Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/24/19

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
548 PM MDT Tue Jul 23 2019 .AVIATION... 00Z TAF CYCLE A meager crop of thunderstorms has developed over the high terrain and are slowly moving clockwise around the upper high centered near the Four Corners. Storms over the Sangre de Cristo Mountains may move into KSAF this evening and a line of storms should move into KFMN shortly after 00z. High confidence exists at these two TAF locations. Storms should dissipate by 06Z across central NM, but may linger across portions of the west overnight. Low clouds are not expected to be as widespread across eastern NM overnight, if any develop at all. Confidence remains too low to insert into any TAF, but KLVS would be the most likely. Another round of showers and thunderstorms are expected to develop Wednesday afternoon across northern and western NM. 34 && .PREV DISCUSSION...330 PM MDT Tue Jul 23 2019... .SYNOPSIS... The upper high center will be located to the west and northwest of New Mexico through early next week. This will allow afternoon and early nighttime showers and thunderstorms to favor the northern and western portions of the state. A weak upper low may circulate around the upper high center Thursday into Saturday, allowing for an uptick in activity. High temperatures through the weekend will be near to slightly below normal. Slow-moving storms will be capable of locally heavy rainfall at times which could lead to flash flooding. && .DISCUSSION... Moisture has increased over New Mexico, with area soundings this morning showing an increase in PW, with KABQ measuring 1.12 inches. Dewpoints over western and central New Mexico, which have in recent days mixed out in the afternoons, have held steady this afternoon, even locales along the Continental Divide were holding in the upper 40s to lower 50s. The HRRR and and the RAP13 indicate the north central will be favored early this evening for storms, with the RAP13 also painting better precipitation west of the Continental Divide. Cell motion in general will be from northeast to southeast, but storms could also develop on outflow boundaries. Little change for Wednesday in the overall weather pattern, although the NAM12 indicates some drier air will work into the eastern plains for a day. Thursday and into Saturday, models indicate a weak upper low will rotate into the northeast, then through eastern New Mexico. This feature is expected to spark an uptick in convection as the upper high center wobbles a bit to the south and west of it`s current position. Early next week, the upper high center drifts back toward the Four Corners. The GFS is more aggressive moving the upper high center to our east towards 240 hrs, but it`s tried that before, while the ECMWF was more conservative. && .FIRE WEATHER... Moisture is up across the area, with good to excellent humidity recovery forecast for the foreseeable future. Decent coverage of wetting storms are forecast through Wednesday as the upper high remains near the Four Corners, but an uptick is forecast Thursday into Friday as the upper high relocates to over Arizona and a shortwave trough rotates around it and moves slowly south across New Mexico. Good chances for wetting storms will then persist through the weekend as the upper high center drifts even further west across the Desert Southwest. The latest medium range model solutions then move the upper high eastward to over northern NM and southern CO going into the middle of next week, leading to a downtrend in daily rounds of storms and an uptrend in daytime temperatures. 11 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
819 PM CDT Tue Jul 23 2019 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...The cold front has pushed into the northern Ranchlands of Deep South TX but has not yet cleared through the lower RGV with the three local airports all reporting a light easterly surface wind. Evening conv continues firing near the cold frontal boundary across Zapata and Jim Hogg Counties. This conv is moving pretty steadily SW and should steer clear of the RGV airports for the short term. The 00Z BRO sounding remains pretty unstable and moist with an MUCAPE of 4085 J/KG and a PWAT of 2.14 inches. Believe that the lack of conv over the central and eastern counties is a temporary break. The cold front is expected to sag slowly southwards later tonight through Wed morning eventually moving south of the Rio Grande late Wed morning. As this front gets a little closer to the RGV airports, it will increase the surface convergence which will likely tap the abundant tropical moisture and the high CAPE levels to help initiate another round of conv later in the upcoming TAF period. As always, the big question for the current TAF set concerns timing of the conv. The HRRR has not initialized on the current western conv very well and keeps the RGV airports generally pretty dry throughout the overnight hours and tomorrow morning. Meanwhile, the RAP13 conv guidance is much wetter for the region and has the conv refiring later tonight and persisting through the early morning hours. Finally, the ARW does pretty well handling the evening conv and keeps the three airport regions generally clear of conv through the overnight and early morning hours. For now, will go on the conservative side for the conv chcs for all three airports throughout the overnight hours but will include a TEMPO group for conv later tonight as the front gets closer to the region. Will include some PROB30 groups later in the forecast period as drier and more stable air will start moving into the region reducing the conv coverage. Overall TAF conditions will likely range from MVFR/VFR mainly for lowered ceilings due to the periods of conv. && .PREV DISCUSSION... /issued 314 PM CDT Tue Jul 23 2019/ SHORT TERM (Tonight through Wednesday Night): 500mb ridge across the western United States and 500mb trough across the eastern U.S. will continue to provide subsidence across most of the state tonight except across the Rio Grande Valley where low to mid level moisture will remain high. At the surface...a weak cold front will become stationary across the northwest Gulf of Mexico extending into portions of deep South Texas. Will continue to mention scattered showers and thunderstorms across the CWA this evening as the front continues to move across southern portions of deep South Texas. Will likely see more showers than storms late tonight into Wed morning. Drier air is expected to move into the northern ranchlands Wednesday but low to mid level moisture will remain high across southwest Gulf of Mexico extending into northeast Mexico. Will continue to mention a chance of showers and thunderstorms across southeast portions of the CWA Wednesday. Rain chances will diminish across the area Wed night as drier air moves into the Rio Grande Valley and northeast Mexico Wed night. LONG TERM (Thursday through Tuesday): Behind the initial frontal passage, the question becomes where the boundary settles or how long it sticks around the lower Texas coast. Drier air behind the front may keep most rain offshore or limited to wherever the front settles on Thursday. As high pressure in the Desert SW continues to stay west, the weak coastal trough of lower pressure along the western Gulf will help boost moisture and rain chances late Friday through Saturday. With multiple boundaries and increased moisture, seabreeze showers and thunderstorms may continue to be active Sunday into Tuesday, but likely tapering off each afternoon. Model guidance have trimmed temperatures back a degree or two Thursday through Saturday. If the frontal boundary can head north, temperatures may rebound warmer. With the increased cloud cover and rain chances into Saturday have indeed trended temperatures down slightly. Overall, the front will bring relief from the heat through the end of the week, especially across the northern ranchlands and western brush country, where lower dewpoints and low humidity should result in a couple of very comfortable days and nights. Early next week, temperatures rebound toward normal with increased humidity, yielding Heat Indices above 105 degrees once again. MARINE (Tonight through Wednesday night): Seas were near 1.6 feet with east winds near 12 knots at buoy020 early this afternoon. Light north to northeast winds will prevail across the coastal waters tonight as surface high pressure builds across east Texas as a weak cold front becomes stationary across the northwest Gulf of Mexico. Winds will increase from the northeast Wednesday as the pressure gradient increases across the northwest Gulf of Mexico. SCEC conditions will develop across the western Gulf of Mexico Wednesday as a result. Moderate to strong northeast winds will prevail across the coastal waters Wednesday before the pressure gradient weakens across the lower Texas coast Wed night. Thursday through Tuesday: Any elevated winds and seas from the frontal passage should decrease and subside on Thursday, with favorable marine conditions expected into the weekend. As low pressure off the coast becomes slightly more defined, the pressure gradient may strengthen enough to increase winds and elevate seas Sunday into Tuesday. Small craft may need to exercise caution across the Laguna Madre at times Thursday or early next week. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV Short Term/Aviation...60 Long Term/Graphicast/Upper Air...62
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
327 PM MDT Tue Jul 23 2019 .SYNOPSIS... A moist airmass remains in place across the region, but with relatively weak instability and a lack of upper level disturbances, showers and thunderstorms will remain isolated to scattered, and mostly favoring the higher terrain. A few storms which do develop through early evening will produce localized torrential downpours, with a risk of flash flooding mainly over the Gila Region. Drier air aloft will push into the area tomorrow, with a significant downtick in thunderstorm activity expected. Additional moisture will flow into the region from the north Thursday and Friday, with increasing thunderstorm chances lasting through the weekend. && .DISCUSSION... Overnight rain showers left a lot of cloud cover across the region again. Satellite imagery shows convection struggling against weak instability, with RAP13 analysis showing MLCAPE (500m) generally 500 to 800 J/Kg across the area, along with weak to moderate CIN. RUC sounding for ELP has a skinny CAPE profile with poor mid-level lapse rates. But moisture is plentiful...PW values are still in the 1.25 to 1.50 inch range, and most areas have held on to surface dewpoints in the upper-50s to lower-60s. Visible satellite imagery also shows a decaying MCV just south of El Paso, and while there have been bands of slightly-enhanced Cu and TCu along its periphery, nothing has really taken off, even as temperatures have risen into the upper-80s. The lack of any other larger scale forcing means we`re at the mercy of orographic lift and perhaps weak convergence along leftover boundaries from this morning`s rainfall. As a result, it`s hard to justify anything more than Isolated PoPs through the evening hours in the lowlands, and scattered in the higher terrain, though even the Sacramento Mountains look worked-over. Some of the showers in the lowlands have been producing brief heavy rainfall rates, but the higher risk for localized heavy rainfall and flash flooding will be over the Gila through the early evening hours. Once cell near Mimbres has shown DPR (dual pol instantaneous precip rate) values consistently in the 3-4"/hr range. Warmer and drier air aloft looks to move in overnight, and Wednesday looks particularly quiet outside of the Gila and perhaps the Bootheel regions, as instability looks to be nearly non- existent east of the Continental Divide, thanks in part to 500 mb temps around -3.5C. While residual low level moisture will help keep temperatures a little cooler, I did bump surface Max Temps a little above guidance near and east of the Rio Grande. The subtropical ridge looks to migrate towards central Arizona Thursday and Friday, with northerly flow actually delivering mid- level moisture to New Mexico, mostly recycled monsoonal moisture that has taken "the long way around" the subtropical ridge. We`l see an uptick in convection in the Sacramento Mountains and Gila Region Thursday, with lowland convection ramping up on Friday, especially west of the Rio Grande. This moisture plume looks to persist over the region through the weekend, as the steering flow shifts more from the NE to SW, this should increase precip chances for the lowlands near and east of the Rio Grande as steering flow becomes more ideal for bringing storms off the Sacramento Mountains into the Tularosa Basin and Mesilla/El Paso Valleys. Still, temperatures aloft look to be a little on the warm side, so thunderstorm coverage in the lowlands will be tempered somewhat by weak has been the case much of the summer so far. && .AVIATION...Valid 24/00Z-25/00Z... Areas of Scattered SHRA/TSRA expected through 07z, will result in periods of MVFR and IFR mainly over the mountains. lower elevation TAF sites will have minimal storm activity and should remain VFR through the valid period. Drier conditions expected area wide aft 09z through the end of the valid period with few clouds and a few isolated mountain based TSRA possible. Winds will remain generally east at 5 to 10 knots with stronger gusts near storms. && .FIRE WEATHER... Scattered showers and thunderstorms will occur this afternoon and evening. Drier and more stable air will move into the region Wednesday and limit thunderstorm chances to mainly isolated mountain areas both Wednesday and Thursday. Moisture levels will increase enough by Friday to generate a isolated lowland and scattered mountain thunderstorms in the afternoon and evening Friday through next Monday. Minimum RH values after today will range from the upper teens and 20s for the lowland with 30 to 40 percent ranges in the mountains. Winds will continue be light and variable with drainage winds occurring overnight. Stronger wind gusts will occur near thunderstorms. Ventilation rates the next few days will vary from fair to good. && .PRELIMINARY POINT TEMPS/POPS... El Paso 88 70 91 71 / 50 10 0 0 Sierra Blanca 82 63 85 63 / 50 10 0 0 Las Cruces 86 66 87 67 / 50 20 0 0 Alamogordo 86 63 89 65 / 50 20 0 0 Cloudcroft 65 47 66 49 / 60 20 20 0 Truth or Consequences 85 67 88 70 / 50 30 0 0 Silver City 81 62 83 63 / 50 30 30 10 Deming 87 65 89 65 / 50 20 0 0 Lordsburg 88 67 90 67 / 30 30 0 0 West El Paso Metro 88 70 91 71 / 50 10 0 0 Dell City 87 63 91 64 / 50 10 0 0 Fort Hancock 90 71 93 70 / 50 10 0 0 Loma Linda 83 63 84 64 / 50 10 0 0 Fabens 88 69 91 68 / 50 10 0 0 Santa Teresa 87 67 89 68 / 50 10 0 0 White Sands HQ 87 69 88 70 / 50 10 0 0 Jornada Range 87 63 88 65 / 50 20 0 0 Hatch 88 64 90 67 / 50 20 0 0 Columbus 89 68 91 67 / 40 20 0 0 Orogrande 86 64 88 67 / 50 10 0 0 Mayhill 75 51 76 54 / 60 20 20 0 Mescalero 76 51 76 53 / 60 20 20 0 Timberon 73 49 73 50 / 60 20 10 0 Winston 81 54 82 56 / 50 40 30 20 Hillsboro 85 60 88 63 / 60 40 10 0 Spaceport 86 62 88 64 / 50 30 0 0 Lake Roberts 83 51 83 53 / 50 40 50 20 Hurley 83 61 85 62 / 50 30 10 0 Cliff 88 58 91 59 / 50 30 30 10 Mule Creek 86 63 85 65 / 40 40 30 20 Faywood 83 63 84 64 / 50 30 20 0 Animas 91 67 92 67 / 30 30 0 0 Hachita 88 65 90 65 / 30 30 0 0 Antelope Wells 89 66 91 66 / 20 30 0 0 Cloverdale 87 65 85 65 / 30 30 20 10 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 25-Hardiman / 04-Lundeen
Area Forecast Discussion
National Weather Service Goodland KS
522 PM MDT Tue Jul 23 2019 .SHORT TERM...(This evening through Wednesday) Issued at 130 PM MDT Tue Jul 23 2019 Sunny skies and quiet weather prevailed across the tri-state region today. Water vapor and RAP analysis showed amplified, upper ridging across the western CONUS with high pressure centered over the Four Corners region. To its east, a trough extended across the east coast. This setup placed the region under northwest flow as a result. Southerly winds of 10 to 20 mph were observed, with gusts of 25 to 30 mph in some locations. At 1 PM MT, temperatures ranged in the upper 70s to low 80s. Surface high pressure and subsidence continue over the High Plains tonight through the day on Wednesday before sliding east. The upper ridge remains the dominate feature during this timeframe. A disturbance travels from the Pacific Northwest towards the northern Rockies, shifting the upper flow from northwest to north and flattening the ridge somewhat. Along with dry weather, expect low temperatures in the upper 50s to low 60s tonight, followed by highs in the upper 80s to low 90s on Wednesday. Southerly winds are forecast as well, with similar speeds on Wednesday as those experienced today. .LONG TERM...(Wednesday night through Tuesday) Issued at 114 PM MDT Tue Jul 23 2019 Through the start of the weekend, flow aloft will remain somewhat stagnant with large H5 ridge centered to the southwest of the area. Initial concerns will center around potential for afternoon and evening thunderstorms and how warm will things get through Friday. Position of H5 ridge makes determining the thunderstorm threat area each day somewhat difficult, but with numerous outdoor activities this week trying to fine tune the particular areas will be very important. For Wednesday night, narrow channel of moisture and instability along the Kansas and Colorado border, but with strongest low level convergence well to the west of the area, have doubts that convective inhibition will be overcome during peak heating and any storm chance would have to wait until storms move in from higher terrain. Have some doubts about how far east storms can make it despite several numerical models suggesting storms marching across the entire area. Given the steering flow will be weak due to position of ridge and overall forcing weak, struggle to see how storms will make much of a eastward push into Kansas. For the time being, think best chances will remain around the Flagler and Yuma areas, tapering off pretty quickly to the east. While upper air pattern remains similar on Thursday lots of uncertainty with respect to how surface responds, mainly due to widely different views on how Wednesday night convection develops. As a result, tend to think pattern will be similar to the day before with storms threat being strongly diurnally driven and limited to the western half of the area. Not anticipating much in the way of organized or severe convection due to limited instability and generally weak bulk shear. In the extended (Friday through Tuesday)...Main concern for the longer term periods will be how fast H5 ridge breaks down over the weekend and the magnitude of cooldown that results. There appears to be reasonable agreement that best shot of precipitation/cooler temperatures will be Saturday evening into Sunday. While not expecting temperatures quite as cool as the last strong cold front, expect temperatures 5 degrees or so cooler than on Saturday, which will likely be one of the warmer days of the week. Thankfully while a period of warm temperatures is expected, does not look like it will reach the magnitude of the heat wave earlier this month. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 520 PM MDT Tue Jul 23 2019 VFR conditions will persist throughout the forecast period at both KGLD and KMCK. Expecting gusty winds around 20 to 25 kts to return late Wednesday morning and into Wednesday afternoon. Winds should remain from the southeast throughout the forecast period. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JBH LONG TERM...JRM AVIATION...PATTON
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
929 PM EDT Tue Jul 23 2019 .SYNOPSIS... A cold front will continue to push south of our region as high pressure builds into our area Wednesday through this weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Shear vorticity and the right rear quadrant of a jet streak associated with the deep upper level trough have brought some showers and isolated thunderstorms to the Potomac Highlands to central Shenandoah Valley. The intensity of these showers has been decreasing, but SPC mesoanalysis and 00Z IAD sounding show up to 500 J/kg of MUCAPE, so wouldn`t be surprised to see a few showers continue to pop up as the trough axis progresses to the east. HRRR solutions have been showing activity to end around midnight-2AM. Main rain shield associated with frontal zone/low near SE VA has now exited south-central MD. However, likely some local convergence and the warm waters of the Bay have been producing showers offshore of Anne Arundel County. We even received a report/photo of a needle waterspout earlier this evening. However, since the convergence is located over the Bay and steering winds are light, most of these showers should not affect land. Some models have this shower activity lasting through the night, but would think increasing northerly winds due to offshore low pressure will lessen local convergence effects by late tonight. Otherwise, clouds should gradually erode from the northwest tonight. Models are hinting there could be some patchy fog where it clears out. Lows ranging from the mid 50s west to mid 60s east look on track. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... High pressure will build into our region from the west. An upper trough axis will slowly move across our region from the west. North to northwesterly flow will continue to transport into drier and cooler air into region which will lead to cooler than normal temperatures in the upper 70s to mid 80s. Some isolated showers can`t be ruled out over the higher elevations due to the trough axis being overhead of our region but a northerly flow should limit the area coverage. I have kept pops in the 20s and should be limited to the afternoon periods and the western part of our forecast area. A coastal low will form off the frontal boundary to our south and move just off our coast Wednesday afternoon. The tight pressure gradient from the passing low may cause some stronger winds over our coastal areas and eastern Maryland and northern VA. On Thursday, the upper level trough axis will lift eastward out of region and high pressure will remain over our region. Winds will be light and variable mainly out of the north. Temperatures will remain mild in the upper 70s to mid 80s with overnight temperatures dropping into the upper 50s to mid 60s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... The long term period will feature an extended period of dry conditions, along with ample sunshine, low humidity, light winds, and near normal temperatures. Heights aloft will rise as high pressure builds overhead on Friday. In the absence of any disturbances at mid-upper levels, this area of high pressure will stay in place through the weekend, before shifting just offshore on Monday. With high pressure in control, quiet weather conditions are in the forecast. Temperatures will be near normal, with highs predominantly in the 80s to near 90, and lows mainly in the 60s. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... There are some showers associated with a mid level trough axis that are slowly closing in on MRB and CHO this evening but are weakening. Will amend TAFs if needed. VFR ceilings may last a good part of the night but should be scattering out by Wednesday with light north winds increasing to 5-10 kt during the day. All MOS guidance has some sort of visibility restriction in BR at CHO late tonight as skies clear, so have inserted MVFR in the TAF. VFR conditions will dominate through Thursday as high pressure remains over our region. VFR conditions will persist through the long term period with high pressure in control. && .MARINE... Wind convergence and warm Bay waters are leading to showers along the main channel, especially near Anne Arundel County. We have received one report of a waterspout, so with conditions remaining similar, additional waterspouts will remain possible this evening. As low pressure moves northeast along an offshore front, north winds will increase late tonight (which would likely end the waterspout threat), and an SCA goes into effect at 3 AM, lasting through 2 PM Wednesday. Sub-SCA conditions expected through the rest of the week as high pressure builds in. A prolonged stretch of precipitation free conditions and sub-SCA level winds is expected this weekend into early next week. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 4 AM to 2 PM EDT Wednesday for ANZ532>534-537-540-541-543. && $$ SYNOPSIS...JMG NEAR TERM...ADS SHORT TERM...JMG LONG TERM...KJP AVIATION...ADS/KJP/JMG MARINE...ADS/KJP/JMG
Area Forecast Discussion
National Weather Service Pueblo CO
329 PM MDT Tue Jul 23 2019 .SHORT TERM...(This evening through Wednesday) Issued at 243 PM MDT Tue Jul 23 2019 Mountain storms so far this afternoon a little less widespread than the past couple days, as precipitable water has drifted downward slightly. Nly steering flow also keeping storms fairly close to the higher terrain with storms drifting south or a little southwest so far. Expect storm coverage to increase slightly this evening as weak upper wave dives south over the ridge, with HRRR and various iterations of the NAM suggesting fairly widespread activity over the eastern mountains until 03z-05z. Given CAPE of 1k-2k J/KG pooling along eastern mountain slopes, localized strong storms and heavy rainfall look likely, with flash flood threat continuing in/near local burn scars. While nly flow aloft will tend to keep most activity west of the I-25 corridor into this evening, late arrival of upper forcing from short wave trough may provide just enough lift to spark a few storms east of the mountains after 00z, especially El Paso/Pueblo Counties. Most activity then fades overnight, though a few showers could persist near the Continental Divide into Wed morning as mid level moisture lingers. On Wednesday, little change in the pattern with upper level ridge along the CO/UT border and plentiful moisture remaining in place across the region. Expect another round of afternoon storms over the mountains, with convection slowly drifting south under very light nly steering flow. Most activity will stay along and west of I-25, though a few weakening cells may drift toward lower elevations late in the day. Main risk again will be heavy rain/burn scar flash flooding, with models hinting that areas back toward the Continental Divide may see the strongest storms. Lee surface trough on the plains may induce some weak downslope flow in the afternoon, which will boost max temps a few degf east of the mountains versus today. .LONG TERM...(Wednesday night through Tuesday) Issued at 243 PM MDT Tue Jul 23 2019 Overall the operational solutions are in decent agreement through the extended period. Ensembles have relatively small spreads through much of the period, with some differences in the upper level high pressure that is forecast to build across the region. Overall, forecast confidence is on the higher side. Wednesday night through Friday...high pressure is forecast to be centered over the Four Corners region through Thursday before it retrogrades into southern California on Friday. This will keep the potential for showers and thunderstorms across the region. Expect ongoing mountain thunderstorms Wednesday evening with northwest steering flow pushing the activity south and east. Locally heavy rainfall and lightning will be the primary threats, but a few stronger cells could produce gusty outflow winds and small hail. This activity will dissipate after sunset and dry conditions will likely prevail across the region by Thursday morning. Across the Plains, an area of low pressure is forecast to move east with a cold front dropping south into the I-25 corridor by morning. For Thursday, expect another round of afternoon and evening showers and thunderstorms across the region. Initial development will once again be over the mountains. Weak northwesterly steering flow should help push storms east into the I-25 corridor and points east, before dissipating overnight. Low level flow will likely be more upslope with abundant moisture across the region. This will lead to locally heavy rainfall and flash flooding may be possible on area burn scars and urban areas. In addition, small hail, lightning and gusty outflow winds will be possible. By Friday, the upper level ridge is forecast to retrograde southwest into southern California. Drier conditions are expected across the region. That being said, isolated to scattered convection is anticipated. Locally heavy rainfall will once again be possible with stronger storms. Saturday and upper level disturbance is forecast to track across the northern Rockies over the weekend. Expect better chances for showers and thunderstorms on Saturday, especially over the mountains. A cold front will arrive by Sunday morning with low level moist flow turning upslope across the region. Sunday may be the day for the greatest flash flood potential, especially over burn scars. This will need to be monitored. Monday into Tuesday...the upper level high is forecast to progress back across the Four Corners region early next week. This will bring a return to hot temperatures. Current model solutions are dry, but isolated to scattered showers and thunderstorms will continue to be possible, especially across the higher elevations. Mozley && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 243 PM MDT Tue Jul 23 2019 Storms developing over the mountains this afternoon will gradually spread to lower elevations into this evening. Will carry a vcts mention at all sites from 22z-03z, with lowest chance of a tsra at KPUB, as steering currents will tend to keep storms closer to the high terrain. Strongest storms will again produce briefly gusty winds 40 kts and low visibility due to heavy rain. Convection ends 03z-06z, with clearing skies and VFR conditions overnight. Similar pattern on Wed, with mainly mountain storms in the afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MOZLEY AVIATION...PETERSEN
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
527 PM MDT Tue Jul 23 2019 .DISCUSSION...(This Evening Through Tuesday) Issued at 139 PM MDT Tue Jul 23 2019 The latest GOES-16 satellite images and RAP analyses indicated a pronounced upper ridge over the Rockies with mostly sunny skies across the CWA. Some cumulus were forming over the BLKHLS in the 1000 J/kg MLCAPE air mass, but the -100 J/kg MLCIN and lack of synoptic forcing were keeping things in check. A few storms were trying to form over the Big Horn Mountains, but these were not making it out over the plains. Thus, think NERN WY should stay free of storms today given marginal lapse rates and moisture. A southerly low-level jet later tonight should focus any storms to the northwest of the CWA. The models are in overall good agreement through at least 84 hours, with the ridge moving east and breaking down on Wednesday, followed by FROPA Wednesday night and Thursday morning, with only minimal thunderstorm chances Thursday and Friday. A plume of steep lapse rates and PWs of 125-150 percent of average will move across the area later Wednesday, resulting in 2000-3000 J/kg of SBCAPE for much of the CWA. Deep-layer shear will be favorable for some supercells, and high cloud bases should favor storms with gusty winds. Coverage may be somewhat limited, so the SPC marginal risk looks good at this time. FROPA should occur from 06-18z on Thursday, which should produce some gusty northwest winds at least early in the day on Thursday. A few storms may redevelop over the BLKHLS, and if the boundary hangs up over SCNTRL SD it is possible that a few storms could fire there as well. Otherwise, flow will be quasi-zonal through Friday with limited moisture and instability, so thunderstorms will be at a minimum. West-northwest upper flow should persist Saturday through next Tuesday, with a more notable wave and another FROPA later Saturday and Saturday night. This should result in additional scattered thunderstorms across the CWA, followed by a relative lull in storms Sunday and Monday. Temperatures will continue to be near average, but the humidity will be higher than average. && .AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening) Issued At 526 PM MDT Tue Jul 23 2019 Mostly VFR conditions will prevail through Wednesday morning. TSRA over the Black Hills with local IFR conditions will end early this evening. Additional storms will develop Wednesday afternoon with local MVFR conditions. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...Bunkers AVIATION...Helgeson