Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/31/23

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
850 PM CDT Tue May 30 2023 .UPDATE... Issued at 846 PM CDT Tue May 30 2023 Watching convection across western SD, especially over southwest SD where better instability and shear exist. Some of this activity looks to bleed into the southwest counties over the next few hours, potentially remaining on the strong side with gusty winds being the main threat. Made some adjustments to PoPs to account for this, and may have to raise the southwest even more if current activity holds together like latest runs of the HRRR are suggesting. && .SHORT TERM...(This Evening through Wednesday Night) Issued at 251 PM CDT Tue May 30 2023 Weak southwest flow will continue tonight and into Wednesday. A few cu have popped up in the eastern portion of the forecast area, otherwise pretty quiet so far today. Lack of any forcing or shear to support growth evident. Activity from western SD and NE will move into the Missouri River valley and west this evening bringing in small chances of thunderstorms through 06Z tonight. Deterministic models are in fair agreement of a small shortwave to move up from the intermountain west tonight and into eastern SD Wednesday. This will be the focus of the next round of thunderstorms for the region. However, with the weak shear aloft it will be hard to get anything organized for a long period of time. A few pulse type storms likely however. SPC only has area in general thunder as well. Pops may be on high side for Wednesday, but still expect a good portion of the are to get wet. Temps will remain above normal for late May. .LONG TERM...(Thursday through Tuesday) Issued at 251 PM CDT Tue May 30 2023 The main forecast challenge in the extended revolves around precipitation chances. The upper level pattern will feature ridging to the east and a low pressure trough over the Rockies Thursday, with the high to the east then meandering its way back to the west Friday, and becoming the main feature over the Northern Plains through the remainder of the period. At the surface, the pattern of high pressure to the east and low pressure to the west will be in place through the entire period, with southerly flow bringing warm and moist air into the region. The warm temperatures and high dewpoints will lead to periods of fairly unstable conditions each day, along with the potential for scattered showers and thunderstorms each afternoon and evening, with quieter conditions during the overnight hours. Therefore, much of the extended period continues to be riddled with slight chance to chance POPs. High temperatures will be mainly in the 80s through the period, with overnight lows in the lower to mid 60s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 639 PM CDT Tue May 30 2023 Terminals KABR,KATY,KPIR,KMBG VFR conditions are forecast through the TAF period. However, threat for isolated -TSRA/TSRA or -SHRA/SHRA exists this evening for KMBG/KPIR, then later in the TAF period for KABR/KATY. TEMPO MVFR VSBY is possible in any heavier downpours, but confidence in location and overall limited coverage prevents inclusion in TAFs at this point. Will await any development and/or more immediate impactful proximity to a TAF site before including TEMPO groups. Will stick with VC mention at this time. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...TMT SHORT TERM...Scarlett LONG TERM...Parkin AVIATION...TMT
Area Forecast Discussion
National Weather Service Denver/Boulder CO
725 PM MDT Tue May 30 2023 .UPDATE... Issued at 720 PM MDT Tue May 30 2023 It took a while, but we finally have seen some convection develop across far northeastern Colorado this evening. While we haven`t seen severe reports from any of these storms yet, the severe threat should continue for the next couple of hours given a favorable environment as they slowly move to the north and east. Have made a few minor updates to the grids this evening and overnight but otherwise the forecast is largely in good shape. && .SHORT TERM...(This evening through Wednesday) Issued at 206 PM MDT Tue May 30 2023 For the rest of this afternoon and evening, observations are showing dew points in the teens and 20s over the mountains. Precipitable water values are under a third inch and CAPE is less than 300 J/kg. With this said, any showers or storms that form here should be weak. Along the Front Range Urban Corridor, dew points range from the upper 30s south to lower 50s north. CAPE is 500 J/kg south to 1000 J/kg north. Over the plains, dew points are in the 50s with CAPE of 1000-1800 J/kg. As convection shifts eastward off the higher terrain and across the plains, storms will increase in coverage and intensity. Raised PoPs earlier across the plains for this. Shear remains limited with 0-6km bulk shear only 20-25 knots. However, like past days, the stronger storms will be capable of large hail. The Convective Allowing Models (CAM) show the storms coming together and producing a line over the eastern plains. Main threat from the storms will then transition from hail to strong winds. Storms will progress east and exit Colorado during the late evening hours. Closed low off the southern California coast will track eastward into Arizona on Wednesday. Ahead of the low over Colorado, flow aloft will back from the southwest to south. Low level flow, roughly below 650mb turns southeasterly and will transport moist westward into the foothills. The initial batch of storms that form over the higher terrain Wednesday afternoon will be stronger with heavy rain and small hail. RAP MLCAPE early Wednesday afternoon reaches 1000- 1500 J/kg along the I-25 Corridor and into the lower foothills. Over the eastern plains, MLCAPE climbs to 1500-2500 J/kg. Like previous days, shear isn`t that great with 0-6km bulk shear around 25 knots. Would expect some severe hail and winds with the strongest storms along the I-25 Corridor eastward across the plains. .LONG TERM...(Wednesday night through Tuesday) Issued at 300 PM MDT Tue May 30 2023 Moisture and rain will certainly not be lacking during the long term period. An upper level trough will move over Colorado from the Desert Southwest and will park itself there through the weekend. As this happens, persistent lee cyclogenesis over the high plains of Colorado and New Mexico will consistently draw in moisture from the Gulf of Mexico. Precipitable water values will be quite high, likely above 0.8" at KDEN and possibly above 1". This would be near the max moving average on the SPC sounding climatology page. With weak forcing aloft from the trough, upslope low level flow, and abundant moisture, there are likely PoPs basically every day during the extended. Unfortunately, there are little details that can be provided about the forecast since the coverage and intensity of the showers and storms that form each day will be dependent on the amount of cloud cover and showers that are around in the morning. The more cloud cover and rain there is in the morning, the less intense the rain will be in the afternoon. The days that have sunshine in the morning, could have severe weather and intense, heavy rain producing storms. Thursday and Friday will have the best chance at sunny skies in the morning. Weak to moderate instability will develop across the plains and storms will form each afternoon. The shear will be lacking as winds on Thursday will be from the south throughout the troposphere and may even have backing flow on Friday. Therefore, severe weather will be limited or nonexistent. On Saturday and Sunday, it appears likely that low clouds will exist throughout each day. This would greatly limit the instability and could lead to light to moderate rain rates as opposed to heavy rain rates. The thing that will need to be watched is the potential for warm rain processes with deep upslope flow. Southeast winds throughout the troposphere may exist so the mountains and foothills could receive the heaviest rain totals. Monday and Tuesday will have a bit more sunshine for instability to form develop. It is hard to say with confidence whether a heavy rain threat will still exist these days but the precipitable water values will remain high. Therefore, likely PoPs are in the forecast. Otherwise, high temperatures will remain below normal with near normal low temperatures. The high moisture values will keep fire weather conditions low. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 535 PM MDT Tue May 30 2023 Most of this afternoon`s convection has dissipated in the past couple of hours, but a few showers are still noted across the western half of the metro. Some weak outflow - leading to variable/gusty winds - will be possible through 01 or 02z, primarily at BJC/APA. Once this activity fades, we should see a return to normal drainage wind patterns overnight, with easterlies expected again tomorrow afternoon. Another round of showers/storms is likely tomorrow, with a bit more coverage compared to today. The main threat will be variable/gusty winds, but briefly heavy rain and reduced ceilings/visibility will also be possible in any stronger storms. && .HYDROLOGY... Issued at 206 PM MDT Tue May 30 2023 The storms over the burn areas today are expected to be on the weaker side due to limited moisture. This should keep the flood threat close to none. Better moisture moves into the foothills and mountains Wednesday. This will increase the flash flood threat to limited. The strongest storms expected to produce more than a third inch of rain in 15 minutes. With ample moisture in place throughout the extended period, there will at least be a limited threat of flash flooding in the burn areas each day. There will likely also be a couple days with an elevated threat but it is unclear which days will have the highest threat. We encourage people with interests in the recent burn areas to follow the forecast closely through the weekend as it could be a period with flash flooding. In addition, there may be a flash flood threat across the plains if there is enough instability. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hiris SHORT TERM...Meier LONG TERM...Danielson AVIATION...Hiris HYDROLOGY...Meier/Danielson
Area Forecast Discussion
National Weather Service Des Moines IA
637 PM CDT Tue May 30 2023 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Tuesday/ Issued at 232 PM CDT Tue May 30 2023 Key Messages: -- Summery pattern with warm conditions, isolated to perhaps scattered storm chance peaking in the afternoon/evening Details: Cumulus clouds have been developing since late this morning over central Iowa and have observed focus in isolated development of storms from north central Iowa into southeast Nebraska/northwest Missouri over the last hour. This area is where there is currently a weak shortwave trough passes through and this coincides with a moisture plume in the 850-925 mb layer. The storm near Fort Dodge at midday had small hail and sub-severe gusty winds as it formed in an environment of uncapped 1500 J/kg MLCAPE with no quantifiable deep layer or effective shear on the 18z SPC mesoanalysis. Proximity forecast soundings show the very weak flow through the column and dry air near and above 500mb is likely also impeding sustained development such that GOES-East clean IR imagery is showing warming cloud tops. The weak flow coupled with surface dewpoint depressions on the order of 15-18C with soundings showing an inverted V sounding could lead to additional gusty winds, especially if dry air entrainment into the column or subcloud layer evaporation occurs that could bolster momentum transport to the surface. As it stands now, 6z RRFS and the latest HRRR and a few earlier morning HRRR runs show wind gusts sub-severe with the latest in the 35 to 40 knot range. These isolated storms will be slow moving in the weak flow and very localized heavy rainfall will be possible. Deterministic models from the 6z run have shown rain totals in the 3 to 4 inch range, but a few 12z models have settled back to 2-3 inches. The 12z HREF localized probability matched mean continues to show 2"+ bullseyes. While there is a strong signal for sub-county localized heavy rainfall, the location of which county is highly variable. While a few storms may linger over northern or western Iowa, there should be a decrease of activity into this evening as the boundary layer stabilizes. Overall, the pattern from the middle of this week into this weekend will evolve as the ridge over the northeastern US will retrograde back into the middle part of the country, which will turn our surface flow from southerly to easterly. While there will be ridging overhead, the sensible weather will remain largely the same with warm days and diurnally driven isolated to perhaps scattered thunderstorms with little in the way of an identifiable forcing. These storms will be mainly sub-severe, but lightning and localized heavy rainfall are likely as well as perhaps small hail and gusty winds given the persistent weak flow, inverted V soundings, and slow storm motions. Next week, there is ensemble agreement on a trough dropping equatorward through the Quebec province into the Northeastern US and eastern Great Lakes that may send another back door cold front toward or perhaps into our region. && .AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/ Issued at 637 PM CDT Tue May 30 2023 An area of thunderstorms is moving across central Iowa with impacts exiting KFOD and moving into KDSM just prior to 00z. Expect to see gusts over 25 kts ahead of the line followed by a period of TSRA. The line has weakened with time and expect that trend to continue as daytime heating quickly drops off. It is anticipated that this line of convection will dissipate before reaching KALO/KOTM, but will continue to monitor for trends as needed. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...Ansorge AVIATION...Hagenhoff
National Weather Service Kansas City/Pleasant Hill MO
617 PM CDT Tue May 30 2023 .Discussion... Issued at 216 PM CDT TUE MAY 30 2023 Key Messages.. - Isolated thunderstorms this afternoon with gusty winds. - Thunderstorms Wednesday morning, potential for pockets of moderate to heavy rainfall across portions of eastern Kansas and western Missouri. Isolated flash flooding concerns. - Warm, above normal temperatures through the week. - Periods of showers and thunderstorms through the end of the week Detailed Discussion... The Rex Block to the east is not expected to budge much over the next several days, leaving upper level flow across the central U.S. rather weak, save for some open H500 short waves potentially clipping from the west. From the boundary layer through the mid- levels, modest southerly return flow will keep moisture up and boundary layer temperatures above normal through the week. For today, some recovery can be expected through the afternoon, as clouds continue to clear from earlier convection and dew points remain in the mid 60s. Mid-level water vapor imagery paints the picture well, with the advance of a short wave trough lifting across the shallow ridge built from the Trans Pecos and along the CO/KS high plains. This will be the focusing mechanism for a cluster of strong to severe thunderstorms this afternoon in CO/KS/NE. For the MO/KS region, an axis of weak boundary layer convergence persists on the trailing end of the surface trough associated with the lee ward side of the upper trough and the lifting short wave across the boundary waters. This will be a focus for widely scattered storms late this afternoon into the evening, a few of which may have some gusty winds. Overnight, concerns for slow moving convection along the MO/KS border region continues to grow. Run to run consistency persists in the CAMs for pronounced isentropic ascent and low level convergence through sunrise, Wednesday. Expect a cluster of storms to develop through daybreak along the border, including the KC Metro. With pwats around 1.30in pooled across the region, and given efficiency of storms this morning, pockets of moderate to heavy rainfall are likely. Even with much of the region remaining in moderate to severe drought, isolated flash flooding cannot be ruled out. How quickly rain ends will depend on overnight persistence and evolution of convection across NE/KS. Current expectations is for convection to clear through midday as the H500 short wave lifts northeast across Nebraska. For the remainder of the week, the unsettled pattern persists, with warm temperatures and near daily scattered shower and thunderstorm chances. && .Aviation...(For the 00Z TAFS through 00Z Wednesday Evening) Issued at 613 PM CDT TUE MAY 30 2023 Complex of storms moving east from eastern KS may impact southern metro including IXD.Main concern with this weaking complex is gusty winds and brief heavy rainfall. HRRR continues to sugges convection developing along lingering convergence line after 09Z tonight. There is less consistecy among other model solutions, so have limited the amount I have lowered ceilings and vis with 00Z issuance. Will keep a close eye on this for next issuance. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ Discussion...Kurtz Aviation...BT
Area Forecast Discussion
National Weather Service Peachtree City GA
756 PM EDT Tue May 30 2023 ...New 00Z Aviation Discussion... .SHORT TERM... (This evening through Wednesday) Issued at 300 PM EDT Tue May 30 2023 The low pressure system located off the coast of North Carolina continues to drift northward along the Mid-Atlantic coast allowing for a wedge of slightly cooler than average air to infiltrate northeast Georgia. The wedge front has surged across much of the forecast area and remains draped across our southwestern counties. At the time of this writing, a few isolated showers have begun to pop along the coast and eastern Georgia. The CAMs suggest a few isolated showers will be possible across the area this afternoon and evening, though the HRRR seems to have the best handle on the current radar trends. If showers and thunderstorms get going this afternoon, they will be primarily cold pool driven propagating east to west as the wedge continues to establish itself. The best locations for rain chances will be across eastern and northern Georgia today, though coverage is expected to be isolated at best. With QPF less than a tenth of an inch, any showers/storms that get going are not expected to be particularly efficient rainmakers. A general thunderstorm risk has been appropriately diagnosed by SPC as upper level support is lacking. With SBCAPE around 750 J/kg this afternoon and evening, there will be enough instability to support a few thunderstorms, but no severe weather is anticipated. As a low in the northern Gulf Coast develops this afternoon and evening, moisture throughout the atmospheric column will gradually increase over central Georgia through Wednesday. This will help bring the chance for afternoon scattered thunderstorms tomorrow afternoon as this moisture overruns the wedge. A general thunderstorm risk is in place again over the forecast area and widespread severe weather us not expected at this time. Showers and thunderstorms are expected to primarily be focused across central Georgia generally south of I-20 and across the north Georgia mountains. Max high temperatures today and tomorrow will be slightly below average in the mid 70s and mid 80s, but will be kicking off a warming trend that will extend into the long term forecast. KAL && .LONG TERM... (Thursday morning through next Monday) Issued at 300 PM EDT Tue May 30 2023 Maintaining a rather uneventful longterm outlook through at least Monday morning. Upper level flow will continue to remain light as jet streaks remain over the GoM. Wedging persists through at least the weekend as a combination of the slow moving surface low off the Carolinas and a High over the Northeast drive Northeasterly flow. Light forcing from the wedge may be sufficient for isolated scattered convection. However, temperatures should remain at or just below normal with highs in the mid to low 80s for much of the region. Moving into the weekend, the wedge begins to break down as the low off of the East Coast weakens and moves out. Temperatures on Saturday and Sunday will begin to climb, with highs reaching into the upper 80s and possibly the low 90s. The potential for diurnally driven convection continues through this time. For Monday and Tuesday, the focus moves to moisture availability. One of two general synoptic modes/patterns may develop. The first is the development of a gulf low to replace the current East Coast low on its way out. This mode is more conducive to dry air advection and CAD enforcement as the surface high is unable to shift southward. The other dominate mode relies on the high over the Northeast sagging southward and reinforcing the more climatologically dominate summertime feature, the Bermuda High. This would allow tropical moisture to ascend further northward and bring wetter conditions across parts of central and north GA. SM && .AVIATION... (00Z TAFS) Issued at 741 PM EDT Tue May 30 2023 VFR ceilings to start this TAF set but MVFR and IFR ceilings will move in over night. There are still some isolated showers across the area but they should stay isolated enough to stay away from the TAF sites. Will see mostly clear skies through 08z-10z Wed when the lower ceilings will move in with moist easterly flow. Will see ceilings in the 1000-2000ft range around daybreak then they will slowly lift into the VFR range by 17z-19z. Will also see afternoon CU develop with more isolated SHRA/TSRA Wed afternoon/evening. Will continue with the Prob30 in the TAFs for now between 20z-00z as they will still be isolated but will have a little better chance to actually see some precip at the TAF sites. Winds will stay out of the east in the 6-12kt range through the period. //ATL Confidence...00Z Update... Confidence high on all elements. 01 && .PRELIMINARY POINT TEMPS/POPS... Athens 63 80 63 81 / 20 30 20 10 Atlanta 64 81 65 82 / 10 20 20 20 Blairsville 58 76 57 79 / 10 30 20 30 Cartersville 63 82 63 84 / 10 20 10 20 Columbus 65 84 66 84 / 0 30 30 20 Gainesville 63 78 63 81 / 10 20 10 20 Macon 65 83 65 84 / 10 30 20 10 Rome 63 83 63 84 / 10 20 10 20 Peachtree City 63 81 63 82 / 10 30 20 20 Vidalia 66 83 66 84 / 10 30 20 20 && .FFC WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...KAL LONG TERM....SM AVIATION...01
As mentioned in the previous forecast discussion, this will
result in increased moisture across northern Arizona, with
forecast PWATs between 0.40 and 0.60 inches. Due to the persistent dry low levels, it is uncertain at this time how much potential precipitation will fall with shower and storm formation, but frequent cloud-to-ground lightning and gusty outflow winds cannot be ruled out. && .AVIATION...For the 06Z TAF Package...VFR conditions will continue through the 24-hour TAF period. Look for light and variable winds overnight becoming gusty from the south to southwest at 10-20 kts gusting to 30 kts after 16Z. A few cloud buildups Wednesday afternoon will lead to isolated showers and even a stray thunderstorm east of a KPRC-KGCN line. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Wednesday and Thursday...Breezy southwest winds continue Wednesday afternoon with gusts 15-25 mph. Highest gusts can be expected along and downslope of the high terrain. Gusts will become westerly and drop to 10-20 mph on Thursday. A slight chance of showers and isolated thunderstorms both afternoons, favoring the mountainous terrain. Chances are low-to-none of wetting rain. Friday through Sunday...Lighter winds with chances of showers and thunderstorms each day, with afternoon temperatures remaining a few degrees below seasonal averages. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...Benji/Varian AVIATION...McCollum FIRE WEATHER...Varian For Northern Arizona weather information visit
Area Forecast Discussion
National Weather Service Grand Junction CO
545 PM MDT Tue May 30 2023 .SHORT TERM...(Tonight through Wednesday night) Issued at 223 PM MDT Tue May 30 2023 Eastern Utah and western Colorado remain under dry and mild southwesterly flow this afternoon with the usual convective buildups over the higher terrain and breezy conditions. Midlevel lapse rates remain in the 9 to 10 deg C/km range with some higher values of CAPE seen across the northern portions of the CWA and the spine of the Continental Divide. CAM guidance has been highlighting some very isolated convection over those same areas and are performing well as both the HRRR and NAMNEST are nailing where convection is currently located. The lower levels of the atmosphere remain very dry so look for another day of gusty outflow winds from any of this convection. Already seen a few gusts reaching around 40 mph from what appears to be weak cells so look for this to continue for the remainder of the day. The rex block remains across the eastern U.S. this afternoon while a closed low has come ashore in southern California. Flow around this low has been responsible for the warm temps and dry air that has advected into the region. The low will continue to move eastward overnight and by daybreak Wednesday will be just about over Las Vegas. As the low continues to move closer to our CWA, moisture values remain fairly constant though instabiliy does increase so look for an uptick in convection. CAM guidance is showing the same with convection moving in a southeast to northwest trajectory...firing shortly after 12PM continuing through the early evening hours. Soundings continue to show inverted V-profiles so, again, look for gusty outflow winds and some brief, heavy rain. .LONG TERM...(Thursday through Tuesday) Issued at 223 PM MDT Tue May 30 2023 The closed low will be just to the southwest of the Four Corners Thursday morning and will fill through the day as it...very slowly... moves to the north. Forecast Skew-Ts keep lower levels dry during this timeframe but midlevels become saturated so any convection that fires, and it will, will likely bring some gusty outflow winds. Guidance is suggesting daytime heating and increased instability and lift from the low will bring widespread showers and storms initially firing over the higher terrain before moving into adjacent valleys, especially for the northern valleys where steering flow winds reach between 15 to 20 mph. From Friday onwards, a notable PWAT increase occurs as indicated through GEFS and EPS ensemble guidance. As one would expect, this increased moisture should cause an uptick in precip coverage which it does. This deeper moisture is also to remain in place through the long term period and beyond, which will keep precip chances elevated from day to day. Flow becomes relatively stagnant through the weekend onwards as a blocking high sets up over the Great Lakes and disturbances flow and ebb around the low pressure. The end result is a rather chaotic period of unsettled weather. The exact details are still murky but the general gist of showers and thunderstorms each afternoon and evening remains. Look for the most widespread precip to occur during the afternoon and early evening hours during peak heating with a few, very isolated showers possibly continuing overnight. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 544 PM MDT Tue May 30 2023 Very light returns in the vicinity of KHDN late this afternoon according to radar imagery. However, suspect this was mainly virga and therefore unlikely to reach the surface given the dry sub-cloud layer. Regardless, diurnal cooling was already resulting in decreased intensity and coverage of moist convection and that trend will continue through 02Z reducing the threat of impacts at any TAF site tonight. Mid-level convective clouds will diminish this evening, though cirrus is likely to continue streaming northward over the area during the night. The low over the southern California coast will move slowly inland over the Desert Southwest in the next 24 hours. Increased lift and moisture ahead of this system, mainly over the Continental Divide, will result in increased showers and thunderstorms Wednesday afternoon. Probability not high enough to mention more than VCTS at this time for KHDN, KEGE, KASE and KGUC after 18Z/Wed. Otherwise, expect VFR conditions to persist during the period with winds again picking up from the southwest Wednesday afternoon. && .HYDROLOGY... Issued at 223 PM MDT Tue May 30 2023 Overall, most forecast hydrographs follow a either a steady or slight negative slope through the end of the 10 day outlook. But first, gages are forecasted rise tonight through Wednesday night, in response to this unseasonably warm weather. However, by Thursday, river and runoff guidance indicate a slow down in snow to flow in response to the approaching low pressure system. As cooler temperatures infiltrate the area, high elevation lows will potentially dip back below freezing overnight and limit the volume of snowmelt. The caveat, though, is that this system is also progged to carry in an abundance of moisture. Expect afternoon showers and thunderstorms to become widespread by the end of the week, and the risk for daily convection sticks around for the foreseeable future. Direct impacts to streams, creeks, and rivers will be highly dependent on rainfall rates, storm duration and extent. Quick moving storms will translate a very different hydrologic outcome compared to a slow moving and/or training storm(s) over the same basin. Thus, despite low confidence in which basin is favored, additional spikes are possible leading into the weekend. Median SWE still exceeds 200 percent of normal for the end of May across the Elkheads, Park, Flat Tops, Elks, West Elks, Grand Mesa, Unc, La Sals, and much of the southwest San Juans. So, basically, there`s plenty of snow pack left to melt out...and the spring runoff season continues. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...TGR LONG TERM...TGR AVIATION...NL HYDROLOGY...ERW
Area Forecast Discussion
National Weather Service Grand Rapids MI
739 PM EDT Tue May 30 2023 LATEST UPDATE... Aviation .SHORT TERM...(This evening through Wednesday night) Issued at 330 PM EDT Tue May 30 2023 Recent GOES water-vapor imagery shows a Rex block persisting over much of eastern North America. In the low levels, broad southeasterly flow has facilitated a modest increase in low-level moisture since this time yesterday, with surface dewpoints across the forecast area ranging from the mid 40s to mid 50s F. This boundary-layer moisture is supporting the development of high-based shallow cumulus across much of the forecast area today, as evident in visible satellite imagery. CAM guidance (e.g., 12z HREF and subsequent HRRR runs) suggests that cumulus should deepen sufficiently for isolated sprinkles/showers later this afternoon and evening, mainly south/east of Grand Rapids. This limited activity will wane after sunset as the boundary layer cools/stabilizes. Somewhat more widespread showers/t-storms are expected on Wed afternoon/evening, albeit "hit and miss" (scattered / chance PoPs). Surface dewpoints in the 50s, combined with temps again climbing into the upper 80s to near 90 F, should yield MLCAPE of generally 500-1500 J/kg across the forecast area, per recent RAP guidance. While overall convective coverage will be limited by the absence of large-scale lift, weak low-level convergence along the expected lake- breeze front may support relatively greater coverage near US-131. Deep layer (0-6 km) bulk shear will be weak (under 10 kts), limiting convective organization. However, locally gusty outflow winds are possible, given appreciable downdraft CAPE accompanying a deep, well- mixed boundary layer. .LONG TERM...(Thursday through Tuesday) Issued at 330 PM EDT Tue May 30 2023 No widespread appreciable rainfall is expected through early next week and the current abnormally dry conditions will only worsen. Upper high centered over the ern GrtLks Rgn retrogrades slowly westward and by early next week will be centered in the vicinity of srn Manitoba. This occurs as upr troughing digs back into New England, which eventually sends another back door cold front through MI around Tuesday of next week. Until then we remain in an early season heat wave of sorts with daily highs around 90, although dew points will remain below 60 keeping the heat index close to the actual temperature. Any rainfall will be isolated at best due to persistence of subsidence and dry air, and probably limited to the afternoon/early evening lake breeze boundary (near/west of Hwy 131) or other mesoscale sfc convergence zones. Fire danger will remain elevated due to lack of rain, particularly for conifer fuels, but thankfully no periods of stronger winds are anticipated at this time. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 739 PM EDT Tue May 30 2023 VFR conditions will continue through Wednesday evening. Isolated showers are possible Wednesday afternoon but these were left out of the forecast for now as coverage is expected to be sparse. Southeast winds around 7 knots this evening will go light and variable tonight. West winds 5 to 10 knots near Lake Michigan as the lake breeze redevelops on Wednesday. && .MARINE... Issued at 330 PM EDT Tue May 30 2023 Synoptic light wind regime continues, with a southerly component generally favored Wed and Thurs. The flow will be light enough to allow the typical diurnal/afternoon onshore lake breezes near 10 kts to kick in and linger into the early evening hours. The weekend features light easterly flow for the nighttime and morning hours, flipping to onshore for the afternoon and early evening hours. && .CLIMATE... Issued at 330 PM EDT Tue May 30 2023 Record High Temps GRR MKG LAN AZO BTL BIV Tue 5/30 92-2019 90-2018 95-1895 94-1978 94-1895 94-1942 Wed 5/31 95-1934 88-2016 96-1895 93-1911 94-1919 92-1934 Thu 6/1 102-1934 88-2014 97-1934 102-1934 100-1934 100-1934 Record Warm Lows GRR MKG LAN AZO BTL BIV Tue 5/30 68-2018 74-2022 70-2022 72-2018 72-2018 70-2018 Wed 5/31 73-1937 70-1970 73-2022 71-2022 71-2022 73-1937 Thu 6/1 74-1934 66-1970 68-1970 71-1895 71-1895 75-1934 && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SHORT TERM...Kenyon LONG TERM...Meade AVIATION...Ostuno CLIMATE...NJJ MARINE...Meade
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
947 PM EDT Tue May 30 2023 .SYNOPSIS... Weak high pressure remains over the area through Friday as a low pressure system near the Carolina coast slowly weakens. A weak cold front drops south across the area Saturday. High pressure returns for early next week. Another cold front will arrive from the north toward the middle of next week. && .NEAR TERM /THROUGH WEDNESDAY/... As of 930 PM Tuesday: A Rex block will evolve tonight into tomorrow as a closed upper low meanders across the northern Gulf of Mexico. Farther north, a high latitude ridge will amplify across New England into the Great Lakes region. At the surface, a backdoor cold front is slowly moving southwest across the area. Lower ThetaE air will move into the region in its wake, particularly above the PBL tonight--dewpoints aren`t exactly tumbling behind it. The convective layer looks so shallow that remaining thunder probs have now been removed from the fcst. Showers however will continue to bubble near the boundary tonight. HRRR continues to depict a rapid increase in coverage in the middle of the night, perhaps a result of flow turning a bit more southeasterly over the sfc airmass, but still think overall coverage warrants no better than isolated to scattered wording. Min temps appear on track but have touched up hourly trends a bit. Another low stratus deck still looks to develop with cloudy skies continuing into much of tomorrow. Isolated showers cannot be ruled out area wide tomorrow, but the greatest coverage will likely reside across the southwest mountains where the greater ThetaE will reside. Cloud cover will also keep high temperatures once again below normal with highs in the 70s. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... As of 130 PM EDT Tuesday: Surface high pressure centered over Pennsylvania through this period will keep east to northeast low level flow across the forecast area. This will be the main mechanism driving the weather through this timeframe as the mid level pattern will not feature any strong system near us. The low level flow will keep some moisture in place but will also keep temperatures normal to slightly below normal. Robust convection is not expected due to limited instability but some upslope mainly mountain showers are possible. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 130 PM EDT Tuesday: The mid level pattern starts to play a more significant role by this weekend as a fairly deep closed low is expected to form off the northeast coast. This will drive another area of surface high pressure down the east side of the Appalachians, which will reinforce the short range surface pattern for Sunday into early next week. Ahead of this feature, Saturday looks to be the warmest day of the period in our area with highs climbing into the mid 80s (slightly above normal) outside of the higher elevations. Highs will slip back to slightly below normal Sunday and Monday. The probability of precipitation looks limited through the extended period. There should be some upslope weak convection in the mountains both Sunday and Monday but otherwise it should be mainly dry. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: A few SHRA linger invof backdoor cold front oozing southwestward thru the area, but chance at all the TAF terminals appears too low to mention. This small chance will drop a bit by late evening, but the boundary and/or easterly flow into the mountains could spawn a stray shower even after midnight. Brief MVFR vsby would be the main threat if one did pass over a terminal. Remnant stratocu in the 045-100 layer will be seen this evening. Moist, easterly low-level flow again looks to produce MVFR to IFR stratus over all terminals prior to dawn. This deck will slowly mix back up to low VFR by around midday Wed, with isolated SHRA again in the fcst Wed aftn, not yet warranting a mention at KCLT. Outlook: Isolated SHRA/TSRA and associated restrictions appear possible near the Appalachians Thu and Fri afternoon. Continuing easterly flow will pose some risk of early morning fog/stratus Thu and Fri mornings, particularly at KCLT/KHKY. The easterly flow regime may last into the weekend. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...TW/Wimberley SHORT TERM...SCW LONG TERM...SCW AVIATION...Wimberley
Area Forecast Discussion
National Weather Service North Platte NE
618 PM CDT Tue May 30 2023 ...AVIATION UPDATE... .SYNOPSIS... Issued at 216 PM CDT Tue May 30 2023 Key Messages: - Scattered thunderstorms this evening and tonight, some of which may be severe with damaging winds and hail being the primary threats, especially across southwest Nebraska where an Enhanced Risk of Severe Thunderstorms exists. - Thunderstorms are possible again on Wednesday evening, however, the severe threat appears limited to portions of southwest Nebraska at this time. - Unsettled weather continues for Thursday into the weekend with daily chances for thunderstorms with heavy rain being the primary concern. - Temperatures remain at or slightly above normal in the 70s and 80s each day through the weekend. Recent GOES-16 WV and RAP 500-mb analysis showed a compact low pressure system centered across southern California. Further northeast of this feature, an upper-level shortwave trough was apparent across southern Manitoba into north central North Dakota, extending southeast across the Nebraska/Iowa border. An upper- level ridge was situated across the Ohio River Valley and a closed low off the coast of North Carolina. Further southwest of these features, a near stationary upper-level trough was evident across the Gulf of Mexico. A weak shortwave disturbance was lifting northeastward across the Four-Corners region. At the surface, low pressure was situated across southeastern Colorado with a dryline extending south across eastern New Mexico. Closer to home, a weak surface boundary was draped across southwest into northeastern Nebraska. At 2PM CT, temperatures ranged from 79 degrees at Imperial to 83 degrees at Valentine and O`Neill. && .SHORT TERM...(This evening through Wednesday night) Issued at 216 PM CDT Tue May 30 2023 This evening and tonight...Scattered thunderstorms have begun to develop across eastern portions of the Cheyenne Ridge and Palmer Divide as of 2 PM CT. As these thunderstorms track eastward into the Nebraska Panhandle, upscale growth is expected resulting in a MCS to track west to east across western and north central Nebraska beginning around 22Z. Surface temperatures in the 80s and dew points mixing into the upper 50s to lower 60s will support steep low to mid-level lapse rates approaching 8.5 C/km, further contributing ample instability (MLCAPE ~2,500 J/kg) across the area. Recent forecast soundings show an inverted-v profile suggesting that these thunderstorms will be high-based. The environment is supportive of severe wind gusts (some gusts may reach 75 mph or greater) and a few cells may be capable of large hail. The window of timing of the greatest severe threat is from 6 PM to 12 AM CT across western and north central Nebraska. The severe threat will diminish across the areas as the system continues to progress towards eastern Nebraska through 10Z due to diurnal cooling and a weak-sheared environment. Wednesday and Wednesday night...The aforementioned upper-level low across southern California will continue to track eastward, centering over the Arizona/Nevada border Wednesday evening. Another shortwave embedded in the flow aloft will propagate across the area in the evening bringing another round of scattered showers and thunderstorms to the area Wednesday evening into the overnight hours. Similar to today, the expectation is that these thunderstorms will begin to develop off the Front Range and eastern Cheyenne Ridge late Wednesday afternoon. Model solutions continue to suggest that this activity will be less organized as compared to today, however, ample instability and meager shear across portions of southwest Nebraska will support an environment capable of strong winds and large hail. Thus, agree with SPC Outlook of a Marginal Risk of Severe Thunderstorms on Wednesday for portions of southwest Nebraska. In addition to the severe risk on Wednesday, the WPC has portions of the Nebraska Panhandle into southwest Nebraska outlooked for a Marginal Risk of Excessive Rainfall. PWAT values approach 1" across southwest Nebraska, some locations may even exceed 1". This combined with ample CAPE values of 1,000 to 2,000 J/kg will support convection capable of heavy rain. .LONG TERM...(Thursday through Tuesday) Issued at 216 PM CDT Tue May 30 2023 The previously mentioned upper-level low will continue it`s eastward progression before settling across the Four Corners region with broad upper-level high pressure centers over the northeastern CONUS. Multiple shortwaves embedded within the flow aloft will track across the forecast area bringing a continued unsettled weather pattern into the weekend. The severe risk appears low during this period with heavy rain being the primary threat across the area. Southeast winds will bring an influx of moisture across the area with PWAT values of 0.75" and potentially exceeding 1" across the area. In fact, both the NAEFS and ENS ensemble guidance NAEFS and ENS ensemble guidance highlights this influx of moisture, suggesting that the mean PWAT will meet or exceed the 90th percentile for Thursday into the weekend. WPC has portions of the area highlighted for a Marginal Risk of Excessive Rainfall for Thursday into Saturday. Given recent heavy rainfall for the last few days across the area, any storms that produce heavy rainfall could exacerbate any flooding potential across the area. Will continue to monitor the heavy rain potential with subsequent forecasts. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 618 PM CDT Tue May 30 2023 Thunderstorms are the primary aviation weather concern for western and north central Nebraska through tonight. Ongoing scattered thunder in the panhandle will grow in coverage and intensity as it spreads east through the evening. The greatest impacts at KLBF and KVTN will occur sometime around 31/03z with strong winds, torrential rain that will limit visby, and possibly hail. Thunder coverage should dissipate by 31/06z for most terminals. Southerly winds ahead of the convection will switch to west with the storms, then become light overnight. Redevelopment of storms is possible by mid-late afternoon Wednesday. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Viken SHORT TERM...Viken LONG TERM...Viken AVIATION...Snively
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1055 PM CDT Tue May 30 2023 .UPDATED TO INCLUDE 06Z AVIATION DISCUSSION... Issued at 1055 PM CDT Tue May 30 2023 .DISCUSSION...(This evening through Tuesday) Issued at 229 PM CDT Tue May 30 2023 Key Messages: - Isolated to scattered showers and thunderstorms expected later this afternoon. A few storms could contain large hail and heavy downpours. - Garden variety thunderstorm chances every day this week due to hot and humid conditions. A lack of strong forcing should keep storms from becoming severe in most cases. - Speaking of the heat, temperatures in the low 90s likely later in the week and into the weekend. Discussion... The MCV that was the cause of the showers and storms this morning has moved over the arrowhead in northeastern Minnesota, with a blossoming cumulus field over much of the MPX CWA this afternoon. As we get into the late afternoon, it is likely a few of these cumulus clouds grow to the point we see showers and a few storms beginning to form, with the peak timing through the mid evening before activity begins to diminish. Per SPC mesoanalysis, we have a healthy amount of instability in the 2000-2500 J/KG area which would support stronger storms, however we have a lack of deep layer shear for storm maintenance as well as a lack of strong forcing. The shortwave trough that was supposed to be the focus for our activity has been pushed northwards along the track of the MCV, which has put it firmly outside of our coverage area and will likely limit the spread of storms this afternoon and evening. Given the instability we do have as well as strong low level lapse rates, scattered garden variety thunderstorms with isolated stronger cells still remains possible, with hail remaining the primary threat to consider as far as severe weather goes. The best opportunity for stronger storms will be if we can get a few cells forming within a close area, with boundary interactions between them acting as the forcing for the strong storms, but this remains a lower likelihood possibility if the days CAM runs are to be believed with only isolated weaker storms within the last few HRRR runs as well as limited coverage in the 12z SPC HREF. As was mentioned in the previous AFD, slow storm motions could result in locally heavy rain for those fortunate enough to see storms forming today, with other areas continuing to remain dry. Heading into the overnight hours, a strengthening low level jet will keep some activity going over southern Minnesota, likely remaining mostly a rain and lightning show rather than a legitimate severe weather threat. Through the rest of the week, we continue to see a lack of even moderately strong synoptic scale forcing for ascent to produce severe storms, with more of this daytime heating forced weaker activity. Our upper level pattern continues to remain stagnant such that deep layer shear remains absent, with storm chances remaining limited to whatever weak shortwave activity we can muster up. These meager storm chances continue throughout the week as mainly an afternoon affair, becoming weaker towards the weekend due to a strengthening upper level ridge, which will also lead to increasing temperatures. NBM bias correction continues to trend high temperatures too low, with low to mid 90s possible towards Friday especially. There are small signs of relief on the horizon with the ridge weakening by the middle of next week, however there has yet to be a strong push within any of our longer range deterministic guidance to truly drop things towards more normal temperatures in the upper 70s to low 80s. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1055 PM CDT Tue May 30 2023 Storms have come to an end tonight and it should remain quiet through the morning. Some chances start again the afternoon, with the better chances coming in the evening. Outside of the thunderstorms chances it will be VFR through the period. Winds will be light overnight and then pick up to around 10 knots on Wednesday from a southerly direction. KMSP... No additional concerns. /OUTLOOK FOR KMSP/ THU...VFR. Chc aftn/eve TSRA. Wind S 10-15kts. FRI...VFR. Chc aftn/eve TSRA. Wind SE 10-15kts. SAT...VFR. Chc aftn/eve TSRA. Wind SE 10-15kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...TDH AVIATION...NDC
Area Forecast Discussion
National Weather Service Marquette MI
737 PM EDT Tue May 30 2023 .SHORT TERM...(This afternoon through tonight) Issued at 241 PM EDT TUE MAY 30 2023 For the majority of the UP, today will be quiet and warm as ridging centered over the Lower Great Lakes still extends out across the Upper Peninsula. RAP analysis shows a shortwave over northeast ND which will track northeast into Manitoba the rest of today and tonight. An associated sfc low just northeast of the shortwave will follow a similar northeast path through Manitoba tonight. Ridging keeps the dry and mostly sunny conditions through the rest of today, with cloud cover moving into the far west this afternoon in association with a small shortwave noted by a swirl in vis/radar imagery over the arrow head of MN and far western Lake Superior. Only a slight chance of showers is expected around Ironwood late this afternoon ahead of the frontal boundary currently located in MN. With CAPE values on most BUFKIT model soundings staying low (100- 200 J/Kg) in Ironwood, I am feeling confident that thunder will stay out of the forecast until Wed. The southerly winds, stronger in the west, will aid in bringing warmer temps to the Superior lakeshores this aftn with highs reaching into the 80s; coolest temps located along Lake Michigan in mid to upper 70s. Tonight could see some slight chances for light rain showers along the far west, but otherwise mostly clear skies and dry weather will continue for the rest of the UP. Lows should settle into the 50s; rain showers and cloud cover may keep the far west and Keweenaw in the low 60s. .LONG TERM...(Wednesday through Tuesday) Issued at 431 PM EDT TUE MAY 30 2023 Mid-level ridging will influence the weather pattern throughout the extended period, resulting in high temperature trends of 15 to 20 degrees above normal across the interior. This puts daytime highs in the mid to upper 80s and even some low 90s across the interior. Lakeshores will be cooler as always with highs topping off in the 60s and 70s. These temperatures combined with min RH values in the mid 20s will elevate the fire threat on Wednesday, but light winds will help to mitigate the threat somewhat. And, as the aforementioned ridge drifts eastward late in the week, an uptick in Gulf moisture will at least push min RH values above the 30 percent mark from Thursday through Sunday. After that though, the very dry conditions return for Monday and Tuesday. Simultaneously, the brief moisture influx will provide just enough instability to maintain daily thunderstorm chances (mainly west and central) from Wednesday through Sunday. The best chances will be in the afternoon and evening hours especially on Thursday and Friday with a surface boundary in the vicinity, but modest MLCAPEs in the 500-1000 j/kg range and limited wind shear will prevent strong to severe convective development. Most activity will likely be pulse-like in nature. Further out, a shift in the pattern starting Monday will start a downward trend in temperatures with daytime highs closer to normal by Tuesday as a low pressure system drops into the northeast U.S. Look for highs generally in the 70s across the interior with upper 50s/low 60s along the lakeshores. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 735 PM EDT TUE MAY 30 2023 VFR conditions will prevail at all sites through the entire TAF period. Some mid-level clouds are beginning to move through IWD with slight chances for rain showers mainly this evening. However, with the dry environment working against all developing precip, confidence remains too low to include any showers in the TAF so will only have VCSH. CMX and SAW will remain dry, but could also see some mid level clouds through tonight. Generally southerly winds are expected through the entire TAF period except for the easterly winds at CMX this evening and late Wednesday afternoon. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 441 PM EDT TUE MAY 30 2023 Winds below 20 kts are expected across the lake for the entire forecast period with mid-level ridging over the region. There will, however, be thunderstorm chances across the western portions of the lake tonight with more widespread chances Wednesday through Friday, especially during the afternoons and evenings. Since storms will be diurnally driven and lacking synoptic support, strong to severe storms are not anticipated at this time. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Jablonski LONG TERM...TDUD AVIATION...Voss MARINE...TDUD
Area Forecast Discussion
National Weather Service Mount Holly NJ
916 PM EDT Tue May 30 2023 .SYNOPSIS... High pressure remains anchored over the Northeast through mid-week while weakening low pressure off the coast of the Carolinas will linger into Thursday. The low will continue to bring some scattered showers to the Delmarva Peninsula, but dry weather should prevail overall with increasing temperatures through the end of the week. A back-door cold front passes through on Saturday and introduces a cooler airmass for the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Forecast on track this evening. Only minor adjustments made to the grids. Previous full discussion below... High pressure south of the Canadian Maritimes will sag to the south and east tonight through Wednesday. Meanwhile, upper low over the Mid- Atlantic continues to dissipate. The other aspect to this forecast is smoke and haze from wildfires in Nova Scotia will spread into the region. More on that in a bit. In terms of sensible weather, onshore flow will continue tonight through Wednesday. Another round of light rain showers may impact southern Delmarva, again with minimal QPF, Wednesday afternoon. With onshore flow and increasing low level moisture spreading into the region, patchy fog and drizzle is likely for coastal areas and areas just inland from the coast late tonight through Wednesday morning. In addition, a stratus deck will spread farther inland to about the I-95 corridor. Clouds scatter out Wednesday morning, giving way to hazy sunshine in the afternoon. Lows tonight will be in the mid and upper 40s to low 50s. Highs on Wednesday will top off in the upper 70s to low 80s inland, and in the upper 60s to low 70s along the coast and just inland. Smoke from wildfires in Nova Scotia will then spread west into the region from the northeast. Latest HRRR and RAP vertically integrated smoke forecasts have one wave spreading into the region into this evening, and then another wave on Wednesday. We currently have a bit of a haze and the smell of smoke at the WFO, but this may be related to an ongoing fire on the base. Have included widespread haze with a smaller area of patchy smoke. HRRR is also indicating the potential for smoke to mix down to the surface. Air Quality Alerts have been issued for all of New Jersey and southeastern PA, including the Philadelphia area. Be prepared for the smell of smoke in addition to some reduced visibility. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... A strong upper ridge will remain overhead for the short term period while upper troughing digs across the Southwest. The flow will be quite meridional aloft and the resultant blocking pattern will hold strong through the end of the week. At the surface, high pressure remains in control while a weak surface low spins off the coast of the Carolinas. Weak onshore flow Wednesday night will introduce a marine layer with low stratus/fog/light drizzle as moisture is trapped underneath a subsidence inversion around 900 mb. Further inland (Lehigh Valley to the Poconos) expect mostly clear skies and, with wind going light to calm, efficient radiational cooling, though warm advection will work to offset the cooling and lows will be a few degrees warmer than Wednesday night in the low 50s. In addition, expect that some haze/smoke will still be around into the early overnight, so maintained the patchy smoke mention. Temperatures will rebound quite quickly on Friday as the NBM is still holding firm with highs in the upper 80s and low 90s, while cooler along the coast. Latest guidance has continued the slight increase of 850 mb temperatures to around 17-19C which is very close to supporting highs in the 90s. NBM prob MaxTs are indicating a >60% chance of MaxTs >90F primarily along I-95 and west, though MOS guidance is still not budging from the upper 80s. Regardless, we`ll be seeing above average temperatures across the board. Forecast soundings show a very deep, dry boundary layer, so do expect that dew points will mix out in the afternoon and apparent temperatures should remain around actual air temperatures. A sea breeze should develop in the afternoon and will drop temperatures some as it progresses inland. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The forecast still remains more uncertain going into the weekend. The deterministic suite of guidance indicates a potent shortwave diving south out of New England and a back door surface front coming onshore on Saturday. Meanwhile, an area of surface low pressure will be sliding up the Atlantic coast, and both the GFS and ECMWF show the shortwave aiding in the low`s development before quickly evolving into a closed low itself. Both deterministic and ensemble guidance remains spread on the timing of the backdoor front as well as the strength and track of the surface low. The GFS and Canadian favor a very early Saturday morning passage with the ECMWF later. Ultimately, the setup is favoring a post-frontal cooldown on Saturday after a quite warm Friday with thickness values falling and cold advection with northeasterly onshore flow. Held with NBM which introduces some PoPs (20-40%) with frontal passage on Saturday, though moisture may be overall lacking with the front. Cool high pressure is expected to build in on Sunday with mostly dry conditions and high temperatures in the low to mid 70s. The beginning of next week looks to stay dry overall for now, but there is quite a bit of model spread regarding where this closed coastal low will end up. Current ensembles keep it a good distance offshore and mostly unimpactful to our area, though a surface boundary may sag south across the area sometime Monday. Run-to- run fluctuations continue essentially after the frontal passage Saturday, so stuck close to the consensus/NBM forecast here until we can narrow down possibilities over the next several days. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight (00Z through 12Z)...VFR initially, then MVFR CIGs likely to develop at KTTN/KPNE/KPHL/KILG and IFR CIGs with MVFR VSBYs in fog, stratus, and drizzle will develop at KMIV/KACY after 09Z. Some haze from wildfire smoke is possible prior to the arrival of fog/stratus. E winds around 5-10 kt. Moderate confidence. Wednesday (12Z through 00Z)...Any sub-VFR conditions will give way to VFR. Latest HRRR/RAP guidance has haze/smoke clearing out of the I-95 terminals by the early afternoon, though hanging around the Lehigh Valley terminals through the day. Cannot rule out VSBY restrictions in smoke, but probabilities are low. E-NE winds 5 to 10 kt, increasing to around 10 kt in the afternoon. Moderate confidence. Outlook... Wednesday night...Sub-VFR conditions expected with low stratus and fog, especially at I-95 terminals and KACY/KMIV. Some haze and patchy smoke at mid-levels through the early overnight. Variable wind less than 5 knots. Moderate confidence. Thursday...Some early morning fog/low stratus may continue sub-VFR conditions early, otherwise expect VFR for the remainder of the day. Northeasterly wind 5-10 knots becoming southeasterly in the afternoon. Moderate confidence. Friday...VFR. Northeasterly wind 5-10 knots. Moderate confidence. Saturday...Sub-VFR conditions possible with passage of a cold front. Northeasterly wind increasing to 10-15 knots with gusts to 25 knots behind the front. Low confidence. Sunday...VFR. Northeasterly wind 5-15 knots. Low confidence. && .MARINE... NE winds continue to diminish this evening, and will eventually settle to around 10 to 15 kt after midnight. On Wednesday, winds will be NE 10 to 15 kt with gusts up to 20 kt. Seas of 5 to 7 feet will subside to 3 to 5 feet tonight through Wednesday. Small Craft Advisory has been allowed to expire for the lower DE Bay, and sub-SCA conditions are expected for DE Bay through Wednesday. Seas remain elevated on northern NJ ocean waters through tonight, then seas will be below 5 feet through Wednesday. For southern NJ and DE ocean waters, seas remain around 5 feet through Wednesday, and SCA remains in effect through Wednesday. Outlook... Thursday...No marine headlines expected. Northeasterly wind 5-10 knots. Seas 3-4 feet. Friday...No marine headlines expected. Southeasterly wind 5-10 knots. Seas 2-3 feet. Saturday...Small Craft Advisory conditions possible. Northeasterly wind 5-10 knots in the morning increasing to 15-20 knots with gusts to 25-30 knots in the afternoon. Seas 2-3 feet building to 5-7 feet from north to south. Sunday...Small Craft Advisory conditions possible. Northeasterly wind 15-20 knots with gusts to 25 knots and seas 5-7 feet in the morning. Conditions may improve later in the day. && RIP CURRENTS... For the beaches of Atlantic County and Cape May County in New Jersey, and for the beaches of Sussex County in Delaware, there is a HIGH risk for the development of dangerous rip currents into Wednesday evening. We are anticipating a northeast wind 10 to 15 MPH with breaking waves of 3 to 4 feet. For the beaches of Ocean County and Monmouth County in New Jersey, we are expecting a northeast to east wind 5 to 10 MPH on Wednesday with breaking waves of 2 to 3 feet. The conditions should result in a MODERATE risk of rip current in those areas. Wind speeds and breaking waves are forecast to diminish slightly for Thursday. An east to northeast wind 5 to 10 MPH is expected with breaking waves of 2 to 3 feet. The rip current risk should be MODERATE for all the Delaware and New Jersey beaches at that time. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...High Rip Current Risk through Wednesday evening for NJZ024-025. DE...High Rip Current Risk through Wednesday evening for DEZ004. MD...None. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ450-451. Small Craft Advisory until 8 PM EDT Wednesday for ANZ452>455. && $$ SYNOPSIS...Brudy NEAR TERM...Hoeflich/MPS SHORT TERM...Brudy LONG TERM...Brudy AVIATION...Brudy/Hoeflich/MPS MARINE...Brudy/Hoeflich/Iovino/MPS
Area Forecast Discussion
National Weather Service Phoenix AZ
420 PM MST Tue May 30 2023 .Update...Updated Aviation && .SYNOPSIS... Mainly below normal temperatures will persist across the region through the end of the week. A weather disturbance moving across the Desert Southwest during the next couple of days will deliver breezy to locally windy conditions, with the strongest winds expected across portions of Imperial County. A warming trend is anticipated by the weekend with temperatures returning back to around normal. No precipitation is expected through at least the next 7 days. && .DISCUSSION... Latest water vapor imagery reveals a closed upper low drifting eastward into southern California. Across much of Arizona, temperatures are running close to what they were this time yesterday, but further west and closer to the low across southeastern California, conditions are considerably cooler. High temperatures so far today have only reached the mid 80s across the Imperial Valley, however this is still several degrees higher than the record low maxes for the date. Otherwise, the main weather story today will be the widespread afternoon and evening breeziness. Latest HREF continues to indicate a 30-60 percent chance of peak gusts reaching 25 mph in the Phoenix area this evening. Further west across the Imperial Valley, latest trends in the HRRR suggest peak gusts will reach 40-45 mph this evening and a Wind Advisory continues for these areas. With the low expected move into northern Arizona during the day on Wednesday, another round of breezy to locally windy conditions is expected once again during the afternoon/evening hours with Imperial County once again seeing the strongest winds with gusts in excess of 30-35 mph while elsewhere gusts will generally range between 20-30 mph. With heights aloft lowering in response to the upper-level low, a cooldown is expected across many areas. In fact, there is a greater than 60% probability according to the latest NBM guidance that temperatures across many of the western desert areas of southwest Arizona and southeast California fail to reach 90 degrees, with highs remaining stuck in the upper 80s. Across the south-central Arizona lower deserts, including the Phoenix area, those probabilities of failing to reach 90 degrees are a bit lower at between 20-40%. Nevertheless these temperatures will be a good 8-10 degrees below normal for this time of the year. The negative height anomalies will persist through Thursday and Friday so temperatures will continue to remain below normal with highs in the lower to middle 90s. By the weekend, as heights aloft rise in response to weak high pressure building in, a warming trend is anticipated with temperatures returning back to near normal with highs in the low 100s. By early next week, model guidance is indicating yet another upper-level low moving from the eastern Pacific and through the Desert Southwest. This low pressure may bring just enough moisture to result some showers mainly across eastern and northern Arizona, where slight chances (20-30% PoPs) exist according to the NBM. Otherwise, with heights aloft lowering, slightly cooler temperatures are anticipated. && .AVIATION...Updated at 2320Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT: Breezy conditions this evening will be the main aviation during the TAF period. Winds will emanate out of the W/SW for the remainder of the afternoon and evening, with gusts primarily 20-25 kts. Due to this enhanced flow, our typical shift to the E is expected to occur later than usual. Current model guidance is not in full agreement about when this shift will take place, but 10-11Z looks like the most likely timeframe as of now. Besides a FEW high level clouds around 20 kt tonight, skies will be mostly clear through tomorrow morning. Southeast California/Southwest Arizona including KIPL and KBLH: Breezy to windy conditions will be the main aviation concern during the forecast period. IPL will see W winds pick up over the next several hours, with peak gusts upwards of 35 kts later this evening. These strong winds have the potential to generate areas of blowing dust, which could lead to reductions in visibility at times. Winds out the S/SW at BLH are not expected to be as strong, but peak gusts of 25 kts are likely this evening. Winds are expected to diminish at both terminals overnight. Clear skies are anticipated through the period. && .FIRE WEATHER... Seasonably dry conditions are expected to prevail through the period along with daily afternoon/evening breezes. Enhanced winds are anticipated today and Wednesday as a weather disturbance moves across the Desert Southwest with afternoon/evening gusts ranging between 20-30 mph across most areas, with the western half of Imperial County likely to observe stronger gusts in excess of 40 mph later today and slightly lower speeds on Wednesday. MinRH values are expected to range between 8-15% today and increase to between 10-20% on Wednesday. The combination of the enhanced winds as well as the low RH values will result in an elevated fire danger threat. Below normal temperatures are anticipated beginning on Wednesday and continuing through the end of the week with MinRH values generally ranging between 10-20%. Thereafter, a warming trend as well as slightly drier conditions are anticipated next weekend. Winds will be weaker during the second half of the week through next weekend, although the typical diurnal breezes will persist. && .HYDROLOGY...Updated 200 AM MST 5/30/2023 GILA: Ongoing releases from Painted Rock Dam have decreased to the point that now the downstream gauges along the Gila River near Dateland as well as near Dome/Yuma have fallen 1.5-2 feet below action stage. Despite the declines, will maintain the current Flood Warnings downstream from Painted Rock Dam until improvement of impacts can be confirmed with officials. The Flood Warnings remain in effect through this evening. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory until 8 AM PDT Wednesday for CAZ562-566. Wind Advisory until 4 AM PDT Wednesday for CAZ563-567. && $$ DISCUSSION...Hirsch/Lojero AVIATION...RW FIRE WEATHER...Lojero HYDROLOGY...Lojero/Benedict
Area Forecast Discussion
National Weather Service Pueblo CO
846 PM MDT Tue May 30 2023 .UPDATE... Issued at 824 PM MDT Tue May 30 2023 Line of thunderstorms has pushed eastward into Kansas with the severe risk ending across the southeast CO counties. Have cancelled the Severe thunderstorm Watch for the rest of this evening. Will still be watching the progression of any westward propagating outflows and higher dew point return from convection to our east. NamNest and HRRR still indicates the potential for more thunderstorms to develop across southern sections of the southeast plains around midnight as a south to southeasterly low level jet increases. Will carry some pops past midnight across southern sections of the area and watch how this evolves. If thunderstorms develop, they should be more elevated and carry less of a severe risk, though some small hail seems plausible with the stronger storms as mid level lapse rates steepen after midnight. -KT && .SHORT TERM...(This evening through Wednesday) Issued at 340 PM MDT Tue May 30 2023 Key Messages: 1) A few strong to severe storms are likely over the far eastern plains the rest of this afternoon and early evening with very strong winds the primary threat. 2) Scattered strong to severe storms will be likely tomorrow afternoon over all of the plains, with all severe modes possible. Heavy rains also likely over plains. 3) Locally heavy rains possible in the mtns tomorrow raising the risk for burn scar flooding. Currently... High based shower activity was noted over the mtns and San Luis Valley at 2 pm. In addition, thunderstorms were developing along the I-25 corridor region, with the strongest storms down along the southern I-25 corridor region. Convective scale parameters were indicating CAPE was rather significant over the plains, with sfc based CAPE well over 3000 over the far eastern plains. Deep shear was quite weak to non-existent (not registering on the SPC meso page). T/Td spreads over the eastern plains were showing depressions of about 30 degrees. Rest of Today into Tonight Main concern in the immediate short term is the potential for severe thunderstorms capable of producing very strong wind gusts to develop over the plains as the convection over the general I-25 region push east into the deeper moisture. Given the shear is pretty much nonexistent, storms should quickly develop upscale and develop strong outflows as the rapidly intensify and push east. Given the high CAPE values, intense convective winds will be likely given the high Dcape values. At this time it appears the strongest convection should be out of the region around 8 pm One concern for later tonight will be how much low clouds push back into the state of CO due to the convection? Models show that the far eastern counties will see low cigs, but the remainder of the plains will remain relatively clear. All guidance later tonight keep winds at a brisk southerly component, and this will likely continue to bring up low level moisture to the region which will set the stage for tomorrows weather. Tomorrow... Thunderstorms are likely during the afternoon and there is a good chance that they will be strong to severe. A potent disturbance over the southwest US will continue to push towards the region. This system will advect low level moisture into the region, and this combined with sufficient solar radiation and cool temps aloft will allow for some hefty CAPE to develop over the entire area by tomorrow afternoon. Unlike today where deep shear is very weak, the shear will be modest by tomorrow afternoon, and this along with the CAPE, and the upward vertical motion supported by the approaching Pacific system, will allow strong to severe thunderstorms to develop. At this time the greatest threat will be large hail and winds, but there will be a tornado threat also, and this tornado threat may be enhanced on how outflow boundaries from todays convection affect the region tomorrow. CAPE values tomorrow will be rather high over the region, with values likely in the 2000 to 3000 range by afternoon. This CAPE will allow for quite a bit of severe convection, so I anticipate a very busy day in the office tomorrow. Watch boxes will more than likely be issued for the region. With increasing moisture in the mountains, thunderstorms will be scattered, and they will likely be capable of locally heavy rain, so flash flooding of burn scars may be enhanced tomorrow. In addition, storms will likely not be moving all that quickly, so this will increase the potential for flooding over the burn scars. /Hodanish .LONG TERM...(Wednesday night through Tuesday) Issued at 340 PM MDT Tue May 30 2023 Key Messages: 1) Increasing chances of precipitation from west to east on Thursday with potential for stronger storms over the far southeast Plains. 2) Cooler and unsettled weather pattern developing Friday and persisting into early next week. 3) Locally heavy rainfall and flash flooding potential increasing through the weekend. Wednesday night-Thursday night...Modest south to southwest flow aloft remains progged across the region as a compact upper low across the Southern Great Basin slowly weakens as it lifts north and east into the Four Corners region Thursday evening. Ongoing strong to severe storms across the southeast Plains Wednesday afternoon move into western Kansas through the evening, with the potential for scattered showers and isolated thunderstorms continuing over and near the higher terrain through the late evening and overnight hours, within weak diffluent flow aloft. Increasing mid level moisture and uvv ahead of the Four Corners system will allow for increasing chances of shower and thunderstorm develop over and near the higher terrain Thursday afternoon and evening. There will be the potential for stronger to severe storms across the far southeast Plains, where enhanced southeast low level flow will keep enough moisture and shear in place. Temperatures on Thursday look to be near seasonal to slightly below seasonal norms. Friday-Sunday...Weak upper low continues to slowly drift north and east across south central and into southeastern Colorado through the day Saturday and into the Southern High Plains on Sunday. This leads to a weak but generally deep easterly flow pattern across the region which will keep daily chances of showers and storms across the area. With models indicating increasing available moisture with PWATS approaching 150-200 percent of normal, there will be the potential for locally heavy rainfall, as well as increasing chances of flash flooding, especially over and near the higher terrain, where weak easterly upslope flow will lead storm training. With the cool upper level pattern, there could also be some light to moderate snow accumulations across the higher peaks through the weekend, with temperatures expected to be some 5-15 degrees below early June norms. Monday-Tuesday...A messy and weak flow pattern remains in the offing into next week, with weak upper ridging being indicated across the Rockies. With moisture expected to remain in place, there will continue to be daily chances of showers and storms, with the greatest coverage over and near the higher terrain, along with temperatures remain generally below seasonal levels. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 340 PM MDT Tue May 30 2023 Isolated high based thundershowers will be possible at KCOS and KPUB late this afternoon and early evening, but overall I anticipate VFR conditions. For tonight, guidance keeps skies VFR through tomorrow morning, however I am a bit concerned that moist outflow from storms well east of KCOS and KPUB may push back towards the mtns affecting the two taf sites. For now I plan to keep VFR tonight, but we may need to adjust this if the outflow materializes. For tomorrow, thunderstorms are expected at all 3 taf sites during the afternoon time period as low level moisture will increase and a disturbance moves towards the region. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KT SHORT TERM...HODANISH LONG TERM...MW AVIATION...HODANISH