Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/22/22

National Weather Service Albany NY
954 PM EDT Sun Aug 21 2022 .SYNOPSIS... An approaching upper level disturbance and frontal system will bring increasing chances for showers and isolated thunderstorms late tonight through Monday. Additional showers and thunderstorms are possible Tuesday as the upper level disturbance moves through the region. Fair weather returns for midweek, along with above normal temperatures. && .NEAR TERM /THROUGH MONDAY/... Updated at 950 PM EDT. Scattered showers from Ohio eastward across NY and PA appear to be holding together and even slightly increasing in coverage during the past few hours as they advance to the east-northeast. Scattered showers will be increasing across the western and southern parts of our forecast area after midnight as a weak wave of low pressure organizes off the mid- Atlantic coast in response to a moderately strong mid-level trough approaching from the Great Lakes. The latest 00z HRRR is still showing that most of the precipitation with this wave will track across eastern and southern New England on Monday with just scattered showers and thunderstorms for eastern NY and western New England, however there remains considerable spread in the CAMs forecasts on coverage and timing of rainfall. Even scattered showers would bring localized heavy rainfall as pwats will be between 1.5 and 2.0 inches with deep warm cloud depths and with slow-moving storms. The models are also indicating a weak (20-25 kt) low-level south- southeasterly jet early on Monday across New England as the weak wave organizes, which could also act to enhance rainfall in areas that can get organized rainfall. Due to the dry conditions, any isolated 1 to 3 inch amounts that fall on Monday would be mainly just beneficial. Updated at 815 PM EDT. A mid-level trough associated with multiple lines and clusters of showers continues to approach the area from eastern Great Lakes this evening. A couple of lines of showers on the eastern edge of this trough have already dissipated earlier this evening as they approached our area while moving east of the strongest mid- level forcing and largest instability. Additional areas of showers over western Pa and western NY will track east toward the area later tonight, and these should hold together more efficiently as they will be associated with stronger forcing as the trough moves east. Expect showers to increase in coverage mainly south of I-90 and west of the Hudson River after midnight tonight as the upper trough approaches. An organized area of showers will likely track across the the area south of I-90 and across southwest New England Monday morning with 6 hour rainfall amounts around half an inch in many areas as a weak wave of low-level low pressure organizes over southeast NY and southwest New England. Farther north rainfall should be lighter and spottier through Monday morning. Previous discussion is below. As of 350 PM EDT, cluster of showers and isolated thunderstorms continues to track northeast across portions of the SW Adirondacks. This should taper off over the next hour. Some sprinkles from a mid level cloud deck continue across portions of the eastern Catskills and Capital Region, and these may persist for another couple of hours before dissipating. Additional showers/thunderstorms are developing across central NYS, in association with a weak low level differential heating boundary remaining from earlier convection, and ahead of next mid level disturbance across central PA. Most of these showers/storms are expected to remain west of the region this evening, however can not rule out a few rogue cells reaching far northern Herkimer County. The remainder of the region should be mainly dry through at least midnight, before some showers possibly develop across the eastern Catskills/mid Hudson Valley, as well as the SW Adirondacks/western Mohawk Valley after midnight. A steadier rain should develop by daybreak across the mid Hudson Valley and extreme southeast Catskills, and may have some embedded convective elements with heavier downpours. Low temps mainly in the 60s overnight. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... Ahead of approaching mid level trough, isentropic lift will increase across the region during the morning. This should allow rain to overspread most areas south of I-90, although may take some time upon reaching areas closer to, and especially north of I-90 and east of I-87. Rain may be moderate to heavy at times across the SE Catskills through the mid Hudson Valley and into NW CT, possibly as far north as the southern Berkshires during the morning hours, with some rumbles of thunder possible. Rainfall rates could approach/exceed 0.25-0.50/hour in some of these areas. Farther north, confidence is less regarding overall rainfall intensity and amounts, as there remains a possibility that best low level forcing from convergence and elevated instability remains across southern areas, while better upper level dynamics remain to our west, resulting in reduced coverage and intensity of showers for areas north and east of Albany. Best chances for these areas to receive rainfall may not be until the afternoon hours, with the approach of better dynamics from the west. Max temps are also questionable for Monday, with some guidance suggesting highs only in the 60s to lower 70s. For now, have sided very close to the warmer NBM (yielding 75-80 in valleys, and upper 60s to lower 70s across higher terrain), assuming there will be at least some breaks in the rainfall during the day. Showers should taper off Monday night, with areas of fog potentially forming. Tuesday could be a more convectively active day, as the main upper level trough/cold pool move through, along with a slow moving cold/occluded front. Models suggest MU CAPES build to 500-1000 J/kg from Albany north and west, and to 1000-2000 J/kg to the south and east. Overall mid level winds remain weak, although 0-6 km shear is a bit stronger south and east of Albany (20-25 KT). It is this area, generally south and east of Albany, where isolated stronger thunderstorms may exist, and trends will need to be watched. High temperatures generally reaching the mid 70s to lower/mid 80s. Lingering showers/thunderstorms Tuesday evening, then clearing with patchy fog developing later Tuesday night, with lows in the upper 50s to mid 60s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... The mid-level long-wave pattern during the second half of this week will feature westerly flow over the northeast CONUS around the south side of mid-level low pressure anchored over northeast Canada. The mid-level trough that will bring unsettled weather early this weak will be pushing east of the area, setting the stage for a return to mainly dry, warm conditions through the second half of the week. Any short-waves that track east across the region through this period will be weak and difficult to time, but at this point the best chance for a round of showers and thunderstorms looks to be on Friday. Bermuda high pressure may build back toward the eastern CONUS next weekend, bringing another round of unseasonably warm weather. Based on this scenario, we have high temperatures mainly in the 80s from Wednesday through Saturday, with lows in the mid 50s to mid 60s. Pops will be below climo, with highest values around 30 to 40 percent on Friday with the possible passage of a short wave trough. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Conditions are currently VFR at all terminals with FEW/BKN layers in the mid and upper levels, and unrestricted vsbys. An increase in cloud density and a lowering of cloud bases can be expected through 00Z Tuesday ahead of an approaching low pressure system. Showers of varying magnitudes and durations are projected to begin prior to 16Z at KPOU and KPSF and after 16Z at KGFL and KALB. Showers will likely begin with VFR cigs and vsbys, but could degrade to MVFR. The highest likely for heavier precipitation will be to the south at POU where IFR vsbys and cigs are possible between 13Z and 17Z. Winds are currently 5 kt and variable at KPOU and KPSF, and lighter out of the south at KGFL. KALB is experiencing 10 kt winds out of the southeast with a 16kt gust. Winds look to remain out of the south and southeast for all terminals throughout the night tonight. KALB will experience more moderate speeds of close to 10 while KGFL/KPOU/KPSF will experience lighter winds. Gusts throughout the day tomorrow will range from 10 to 15 kts starting at 16Z as the low pressure system moves through our area. Outlook... Monday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Tuesday: High Operational Impact. Likely SHRA...TSRA. Tuesday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Wednesday: Low Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. Thursday Night: No Operational Impact. NO SIG WX. Friday: Moderate Operational Impact. Chance of SHRA...TSRA. && .HYDROLOGY... A period of moderate to heavy rain is possible across portions of the SE Catskills, mid Hudson Valley, NW CT, and the southern Berkshires Monday, especially during the morning. Rainfall rates of 0.25-0.50/hour are possible, with locally higher rates possible within any thunderstorms. This could lead to some ponding of water in urban/poor drainage areas. Total rainfall amounts through Tuesday of could reach 1-1.5 inches across some southern portions of the region, while northern areas (upper Hudson Valley and southern VT) generally receive 0.25-0.50 inches. Locally higher amounts will be possible where thunderstorms occur. This rain will be highly beneficial due to overall worsening drought conditions across portions of the region. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...KL NEAR TERM...MSE/KL SHORT TERM...KL LONG TERM...MSE AVIATION...MSE/Gant FIRE WEATHER... HYDROLOGY...
Area Forecast Discussion
National Weather Service Cleveland OH
957 PM EDT Sun Aug 21 2022 .SYNOPSIS... A slow moving low pressure system will move to the eastern Great Lakes through Monday and maintain an unsettled weather pattern. High pressure will build overhead through the mid-week period. The next trough will approach from the north by Friday. && .NEAR TERM /THROUGH MONDAY NIGHT/... Very heavy rain continues along the lakeshore from Geauga County through eastern Lake County, Ashtabula County, into Erie. The storms have been producing rainfall amounts between 1 and 2 inches an hour based on ground observations. Locally higher amounts occurring in the heaviest rain. Activity is expected to move slowly northeast out of the area. Another round of showers continues to rotate southeast out of Michigan in a weakened state at this time. Short term models suggest this band will move southeast across Lake Erie and produce more showers and thunderstorms over the northeast overnight. Will have to monitor trends due to ongoing flooding across the area. Otherwise, patchy dense fog is expected across the area during the night. Previous Discussion... Surface analysis has a broad 1015mb low extending across eastern Indiana/western Ohio with an upper level low nearly vertically stacked overhead. Sufficient clearing earlier this afternoon allowed the airmass to destabilize with ML CAPE values of around 1500 J/kg. However convection over Central Ohio has produced a lot of cirrus debris which has limited further destabilization across central Ohio. Convection continues to fill-in across NW Ohio and closer to the lakeshore and will continue to shift east through the evening. In addition, the HRRR suggests additional convection will fill in across SW Ohio where heating continues and may drift towards the Central Highlands with time. As the upper trough continues to slowly pivot eastward tonight, storm motion will continue to the northeast. The one area where pops may end up being to high could be across inland NE Ohio but will adjust with future updates as needed. Broad rotation associated with the upper level system, especially co-located near the better surface convergence, has led to the development of several funnel clouds in NW Ohio. While funnel clouds may occur, the overall tornado threat remains low given the lack of stronger shear and storm organization. Thunderstorms have maintained a relatively low centroid making heavy rain a concern, especially where training occurs with southwest to northeast storm motion. Pockets of rainfall in excess of 2 inches is possible and flood products may be needed, especially where heavy rain has occurred over the last 24 hours. Will continue to monitor severe weather potential but the threat remains fairly isolated given effective shear values of only 20-30 knots. Most likely case would be if a storm with a stronger core collapses. Coverage of precipitation will decrease considerably as we move past peak heating and mid-level dry-slot wraps in from the west. Where breaks develop in the clouds overnight, patchy fog may develop with light winds and a moist boundary layer. As the 850-700mb trough pivots across eastern Lakes Erie towards dawn, we expect to see lake enhanced showers move in off the lake. Fairly good coverage is expected across the eastern forecast area again on Monday, with coverage increasing with daytime heating. Both temperatures and instability will be a little lower with the cooler airmass overhead on Monday. Chances for showers will become increasingly confined to just off the far east end of Lake Erie on Monday night. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Upper level trough moves eastward very slowly through Wednesday night. A surface trough should linger over/near Lake Erie through at least Wednesday morning. This may assist with shower/thunderstorm development through Tuesday afternoon, especially across the eastern half of the CWA. Models then attempt to move everything eastward with the upper level trough. Still slightly concerned we will add some rain chances to Wednesday with later updates as some jet energy moves across southern Ontario. Temperatures look to be near seasonal averages through the short term period. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A broad surface trough will linger over the area through Friday night as a surface high pressure gradually shift southeast. On Friday, a weak cold front associated with a low pressure near the Gulf of St. Lawrence is forecast to move southeast across. This boundary will bring a brief chance of precipitation, unless it stalls across the area. Opted to maintain a front that stalls to the southeast of the area for now, keeping chance PoPs in the forecast. There is a non-zero chance of thunder with this system, although it will be highly dependent on instability developing and any upper level support present. Late Friday into Saturday, an upper level ridge, and associated surface high pressure, will build over over the Eastern U.S. and persist through the remainder of the period. On Sunday, an increase in southerly winds will mark an increase in high temperatures, reaching into the mid 80s, which is expected to be the warmest day for the period. Dewpoints on Saturday and Sunday will climb into the low to mid 60s, marking a return of humid, muggy conditions across the area. && .AVIATION /00Z Monday THROUGH Friday/... Thunderstorms with locally heavy rain across the area continue to move east across the region. Expecting activity to be scattered in nature with a possible round moving into the area later tonight. Then, as day time heating picks up again tomorrow, expecting more showers and thunderstorms to develop again. Ceilings will be on the low side overnight down to IFR and visibilities down to IFR/MVFR at times due to fog developing across the area. Winds should be light through the period. Outlook...Non-VFR possible with scattered rain showers and thunderstorms through early Tuesday, with the best chance Saturday afternoon through Monday. && .MARINE... Low pressure is expected to track eastward near the south shore of the lake tonight into Monday morning. In the lows wake a cold front crosses the lake with winds becoming northwest to north. Speeds generally remain under 15 knots which typically wont build waves above the 2 to 4 foot range. These northerly winds persist into Monday night with maybe a slight increase in the speed. A short small craft advisory may be needed Monday evening into the overnight. Will definitely need to mention a moderate risk of rip currents in the HWO for a decent portion of the lake east of the Islands Monday into Monday night. Will also need to monitor for waterspouts along the frontal boundary. A surface trough then lingers on/near the lake into Wednesday. Just cool enough air aloft and the convergence along the trough axis may be enough to produce some waterspouts. Confidence not as high with this potential to mention in the forecast at this time. If conditions look more favorable over the next couple days we will add them. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...KEC NEAR TERM...KEC/Lombardy SHORT TERM...MM LONG TERM...Campbell AVIATION...Lombardy MARINE...MM
Area Forecast Discussion
National Weather Service Cheyenne WY
445 PM MDT Sun Aug 21 2022 .SHORT TERM...(This evening through Monday) Issued at 201 PM MDT Sun Aug 21 2022 Isolated showers and thunderstorms have developed in far southern Wyoming in the Sierra Madre and Snowy ranges near the Colorado border. PWAT values in the 0.8-0.9 inch range have fueled a few briefly heavy downpours, however morning cloud cover ultimately stemmed any stronger instability from developing. Another boundary, noted on visible satellite imagery over Laramie county, has made a few attempts at firing a convective shower or two and this trend may continue over the next few hours. However, most CAM guidance including latest HRRR runs indicates a rapid downtrend in any activity in southeast Wyoming soon after sunset. Overnight, expect partly to mostly clear skies with lows running near or perhaps a degree or two below average. Broad, weak northerly flow will push lingering elevated PWAT values south and east on Monday. An isolated shower remains a possibility in the higher terrain of the Sierra Madre and Snowies, however even the more bullish HREF members still keep this activity quite limited. Expect a mainly dry day with afternoon highs near climatological average for late August. .LONG TERM...(Monday night through Sunday) Issued at 201 PM MDT Sun Aug 21 2022 Increasing activity in the long term forecast with precipitation chances climbing towards the end of the week. On Tuesday, models show a weak upper level low tucking underneath the broad ridge covering much of the western half of North America. It looks likely that this feature will cutoff from the flow aloft over Washington and then slowly meander eastward through the remainder of the week. Precipitable water reach their minimum for the week on Tuesday as a jet streak over the southern Plains helps to divert much of the monsoon moisture eastward into Texas. A few storms may develop over the higher terrain but convection should be fairly isolated Tuesday. A subtle area of 500-mb vorticity rotating around the cutoff low will pass to our north, and could provide enough lift to initiate convection across the northern counties too. This is reflected with 15-30% PoPs introduced for Converse county eastward to Dawes county. Wednesday looks similar with fairly low moisture content over our southern counties, but building moisture to the north. Thus, continuing a chance for isolated storms in the mountains, but this could need to be decreased with later updates. Temperatures on Tuesday and Wednesday look generally near to slightly above average for late August. The main upper level low nears our area on Thursday and Friday, bringing the best chance for storm activity of the week. The flow aloft turns weakly WSW, and fills in better moisture over much of the area. The GEFS and ECMWF ensembles show a mean PW of around 0.9 inches over KCYS by 00z Friday before starting to gradually decrease again. Models differ somewhat on the low level moisture availability and flow. The GFS depicts a 700-mb anticyclone setting up Thursday over Kansas which would help to advect in improved moisture and southerly low level winds, but this is not yet a consensus position. Regardless, with the higher precipitable water and enhanced lift associated with the passing shortwave, expecting more widespread shower and storm activity both Thursday and Friday. Confidence is higher in SE Wyoming, where over 75% of major ensemble members have some precip at KCYS both days. Lesser confidence in the Nebraska panhandle but still have higher PoPs for the entire CWA both days. Forecast uncertainty increases dramatically for the weekend with a large spread in the ensembles developing. The deterministic ECMWF is a bit of an outlier right now in showing a stronger shortwave diving further south to pass directly over the CWA and bring more widespread stratiform precipitation to the area, but the period bears watching nonetheless. Ensemble mean 500-mb heights are generally below normal for the weekend, but start to climb above normal again for the early part of next week, outside of the operational period. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 445 PM MDT Sun Aug 21 2022 Prevailing VFR. A few showers may develop in the vicinity of KCYS until 02Z, otherwise no weather impacts are expected. Mostly cloudy skies this evening will become mostly clear overnight. Surface wind directions will vary from southerly to southwesterly with speeds less than 10 kt. && .FIRE WEATHER... Issued at 201 PM MDT Sun Aug 21 2022 Dry and warm weather will continue across much of east-central Wyoming from now through early next week. Afternoon RH values will approach 15% in Converse and Carbon Counties. Wind speeds however will remain generally light and below 20 mph even during peak afternoon heating. A return of moisture will arrive on Thursday and Friday of this coming week. Scattered afternoon storms are likely which could bring instances of wetting rains over a large portion of southeast WY and W NE. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...MAC LONG TERM...MN AVIATION...MAJ FIRE WEATHER...MAC
Area Forecast Discussion
National Weather Service Green Bay WI
625 PM CDT Sun Aug 21 2022 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Monday Issued at 235 PM CDT Sun Aug 21 2022 The latest RAP analysis and satellite/radar imagery show upper level low pressure exiting across Michigan early this afternoon. Meanwhile, high pressure was centered across the northern Mississippi Valley. Back edge of the clearing line has steadily been progressing south across central and northeast Wisconsin, and is approaching areas from Green Bay to Clintonville at 2 pm. Shallow fair weather cu exists further northwest closer to the surface high where dewpoints are dropping into the 50s. Forecast concerns mainly revolve around fog potential tonight, followed by temps. Tonight...High pressure will become centered across the region. Any lingering shallow cu should dissipate early this evening, which will leave clear conditions and light winds. These conditions will promote fog development, similar to what occurred over Minnesota this morning. Statistical guidance favors central and north-central WI for the greatest potential, while ensemble guidance favors east-central WI where cross-over temps remain high. Either way, will show patchy to areas of fog across the region. Locally dense fog is possible. Cooler lows ranging from the mid-40s to upper 50s. Monday...High pressure will remain across the region resulting in mostly sunny skies with fair weather cu developing with the heat of the day. High temps ranging from the upper 70s to the lower 80s. .LONG TERM...Monday Night Through Sunday Issued at 235 PM CDT Sun Aug 21 2022 NW flow regime will continue through the middle of the week, then transition to a baggy WSW flow by the end of the week. Any embedded disturbances within this flow regime will be underwhelming, accompanied by overall weak wind fields and weak deep layer shear. The next opportunity for a more substantial system to impact the area will likely not be until this weekend. First weak short wave disturbance and accompanying weak surface frontal boundary to impact the forecast area looks to be Tuesday afternoon into the early evening. Positively tilted shortwave is forecast to drop southeast across the forecast area while a weak W-E orientated surface boundary will be located somewhere across northern Wisconsin by 7pm Tuesday. There appears to be sufficient low-level convergence and mean instability on the order of 1000 J/kg to continue low-end chance pops north of Highway 64 where an isolated shower or thunderstorm could develop. NAMNest forecast soundings indicate very weak winds up through 9km and long skinny CAPEs of ~ 500 J/Kg, thus anything that can develop would be pulse-like, slow-moving and a relatively efficient rainfall producer. Any isolated activity that does form could persist for an hour or two after sunset. Weak surface frontal boundary hangs around during the day on Wednesday as well with the NAM, GFS and ECMWF suggesting boundary will be most likely positioned somewhere along the I29 corridor by 21Z Wednesday. Medium range guidance seems to suggest a greater discrepancy in the amount of instability along and south of the frontal boundary. NAM suggests MLCAPEs around 1500 J/kg, while the GFS closer to 500 to 750 J/kg. Given NAM has a tendency to be too high on surface Tds, prefer the much more conservative GFS in this regard. Although, upper-level support seems to be quite weak, boundary layer convergence looks fairly substantial especially over far NE and EC Wisconsin, where some enhancement by an afternoon lake breeze may also be in play. Convective initiation and propagation will likely be strongly modulated by low-level forcing/boundary interactions. This seems to be supported by somewhat higher POPs and QPF in this part of the forecast area late Wednesday afternoon and early evening via the GFS/NAM. For now, opted not to get cute with details this far out and just go with the model blend POP and QPF for Wednesday afternoon. Given somewhat higher available moisture, instability and more focused boundary layer convergence, shower and thunderstorm activity will be somewhat more widespread Wednesday afternoon. Again, with weak wind fields and long/skinny CAPEs, precipitation efficiency looks pretty good. Another weak and transient impulse will also quickly traverse the area Wednesday night, thus scattered shower and isolated thunderstorm activity will likely persist for much of Wednesday night. High pressure will become re-established over the forecast area for Thursday into next weekend with temperatures near normal for the later part of August. The next chance for measurable precipitation does not appear to be until Sunday afternoon. && .AVIATION...for 00Z TAF Issuance Issued at 618 PM CDT Sun Aug 21 2022 The potential for FG/ST is once again the main aviation weather concern. Plenty of sunshine and mixing allowed Tds over C/N-C WI to drop off during the aftn, though probably not enough to prevent FG/ST overnight. Low-level moisture was not able to mix out in E-C WI, as Tds were still in the 60sF. Conditions seem more favorable for fog tonight (as opposed to last night when ST was favored). Handled similar to the 18Z TAFs in the west, but was a little more aggressive with FG development in the east. Did not include any VLIFR conditions with the 00Z issuance, but it is possible a TEMPO group for those might be needed with the next issuance. Want to see the specifics of how temps and dew points react after sunset before making a decision on that. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM.....MPC LONG TERM......ESB AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1019 PM EDT Sun Aug 21 2022 LATEST UPDATE... Update .UPDATE... Issued at 1019 PM EDT Sun Aug 21 2022 Now that the scattered showers and storms have dissipated with loss of sfc heating, attention turns to fog potential overnight. While the sfc winds have become light or calm, The RAP 925mb winds remain higher through the night at around 10-15 kts. Typically in a situation like this a low stratus deck and lighter fog is a more likely outcome than having dense fog. HiRes guidance consensus is for a low cloud deck to develop south and east of GRR after 3-4 AM and linger through 8-9AM. However with the currently elevated sfc dew points in the mid 60s and recent rains will keep patchy fog in the fcst late tonight/early Monday. The Beach Hazard Statement and Small Craft Advisory have been working out very well as the Port Sheldon and South Haven buoys have recently peaked near 4 feet. Meanwhile winds have diminished to around 10 kts up at Big Sable Point. Will maintain the headlines through 5 AM from Grand haven southward but have recently let the headlines expire north of Grand Haven where diminishing trend is occurring. && .DISCUSSION...(This evening through next Sunday) Issued at 346 PM EDT Sun Aug 21 2022 - Showers and Thunderstorms into this evening We expect showers and a few thunderstorms (not severe) into this evening as a cold front slowly slides south across the area. There is very little effective bulk shear, but we have decent surface convergence thanks to both the front moving through the area and the cold air making better progress over Lake Michigan than over land. There is around 1500 j/kg of mix layer cape to work with and the air is very moist up to near 250 mb. This means slow moving wet storms. The area getting the showers will be mostly near and west of US-131 into later afternoon then as evening wears on, the area of convergence is expected to move inland. By late evening there may still be a few storms near US-127. This should all come to an end by midnight. - Some fog possible toward Monday morning The combination of a weak front and clearing skies after 2 days of significant rainfall will lead to areas of fog Monday morning. Some of the high res models have areas of dense fog near and west of US-131 (where the afternoon convection today has been and is expected to continue to be into early evening). - Monday should see a fair amount of sunshine With the surface high building in from the northwest and the mid level jet axis close to us but west of us, we stay in the cooler air Monday. That will allow for some convection over the eastern CWA Monday and puffy cumulus clouds elsewhere Monday. - Tranquil Weather into Thursday A rather powerful storm over northern Hudson Bay rotates around itself most of this week. Over time the upper level circulation around this system gets larger. By Thursday it should be just large enough to push a cold front into our area. The air behind this front is very cold, there was snow at Resolute Bay from this system. The air cold enough to snow gets down to central Hudson Bay by midweek. Not to worry through, the polar jet the hold this air does not get this far south so we will not get into the really cold air just yet! Nonetheless, we do get the surface cold front and it would not be out of the question to see some convection on the front Thursday. However with the polar jet in Canada there would not be a lot of dynamics for this front so any convection would likely be isolated and weak. - Next significant rain event early next week Eventually a strong enough Pacific system comes on shore over Western Canada and pushes that other system toward Europe. That brings in a digging shortwave for the Great Lakes. That would tap Gulf moisture by Monday into Tuesday and bring another several day rain event for us. Likely we would have thunderstorms with locally heavy rain and warm up but still I do not see highs much warmer than the mid 80s, even so. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 759 PM EDT Sun Aug 21 2022 Scattered showers and isolated thunderstorms ending by midnight otherwise VFR prevailing through 06Z. Areas of fog/stratus possible late tonight, with a 3-4 hr period of LIFR cigs possible 09z-13Z -- mainly south and east of GRR. VFR expected Monday after any fog/stratus lifts although can`t rule out an isolated shower or tstm around LAN/JXN after 18Z. && .MARINE... Issued at 346 PM EDT Sun Aug 21 2022 We are still expecting the cold air moving in behind the front to bring stronger winds and larger waves the near shore late this afternoon into early tonight so we are holding on to our Beach Hazard and Small Craft Advisory. We have a secondary, similar event by a little weaker Monday afternoon as the drier air finally moves in. Late in the week, behind that Canadian cold front we may get another one of these events with an advancing high causing higher winds and waves. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement until 5 AM EDT Monday for MIZ056-064-071. LM...Small Craft Advisory until 5 AM EDT Monday for LMZ844>846. && $$ UPDATE...Meade DISCUSSION...WDM AVIATION...Meade MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
743 PM CDT Sun Aug 21 2022 .SYNOPSIS... Issued at 155 PM CDT Sun Aug 21 2022 Quiet weather is expected through much of this week as a seasonably warm but otherwise dry airmass settles over the Midwest and Great Lakes regions. The next best chance for widespread rain comes late next weekend as conditions become more humid ahead of a frontal system. && .UPDATE... Issued at 743 PM CDT Sun Aug 21 2022 Isolated showers that had been dropping southward across eastern Illinois have been fading early this evening, and scattered clouds are also diminishing. Main focus overnight will be with fog potential again. Latest high-res visibility guidance has been focusing on a narrower corridor from Rockford to Bloomington for dense fog potential, in line with the higher probabilities shown on the midday HREF. RAP and GFS soundings for Bloomington would suggest more of a ground fog issue, though the NAM shows a fairly moist layer up to 5,000 feet. Will keep the fog mention going for areas north of I-72 overnight. Temperatures currently appear on track to drop into the lower 60s by sunrise. && .SHORT TERM...(This evening through Monday) ISSUED AT 155 PM CDT Sun Aug 21 2022 Areas of dense fog will again be a concern tonight as skies clear and winds turn light beneath high pressure. Latest HREF guidance exhibits a 40-60% chance of fog below a 1/2 mile. While the model seems to emphasize locations along and north of I-74, its quite possible for patchy dense fog to develop in other portions across central Illinois. Regardless, the fog signal appears to mix away by 15z Monday morning with the onset of diurnal heating. && Temperatures on Monday will warm into the low 80s beneath mostly sunny skies. Overnight lows will cool to around 60 degrees. .LONG TERM...(Tuesday through Sunday) ISSUED AT 155 PM CDT Sun Aug 21 2022 A relatively benign forecast is in place through midweek as a broad ridge of high pressure works to pacify thunderstorm activity. A slight chance (< 20%) for showers and thunderstorms returns to the forecast Thursday into Friday as a mid-level shortwave trough and its attendant speed max clip the southern fringes of the Hudson Bay and help drive a surface cold front through the Great Lakes region. This front is expected to sag south into central Illinois and wash out by Friday as the upper- level kinematics and forcing become displaced too far east. While this boundary, in theory, could become the focus for isolated showers and thunderstorms, we`d like to see moisture and instability progs edge higher. The better chance for widespread showers and thunderstorms comes Sunday or Monday of next week as a frontal system lifts across the region. Temperatures this week will be seasonably hot with highs in the low 80s Monday and Tuesday. Slightly warmer readings (mid 80s) are then anticipated Wednesday and Thursday as surface high pressure departs and winds veer southerly. The weekend could then feature upper 80s as heat and humidity build ahead of the next frontal system. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 609 PM CDT Sun Aug 21 2022 Main aviation concern will be with potential IFR conditions late night and early Monday morning. Latest guidance shows a widespread expansion of lower visibilities after 09Z, though maybe not quite to the extent that occurred this morning. Will hit the visibilities a little harder in the new TAF set and bring them down to about a mile toward early morning at KPIA/KSPI/KBMI. Influence of a weak lake breeze this afternoon further east may work in KDEC/KCMI`s favor, and will keep them at MVFR as before. Rapid improvement expected by 13-14Z, with VFR conditions prevailing the balance of the forecast period. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SYNOPSIS...MJA SHORT TERM...MJA LONG TERM...MJA AVIATION...Geelhart
National Weather Service Jackson KY
1100 PM EDT Sun Aug 21 2022 .UPDATE... Issued at 1100 PM EDT SUN AUG 21 2022 Just a few scattered showers and potential thunderstorms around currently, but with instability now flagging any of the storms should not be able to get too strong. Have updated the forecast to fine tune the PoPs per the current radar and CAMs guidance through the rest of the night. Did also include the latest obs and trends for the T/Td grids. These updates have been sent to the NDFD and web servers along with a freshening of the zones, SAFs, and HWO. UPDATE Issued at 740 PM EDT SUN AUG 21 2022 23Z sfc analysis shows a cold front pressing into Kentucky from the northwest and this is prompting scattered showers and thunderstorms throughout the state. Locally, earlier cirrus clouds kept instability in check for much of eastern Kentucky with a current convective minima through the JKL CWA. Even so, several storms are heading this way from central Kentucky and conditions are favorable for new spawns downstream - likely driven by outflows from earlier storms as well as the cold front`s approach - through the evening. A few of these could still be rather strong. Otherwise, temperatures are fairly uniform in the low and mid 70s while dewpoints are around 70 degrees - fueling continued concerns for heavy rains and a threat for storms. Away from any storms, winds have been mainly light from the southwest. Did update the forecast primarily to include the latest radar and CAMs trends for the PoPs and storm chances, as well as to incorporate the current obs and trends for the T/Td grids. These updates have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Monday night) Issued at 455 PM EDT SUN AUG 21 2022 Late this afternoon, an upper level low was located just east of James Bay with a trailing 500 mb trough axis south into the Lower OH Valley to the Ozarks to portions of the southern Plains while ridging encompassed much of the western Conus and another ridge was centered near Bermuda. At the sfc, an area of low pressure was tracking across the Lower Great Lakes region while a cold front trailing southwest to western KY and then west toward the Ozarks and became nearly stationary west to portions of the Plains to the lee of the Rockies. 20Z SPC Mesoanalysis reveals MLCAPE generally in the 1250 to 1500 J/KG range across much of eastern KY with slightly higher values in the Lake Cumberland Region and across the far north and northeast. Mid level lapse rates are also quite marginal to modest at 5.5 to 6.5 C/km with the higher values across the southeast portion of the CWA. Low level lapse rates are somewhat steep near 7 C/km on average across the area. Effective shear was also on the marginal side in the 20 to 30KT range in general. Stronger convection that has moved toward the Lake Cumberland region has weakened as it neared or enter the CWA with some stronger storms also having moved near the Big South Fork region. The extensive cirrus that has been over the region has generally limited instability and convection coverage and intensity so far. As the evening progresses, the better mid level lapse rates though only marginal will shift east of the region over the next 2 to 3 hours per RAP with the rather steep low level lapse rates also fleeting as the evening progresses as we pass peak solar insolation with effective shear remaining marginal. UH probabilities from the 12Z HREF also decrease with eastward extent into the CWA this evening. The axis of the 500 mb trough will shift east across eastern KY this evening with the axis of this trough moving east of the area overnight. The Sfc cold front will be slower to move east and should only near the western portion of the CWA toward dawn. The potential for strong to perhaps locally severe thunderstorms looks to only linger through about sunset and then diminish significantly thereafter with the loss of daytime heating, especially considering the sfc front hangs back well to the west. Chances for convection should drop off markedly toward midnight. The axis of the 500 mb trough will be east of the region in general on Monday, though a shortwave or two in northwest flow should also cross the region. At the same time, the sfc cold front will cross the area during the morning to mid afternoon timeframe. Near this boundary, isolated to scattered showers and a few thunderstorms are possible on Monday. Weak high pressure at the sfc will build build in behind this boundary. This should set the stage for some valley fog with clearing skies and light winds that may be quite extensive and possibly dense in some places on Monday night. .LONG TERM...(Tuesday through Sunday) Issued at 439 PM EDT SUN AUG 21 2022 An upper level trough will be in place across much of the eastern Conus to start the period, with a secondary trough/upper level low located across the southeast Conus. This general troughiness will remain in place into the first part of the weekend, as the upper level low and large-scale troughing finally begin to shift eastward and out of the Conus. However, another upper level low and longwave troughing will begin to impact the Pacific Northwest and Alaska, bringing lowering heights and a series of upper level shortwaves to the western Conus for the second half of the weekend - just outside of the forecast period. As for sensible weather, the frontal boundary that impacted us today into Monday will have shifted southeast of the state by Tuesday. So while upper level troughing is still in place, high pressure will be in charge at the surface. Models are all in pretty good agreement that pops should remain out of the state through Wednesday thanks to the surface subsidence. However, an abundant amount of moisture will be in place across the Deep South and Mid-Atlantic states, as the surface boundary will remain in place here. There is some question on Thursday afternoon and again on Friday afternoon if moisture will be able to expand far enough northward to infiltrate the southern part of the Commonwealth. There is still some uncertainty on this, so keeping with the NBM at this point which does bring isolated to scattered activity during the afternoon and early evening hours Thursday, and more isolated activity in the same locations for Friday. A secondary cold front is analyzed by WPC to push southward across the Ohio Valley on Saturday, making its way towards the state during the day. Despite this, the pops of the GFS seem to continue to follow consistency from the previous two days, only expanding into the southeast portion of the state during the afternoon and early evening hours. The ECMWF seems to be a bit more liberal with the precip chances across the state in comparison. Again, given then is Day 7, went ahead and stuck with the NBM - which seems to favor more of the GFS solution at this point. Temperatures should be fairly steady state through the period, without any major changes in airmass expected. Highs should generally top out in the mid and upper 80s. Humidity doesn`t seem to be playing a major role given the generally northern to eastern flow throughout much of the period, so heat indices are not much higher than the daytime highs. The same pattern will be applied to the lows, as temperatures are expected to bottom out in the low 60s through much of the period, with the exceptions of any ridge/valley splits that may develop. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 820 PM EDT SUN AUG 21 2022 VFR conditions were reported at issuance time and mainly VFR CIGs are expected to prevail during the first 6 or so hours - outside of convection. Within convection, though, MVFR to IFR and briefly lower conditions are anticipated. Some wind gusts up to around 30 kts could also occur if a thunderstorm directly impacts a location. Chances for showers and thunderstorms should persist during the first 3 to 6 hours of the period ahead of a shortwave trough and a cold front. However, chances for rain will decrease from west to east thereafter as the 500 mb trough axis moves past. Late tonight, after 06Z, conditions are expected to deteriorate through the MVFR range to IFR and perhaps even lower and remain mostly IFR through 14Z or so, before gradual improvement into the MVFR and VFR ranges later Monday. Winds will be light and variable away from storms through Monday morning before picking up from the northwest at 5 to 10 kts by midday. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JP LONG TERM...JMW AVIATION...JP/GREIF
evening. Please refer to the previous forecast discussion for more
details on this week`s weather. -Miles
&& .AVIATION...22/00Z TAFs...VFR weather inland through Monday evening, with scattered cumulus buildups this evening from Siskiyou County northeastward into Klamath and Lake counties. At the coast, patches of LIFR/IFR early this evening will expand in coverage overnight into Monday morning, and extend into the Coquille Valley. Ceilings will lift and dissipate, and visibilities will improve during Monday morning, though with areas of MVFR likely to persist into Monday afternoon. -DW && .MARINE...Updated 830 PM PDT Sunday 21 August 2022...Fairly benign marine conditions area expected through Monday. Have decent confidence in the idea of a strengthening thermal trough bring increased winds and seas south of Cape Blanco Tuesday afternoon and evening. Looks like a low end chance of gales in this period. Similar conditions continue Wednesday and Thursday but with winds and seas just a little bit lower. On Friday and Saturday, winds and seas build again into stronger small craft advisory conditions with some low-end gales possible, again only south of Cape Blanco. -Stavish/DW && .FIRE WEATHER...Updated 230 PM PDT Sunday 21 August 2022...An incoming trough will bring gusty west winds to the ridges and east side today and Monday. No thunderstorms are expected through next Sunday, but hot and dry conditions will persist. -Stockton && PREV DISCUSSION... /Issued 256 PM PDT Sun Aug 21 2022/ DISCUSSION... The weather pattern remains rather typical for mid to late August across southern Oregon and northern California. The most notable feature on satellite this afternoon is the slow building of cumulus clouds east of the Cascades. We did have a mention of thunderstorms in the forecast previously, although model data does not support that this afternoon. The latest runs of the HRRR don`t show anything and the latest run of the HREF does show some radar reflectivity on the time lagged ensembles, although those runs are based on older data sets. In any case, the threat of lightning is around 5 percent east of the Cascades this afternoon. Heading into the evening hours, the upper level low will swing into north west Oregon with deeper onshore flow. The coast will see yet another night in the low stratus and fog. It`s not as clear how widespread fog will be, although we would expect some patchy fog at the very least. By Monday, we`ll see temperatures trend a few degrees cooler compared to this afternoon. Interestingly enough, this will result in highs right around normal for this time of year. This upper level trough ends up cut off from the upper level flow over Washington around the Tuesday to Wednesday time frame. In addition, a short wave does move into northern California around Tuesday morning. Anytime a shortwave does move in, one would think thunderstorms. However, the airmass is exceptionally dry ahead of this shortwave on Tuesday. We should just see some spotty cloud cover at best. From Thursday into Friday, the flow pattern looks more muddled with high pressure struggling to build into southern Oregon. However, the NBM suggests high temperatures will push back into the upper 90`s in Medford and above station`s normal highs for this time of year. In fact, we`re forecasting a high of 94 in MHS On Friday which is one degree short of the record set in 2017. Another topic worth discussing for the weather nerds out there is next weekend. Some of the deterministic models suggest an upper level low quickly moving through the Pacific Northwest. Both the ECMWF and GFS do show a cold front driving down coast and perhaps pushing inland a bit. Most ensemble members likely show something similar with daytime high temperatures trending notable lower on Saturday. This doesn`t impact the public side of things, although it may have some fire weather impacts. Lastly, ensembles show the four corners high building back in around the day 7 to 9 time frame. Temperatures will trend higher and the NBM does give some low probabilities for an impactful heat wave. Currently a high of 108 is in the 75th percentile of solutions for Medford. However, 95 degrees falls within in the 25th percentile of solutions. Obviously there is a fair amount of spread in the day 7 to 9 time frame. One could conclude there is a low potential of moderate to high heat risk towards the start of September. Thanks for reading this reading this far in this rather boring weather pattern. -Smith && .MFR WATCHES/WARNINGS/ADVISORIES... OR...None. CA...None. Pacific Coastal Waters...None. && $$
Area Forecast Discussion
National Weather Service Mobile AL
709 PM CDT Sun Aug 21 2022 .AVIATION... 00Z issuance...Generally VFR conditions expected at all TAF sites through the critical TAF period. Numerous showers and storms continue to move across our region through the evening hours. Expecting coverage to become more scattered to isolated in nature later tonight. Ceilings may become locally reduced to MVFR thresholds with visibility briefly dropping to MVFR/IFR categories or lower in and near the heavier showers and thunderstorms. Additionally, MVFR to IFR ceilings may develop late tonight into early Monday morning, especially across interior portions of southeast MS and southwest/south central AL (currently not expecting impacts at any of the TAF sites). Going into Monday, additional numerous showers and storms are expected to develop again during the day on Monday with similar concerns of localized ceiling/visibility reductions near showers/storms that develop. Winds will generally be light and variable through tonight (outside of stronger gusts within any storms). Winds then become generally northeasterly around 5kts Monday morning with variable stronger gusts in and around any storm development. JEH/88 && .PREV DISCUSSION... /issued 417 PM CDT Sun Aug 21 2022/ NEAR TERM UPDATE /Now Through Monday/...Early afternoon vapor imagery/500 mb height plots continue to show a shortwave trough digging across the Great Lakes/Upper Midwest/Ohio Valley region, while deep layer ridging continues to extend across the western Atlantic and into the Gulf of Mexico. A deeply moist airmass remains firmly entrenched across the north central Gulf Coast region early this afternoon, with precipitable water values remaining high between 2.1 and 2.2 inches. PWAT values may continue to trend a little higher up to between 2.2 and 2.4 inches across our forecast area through the course of the afternoon and into early this evening. Shortwave impulses translating eastward across MS/AL will continue to support enhanced convective coverage within the deeply moist and rather unstable environment this afternoon. We will continue to monitor radar trends for heavy rainfall and localized flooding potential as clusters of storms and/or storm mergers will have the potential to produce rainfall amounts in excess of 1-2" within a short period of time. The HRRR and ARW models have also shown some agreement with the development of clusters of showers and thunderstorms capable of producing heavy rainfall across our southeast MS and adjacent southwest AL counties later this afternoon into early this evening, so this will be an area to watch for localized flooding concerns this afternoon and evening. We cannot entirely rule out a couple of stronger storms capable of producing frequent lightning strikes and brief gusty winds, but the wet microburst wind threat currently appears limited this afternoon. Scattered to numerous showers and thunderstorms are expected to linger into the early to mid evening hours before gradually diminishing by around or shortly after around 10-11 PM. Another mid level impulse could aid in the initiation of additional scattered showers and perhaps a thunderstorm over portions of the area, particularly our interior northern counties overnight into the early morning hours Monday. Additional shortwave impulses embedded within the westerly flow pattern aloft will continue to translate across our forecast area through the day Monday. The atmosphere will remain extremely moist with precipitable water values continuing to average toward the upper end of the spectrum between 2.25 and 2.5 inches per the latest forecast guidance. Numerous to widespread showers and thunderstorms will develop over the forecast area, with the greatest coverage in the late morning and afternoon hours. Heavy rainfall and localized flooding will remain the primary concerns given the depth of moisture and the associated potential for rainfall amounts to exceed 2" in a short period of time. Instability will not be overly impressive given the abundant cloud cover, but there could be pockets of MLCAPE in excess of 2000 J/KG which could lend to a localized strong storm or two capable of producing gusty winds. Low temperatures tonight are forecast to range from around 70 degrees to the lower 70s over inland locations and in the mid to upper 70s along the immediate coast and beaches. Highs Monday currently only appear to range in the lower to mid 80s over interior southeast MS and southwest and south central AL and in the upper 80s over southern portions of the forecast area. /21 SHORT TERM /Monday night Through Wednesday night/...Upper level troughing will largely persist over the Southeastern US through the period as a few shortwaves progress (and at times deepen) within the overall flow. At the surface, a weak boundary will remain draped with a west to east orientation across central portions of Mississippi, Alabama, and Georgia. Guidance is still hinting at the potential for a surface low to develop along the weak boundary and move over the Lower Mississippi Valley late Monday and into Tuesday. Although, there are still discrepancies among the guidance with the strength of this feature it will help weaken the surface ridge across the local area. Moisture will be abundant across the region regardless of the low pressure development with precipitable water values around 2.1 to 2.4 inches through Wednesday night. This moisture combined with the upper level support of the shortwave series will keep the elevated rain chances into the middle of next week with coverage generally peaking during the afternoon and early evening hours. Decent instability will be in place each day with MLCAPE up to around 1500 to 2000 J/Kg. Considering the appreciable water loading into storms, can`t rule out a few wet microbursts each afternoon resulting in strong to locally damaging wind gusts and frequent lightning. However, the main concern will continue to be heavy rainfall especially in areas where storms repeatedly move over the same areas due to generally weak shear aloft. These training storms could lead to localized flooding concerns given the wet antecedent conditions. Temperatures will remain on the cooler side compared to normal for this time of year given the increased cloud cover and rain chances. Highs on Tuesday and Wednesday should generally top out in the upper 70s and lower 80s inland with middle 80s along the coast. Overnight lows drop into the lower to middle 70s with the warmest temperatures occurring near the coast. Some far interior areas could even see some upper 60s for lows Tuesday and Wednesday nights. /14 EXTENDED TERM /Thursday Through Sunday/...The upper level trough over the Southeast will linger through the early part of the extended with plenty of moisture in place. The numerous to widespread showers and storms will likely continue into Thursday given the similar pattern. Heavy rainfall and localized flooding will likely persist into Thursday. As we head into the weekend, the upper trough will begin to weaken as the western Atlantic upper ridge tries to nudge into eastern portions of the region. There are still some discrepancies among the ensemble and operational guidance with the timing of the upper ridge influences, but the general consensus is that we could see some slightly drier air filter into interior portions of the area on Friday and into Saturday as the weak boundary mentioned in the short term pushes into the area. Showers and storms will still be possible each day, but coverage may be a little lower than what we`ve seen lately as we head into the weekend. Temperatures should begin to warm through the period to more seasonal norms as the upper ridge begins to move into the region. /14 MARINE...No notable marine impacts for the next several days given generally light winds and low seas. Locally higher winds/seas will remain possible near showers and thunderstorms. /21 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at:
Area Forecast Discussion
National Weather Service Nashville TN
802 PM CDT Sun Aug 21 2022 ...New UPDATE... .UPDATE... Issued at 757 PM CDT Sun Aug 21 2022 A broken line of storms is situated along the KY/TN border as part of a weak cold front that is inching its way toward Middle Tennessee. The HRRR shows this line gradually pushing southward and then weakening after midnight as the atmosphere becomes more stable. The evening sounding from OHX does show good instability for now (CAPE of 1,396 J/kg, LI of -5), but also remarkably dry above ~700 mb. Will keep low chance POP`s in the grids during the overnight period as we may not ever go completely echo-free with the cold front remaining in the vicinity. && .SHORT TERM... (This afternoon through Tuesday Night) Issued at 224 PM CDT Sun Aug 21 2022 Frontal boundary now approaching the Ohio river. Activity has been having a tough time getting going and it is appearing more and more likely that the Hrrr solution may have the best handle on convection going on into this evening. However, latest gfs and nam solutions suggest a strong increase in lift across the area as we move into the late afternoon hours. So, as we get toward posting time I will make some adjustments potentially downward a touch from the 70 pops I have for the late afternoon timeframe. At any rate, a marginal risk is still in play into early this evening. Instability and wind energy will drop off notably by 03Z. Prior to that time, a few storms could contain some stronger winds. Patchy fog development appears likely late tonight. Moving on, the frontal boundary is expected to push into the area tonight and attempt to move through by Monday afternoon. Low pops will be included across our south during the day. The drier air for the most part will win out Monday night and Tuesday. Having said that, patchy fog does look likely as moisture remains in the lowest levels for late Monday night. Numerics all seem to peg the south and east with rather low vsbys. For the near term temps, numbers are looking seasonal with lows upper 60s and highs upper 80s. && .LONG TERM... (Wednesday through next Sunday) Issued at 224 PM CDT Sun Aug 21 2022 For the extended forecast, its important to note that the heavy rain fcst which was located over ne TX and eastward through northern LA is now shifting eastward. Not much northward movement but the heavy rain potential axis is a little closer to middle TN now. At any rate, it still appears that the focus of the stationary boundary will be to our south. Differences in the GFS and Euro solutions are rather apparent. The Euro hangs on to the upper troughing with stronger forcing along the aforementioned boundary to our south. The GFS is much stronger with the mid/upper level ridging over the nations interior. This is acting to drive drier air southward, keeping the extended period drier. Will opt to lean toward a blend with low pop inclusion mainly across the south with diurnal emphasis. For the extended temps, continuing the theme of blending the GFS and the euro, it looks like temps will run a few degrees above normal. Even with the Euro, the weak upper troughing still carries some relatively higher height values. Highs near 90/lower 90s will return over the extended period. && .AVIATION... (00Z TAFS) Issued at 633 PM CDT Sun Aug 21 2022 SHRA/TSRA will affect airports at varying times this evening as a cold front sinks southward across the area. Overnight, fog is expected at CSV with LIFR/VLIFR conditions, and cannot rule out vis reductions at the other airports as well but uncertainty is high. Light southwest winds this evening will veer to northwest with fropa. && .PRELIMINARY POINT TEMPS/POPS... Nashville 69 87 67 89 / 40 10 10 10 Clarksville 67 87 64 87 / 30 10 10 10 Crossville 66 79 64 81 / 60 30 10 10 Columbia 68 87 66 89 / 50 20 10 10 Cookeville 68 81 66 83 / 60 30 10 10 Jamestown 66 78 65 81 / 60 30 10 10 Lawrenceburg 68 86 67 87 / 50 30 10 20 Murfreesboro 68 87 66 89 / 50 20 10 10 Waverly 65 87 64 87 / 30 10 10 10 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.......Rose SHORT TERM...21 LONG TERM....21 AVIATION.....Shamburger
Area Forecast Discussion
National Weather Service Tucson AZ
349 PM MST Sun Aug 21 2022 .SYNOPSIS...Daily showers and thunderstorms will continue this coming week into next weekend although the heavy rainfall threat will be much less than this past weekend. Temperatures will be well below normal today then follow a warming trend during the work week. && .DISCUSSION...500 mb analysis this morning showed weak trofiness over far SE AZ, likely the remants of the tropical wave that impacted the area Fri/Sat, and a mid-level high centered off the srn CA cst. This put the western half of the forecast area under N/NE flow aloft which will have transitioned east across the area today as the above mentioned weak trof moved east into srn NM. 21/12z Tucson showed steering flow out of the N/NE, upper level winds out of the W/SW and PW value still very moist at 1.81" but down from the near record levels of 24 hours. Mid-afternoon radar showed isolated storms south and east of Tucson. Latest HRRR propagates widely scattered storms S/SW across the lower elevations thru midnight. Main threats will be strong gusty winds and localized flash flooding. Daily chances of showers and thunderstorms will continue this week into next weekend. Primary threats each day will be strong gusty winds, lighting and localized flash flooding. Temperatures will be warmer Monday then run a few degrees below normal for the remainder of the week into next weekend. && .AVIATION...Valid through 23/00Z. Scattered cloud decks at 6k-9k ft AGL thru 22/04Z with WDLY SCT SHRA/TSRA. The stronger SHRA/TSRA could reduce visibilities in heavy downpours, briefly lower CIGS to 3k-6k ft AGL and produce gusts to 40+ kts. Expect skies to slowly clear aft 22/04Z. Storms developing again Monday afternoon. Otherwise, winds will follow diurnal trends at speeds of 10 kts or less. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Daily chances of showers and thunderstorms through next weekend. Primary threats will be strong winds, lightning, and flash flooding. Outside of thunderstorm activity, wind trends will remain light and follow typical diurnal trends. && .HYDROLOGY...Rainfall over the Gila Basin in New Mexico over the past 36-48 hours has led to a significant increase in the flow in the Gila River. River Flood warnings have been posted in New Mexico for the Gila River with the higher flows moving downstream through Duncan over the next 12 hours. The latest forecast from the Colorado Basin River Forecast Center (CBRFC) has water levels remaining below flood stage at Duncan with the water level creasting between 10 pm and midnight then gradually falling through Monday morning. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Visit us on Facebook...Twitter...YouTube...and at