, though this is supported by only a small minority of global model ensemble members on Saturday and still less than half of members on Sunday. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 730 PM EDT Tue Sep 10 2024 VFR is expected throughout the TAF period as high pressure dominates the forecast. A chance of mist impacting visibility at JXN between 08-13z exists but confidence is to low to include in the TAF. Mid-level (about 10-15 kft) clouds will affect the I96 terminals (MKG/GRR/LAN) tonight into Wednesday with the skies staying clear towards I94 (JXN/AZO/BTL). North of the terminals, virga or isolated light showers will potentially impact RQB, MOP, and LDM. A low chance exists that these showers could cause turbulence underneath them given low-level dry air. && .MARINE... Issued at 142 PM EDT Tue Sep 10 2024 Dense fog advisory for a few hours this afternoon between Grand Haven and Whitehall based on webcams showing half to quarter mile visibility. Satellite shows a narrow stripe of fog abutting the shoreline in that zone, presumably from moist air flowing in from the south-southwest and cooling off over the 54-58 degree water temperatures in the nearshore. The 12z HRRR`s surface visibility progs show a reasonable placement of this localized fog bank this afternoon, but indicates improving conditions as winds become south-southeast this evening and drier air moves in from the land. Have put areas of marine fog into the forecast for Wed morning between Holland and Little Sable Point based on HRRR guidance. Otherwise, little concern for hazardous winds or waves the next few days. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ UPDATE...Meade DISCUSSION...CAS AVIATION...Thomas MARINE...CAS
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
611 PM CDT Tue Sep 10 2024 .KEY MESSAGES... - The remnants of a tropical depression will lift into portions of southern and central Illinois beginning Thursday evening. Periods of rain will then persist through the weekend. There is currently a good chance (greater than 50% probability) that rain will exceed 1" in areas along and south of Highway 50 between Thursday evening and Saturday evening. Widespread flooding is not a concern. && .DISCUSSION... Issued at 114 PM CDT Tue Sep 10 2024 We remain under a bit of blocking pattern as a split-flow regime provides stronger westerlies across the northern U.S. and southern U.S. Meanwhile across our area, weak surface high pressure will continue to linger, supporting clear and dry conditions. Afternoon RH values will crater below 25%, but with slow transport winds in place, fire spread remains low. The only artifact of dry surface conditions will be large diurnal temperature swings, as temperatures dip into the low 50s overnight. Low-impact weather will continue through mid-week. Temperatures will continue to modify a few degrees warmer on Wednesday (85-90 degF) as weak surface high pressure loiters over the forecast area. Elevated smoke will remain stagnant over the central U.S., maintaining the faint hazy-looking skies, though both the HRRR and RAP keep near-surface smoke concentrations low (below 10 ug/m3). Hurricane Francine is well-forecast to make landfall late Wednesday morning across the Gulf Coast. As it weakens to a tropical depression and makes its extra-tropical transition over the Lower Mississippi Valley, it is certain to bring low clouds and rain to portions of southern and central Illinois. Current blended (NBM) and ensemble (LREF) guidance keep the highest probabilities for beneficial rainfall south of the Interstate 72 corridor, with the main QPF axis favoring locations south of Highway 50 where there is a 50-70% probability for 48-hour rainfall totals to exceed 1" between Thursday evening and Saturday evening. Flooding is not a concern given the dry antecedent conditions, and this is further supported by lofty 6-hr flash flood guidance values. The remnants of the tropical disturbance will then linger over the region through early next week as it evolves into a bit of a rex block. Persistent cloudiness and occasional light showers should tamp temperatures down in the upper 70s and low 80s next week, but generally speaking the weather will remain fairly low-impact through the middle of next week as the region remains on the dry side heading into early fall. MJA && .AVIATION... (For the 00z TAFs through 00z Wednesday Evening) Issued at 611 PM CDT Tue Sep 10 2024 VFR through the period. Southeast winds will continue under 10 kt. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
630 PM CDT Tue Sep 10 2024 .KEY MESSAGES... - Elevated wildfire smoke expected to last through at least Wednesday night. - Summer-like temperatures through the end of week. && .DISCUSSION... Issued at 246 PM CDT Tue Sep 10 2024 Current radar imagery shows isolated showers over portions of southwestern MN early this afternoon. This activity has slowly been decaying as its moved east. However, visible satellite imagery does reveal an eastward moving, weak MCV over Lac Qui Parle and Yellow Medicine counties. The HRRR seems to have a decent handle on this feature and depicts isolated showers moving through south-central MN and into western WI through this evening before finally dissipating tonight. Any rainfall will be brief and likely insignificant. Once the precip clears, hazy skies from wildfire smoke will remain. Lows tonight, as well as through early next week, are forecast in the mid 50s to lower 60s. With strong 850 hPa thermal ridging remaining over the Northern Plains and no precip expected, highs should warm for Wednesday and Thursday. 80s are expected across the area with even a 90 or two possible in western MN. However, continued smokey skies could limit our temperatures by a couple degrees. Highs should cool a few degrees Friday through Sunday (but still upper 70s to mid 80s) as a closed upper-level trough nears from the west. Southerly flow ahead of the trough will also advect smoke north, allowing most of it to clear the MPX CWA by Friday. Our next chances for rain arrive during the weekend as the forecast models show the trough moving through the Dakotas and into Ontario. However, the trough will also be weakening with the majority of its energy remaining to our north and west. Deterministic models do show some weak impulses moving through MN/WI but differences exist in the production and timing of QPF as a result of the weak synoptic dynamics. Thus, the NBM still gives us a smearing of 15-30% PoPs during the weekend with more focused periods of timing not being feasible until model differences are resolved. It seems probable, however, any precipitation that does result should not be significant or widespread. Temperatures during next week look to remain stagnant and above normal. Precipitation chances will be low to begin the week but our fortunes may change by late week as long- range guidance shows a strong trough coming on shore of the west coast and continuing east into the Rockies. Synoptically, an influx of southerly moisture would occur ahead of the trough before the trough dynamics arrive and create large-scale lift. Indeed, the CPC 8-14 Day Precipitation Outlook shows a 50-60% chance of above normal precipitation over portions of the Dakotas and Minnesota September 18-24. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 630 PM CDT Tue Sep 10 2024 A few isolated showers continue to track across central and southern Minnesota into western Wisconsin. Overall these are VFR SHRA, but there is a small chance of some MVFR visibility in some of the heavier showers. Winds will calm down after sunset and remain under 10 knots going into tomorrow. VFR and light winds on Wednesday. KMSP...Some VFR showers moving through this evening and then calm and mostly clear tonight. VFR on Wednesday. /OUTLOOK FOR KMSP/ THU-FRI...VFR. Wind SE 10-15 kts. SAT-SUN...VFR. Wind SE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...CTG AVIATION...NDC
Area Forecast Discussion
National Weather Service Marquette MI
426 PM EDT Tue Sep 10 2024 .KEY MESSAGES... - Scattered showers and maybe a rumble of thunder possible through tonight. - Extended stretch of above normal temperatures through the forecast period with highs mainly in the upper 70s and 80s. && .SHORT TERM /THROUGH TONIGHT/... Issued at 133 PM EDT Tue Sep 10 2024 Afternoon water vapor imagery shows a couple of shortwaves impacting the Great Lakes this afternoon, the first moving into the UP/northern WI, and the second through northern MN with a surface low analyzed over Manitoba and a frontal boundary moving into western MN. The first wave is moving through the UP and northern WI already, with the latest RAP analysis also showing a LLJ nosing into the area. Resulting isentropic ascent already has kicked off some spotty showers/storms across the western UP. Simulated reflectivity continues to favor an increase in coverage from M-95 eastward from the late afternoon onward, and given better elevated CAPE analyzed across the east-central UP per the latest RAP, this solution is believable. This first batch of convection continues to move eastward through the evening. Given limited CAPE and shear, strong/severe convection is not expected. Meanwhile, apart from midlevel cloud cover associated with the scattered convection, the UP remains under wispy high cirrus and patchy haze from upstream wildfires. This doesn`t appear to be having much of a limiting effect on temperatures, however; temperatures area-wide are generally in the lower to mid 70s, and plenty of spots should peak in the upper 70s to near 80F today. The first batch of showers moves out of the eastern UP later this evening, but another batch of convection associated with the frontal boundary in western MN could scrape the southern UP late tonight. Expect otherwise quiet weather as temperatures fall back into the 50s. Some of the model guidance favors patchy fog again early Wednesday morning, but with winds looking to remain more elevated compared to previous nights as our couple of waves move through, I am not entirely confident in fog development. && .LONG TERM /WEDNESDAY THROUGH TUESDAY/... Issued at 424 PM EDT Tue Sep 10 2024 Quiet and warm weather is expected through much of the long term. Weak shortwave troughing currently skirting through the Upper Midwest departs Wednesday and strong upper level ridging builds across the Upper Great Lakes down to the eastern seaboard. Surface high pressure over the Hudson bay issues in drier air tomorrow through Friday with dewpoints in the southwest UP maybe dipping into the low 50s, but since winds remain light fire weather is not much of a concern. Speaking of fire, current visible satellite imagery shows a rather impressive conglomerate of smoke meandering our way. Slow moving upper ridge will keep hazy skies in the area, prompting a slight drop in forecast highs for Thursday. High pressure will also shunt Hurricane Francine away from Michigan as she tries to make a run up the Mississippi River Valley Friday. Residual tropical moisture eventually makes it way UP here as the ridge finally shifts eastward late this weekend, potentially bringing our next batch of precipitation. Overall temperatures will remain much above normal through the weekend underneath the ridge and consistent 850 temps near 16-19C. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 133 PM EDT Tue Sep 10 2024 VFR conditions will prevail in this TAF period with mid-level cloud cover overhead this afternoon. A few showers are moving through the western UP this already, and showers with some rumbles of thunder will be possible at SAW by late afternoon - but confidence is too low for thunder in the TAF as coverage will be spotty. Scattered high cirrus and haze from upstream smoke remains overhead tonight. Winds should stay elevated enough to preclude fog development overnight, but will note that models indicate a slight chance (below 20%) of IFR fog at SAW into early Wednesday morning. && .MARINE... Issued at 424 PM EDT Tue Sep 10 2024 No marine weather concerns for the remainder of the week. South winds 15-20 kts taper down Wednesday morning as high pressure settles over the Hudson Bay and extends across the eastern seaboard. A developing surface low west of the Dakotas slides northward Thursday into Friday, tightening up the pressure gradient over Lake Superior. East-northeast winds peak to near 20 kts west of the Keweenaw. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...LC LONG TERM...BW AVIATION...LC MARINE...BW
Area Forecast Discussion
National Weather Service Nashville TN
856 PM CDT Tue Sep 10 2024 ...New UPDATE... .UPDATE... Issued at 856 PM CDT Tue Sep 10 2024 Tweaked hourly temperature, dewpoint, sky condition, and wind speed/direction grids blending them with associated previously forecasted hourly late evening gridded values. Current regional temperature trends continue to be in line with previously forecasted overnight low values. Some upper level moisture noted streaming in from deep south as these early evening hours have progressed with latest HRRR model trends showing this trend continuing. KOHX 11/00Z sounding profile and associated derived indicies showing a rather dry and stable airmass continuing across our area this evening. All in all, no significant changes made to current suite of forecast products. Made some minor tweaks to cloud coverage as overnight hours progress. Made also some minor tweaks to grids after tonight to make them more in line with neighboring offices and latest CAMs trends, but again, no significant deviation(s) from previous forecast reasoning. Remainder of forecast continues to be on track. && .SHORT TERM... (Rest of today through Wednesday) Issued at 1123 AM CDT Tue Sep 10 2024 The quiet pattern we`ve enjoyed over the last several days continues today. Temperatures are a little warmer thanks to some higher heights, so expect highs to get into the upper 80s to lower 90s this afternoon. The good news is that humidity remains low thanks to dew points in the 50s. Temperatures overnight will be warmer than the last couple nights but temperatures should still drop to the upper 50s to lower 60s. Wednesday will be similar to today except for high clouds starting to filter into the area ahead of Francine. && .LONG TERM... (Wednesday Night through next Tuesday) Issued at 1123 AM CDT Tue Sep 10 2024 The story of the long term forecast continues to be Francine. Currently, Francine is a tropical storm in the western Gulf of Mexico moving northeast. It is expected to make landfall on Wednesday as a hurricane along the Louisiana coast. It will then track up the Mississippi River weakening as it lifts northward. Showers will move into southern Middle Tennessee late Wednesday night/Thursday morning. Some embedded storms look to become possible Thursday afternoon as weak instability moves into the area. The winds fields will be backed with the remnant low over western TN/eastern AR. A few cells could have the propensity to rotate late Thursday into Friday. The low instability values could limit the tornado threat though. The remnants of Francine will be in no hurry to go anywhere. The winds fields weaken on Friday but there will be a little more instability. I won`t completely rule out a low end tornado threat on Friday at this point. As we go into the weekend the remnant low becomes more broad which will keep shower and storm chances around,but the rain chances won`t be as organized. Regarding rainfall with this system, the western half of the area continues to be favored for higher rainfall amounts which is good news for the drought. With that said, rainfall could be heavy and efficient Thursday into Friday morning which could lead to a couple instances of flash flooding. Overall creeks and rivers are running low, so they should be able to take a bit of water. Looking at the LREF through Friday, the 90th percentile total precipitation has 4-4.5" in the west which we should be able to handle. Still, a couple instances of flash flooding can`t be completely ruled out. Temperatures in the long term will be fall back from what we are seeing today and tomorrow thanks to the clouds and rain. Highs are expected to be in the 70s to lower 80s through the extended forecast. && .AVIATION... (00Z TAFS) Issued at 641 PM CDT Tue Sep 10 2024 With ridging influences sfc/aloft continuing to prevail thru 11/24Z, VFR conditions expected. Introduced bkn CI, sct CI CKV, with upper level moisture depicting to stream northward in association with eventual movement northeastward out of western gulf coastal region of current Hurricane Francine. Winds will continue to remain generally light. Some variability to wind direction anticipated. Forecasted mean direction. && .PRELIMINARY POINT TEMPS/POPS... Nashville 62 90 66 78 / 0 0 40 70 Clarksville 57 90 63 77 / 0 0 30 70 Crossville 57 83 58 71 / 0 0 30 60 Columbia 62 90 63 75 / 0 0 60 80 Cookeville 60 85 63 73 / 0 0 20 60 Jamestown 57 83 59 73 / 0 0 10 50 Lawrenceburg 62 88 63 73 / 0 0 60 80 Murfreesboro 62 89 65 76 / 0 0 40 70 Waverly 62 91 63 75 / 0 0 50 80 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.......JB Wright SHORT TERM...Reagan LONG TERM....Reagan AVIATION.....JB Wright