Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/16/21

Area Forecast Discussion
National Weather Service Bismarck ND
956 PM CDT Thu Jul 15 2021 .UPDATE... Issued at 955 PM CDT Thu Jul 15 2021 Minimal updates needed to the forecast late this evening. Hi-Res models still indicating thunderstorms possible later tonight across the northwest. Around or shortly after midnight, the nose of a low level jet looks to set up across northwestern ND where MU Cape of 1000 to 2000 j/kg and somewhat steep mid level lapse rates will be found. Modest shear looks to be the limiting factor with these storms. That said, high amounts of dcape and an inverted-v sounding will support perhaps a gusty wind threat from these storms. Perhaps some small hail is also possible, although dry air near the surface should limit this threat. Overall made some minor adjustments to the pops in the northwest for the potential for thunderstorms tonight, with severe weather not expected at this time. Lingering isolated storms will diminish Friday morning. More warm temperatures in the 90s are expected, with perhaps another round of thunderstorms possible late Friday afternoon through Friday night mainly in the north and west. Expect haze and smoke to continue across the region as the latest HRRR Smoke Model projects smoke starting to filter in from the west Friday into Saturday. UPDATE Issued at 645 PM CDT Thu Jul 15 2021 Limited changes needed early this evening. Thunderstorms in the eastern part of the CWA have diminished or move eastward, thus pops have been reduced or removed. Mainly dry conditions are expected through the evening hours. A low level jet and weak elevated instability could still bring some thunderstorms across the northwest overnight tonight. Satellite showing some elevated smoke entering the area from the northwest, although should bring limited impacts through the night. More smoke may return tomorrow from western US fires, especially across the west. Friday overall remains on track to be continued warm with perhaps an isolated afternoon/evening thunderstorm in the west. && .SHORT TERM...(This evening through Friday) Issued at 348 PM CDT Thu Jul 15 2021 A chance of thunderstorms in the west Friday and warming temperatures highlights the short term forecast period. At 20Z water vapor imagery shows a relatively low amplitude mid- level ridge over the Northern Rockies, shifting east. An embedded circulation was centered over north central Montana, with a surface low under this wave. Southerly winds in the eastern periphery of the low were observed across western and central North Dakota. Isolated thunderstorms were located over eastern North Dakota this afternoon in a region of steep low level lapse rates and a subtle open mid-level northwest flow wave. This evening, convective activity in the east should decrease as insolation is lost. A modest low level jet should develop tonight as the aforementioned upstream arrives in the west. A few elevated showers and thunderstorms will be possible, more likely northwest. Best high-res guidance agreement is in the placement of this activity in the northwest on the nose of the southerly low level jet, then with varying degrees of eastern progression between models. POPs may need to be adjusted tonight as predictability is low. With steep mid-level lapse rates arriving as well, a few stronger thunderstorms can`t be ruled out. Convective activity may linger in the early Friday morning hours before diminishing after sunrise. Then convection in the west will be possible again late Friday afternoon and evening, as shortwaves continue to push through the eastward progressing ridge. With continued southerly flow, surface dew points may reach 60 degrees in the central (though GFS/RAP keeps dew points in the 50s compared to higher values from NAM/ECMWF), producing MLCAPE of 1500-2500 J/kg. Bulk shear of 20 to 30 kts will be on the lower side for severe thunderstorms, but with the steep mid level lapse rates in place several strong to marginally severe thunderstorms are possible. .LONG TERM...(Friday night through Thursday) Issued at 348 PM CDT Thu Jul 15 2021 Above normal temperatures continue through the long term forecast period. In the long term period, the upper level pattern becomes more amplified as a ridge builds and becomes centered over eastern Montana and the western Dakotas. This will feature a prolonged period of above normal temperatures with daily highs in the 90s with some areas of the west likely hitting 100 at times. At this point surface dew points look low enough to keep heat index values below the advisory threshold, with forecast max apparent temperatures remaining below 100 F each day. This pattern will also feature weak embedded impulses which will provide low-predictability chances for convection periodically through the period. Current consensus gives the best opportunity Saturday evening, with inherent uncertainty during the period of building mid-level heights. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 645 PM CDT Thu Jul 15 2021 Overall VFR conditions are expected through the forecast period, with perhaps an isolated thunderstorm at times. Look for southerly winds to diminish somewhat tonight, while mainly clear and VFR conditions remain. An isolated thunderstorm is possible overnight tonight, mainly in the northwest. This could impact KXWA, although confidence is not high enough to include at this time. Friday then sees a light breeze from the south, continued warm temperatures, and mainly VFR conditions. An isolated thunderstorm is also possible Friday afternoon/evening, although confidence remains to low to include at this time. Haze due to smoke from wildfires continues, but so far visibility has remained generally around 10 miles. Some increased haze and smoke is possible for Friday, although will refrain from adding to TAFs unless visibility becomes further impacted. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Anglin SHORT TERM...AE LONG TERM...AE AVIATION...Anglin
Area Forecast Discussion
National Weather Service Boise ID
838 PM MDT Thu Jul 15 2021 .DISCUSSION...Isolated showers and thunderstorms which formed over eastern Valley County and south central Idaho earlier today have dissipated. On Friday, southwest flow aloft will continue to bring elevated moisture to these same areas with additional afternoon and early evening shower and thunderstorm development possible. An upper trough along the Pacific coast will shift slightly east tomorrow, resulting in temperatures a couple degrees lower than today but still 3 to 5 degrees above normal. Smoke from area fires will continue to move through the area, although the HRRR near-surface smoke indicates some improvement over today is possible. No changes to the current forecast. && .AVIATION...VFR with areas of low VFR and local MVFR visibilities due to smoke from wildfires. Significant visibility restrictions aloft due to smoke layers. Surface winds: mainly west- northwest 5-15 kt. Winds aloft at 10kft MSL: variable 5-15 kt. Density altitudes will remain high due to hot temperatures. Weekend outlook...Generally low VFR with areas of MVFR due to smoke. Significant visibility reductions aloft due to smoke layers from wildfires. Light winds. && .PREV DISCUSSION... SHORT TERM...Tonight through Saturday night...A few showers popping up across south-central Idaho this afternoon, with thunderstorms possible. Forecast includes some mention of showers into the evening as a result of current radar trends. Similar conditions expected tomorrow, with a few afternoon showers and thunderstorms possible in continued southwest flow. Gusty winds possible, with the strongest wind south of the Snake Plain. A building ridge over the Four Corners Region will continue warm and mostly dry conditions this weekend, though smoke will continue to influence area temperatures. Temperatures currently forecast to be 5 to 10 degrees above normal through the forecast period. LONG TERM...Sunday through Thursday...Hot dry and smoky conditions to continue through the long term. Record high temperatures possible on Sunday afternoon, although smoke will likely keep temperatures just below records. Otherwise temperatures will be around 10 degrees above normal through the period. Monsoon moisture will move northward over the region on Monday through Thursday, which will increase the threat of thunderstorms during this period. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...Red Flag Warning until 11 PM MDT Saturday IDZ402-403-421. OR...None. && $$ DISCUSSION...ST AVIATION.....BW PREV SHORT TERM...KB PREV LONG TERM....KA
Area Forecast Discussion
National Weather Service Caribou ME
915 PM EDT Thu Jul 15 2021 .SYNOPSIS... High pressure southeast of the region will maintain warm and humid air across the region tonight. A cold front is expected to approach tomorrow and slowly cross the area tomorrow afternoon and evening before stalling to the south this weekend. A broad trough will linger across the region into early next week. && .NEAR TERM /THROUGH FRIDAY/... 9:15 PM Update... A few convective showers have popped up over the western North Woods this evening. Thus, kept the precip forecast as is. Fog has started to creep northward as the night has progressed. Visibilities have continued to decrease in Bar Harbor while the stratus layer has continued to lower over Bangor. Recent satellite images show patchy fog developing to our east in NB. Adjusted the weather forecast to show fog development in the north. In addition, a Dense Fog Advisory has been issue for Hancock and Washington counties, per current observations and the RAP and NAM soundings. Previous Discussion... Any lingering isolated shower activity will diminish early this evening with loss of daytime heating and a continuation of very dry air aloft. Low stratus and fog will return, mainly south and east of the mountains as a 500mb shortwave and area of surface low pressure passes to the north, pulling subtropical moisture northward once again. Overnight lows will be very mild, ranging from the upper 50s along the coast to mid 60s for the rest of the forecast area. A cold front will rapidly approach from the northwest around daybreak Friday, increasing chances for showers and thunderstorms. An initial band of weakening showers is possible along a pre-frontal trough across northern Maine, followed by a line of convection along the cold front itself forecast to enter western Maine from Quebec around 12z. Timing of the front will preclude any severe weather threat across the northwest. However, to the southeast daytime heating may contribute to a band of around 1000-1500 j/kg of MLCAPE from roughly Houlton to Bangor and down to the coast if the marine layer erodes quickly enough and convective debris from nighttime and early morning activity along the front is not as significant. While the instability is uncertain, other factors are not; There will be around 35 to 40 kts of effective bulk shear and strong surface convergence along the front leading to linear structures capable of producing strong, gusty winds. Surface delta theta-e values will also be as high as 25 to 30K based on forecast soundings. High precipitable water values around 1.5 to 2 inches and a deep warm cloud layer will support potential for heavy rainfall. However, with the front forecast to move faster than previously expected, the risk of training cells and flash flooding is lower. Hail is also possible but should not be the dominant threat given high freezing levels and linear storm structures. Conditions will dry out quickly from northwest to southeast during the evening as the front moves over the coastal waters. Highs are generally expected to be similar to today in the low to mid 80s except along the coast and across northwestern Maine and the Saint John Valley where the front will cross before peak daytime heating can occur. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... Cdfnt wl be approaching the coast by Fri evening with showers and thunderstorms remaining over far sern portions of the area for several more hours. By the start of the period, strong storm threat wl likely be waning as it runs into marine layer with storms becoming elevated over time. Latest 12z guidance is fairly insistent on mvg frontal bndry over the waters overnight with dry air encroaching in fm the north to lessen chcs for showers drg the day Saturday. Due to discrepancies in models hv introduced slgt chc showers into the far southwest late on Saturday though confidence continues to rmn low in potential for rain chcs Sat afternoon. Confidence becomes even murkier for Sat night and how far north rain wl overspread the region as guidance becomes even more out of agreement with track of sfc low up through the northeast. For now have gone with chc pops mvg to near Baxter by daybreak Sunday with northern Aroostook remaining dry throughout the end of the period. Due to showers and cldy skies being confined to southern half of the area, expect that temps on Sunday wl be warmest across the St. John Vly. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... The long term wl start off as it has most of this summer, with an upr lvl high sitting acrs the west and a trof in the east. With little reason to move anywhere this wl likely be the same pattern throughout the course of the week. Thus continued chcs for showers, and possibly storms in the afternoon, can be expected. Temps wl be near normal drg the first half of the week but lkly dropping aft mid- week due to showery conditions expected to persist. Looking further ahead deterministic models are indicating an upr lvl low dropping thru the northeast over the weekend, including the GFS and EC ensemble means. CMC meanwhile keeps it further north into the Maritimes but time will tell. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/... NEAR TERM: Tonight...Deteriorating from VFR to IFR/LIFR this evening with low clouds and fog. The greatest impacts will be from KHUL south where ceilings and visibility are forecast to drop below airfield minimums. Light S/SW winds are expected. Friday...Improving to MVFR/VFR during the day with tempo IFR in a line of showers/t-storms. VFR at all sites by the evening. SW winds 5 to 10 kts with gusts to 15 to 20 kts, shifting NW. SHORT TERM: Fri night-Sat...Mainly VFR, but cannot rule out IFR vsbys in early morning fog at all terminals. Light WNW winds. Sat night-Sun...MVFR/IFR at BGR and BHB in showers and possible fog. Light winds. Sun night-Tue...MVFR in showers and possible storms each afternoon with low MVFR/IFR fog possible each morning. Light S Sun night-Mon night, then WSW around 5 kts. && .MARINE... NEAR TERM: Areas of fog and patchy drizzle will continue to reduce visibility tonight into tomorrow. Some breaks in the fog are possible Friday afternoon and evening. Winds and seas will remain below SCA levels with gusts to around 20 kts and seas of 2 to 4 feet. SHORT TERM: Seas likely to remain below 3 feet through the period with wind gusts below 20kts. Fog will reduce visibilities over the water at times into early next week. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Dense Fog Advisory until 8 AM EDT Friday for MEZ016-017-029- 030. MARINE...None. && $$ Near Term...LaFlash/MStrauser Short Term...Farrar Long Term...Farrar Aviation...LaFlash/MStrauser/Farrar Marine...LaFlash/MStrauser/Farrar
Area Forecast Discussion
National Weather Service Duluth MN
751 PM CDT Thu Jul 15 2021 .DISCUSSION...(This evening through Wednesday) Issued at 333 PM CDT Thu Jul 15 2021 Dry conditions will continue into early next week for most of the Northland and highs will be increasing to the lower eighties to lower nineties Friday into next week. Tonight will feature clearing skies for most areas with some fog/haze expected. The visibility may drop to a half mile or so in a few spots later tonight, similar to last night. Friday will be warmer with highs in the eighties, except a bit cooler along the North Shore. A weak upper trough may lead to a few showers/thunderstorms Friday afternoon, mainly over western areas. Forecast soundings show deep mixing and dry lower layers, so we expect isolated coverage. The HRRR forecasts some improvement in the smoke aloft, mainly over Minnesota with some increase over northern Wisconsin. Dry conditions will continue into the weekend as high pressure remains near/over the region. Temperatures will climb into the mid eighties to lower nineties Saturday into Monday. The pressure gradient will be relatively weak or not very conducive to stronger lake breezes. 850MB temperatures will remain from 16-19C for most of the period. A series of upper waves and a low level boundary will affect mainly northern portions of the Northland Monday into much of next week bringing periodic, mainly low chances for showers and storms. The models are not in the best agreement with the details but they do agree that widespread rain is looking unlikely. Temperatures will remain above normal through the week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 748 PM CDT Thu Jul 15 2021 A ridge of high pressure to keep predominantly VFR conditions and light winds. Smoke and haze from fires is expected to reduce visibilities at several terminals overnight, and have gone mostly with a persistence forecast as guidance is not picking up on this very well. KHIB and KBRD are most likely to be affected by this, and have LIFR visibilities for both sites generally between 06z and 11z. Have included MVFR visibility for the other sites as well, and we will see how things develop this evening. VFR cumulus are expected to develop once again during the late morning, and there may be some SHRA/TSRA near KINL after 18z, but given the low probability have left these out for now. && .MARINE... Issued at 333 PM CDT Thu Jul 15 2021 Due to high pressure over or near the Northland, the gradient will remain relatively week for the next few days leading to winds less than 15 knots and waves less than 3 feet. && .PRELIMINARY POINT TEMPS/POPS... DLH 58 84 59 86 / 0 10 0 0 INL 54 88 59 90 / 0 20 0 10 BRD 58 85 59 88 / 0 10 0 0 HYR 51 85 55 87 / 0 0 0 0 ASX 54 86 57 86 / 0 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ DISCUSSION...Melde AVIATION...LE MARINE...Melde
Area Forecast Discussion
National Weather Service Quad Cities IA IL
948 PM CDT Thu Jul 15 2021 .UPDATE... Issued at 947 PM CDT Thu Jul 15 2021 With the clearing skies, light winds and moist ground from the recent heavy rainfall, it is looking like a setup for fog tonight. This looks especially the case initially for areas north of the current area of slow moving showers over southeast Iowa into west central Illinois. These showers are occurring along and north of a stalled low level boundary, with some forcing from a passing shortwave. The forecast has been updated to focus showers along this boundary over the next several hours and also to add patchy fog for roughly the southern 2/3rds of the forecast area for after midnight. Fog could potentially get much thicker or more widespread, depending on cloud trends the next several hours and will be monitoring closely for possible updates. && .SYNOPSIS... Issued at 259 PM CDT Thu Jul 15 2021 18Z surface data has a weak low east northeast of KUGN, over Lake Michigan. A front runs west southwest from the low across northern Illinois and into southern Iowa. Dew points were in the 70s south of the front with 50s and 60s north of the front. && .SHORT TERM...(This Evening through Friday) ISSUED AT 259 PM CDT Thu Jul 15 2021 Trends with satellite and radar data along with the very short term models indicate the rain chances should remain south of a Sterling, IL to Ottumwa, IA line through sunset. Cloud cover has helped stabilize the atmosphere so most of the precipitation will be in the form of showers/rain with some embedded thunderstorms. Localized heavy rainfall will be possible especially across the southern halves of Hancock and McDonough counties. After sunset another upper level disturbance will move through Missouri and into Illinois generating an additional round of showers and some thunderstorms. The current forecast has rain spreading back across the area with only areas north of a Dubuque to Vinton, IA line remaining dry. However if very recent trends with the HRRR and RAP are correct there is a potential for most of the area to remain dry after sunset. For Friday the current forecast has a risk of isolated to scattered showers and some thunderstorms for most of the area. However if no organized rain occurs prior to sunrise then there is a very good chance that Friday will be dry, especially during the morning. If Friday morning turns out to be dry then differential heating may allow isolated showers and possibly some thunderstorms to develop during the afternoon. Friday night any showers or storms that develop during the day will dissipate with sunset leaving the remainder of Friday night dry. .LONG TERM...(Friday Night through Thursday) ISSUED AT 259 PM CDT Thu Jul 15 2021 The flow aloft will change and push the active storm track well south of the area. Saturday through Thursday Assessment...medium to high confidence The model consensus has dry conditions for the area as high pressure slowly moves through the Midwest during the weekend and first part of next week. However there will be weak upper level disturbances moving through in the flow aloft, especially toward the middle of next week. Thus I cannot rule out the possibility of isolated rogue diurnal convection occurring from Tuesday through Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) ISSUED AT 619 PM CDT Thu Jul 15 2021 Low clouds and showers lingering along a slow moving front will impact the BRL site tonight. The showers are most likely early this evening, but MVFR conditions due to low ceilings and developing fog are expected through the night. Conditions may drop to IFR or even LIFR there around sunrise. MLI, CID and DBQ will see prevailing VFR conditions tonight with light fog producing a period of MVFR conditions roughly from 09Z to 14z Friday morning. All sites are expected to improve to VFR by Friday afternoon with light easterly winds. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...Sheets SYNOPSIS...08 SHORT TERM...08 LONG TERM...08 AVIATION...Sheets
National Weather Service Eureka CA
248 PM PDT Thu Jul 15 2021 .SYNOPSIS...Seasonable temperatures are forecast to occur across the region through Saturday, followed by a warming trend over interior portions of northwest California Sunday into early next week. Otherwise, conditions will mainly be dry during the next seven days, though a threat for thunderstorms can`t be ruled out on Monday. && .DISCUSSION...Broad and weak upper troughing was occurring over the NERN PAC and adjacent coastline this afternoon, and was aiding in seasonable temperatures over NWRN CA. Meanwhile along the coast, periods of marine stratus will continue to be probable during the next several days, and drizzle can`t be ruled out along and in the vicinity of the windward facing north slopes of the King Range. After Saturday, model guidance indicates an upper- level anticyclone centered over the Intermountain West will expand slightly westward and northward Sunday into early next week. That process will favor slightly warmer temperatures across interior portions of NWRN CA, with valley highs ranging from around 90 to 100F. In addition, an upper-level disturbance emanating from the sub-tropics offshore from Mexico may migrate northward across California during Monday. Various deterministic model runs show that feature ingesting midlevel monsoonal moisture resulting in sufficient MUCAPE values for elevated thunderstorm development. This low probability evolution will continue to be monitored during future shifts. Garner && .AVIATION...Skies across the interior are mostly clear this afternoon, with just a few cumulus clouds developing over the far interior mountains. Stratus has persisted once again along the North Coast and extending well inland from E of Patrick`s Point to the Eel River Valley. Drier air is once again infiltrating S over the coastal waters W of the North Coast this afternoon, and this may act to scatter out clouds briefly again at KCEC. It appears that only a few peeks of sun are possible at KACV before evening, if that. Clouds are expected to fill back in and spread inland overnight. Present marine layer depth is running around 2500 ft at the McKinleyville profiler, while the Bodega Bay profiler indicates the marine layer remaining closer to 2000 ft deep, if not a bit shallower. Stratus is expected to expand back inland overnight, particularly near and N of Cape Mendocino. Visibilities are expected to drop into the MVFR to occasionally IFR range, but the deep marine layer and weaker inversion should keep most visibilities from going much lower. Patchy drizzle is again possible overnight, but it is not expected to be as persistent or heavy as last night. It doesn`t appear that the marine layer is deep enough for stratus to make it to KUKI from the W, and the HRRR doesn`t indicate much in the way of upvalley flow in the Russian River Valley. Winds will be generally light, with some late afternoon and early evening gustiness at KCEC. /SEC && .MARINE...Northerly winds will increase a bit overnight, with the strongest winds across the S outer waters. Have also extended the Small Craft Advisory in that area as well, as advisory-level winds look to continue through the weekend. A generally small NW mid- period swell will continue through the next 5 days, and a periodic S long period swell will persist into the first half of the weekend. /SEC && .FIRE WEATHER...An upper trough located over the northeast Pacific will aid in seasonable temperatures across northwest California through Saturday. Thereafter, a westward expanding dome of high pressure over the Intermountain West is forecast to occur Sunday into early next week, and will support a warming trend across interior areas. In addition, an upper disturbance may move from south to north across the region during Monday. That feature may yield a threat for dry thunderstorms, though the exact timing and magnitude of the threat is uncertain at this time. Garner && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 3 PM PDT this afternoon for PZZ450. Small Craft Advisory until 3 PM PDT Friday for PZZ470. Small Craft Advisory until 9 PM PDT Friday for PZZ455. Small Craft Advisory until noon PDT Sunday for PZZ475. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Grand Forks ND
1003 PM CDT Thu Jul 15 2021 .UPDATE... Issued at 1003 PM CDT Thu Jul 15 2021 Thunderstorms have ended with sunset as expected with a few locations still reporting visibilities around 6 miles in smoke. Forecast is currently on track, and only minor adjustments to near term trends were necessary. UPDATE Issued at 713 PM CDT Thu Jul 15 2021 Very isolated thunderstorms are ongoing over eastern ND and northwest MN, but intensity/coverage is actively diminishing. This trend should continue through sunset. Impacts will tend to include lighting and locally heavy rain (due to slow motion and PWATS in excess of 1"), though the current storms are unlikely to produce rates/amounts like activity earlier based on weakening trends. Adjustments were made to reflect location/coverage. && .SHORT TERM...(This evening through Friday night) Issued at 226 PM CDT Thu Jul 15 2021 Decreasing impacts are expected tonight as southwesterly winds increase and help scour out the low-level smoke across eastern ND and west central MN. A few weak cells may develop west of the valley this afternoon but will be short-lived and erode after sunset. High pressure now over the top of Lake Superior is resulting in increasing return flow into central ND. The increase in WAA is resulting in widely isold showers/possible a clap of thunder from the upper James Valley into the northern Red River Valley, where MLCAPE values are around 500 to 750 J/Kg. Shear values continue to remain nil so any cells that develop will be rather slow moving and short lived. More likely to see some spits of rain with this activity, although some small hail with the strongest storms is possible. The SW winds are improving visibilities across eastern ND and smoke smell is not as noticeable, however some reports or irritated eyes remain. Will keep FU in on the east side of the river where winds will be lighter and persist through mid-morning Friday. South winds increase more in velocity tomorrow, resulting in highs in the upper 80s and lower 90s. There is potential for elevated smoke from fires over the PAC NW to move into eastern ND late in the period, which could impact afternoon highs. This episode should not be as noticeable at the surface. Overall, a dry and breezy next couple of days as a hotter airmass returns to the area. .LONG TERM...(Saturday through Thursday) Issued at 226 PM CDT Thu Jul 15 2021 Overall dry and warm conditions are expected across the region in the extended time frame. Ensemble guidance brings the strong upper ridge to the area this weekend and through the first part of the week with the heat wave having a high confidence of occurrence. Short term impacts will primarily be tied to above normal summer temperatures with highs in the mid to upper 90s most likely with some guidance suggesting triple digits are possible on the warmest days of Tuesday and Wednesday when the thermal ridge axis settles over the area. Long term impacts would be to enhance the ongoing drought conditions and deteriorating crop conditions. As the upper ridge weakens, weak short wave activity and weak surface wind shifts or boundaries will eventually bring the chance for thunderstorms by Tuesday night or Wednesday to the northern half of the area. This will bring cooler temps however still above normal temps to the area. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 713 PM CDT Thu Jul 15 2021 Isolated showers/thunderstorms developed near some terminals in the afternoon and have lingered into the early evening. The activity is very slow in nature and should quickly weaken/fall apart through sunset, so possible impacts at terminals are diminishing. Smoke continues to complicate visibility forecast across eastern ND and northwest MN, with pockets of MVFR conditions possibly lingering into the night (especially in MN). HRRR smoke model indicates a more pronounced clearing trend at the surface by Friday morning (especially in ND). && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...DJR SHORT TERM...Speicher LONG TERM...JK AVIATION...DJR
Area Forecast Discussion
National Weather Service Gray ME
949 PM EDT Thu Jul 15 2021 .SYNOPSIS... Very warm and humid weather will continue through Friday. Showers and thunderstorms will be possible Friday through Sunday as a frontal boundary slowly sinks south of our area this weekend. Coastal and river valley fog remains likely tonight into Friday night. A broad trough will linger across New England early next week, with additional shower chances and seasonable temperatures. && .NEAR TERM /THROUGH FRIDAY/... 945PM Update... Issued a Dense Fog Advisory for the Mid-Coast of Maine through the Capitol Region and coastal Cumberland County. Visibility continues to decrease in these regions and satellite imagery indicates this will continue through the overnight. There is lower confidence further inland where the increasing LLJ should keep visibility above a quarter of mile in most locations. Across the north, some patchy fog will be possible along with increasing chances for a scattered shower towards dawn ahead of an approaching frontal boundary. Other than some minor adjustments to temperatures and dew points, the rest of the forecast remains on track. Previously... 615PM Update... Made some minor adjustments to temperatures, dew points, and winds to better align with surface observations. PoPs were adjusted across the north, where high resolution forecast guidance such as the HRRR indicates that a stray shower will be possible through around 02Z. There is currently a shower located to the north of Berlin, NH and the latest run of the HRRR did a decent job at capturing this. The only real weather concern overnight will be for areas of dense fog, which continues to lurk just offshore. Trends will be watched throughout the evening and a Dense Fog Advisory may eventually be needed for portions of the area. Previously... Pretty quiet around the region as of this Thursday afternoon with little forcing for ascent for robust showers and thunderstorms. A few small showers have popped up in the mountains and the hills of Waldo County but capped environment will keep them at bay. Otherwise, low clouds have exited most of the coastline except portions of the Midcoast. There`s some sort of weak wave moving through at this time and the descending motion associated with this feature is aiding in the low clouds and fog dissipating or accelerating out to sea, especially across southern zones. With a southwesterly low level jet increasing tonight, I am currently unsure how widespread low cloud and fog coverage will be tonight. Current thinking it will be less widespread than last night, with the best chances for a few-hour period of dense fog on the Maine Midcoast northwestward to around Augusta. No dense fog advisory at this time. Otherwise, some valley fog once again possible tonight in the CT Valley, but not likely as extensive as late last night. && .SHORT TERM /FRIDAY NIGHT/... A short wave trough will approach from the west early Friday and aid in the approach of a surface cold front. A hot and humid air mass will be in place ahead of the front which will aid in an environment conducive to thunderstorms. The path of best forcing for ascent as well as frontal timing will favor central ME to Midcoast ME for best chance of storms, a couple of which could be strong to severe. Can`t rule out a couple of storms in the rest of the region, but coverage should be much more isolated. Heat indices may reach 95 degrees for a few hours in portions of the Merrimack Valley on Friday afternoon. A small heat advisory may be required. Aside from a low probability of a few showers across southern zones Friday night, the weather should be quiet a more comfortable in terms of humidity in the post-frontal air mass. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Long wave pattern presents with a trough over the central US and ridging over the east and west coast. The overall flow remains progressive and expect the trough to move eastwards into our region through the weekend. Saturday the surface boundary that has been lingering across Massachusetts will remain in place as yet another wave moves along it. With a warm and moist airmass in place, heavy rain will be possible as showers move through this area. Excessive Rainfall outlook continues to highlight the southern portion of NH, which remains appropriate. As we`ve seen the past few cases MA and southern NH remain the focus of the convection with training storms being the main threat for heavy rain rates. Still quite a bit of north south spread amongst the deterministic guidance for the location of the highest precip totals during the day Saturday, however with this package I have leaned somewhat south which is favored by persistence, climatology and topography. Thus Pop has been lowered across the northern portion of the area for Saturday. Saturday night sees the front move east of the area, expect some low level moisture to remain, especially in the valley bottoms and bring fog through morning. By Sunday the fropa is complete and skies will slowly clear. Have kept temperatures on the lower side for this day,with the residual cloud cover but still pushing comfortably into the low 70s. A brief break as high pressure moves in with drier northwesterly flow for Sunday night into Monday. By the start of next week the upper level trough axis has shifted east over our region, leading to more unsettled weather. Tuesday late into Wednesday looks to be the focus for the next most likely round of precipitation but in general the forcing is weak and scattered showers may occur throughout the mid week. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Short Term...Fog should reform over the coast tonight, but unsure of the coverage. Right now, the best bet is northeast of PWM to the Midcoast where LIFR conditions move on in once again. However, there is a chance that these conditions are shorter- lived and less widespread than early this morning as a southwesterly LLJ kicks up tonight. VFR on Friday and likely Friday night with a few thunderstorms possible Friday afternoon. Long Term...Showers with heavy rainfall across the southern portion of the area on Saturday may briefly bring IFR conditions. Overnight Saturday into Sunday expect IFR in fog for the Connecticut and Merrimack river valley. Conditions will clear on Sunday and remain VFR through the start of next week. && .MARINE... Short Term...Winds and seas likely remain below small craft thresholds (5 ft seas, 25 kt) tonight through Tuesday. However, fog will be dense over the waters tonight, primarily off the Midcoast of Maine. A cold front will drop across the waters Friday evening and this will result in winds switching to northerly. Long Term... A front will remain draped across the waters on Saturday with showers, front will clear through on Sunday with northwesterly flow. Winds and seas will remain below SCA. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Dense Fog Advisory until 8 AM EDT Friday for MEZ021-022- 024>028. NH...None. MARINE...None. && $$ NEAR TERM...Tubbs
Area Forecast Discussion
National Weather Service Tucson AZ
847 PM MST Thu Jul 15 2021 .SYNOPSIS...An active monsoon period of daily scattered showers and thunderstorms will continue during the next seven days. High temperatures will remain below normal into next week as well. && .DISCUSSION...Pretty wild afternoon and evening for Graham County. A series of severe storms from Safford to northwest of the town of Pima had several bouts of severe winds and heavy rains that resulted in Flash Flooding with washouts and debris over area roads. Further north in Graham County another group of storms dumped at least 4 inches of rain just south of Point of Pines in the Bonita Creek watershed. At least some of this water (what the dry ground doesn`t suck up) should make it down the creek toward the Gila. We are watching the gauge in the area to see how much of any increase there may be. At this time flooding is not expected on the Bonita Creek. All that is left is a group of storms that are holding together surprisingly well and appear to have Tucson in their sights. It will be interesting to see if they hold together that far although they are already providing a good light show. Going forward it appears that it will be a fairly quiet night overall. Some of the CAM solutions are again pointing to a flare up of convection just before or around dawn tomorrow for areas west of Tucson. This is likely helped along by the nightly SW moisture surge that we get in the lower deserts from the gulf. I tweaked pops just a bit in the pre-dawn, to several hours after dawn period to account for this. Other than that, I only needed to adjust the temperatures and dewpoints through Friday morning. Grids and updated forecast already sent and looking forward to another active day Friday. && .AVIATION...Valid through 17/00Z. SCT-BKN clouds at 8k-12k ft MSL and BKN-OVC clouds AOA 20k ft MSL over most of the period. There could be some isolated storms overnight potentially affecting KTUS after 16/05Z but confidence is somewhat low. Wind gusts to 40 kts possible near any TSRA along brief MVFR conditions. Otherwise, SFC wind generally less than 12 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...There will be a good chance of showers and thunderstorms across southeast Arizona the next week. Gusty outflow winds will be the primary concern with the daily storms along with heavy rainfall. Min RH values will be in the 25-35 percent range at the lower elevations, with higher values in the mountains. Outside of some stronger NWLY winds at 15-20 mph in the Gila River valley this afternoon, 20-foot winds will generally be less than 15 mph and follow normal diurnal trends when not influenced by thunderstorms. && .PREV DISCUSSION... /issued 126 PM MST Thu Jul 15 2021/ After morning convection from Tucson westward, considerable debris cloudiness remains with temperatures very slow to warm. We`re starting to see some breaks in the overcast in these areas and expect that trend to continue through the afternoon. Meanwhile, for locales east of Tucson, there has been plenty of solar insolation resulting in increased instability. Latest RAP analyses shows MLCAPE values of 1000-2000 J/KG with little to no CIN across Cochise/Graham/Greenlee Counties. We`re already starting to see shower and thunderstorm activity develop on the higher terrain to the east of Tucson. Given the favorable environment, expect scattered to numerous showers and thunderstorms to continue through the afternoon. The larger scale northerly flow will tend to push the thunderstorms from north to south into the early evening hours. Main concerns will continue to be heavy rain and gusty winds with the stronger storms. Starting tonight and through Friday there are some apparent differences in the CAMs with how convection will evolve. In the bigger picture, there is a mid level disturbance across north/central Arizona that is progged to move to the south, then southwest tonight and become fairly stationary as an inverted trough on Friday over southeast Arizona. One possible scenario is that the thunderstorm activity building across eastern areas this afternoon diminishes this evening, but then as that aforementioned disturbance moves to the south and west, some new convection develops late at night or in the early morning hours Friday. If that occurs, some areas could be worked over and have more limited chances for renewed thunderstorm development Friday afternoon and evening. On the other hand, if we see little in the way of thunderstorm activity late tonight or Friday morning, that will likely set the stage for more widespread showers and thunderstorms Friday afternoon into Friday evening. In either scenario, given the deep moisture in place along with fairly slow storm movement, we felt it was prudent to extend the Flash Flood Watch through 11 PM Friday. For this weekend and continuing through the middle of next week, we are in a solid continuous active monsoon pattern. With the mid level high to our north, easterly flow with ample moisture will continue. Certainly there will be some up and down days relatively speaking which we`ll try to hone in on in the shorter term. Given this pattern, temperatures will remain below normal. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Friday evening for AZZ503>515. && $$ Public...Cerniglia/Lader Aviation...Hardin Fire Weather....Hardin Visit us on Facebook...Twitter...YouTube...and at