Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/19/22

Area Forecast Discussion
National Weather Service Gaylord MI
1154 PM EDT Mon Jul 18 2022 .UPDATE... Issued at 942 PM EDT Mon Jul 18 2022 00Z APX sounding has an MlCape in single digits. Our airmass isn`t moist enough (yet) for deep convection. That isn`t true upstream. Some showers were cooked off south of Munising mid-afternoon, but these fell apart as they moved se toward and over northern Lake MI. A few spots in far western Chip/Mack Cos may have had a few raindrops. Some residual cloud cover is over nw lower MI. Some clusters of convection continue to fire in part of northern WI and western upper MI. This activity is moving se/sse, and is not our direct concern. Our convection of concern is just north of the MN arrowhead and over Isle Royale. This activity will develop se-ward toward central/eastern upper MI and nw/n central lower MI as the night proceeds. This will occur as the low level jet veers with time, finally bringing a plume of MuCape into the area. MuCape values will rise to around 1500j/kg. We should have a somewhat favorable environment for deep convection to dive toward the forecast area. It should be weakening when it gets here, since it will be so late that the low level jet will be weakening. Main axis of convection seems most likely from the Keweenaw, to roughly Alger/S`craft Cos in upper MI, to Beaver Isl and Charlevoix Co. Any impact in this forecast area looks to be after 3-4am (though would not rule out earlier isolated cells). Hail and straight-line winds will be the main threat, for storms that are only slightly elevated. Min temps tonight quite warm, mid 60s to around 70s. && .NEAR TERM...(Through Tonight) Issued at 251 PM EDT Mon Jul 18 2022 ...Severe Thunderstorms Tonight?... High Impact Weather Potential...Thunder, maybe severe overnight. Pattern Synopsis/Forecast/Concerns...High pressure, centered over the Tennessee valley, has extended its reach into N Lower and E Upper today. Low pressure in North Dakota has a warm front that extends ENE into the Boundary Waters region of Minnesota, where thunderstorms are forming and dying along, currently. This evening, Another round of convection is expected to fire along the warm front, and extend from N Minnesota to W Upper across Lake Michigan. The convection is expected to move across N Lake Michigan around 09z/Tue, and enter NW Lower and NC Lower. The major models (GFS/ECMWF) and the HRRR and ARW models have this. The FV3 has the convection moving over E Upper and then into NE Lower and into Canada by 12z/Tue. The NAM is weaker, but the NAMNest is similar to the ARW/HRRR idea. So the expectation is for the convection to make it into NW Lower, by sunrise, and move through the forecast area by 15z/Tue. So the next question is will it be severe? It`s possible. The GFS has a 30 knot LLJ at 950 mb over GLR and TVC which would help the forcing of the more than likely elevated convection. The Showalter Index shows -3c to -4c values, which shows the decent thermo profile (MUCAPES around 1800J/kg) for the convection. So if the LLJ can tap that instability, thunder does have the potential for wind gusts (DCAPE is 1130J/kg). && .SHORT TERM...(Tuesday through Thursday) Issued at 251 PM EDT Mon Jul 18 2022 ...Very Warm with Increasing Shower and Storm Chances... High Impact Weather Potential...Severe storms are possible. Any ongoing convection from a possible MCS is expected to exit the area during the morning hours. Still questions about how much lingering cloud cover there will be during the day which could affect the extent of diurnal heating and subsequent amount of instability. At this point am banking on there being enough breaks in the clouds to allow for highs in the 80s to low 90s. This could lead to a popup storm or two in the afternoon and evening (aided by a possible lake breeze off of Lake Huron). More widespread showers and storms are then expected late Tuesday night into Wednesday from a short wave evident on water vapor imagery across the Pacific Northwest moving into the region. Severe storms are possible as the left front quad of a 90 knot jet streak approaches. The main severe weather threat is damaging wind gusts with 0-6 km bulk shear of 40 to 50 knots (large hail is also a possibility). Humidity levels will be high with dewpoints of well into the 60s expected. Lows Tuesday night in the muggy mid 60s to around 70. Highs Wednesday ranging from the mid 70s north to the upper 80s southeast. .LONG TERM...(Thursday night through Monday) Issued at 251 PM EDT Mon Jul 18 2022 ...Seasonably Warm but not as Humid... High Impact Weather Potential...Low for now. Zonal flow to start off the period, followed by slowly building heights into the first half of the weekend. Another trough then follows for Sunday. So overall very low pops into the day on Saturday followed by chances for showers and storms Saturday night and Sunday. Temperatures are expected to be near normal late July averages. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1154 PM EDT Mon Jul 18 2022 SHRA/TSRA possible late tonight into Tue morning. High pressure is in the OH/TN Valley, while a cold front is north of Lk Superior. Increasing wsw flow between these features will increase moisture and instability tonight. Showers/TSRA will have a better chance of developing se-ward into northern MI as the night proceeds. PLN/TVC/MBL will have increasing chances of precip late overnight (after 07-08Z), with brief MVFR conditions (or worse) possible. That lingers into morning. In the afternoon/early evening, some TSRA could redevelop in ne lower MI, impacting APN. Sw winds increasing, becoming somewhat gusty Tuesday. && .MARINE... Issued at 251 PM EDT Mon Jul 18 2022 Tonight through Wednesday...Winds generally overnight will be variable at 10 knots (Lake Michigan would probably have SW winds as the return flow begins) as the sfc high moves to the east. Although thunderstorms could be producing squalls to 30-35 knots or higher, if they become severe. Tuesday, low pressure will move toward the region, and southerly flow is expected out ahead of the low. The winds over lake Michigan will get into small craft criteria by late Tuesday afternoon and will continue into Tuesday evening, spreading eastward. Lake Huron may see the small craft criteria gusts Tuesday night, and Wednesday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JZ NEAR TERM...JSL SHORT TERM...AJS LONG TERM...AJS AVIATION...JZ MARINE...JSL
Area Forecast Discussion
National Weather Service Bismarck ND
904 PM CDT Mon Jul 18 2022 .UPDATE... Issued at 900 PM CDT Mon Jul 18 2022 ** MESOSCALE UPDATE DISCUSSION ** As of 02 UTC, new, and rapidly-intensifying storms are forming west of Williston, on the leading edge of greater forcing aloft and just north of the surface triple point. The downstream air mass is characterized by increasingly-rich low-level moisture, with the storms beginning to impinge on an axis of lower 70s F dewpoints that extend from northern ND into far northeastern MT. This is generating strong to extreme bouyancy, albeit with some residual inhibition, with MUCAPE upwards of 4500 J/kg. Strong wind fields are in place with deep-layer shear of 50-60 kt, and low- level hodographs possess enough curvature and size to support up to 200 m2/s2 of 0-1-km SRH. Thus all severe hazards are possible, but the tornado risk may be somewhat mitigated if storms are not fully surface-based owing to residual inhibition. On the other hand, that inhibition could maintain semi-discrete supercells, which would bolster the risk of large to very large hail given the deep-layer shear and favorable lapse rates and bouyancy. Finally, the strong wind fields including 0-3-km bulk shear of 30-40 kt and DCAPE of 1000-1500 J/kg will favor damaging wind risk, especially if bowing segments develop, which could be the case if cold pools expand sufficiently to overcome residual capping. The main uncertainty with this scenario remains focused on convective coverage, especially with southward extent, owing to that capping. Even areas along the U.S. Highway 2 corridor may maintain some degree of capping as the upstream convection approaches. Further south yet, the 00 UTC Bismarck RAOB sampled considerable CIN for boundary-layer based parcels, so the high-based convection south and east of Bismarck is not realizing the full potential of the bouyancy profile. It has occasionally strengthened, but the severe-storm threat with those cells is lower. CJS UPDATE Issued at 848 PM CDT Mon Jul 18 2022 Quick update to expire the Heat Advisory at 9 PM CDT/8 PM MDT. UPDATE Issued at 802 PM CDT Mon Jul 18 2022 SPC has issued Severe Thunderstorm Watch 475 for basically the northern two tiers of counties in northwest and north central North Dakota plus McKenzie county. UPDATE Issued at 643 PM CDT Mon Jul 18 2022 Decided to go ahead and extend the Heat Advisory until 02z with plenty of stations still seeing heat index values in the 100 to 105 degree range. The other challenge tonight will be approaching severe thunderstorms coming from northeastern Montana. These storms should continue to become better organized as they approach northwest North Dakota in the next one to three hours. Very large hail up to two inches in diameter are possible with any of these storms that can stay discrete (one cell northwest near Poplar Montana continues to try and develop ahead of the main line of storms further west). However, it appears upscale growth into an MCS or multiple line segments/bows will start the transition to a wind threat rather quickly. A brief tornado also can`t be ruled out with either storm mode as the low level jet starts to kick in. By the time this MCS reaches northwest North Dakota, the environment will be favorable for severe wind gusts to 75 mph given large DCAPE, strong 0-3km bulk shear, and strong BRN shear per RAP mesoanalysis trends. These storms will likely continue through the night across the northern third of the state. For this update, the main change was to tweak the precipitation chances to better account for storm timing/radar observations and to extend the Heat Advisory. Otherwise, just blended in the latest observations to the going forecast. && .SHORT TERM...(Today and tonight) Issued at 230 PM CDT Mon Jul 18 2022 Forecast highlights in the short term period will be the warm and humid conditions today and strong to severe thunderstorm chances later today into tonight. Currently, upper ridge axis extending north/northeast across the Dakotas this afternoon, with a developing sfc low over the lee of the Montana rockies and another low over the Black Hills. Sfc trough extends from southwest ND to northeast ND as evident in sfc wind obs. Persistent band of mid to upper level clouds, associated with a mid level wave, has been over southwest ND into east central ND for much of the day, and has wrecked havoc on the daytime temperature forecast. No signs of this eroding, so went ahead and lowered highs for today by several degrees for those locations impacted by the cloud cover. Still very humid with sfc dewpoint temperatures in the low to mid 70s most areas. Have opted to leave the heat advisory as is with this product issuance as even despite the clouds, we will still approach and exceed 100F heat index over most areas this afternoon. A few CAMs still indicate that we may see a few storms south central and east into the James River Valley this afternoon or early evening. High CAPE here along with modest shear, so an isolated severe storm remains possible if any convection can fire up. As of 19Z there are a few towering CU just northeast of the Black Hills moving northeast, so perhaps this is what we will get in a few hours. The main threat remains over northwest and north central North Dakota later today through this evening, and perhaps for a few hours overnight. The strong/compact mid level low will be over north central MT by 00Z, then developing into far northwest ND by around 06Z. As forcing aloft approaches and interacts with an eastward moving cold front, expecting to see discrete storm development with large to very large hail a threat given straight hodographs, and also a severe wind threat with high DCAPE and as 0-3km wind shear increases. RAP and HRRR sfc low placement and forecast wind fields put the frontal triple point across northeast MT and northwest ND this evening, so this area will see the max forcing for potentially high end severe storms. A tornado or two will be possible as well given the low level wind shear projected and the potential strength of any updrafts. Discrete cells are then expected to congeal into one or two segments as they march across northern ND late in the evening and overnight. Steep lapse rates will maintain a large hail threat, in addition to the severe wind gust potential. Would expect a severe weather watch to be issued at some point over the next few to several hours. How far south the severe threat goes is in question. In the wake of the cold front, gusty northwest winds will develop west into central after midnight. There may be an hour or two period along to immediately behind the cold front where we may see stronger winds with gusts to 40-45 knots. .LONG TERM...(Tuesday through Monday) Issued at 230 PM CDT Mon Jul 18 2022 The long term begins with the strong mid level over northwest North Dakota, and its associated sfc low across the Red River Valley. Gusty west/northwest winds will develop quickly from west to east Tuesday morning as the boundary layer starts to mix. The gusty winds will then continue through the day Tuesday before slowly winding down west to east Tuesday night. Gradient forcing isn`t overly impressive, but there is a good unidirectional wind profile so decent momentum transfer is expected. In addition, scattered wrap around showers and isolated thunderstorms are forecast for much of the day Tuesday, so potential is there for this activity to mix down an occasional isolated strong wind gust most anywhere. More favorable location for the stronger winds and future wind headlines is still over the higher terrain of the southwest, though may need headlines over a broader area to cover the mix down potential. Will let the midnight shift issue any possibly wind headlines as we focus for now on the heat and severe potential today and tonight. Behind the cold front, much drier and cooler air will push into the region for Tuesday, with dewpoint temperatures in the 50s and highs in the 70s and 80s. A slow warming trend and mainly dry weather can then be expected through Friday with a west/northwest flow aloft in place across the Northern Plains. There may be a few embedded waves moving through the flow aloft, which could bring some precipitation to our area, more so towards the end of the work week. Ensembles and NBM remain in somewhat agreement with more defined wave moving across the region this coming weekend, which would bring our next best chance for widespread precipitation and thunderstorm chances. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 643 PM CDT Mon Jul 18 2022 VFR conditions should prevail for most areas through the period. Showers and thunderstorms will be on the increase from west to east and mainly across the northern third of the state tonight, possibly impacting KISN and KMOT. Some of these storms could become severe with very large hail up to two inches in diameter and damaging wind gusts to 75 mph. Brief MVFR/IFR conditions are possible if any of the heavier storm cores move overhead. Storms should diminish from west to east overnight, but a few more showers are likely north and central on Tuesday. Strong northwest winds will start to develop by late Tuesday morning and last through the afternoon, with the highest gusts up to 45 mph. The strongest winds on Tuesday will be across the south. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE...CJS UPDATE...ZH SHORT TERM...NH LONG TERM...NH AVIATION...ZH
See previous forecast discussion below.

400 PM Update: Heading into a fairly active late afternoon to mid evening period as current radar mosaic shows some heavier showers and a few lightning strikes across northern CT and portions of western RI. Air mass remains tropical with dewpoints commonly in the low to mid 70s; but warm frontal cloudiness still remains across a large portion of SNE. Portions of Hartford, Tolland Counties in CT and Washington Counties in RI are trying to destabilize further but anvil cirrus is limiting this to an extent. CAPE values for a 100-mb averaged parcel (MLCAPE) is only around 500-1000 J/kg in northern CT per SPC`s mesoanalysis page. However an expanding risk for strong- severe appears possible as those values rise to 1000-1500 J/kg through 00z/8pm. Mid-level wind fields have begun to strengthen per Dopper wind profiler data from OKX and ENX radars. While gusty winds capable of localized straight line wind damage still is the greatest risk, the low LCL heights and lengthening hodographs due to the strengthening winds through 850-500 mb could support a short-lived rotation/brief tornado risk. Indeed, several of these showers/a few t-storms that have moved into northern CT and part of southern RI have shown some broad rotation but couplets have not been necessarily focused and tight. We also need to be cognizant that storms have potential to produce torrential downpours; as rains have been more stratiform, think any hydro issues would be mostly centered over the Utilized a blend of the 18z HRRR and 12z NAM-3km for PoP/Wx which focuses the greatest thunder risk to northern CT, western MA and southern RI at least until 10 PM. Mainly moderate showers across eastern MA and the Cape/Islands, but some risk for isolated thunder could exist into Boston-Providence area after 10 pm as cool front moves eastward and offshore overnight. Dewpoints may come down slightly post-frontal but still expecting a muggy night with lows in the upper 60s to low 70s. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... 300 PM Update: Tuesday through Tuesday Night: Tuesday is setting up to the first of a couple of hot days, with westerly flow and broad cyclonic flow aloft. Unlike today where cloud cover has prevailed, we are looking at a mostly clear to partly sunny day. Translates to both several hours of heating but also dewpoints that should mix lower in the afternoon as taps into drier air aloft. A few models simulate convection across northern New England which could slip into northern MA; but given drier air aloft, mixing lower dewpoints (and by "lower", still in the low-mid 60s which still is fairly sticky) as well as westerly non-convergent flow, opted for a dry forecast for now. Highs in the mid 80s to the lower to middle 90s. Westerly gusts in the 20 to 25 mph range. For Tuesday night, initially mostly clear skies after any diurnal cu diminishes. RH cross sections for the overnight show increasing mid to high clouds from the NW but anticipating generally dry weather. Lows in the upper 60s to mid 70s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Highlights... * Heat and Humidity build in for a prolonged period of 90F+ high temperatures. * Strongest signal for another round of widespread convection looks to come Thursday. * Given severe weather potential today, the forecast beyond 12Z Friday was populated with the NBM. Please refer to previous AFD for more detail. Wednesday... There is increasing confidence that Wednesday may feature the hottest weather of the week, as 925 mb temperatures surge to 27-28C across much of the CWA as a result of persistent southwest flow. Little relief is to be felt in regards to a breeze, even with deep mixing to about 800mb, as both 925mb and 850mb winds linger below 15 kt. Dewpoints also continue to flirt with oppressive levels in the upper 60s and low 70s. To account for the tremendous heat signal at 925mb, 90th percentile NBM guidance was blended with the NBM to increase daytime highs by a few degrees. Overall, temperatures will be in the low 90s, with temperatures reaching into the mid and even upper 90s across metro-west and the Connecticut River Valley. Lows overnight will be limited by dewpoints in the upper 60s and 70s. Thursday... Heat persists and humidity continues to build Thursday as dewpoints surge into the mid 70s. A shortwave and cold front associated with low pressure passing to our north over Quebec look to pass through our area on Thursday afternoon. Increasing clouds ahead of the front may look to limit daytime heating compared to Wednesday, with high temperatures expected to be about 2-3F cooler. With the shortwave/cold front looking to provide the lift needed to initiation convection, several severe weather parameters look to be in line to generate convection between 12Z and 00Z with MUCAPE exceeding 2000J/kg ahead of the front. Extremely moist PWATs, at about 160% of normal, aided by dewpoints in the low and mid 70s, combined with generous instability causes K indicies to surge in excess of 40 (typically, our area will see thunderstorms with K indices around 30). Shear also looks to be moderately healthy, exceeding 40 kts across portions of our area. One limiting factor in regards to severe weather on Thursday will be poor mid level lapse rates, which seem to linger between 5 and 6C/km for much of the day. A second limiting factor will be a strong capping inversion that looks to be in place on Thursday morning. This inversion looks to mix out by mid afternoon, but if this process is delayed, it may have an effect on the timing and potency of convection. One other thing to note is that a low level jet looks to develop across southeast MA and the Cape and Islands Thursday afternoon, with 925mb winds between 40 and 45 kt. With high winds across the Cape and the Waters, small craft advisories will likely be considered for the period. After the capping inversion erodes by mid afternoon, pre-frontal mixing is expected to be deep, to about 800mb, it is likely that SW winds will be quite gusty across the Cape and Islands during the afternoon hours. Unlike much of the Spring, mid level dry air does NOT look like it will inhibit convection, however, there looks to be a layer of dry air at around 500 mb, which, combined with lackluster lapse rates, may limit tremendous height growth of updrafts. Nonetheless, convection is likely ahead of and along the front on Thursday afternoon/evening. SPC has caught on to the severe weather risk on Thursday as well, placing us in the 15% risk category. Beyond Thursday Night... Given the risk of severe weather in our CWA this afternoon, NBM was used to populate the forecast after 12Z Friday. Dewpoints look to dip to more comfortable levels post frontal passage on Friday, but will build back into the mid and upper 60s by the end of the weekend. Please refer to previous AFD for more detailed discussion. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 00z TAF Update: Tonight: Moderate confidence. Still appears greatest risk for TSRA in the 00-04z timeframe across western/central MA into northern CT, with some risk for weakening TSRA into the BOS-PVD corridor 00-02z. MVFR-LIFR to continue until improvement with frontal passage 04-08z, bringing a wind shift from SW to W. Longest period of degraded conditions likely at FMH, HYA and ACK. Tuesday through Tuesday Night: High confidence. VFR. W winds around 8-12 kt with gusts 20-25 kt. KBOS...Moderate confidence in TAF. Mainly SHRA before 22z, then risk for embedded TSRA after 22z. Overall lesser TSRA risk than across interior New Eng. KBDL...Moderate confidence in TAF. Better chance for TSRA, some strong in the 19-00z window, may linger until 02z. Outlook /Wednesday through Saturday/... Tuesday Night: VFR. Breezy. Wednesday through Wednesday Night: VFR. Thursday: Mainly VFR, with areas MVFR possible. Breezy. Slight chance SHRA, isolated TSRA. Thursday Night: VFR. Breezy. Friday: VFR. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. SCAs continue through Tuesday due to gusty SW winds and seas 4-7 ft. In addition, given SW winds and seas in the 5-7 ft range, a Rip Currents statement is in effect on Tuesday for especially the south- facing beaches on Nantucket. Tonight: High confidence. S/SSW gusts 25-30 kt peaking tonight. Patchy fog and low clouds today into tonight until the front passes through. Tuesday: High confidence. SW/WSW 20-25 kt gusts especially early, then diminishing to around 15-20 kt by afternoon. Seas 4-7 ft, highest southern offshore waters. Tuesday Night: High confidence. WSW winds decrease to 10-15 kt, with seas also lowering to 3-5 ft. Outlook /Wednesday through Saturday/... Tuesday Night: Winds less than 25 kt. Local rough seas. Wednesday through Wednesday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Slight chance of rain showers, isolated thunderstorms. Thursday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Slight chance of rain showers, isolated thunderstorms. Friday: Winds less than 25 kt. Areas of rough seas. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...High Rip Current Risk from 8 AM EDT Tuesday through Tuesday evening for MAZ024. RI...None. MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ231-236-250- 251. Small Craft Advisory until 8 PM EDT Tuesday for ANZ232>235-237. Small Craft Advisory until 2 AM EDT Wednesday for ANZ254>256. && $$ SYNOPSIS...Loconto/KS NEAR TERM...Loconto/Gaucher SHORT TERM...Loconto LONG TERM...KS AVIATION...Loconto/KS MARINE...Loconto/KS
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1023 PM CDT Mon Jul 18 2022 .MESOSCALE UPDATE... Issued at 1021 PM CDT Mon Jul 18 2022 Continuing to watch and wait as storms begin to percolate over eastern North Dakota. Low-level jet continues to strengthen over central South Dakota into the Red River Valley and northwest Minnesota. Additional storms have recently developed just north of the border into Ontario. There are two focus areas for storms over the next 3 to 6 hours. The first will be over the Arrowhead. The storms in Ontario are on a southeastward trajectory and may affect northern St. Louis, Lake, and Cook counties. The other area will be closer to the LLJ as it continues to strengthen over the next few hours. The storms in eastern North Dakota appear to be forming in a region of convergence and diffluence as the southerly branch of the LLJ moves out of South Dakota into North Dakota. Winds farther north and east veer southeasterly as they move into the southern Red River Valley. Those storms, should they persist, will likely move into north- central Minnesota in the 1 AM to 4 AM timeframe. Effective shear continues to support organized convection, particularly with the Ontario storms. The storms in eastern North Dakota have a greater potential to evolve into a forward- propagating QLCS with time. Large hail and damaging wind gusts will remain the primary threat from the storms overnight. 0-3 km bulk shear and steep low-level lapse rates over northern Minnesota may be able to support a few brief and weak tornadoes, provided the storms in eastern North Dakota evolve into a QLCS. Locally heavy rain will remain a concern, especially if the storm motions shift orthogonal to the 850 mb FGEN. MESOSCALE UPDATE Issued at 748 PM CDT Mon Jul 18 2022 MLCIN has increased over northwest Wisconsin over the past 2 hours which has tapered convection along the lake breeze. A few isolated storms are still possible, but overall quieter trend should continue during the next 4 to 6 hours. Attention shifts to northern Minnesota into Ontario. A persistent TCu field was noted on GOES-East Day Cloud Phase imagery stretching from near Cloquet to near Roseau, along the nose of a developing 850 mb LLJ. Additional towers were found southwest of that boundary. There was a congested area of showers from around Park Rapids to Detroit Lakes and Fergus Falls which were steadily moving eastward. The main area of concern over between now and 10 PM will be the potential for storms in the area of convergence on the nose of the LLJ as it strengthens. 850 mb FGEN was maximized about 10 to 20 miles south of the TCu on satellite and will likely strengthen and shift north with time. Meanwhile an shortwave trough will move eastward out of North Dakota and Manitoba resulting in height falls and broad scale forcing for ascent. Effective bulk shear over northern Minnesota was in the 40 to 50 knot range per the 00Z SPC RAP mesoanalysis. Hodographs are forecast to lengthen and develop cyclonic curvature in the low-levels over the next 6 hours in that area. Large hail, damaging wind gusts, and a very limited risk of tornadoes seems to be the main concern. Heavy rainfall is possible as well as the steering flow is roughly parallel to the 850 mb FGEN. MESOSCALE UPDATE Issued at 458 PM CDT Mon Jul 18 2022 Storms continue to fire in northwest Wisconsin along the lake breeze boundary. SPC RAP mesoanalysis indicates an uncapped area of MLCAPE of 2000 to a little more than 2500 J/kg. Storm motions are generally southeasterly at 20 mph, which raises slight concerns of heavy rainfall given the slow movement. Effective bulk shear of 30 to 35 knots is featured over that area, too, which is helping to maintain storms. The dominant storm between Glidden and Mercer is on the Bunkers right-moving supercell vector and has exhibited a weak mid-level meso in the last 15 minutes. Downdraft CAPE per the RAP analysis features a minimum where storms are currently located, which may reflect more of the convective working of the column than an actual decrease in DCAPE. Outside of the minimum area, DCAPE ranges from better than 1400 J/kg north of Green Bay along the WI/MI border to around 1100 J/kg over Douglas County. Think a marginal wind and severe hail risk will persist in that area over the next several hours as storms continue to fire along the lake breeze and, perhaps eventually, the outflow boundaries from earlier convection. The other area of concern is over northwest Ontario. Low-level convergence seems to be maximized from southern portions of Lake Winnipeg in Manitoba to near Atikokan, ON per radar and GOES-East Day Cloud Phase imagery. High-resolution models feature this area for storm initiation this afternoon with storms propagating southeastward into northern Minnesota by the 7 to 8 PM timeframe. && .DISCUSSION...(This evening through Sunday) Issued at 411 PM CDT Mon Jul 18 2022 Summary: Showers and storms, some severe, will be possible this evening and again Tuesday afternoon and evening. Hot weather will also continue into Tuesday with slightly less hot weather from Wednesday onward. It`s shaping up to be an interesting evening with some thunderstorms in the forecast. A CAPE gradient exists across the Arrowhead down into northwest Wisconsin in far eastern Price County. A few storms have already popped up in northwest Wisconsin and are just starting to pop up across the Arrowhead. Models seem to have only a fair handle on things this afternoon, and weak synoptic forcing is a likely culprit. Some pre-existing clouds from earlier convection persisting across the Arrowhead are likely limiting convective potential there, but also contributing to a warm frontal boundary where storms will likely fire over the next one to three hours. There is a pretty favorable environment for storms to grow if they can initiate, with favorable instability (up to 3k-4k J/kg SBCAPE), up to 40-50 kt 0-6 km shear, and favorable low-level shear that could support a tornado if storms remain single-cell. Large hail (up to ping-pong ball size or golf ball size) and damaging winds up to around 70 mph will be the main threats. While instability will decrease tonight after the initial round of storms, there will still be plenty of low-level warm air advection with frontogenesis occurring around the International Border. Persistent thunderstorms may develop along the front, with some training possible due to westerly mid-level flow quasi-parallel to the northwest-to-southeast oriented front. If frontogenesis occurs a bit further south than currently expected, places along the border may have a chance at seeing some heavy rain and perhaps some localized flooding issues. With PWAT values around or a bit greater than 1.5", there is plenty of moisture to produce some high rainfall totals if all other factors line up. On Tuesday, a low pressure system will approach from the northwest. Additional showers and thunderstorms are expected, and unlike this evening, may be a bit more organized as they will be attached to fairly well-organized frontal passages. A couple thousand J/kg of CAPE and decent wind shear to around 30-40 kt could result in some scattered severe storms capable of large hail and gusty winds. Heavy rain will be possible as well with PWATs remaining above 1.5". A cold front will pass through during evening and effectively end convective processes behind it. Going into Wednesday, some lingering showers and possibly storms will be possible with remnants of the upper level trough remaining over the region with warm northwest flow. Weak ridging and northwest flow will persist for the rest of the week, resulting in drier weather overall. Additional rain chances may return next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 655 PM CDT Mon Jul 18 2022 Predominant VFR conditions expected through the TAF period. Thunderstorms may develop late this evening and overnight in the vicinity of KINL or KHIB with a brief period of MVFR conditions. Due to the uncertainty of timing and/or distribution, have put in VCTS groups for now. LLWS is likely tonight with a strengthening low level jet, ending by 14Z. Gusty southerly winds are expected to develop Tuesday ahead of a cold front that will move through the area during the late afternoon. Additional showers and storms will develop after 19Z Tuesday, and have included VCTS groups for now, but a period of MVFR ceilings is expected with any storms. && .MARINE... Issued at 411 PM CDT Mon Jul 18 2022 Winds will become more northeasterly this evening. While they are generally expected to remain light tonight, gusty and erratic winds are expected in and around thunderstorms that are expected this evening. Storms may be strong to severe with large hail, strong winds, and frequent cloud-to-water lightning. On Tuesday, northeasterly winds are expected to increase ahead of an incoming cold front. Some gusts up to 20 to 25 knots and wave heights up to 2 to 4 feet will be possible during the daylight hours. With some uncertainty remaining on how strong winds may become, headlines have not been issued for this update. However, Small Craft Advisories may be needed for many of the nearshore waters. Additional showers and thunderstorms are likely Tuesday afternoon and evening. && .PRELIMINARY POINT TEMPS/POPS... DLH 66 82 60 81 / 20 50 50 40 INL 66 83 61 81 / 50 80 80 30 BRD 72 88 64 84 / 30 30 40 10 HYR 70 89 60 81 / 10 40 50 50 ASX 66 89 60 81 / 20 50 60 60 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ MESOSCALE UPDATE...Huyck DISCUSSION...JDS AVIATION...LE MARINE...JDS
Area Forecast Discussion
National Weather Service Grand Rapids MI
1011 PM EDT Mon Jul 18 2022 LATEST UPDATE... Update .UPDATE... Issued at 1011 PM EDT Mon Jul 18 2022 I am still on the page that suggest no convection in our CWA through sunrise Tuesday. This is based on where the best mid level warm advection is, the latest RAP low level jet location over time, the best upper divergence associated with the jet left entrance region, corfidi vectors, and the 850 to 300 mb thickness. All of this tells me the convection will largely continue to develop ahead of the cold front trailing the low over eastern Canada and that will drop across northern Lake Huron overnight. Meanwhile the incoming system`s warm advection push will develop other convection just west of the cold front convection. These will merge during the early morning hours had head across NE lower Michigan northern and central Lake Huron. Of course it would not be out of the question a few stray storms would track into our northern CWA around sunrise but they would be running into a hostel informant (air to dry and marginal at best instability). So whatever storms could do that they would be dissipating. I did not increase the pop for the early morning hours in our grids as a consequence of my thinking on this. && .DISCUSSION...(This evening through next Monday) Issued at 351 PM EDT Mon Jul 18 2022 ...Marginal Severe Weather Risk late Tonight/Tuesday Night... Model agreement and run to run consistency remains good for the vigorous, closed 500 mb low moving east along the U.S./Canada border through Wednesday. For tonight, convection forming in an area of warm advection/isentropic ascent across Minnesota will progress east into the western U.P of Michigan and northern Wisconsin along the northern periphery of the upper ridge, then continue southeast into northern Lower Michigan after midnight. The storms should weaken as they move further south into a dry and stable atmosphere with forecast soundings showing warm mid level temperatures persisting under upper ridging. The ridging continues on Tuesday with another round of convection Tuesday night developing in an area of low level convergence ahead of the surface cold front. Once again, a capping inversion is present and lowers the risk of widespread severe storms, though it slowly erodes by 12Z Wednesday with showers and thunderstorms potentially flaring up during the morning and afternoon across eastern Lower Michigan. ...Rain Chances over the Weekend into Next Week... There is a signal for some drought-easing rain/convection over the weekend as the subtropical ridge begins to be flattened and shunted off to the southwest by an upper longwave trough becoming established across the northeast quarter of the CONUS. The amplification to this flow regime could see a period of MCS activity on Saturday and Sunday and/or a surface low moving along a baroclinic zone late in the weekend into early next week that could bring more widespread and heavier rain amounts than have occurred over the past several weeks. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 737 PM EDT Mon Jul 18 2022 The short story is nearly clear skies into Tuesday evening. Winds are from the northwest mostly at this time but should very soon shift to the southwest or even south southwest late tonight. Winds will at the surface will stay below 10 knots overnight but will be in the 15 to 20 knot range between 1000 feet AGL and 5000 ft agl overnight. As the incoming frontal system and unseasonably deep surface low approaches the area from the west Tuesday winds will begin to become gusty to mid to late afternoon. As for any convective threat, I am going with the idea that the convection over northern Wisconsin is related to jet entrance region lift and a quasi stationary front near the Lake Superior shore area. The front should not move much overnight actually, so it is more or less stationary. That convection will keep try to move south southeast based on the 850 to 300 mb thickness but will also new cells will keep redeveloping on the upstream side of the mid level inflow. Even so since the jet core is moving east, so will the area of convection. Slowly the area of convection should shift to the east southeast over time. The storms should be over northeast Lower Michigan, mostly north and east of HTL. Our TAF sites are far enough south that the upper ridge and associate subsidence should keep this area mostly clear for the most part (through Tuesday afternoon). && .MARINE... Issued at 351 PM EDT Mon Jul 18 2022 Conditions will become hazardous to small craft on Lake Michigan on Tuesday as south winds increase to 25 knots and build waves over 4 feet by Tuesday night. A Small Craft Advisory and Beach Hazard Statement will be needed. Conditions will begin to improve on Thursday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM DISCUSSION...Ostuno AVIATION...WDM MARINE...Ostuno
Area Forecast Discussion
National Weather Service Gray ME
1134 PM EDT Mon Jul 18 2022 .SYNOPSIS... Much-needed rains are expected today with pockets of heavy rainfall and potential for strong to severe thunderstorms. A cold front crosses early Tuesday, with more shower and storm potential during the afternoon. High pressure moves overhead Wednesday, with another low pressure approaching from the Great Lakes Thursday bringing another round of showers and thunderstorms. Warm and mainly dry conditions will then return for Friday through the weekend. && .NEAR TERM /THROUGH TONIGHT/... 1130 PM Update...Only minor updates to the forecast, mainly refreshing the suite with latest hires data. At this hour... radar shows training showers over the mountains and toward the international border with convective showers advancing west-to- east across New Hampshire into Maine... ahead of the cold front currently crossing the Hudson River Valley. Will continue to see pockets of moderate to heavy rainfall with embedded thunderstorms, along with a low-end tornado threat given the very strong helicity, through the coming couple hours. 750 PM Update...Impressive warm season satellite picture of a low pressure system pivoting towards New England this evening. Rainfall: Warm sector is lifting through New England, with heavy rain precip shield now exiting NH and combing across ME. Impressive precip rates of 1 to 2 inches per hour have been measured, perhaps close to 3 inches for a brief period of time in stronger cells. Greatest amounts have fallen across the White Mountains where orographic lift and convergence along a boundary have brought persistent moderate rainfall rates. So far, up to 2 inches have fallen in that region. There was also a strong storm that tracked through far east-central NH into southern ME that produced torrential rainfall. Thunder: has been fairly absent, mainly due to how shallow cells have been and higher freezing lvls. That said, additional instability within the warm sector will be moving in over the next 3 to 5 hours that will bear watching with good shear and low LCLs across the region remaining in place. Updraft helicity paths on short term guidance eye up now through 6z as most likely to see potentially stronger storms or showers with some rotation possible. This comes on the heel of a region of 200-300 0-1 and 0-3km helicity tracking through Maine as the evening goes on. So there is still uncertainty how much convection can take place after sunset, if it is elevated, and how much of the remaining helicity can be used. So, remains a gusty wind and heavy rain/hydroplaning threat. Will be watching the Whites for continued training rain/flooding threat. Showers/storms in the Northeast have exhibited some rotation in the low levels through the afternoon and evening, but shear has overpowered updrafts such that they have been sheared before gaining respectable depth. This is still apparent on radar with large precip trails ahead of the main cell some 30 to 40 miles upwind. Will continue to monitor convection upstream as it tracks towards central New England through midnight. Previous Discussion... Precipitation shield associated with an advancing warm front has overspread all of New Hampshire into far western Maine and will continue to spread northeastward as low pressure tracks into the St Lawrence Valley this evening. South of the warm front convection has blossomed from northern New Jersey into south west New England with several storms exhibiting rotation and approaching severe thresholds. This warm sector is expected to move into the southern half of New Hampshire into extreme SW Maine over the next couple of hours. The environment within the warm sector will be characterized by dew points in the low to mid 70s contributing to around 1500 J/kg of CAPE. In addition, effective shear will increase to 40 to 50 kts and CAMs continue to show clockwise turning hodographs becoming elongated this evening with impressive low level helicity. Ample cloud cover and poor mid level lapse rates will work against robust convection and CAMs are bit messy with no clear trend towards increased or decreased potential for strong to severe storms. Thus, forecast thinking has not changed much with potential for isolated to multi cells clusters that due form in the warm sector to exhibit rotation and the potential for strong to damaging winds across the southern half of NH and SW Maine from late this afternoon through this evening. SPC has continued a Marginal risk across much of NH into western Maine with a Slight risk across SW New Hampshire. Within portions of the Marginal and all of the Slight risk SPC shows 2 to 5 percent tornado probs, which seem reasonable given the low level helicity. The last couple runs of the HRRR have also started to show some linear structures forming ahead and along a cold front that will approach SW NH around 9-10 PM tonight with these linear structure showing signs of weakening as they track across southern NH through midnight. The severe threat will diminish after midnight tonight while chances for showers and thunderstorms continue overnight. On the hydrological side there also has not been much changes to forecast thinking with potential for rainfall rates to approach one inch per hour and a modest signal for some training. WPC`s excessive rainfall outlook continues to put the entire forecast area in a Marginal risk for flash flooding, which continues to seem reasonable. One hour flash flood guidance across much of the area is well over 2 inches and 3 hour flash flood guidance is generally in the range of 2.5 to 4 inches. With the exception for some training the overall flash flood threat seems low except for ponding of water in poor drainage areas. That said, will need to monitor the potential for training this evening through tonight as multiple cells that can produce 1 inch per hour rates that due track over the same area will increase the flash flood threat. Current QPF forecast has 0.75 to 1.25 inches along and south of the foothills with potential for some areas to come in with much lower amounts. In the mountains QPF ranges from 1.5 to 2.25 inches with potential for higher amounts exceeding 3 inches in the White Mountains. North of the mountains amounts range from 1.25 to 1.75 inches. The brunt of the rainfall will push east of New Hampshire shortly after midnight and push east of Maine zones around 3 am. As the surface low tracks towards Atlantic Canada Tuesday morning upslope flow will maintain chances for showers in and north of the mountains into Tuesday morning. It will be a warm and very humid night with lows in the mid 60s to low 70s with similar dew points. This will allow for areas of fog tonight as well. && .SHORT TERM /TUESDAY THROUGH TUESDAY/... Low pressure will continue to exit to the northeast Tuesday. Aloft a secondary short wave will approach from the NW acting to steepen lapse rates. Bufkit profiles show favorable mixing with momentum transfer around 25 to 30 kts at the top of the mixed layer. This will lead to gusty a day with westerly winds gusting 25 to 30 mph. It will also be a very warm day with highs in the upper 80s to low 90s south of the mountains with little reprieve along the coast as steady offshore winds will inhibit the sea breeze. Humidity will also be on the uncomfortable side with dew points starting in the upper 60s to low 70s and only dropping into the low to mid 60s during the afternoon. These dewpoints combined with strong surface heating will allow for CAPE to climb to around 1500 j/kg and close to 2000 J/kg across northern areas. The approaching short wave will have an associated cold front that will bring the threat for thunderstorms Tuesday afternoon and evening. Model soundings are quite impressive with inverted-V profiles and steep low to mid level lapse rates along with effective shear around 30 kts. Thus, the environment will be favorable for strong to severe storms with both hail and gusty winds a threat. However, the overall signal from CAMs show very little coverage if any storm due initiate. SPC has placed far northern areas and the mountains in a Marginal risk for severe storms as the terrain will likely aid in triggering convection. Have held off on enhance wording in the forecast due to the limited coverage. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Overview: Scattered showers and thunderstorms will be possible Tuesday night as a shortwave moves across the region. High pressure will then begin to build into the region on Wednesday, allowing for dry conditions and very warm temperatures. There will then be an increasing chance for scattered showers and thunderstorms on Thursday as a closed low moving over Quebec sends a warm front across the area. Mainly dry conditions will then return for Friday through the weekend, although a few mostly diurnally driven showers cannot be ruled out. Impacts: A lingering strong to severe thunderstorm will be possible on Tuesday evening, especially across northern and eastern locations. Heat indices may approach the middle 90s on both Wednesday and Thursday afternoon. Forecast Details: A negatively tilted upper level trough will be beginning to exit the area to the east on Tuesday evening, with lingering showers and scattered thunderstorms across the north and eastern locations. Forecast soundings from the latest CAMs indicate that there will likely be up to around 1000 J/KG of MLCAPE, 700-500 mb lapse rates in excess of 6C/KM, and 30 kts of 0-6km shear present during the early evening, and therefore a strong to locally severe storm cannot be ruled out through the evening hours. Given a strong LLJ, gusty to locally damaging winds would be the primary threat with any stronger storms. Severe potential and PoPs will then quickly fade by around 10 pm as the trough moves east of the area and we lose daytime instability. Heights will then begin to rise on Wednesday ahead of a ridge to our west. It will be a very warm and mostly sunny day with highs ranging from the upper 70s across the mountains to the lower and middle 90s along and south of the I-95 corridor. To make matters worse, dew points will be well into the 60s, which will make it feel a couple of degrees warmer. Clouds will then begin to increase on Wednesday night as a warm front approaches from the south ahead of a closed surface low over Quebec. The best chance for an overnight shower will be across the north and mountains where better forcing will be present but much of the area will likely remain dry through the overnight hours. It will be another uncomfortably warm and muggy night with some southern urban areas likely not falling below 70 degrees. There will be a better chance for showers and thunderstorms on Thursday as we sit in the warm sector of the low to our north. Skies will be partly to mostly cloudy, which should limit surface mixing some and hence limit highs some to the upper 80s across much of interior western ME to the lower 90s in southern NH. While it is still several days out, forecast soundings are somewhat favorable for the potential of strong to locally severe storms and this will therefore need to be watched over the coming days. Showers and thunderstorms will then end from west to east on Thursday night as a cold front clears the coast. Mainly dry conditions will then prevail for Friday through the weekend, although we will still be sitting under broad upper level troughing and this combined with daytime heating may spark a few diurnally driven showers and thunderstorms each afternoon. Shower chances then once again look to increase again early next week. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... Short Term...Periods of heavy rain with embedded TSRA, low cigs, and fog will bring IFR to LIFR conditions this evening through tonight. Southerly winds will prevail through the evening, perhaps turning gusty along the immediate coast and for southern terminals later this evening. With gusts diminishing overnight, a period of LLWS is expected at least for southern and eastern terminals... on the order of 35-45 kts out of the SSW. A cold front crosses Tuesday morning with winds turning westerly and conditions improving to VFR by mid morning. VFR prevails through Tuesday afternoon although widely scattered afternoon TSRA are possible and will bring restrictions if a TSRA crosses a TAF site. Long Term...Lingering SHRA/TSRA on Tuesday evening will result in brief pockets MVFR/IFR restrictions, especially across northern and eastern terminals. VFR conditions will then prevail on Wednesday before shower and storm chances increase again on Thursday in association with a passing front. Mainly VFR conditions are then expected on Friday and Saturday outside of any SHRA. && .MARINE... Short Term...SCA conditions are expected tonight into Tuesday morning as southerly winds gust 25 to 30 kts. Southerly winds will bring building seas greater than 5 ft that will persist until Tuesday evening outside of Casco Bay. Southerly winds shift to the southwest Tuesday morning and will drop below 25 kts while elevated seas will continue the SCA through Tuesday evening. Long Term...Winds and seas will fall below SCA criteria Tuesday night through Wednesday as high pressure builds over the waters. Southerly winds may gust up to 25 kts on Thursday ahead of an approaching warm front. Winds and seas will then begin to subside on Friday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 11 AM EDT Tuesday for ANZ153. Small Craft Advisory until 8 PM EDT Tuesday for ANZ150>152-154. && $$ UPDATE...Casey/Cornwell NEAR/SHORT TERM...Schroeter LONG TERM...Tubbs
Area Forecast Discussion
National Weather Service Jacksonville FL
905 PM EDT Mon Jul 18 2022 .UPDATE... Surface analysis shows ridge of high pressure over south FL with weak troughing over NC to central AL. Between these features, southwest to south flow prevails below 850 mb. Further aloft in the mid levels, a trough is over the FL panhandle to nrn AL. Moisture is fairly high in the area with PWATs at about 1.8 to 2.1 inches and dewpoints are in the mid 70s. Only isolated showers and thunderstorms over the region at this time. Main activity at this time is over Echols county which should slowly weaken over the next 1-2 hours while moving east at about 15 mph. Otherwise, based on agreement in the HRRR and HREF guidance, anticipate a resurgence of isolated to possibly scattered showers and potential storms moving in off the Gulf of Mexico in the moist low level convergent flow from late tonight and early Tuesday morning over inland northeast FL. The main updates were to adjust POPs for this evening based on latest radar data. .MARINE... The JAX 00z sounding, JAX vad wind profile, sfc data, and model guidance suggests an uptick in winds from the south and southwest tonight so tweaked up a bit rest of tonight. This required including an SCEC headline for the offshore waters for 15-20 kt winds. && .PREV DISCUSSION [749 PM EDT]... .Near Term.../through Tonight/... High pressure will be centered to the southeast through Tonight. A 500mb short wave is moving across the area this afternoon, helping to aid in convective development. The organized line of convection which has moved to the east was on the leading edge of this wave. Additional convection is expected behind this line, but will be more isolated to scattered in coverage. Interior SE GA did not receive as much activity this morning into early afternoon, so coverage should be greatest there through the remainder of this afternoon. Much of this activity will dissipate by midnight with the loss of day time heating. Lows will be around seasonal levels. .Short Term.../Tuesday through Friday/... Surface high pressure will be southeast of the region this period. A 500mb trough axis will be just west of the area through Tuesday night, then over area Wednesday. The combination of diurnal heating, ample moisture, and additional instability from upper trough will result in above seasonal coverage of convection. The upper trough will lift to the northeast Thursday into Friday, as high pressure at the surface builds across area from center to the east southeast. The surface ridging in the area, will limit the convective coverage somewhat later this week, with activity more isolated to scattered in coverage. Temperatures this period will trend a little above normal. .Long Term.../Friday night through Monday/... A high pressure ridge will extend across central FL from a center to the southeast Friday night into Saturday, as a stalled trough lays northeast to southwest across SE GA. The combination of convergence along the trough, ample moisture and diurnal heating will lead to above average chances for convection into Saturday. The trough breaks down later in the weekend, as the high builds more toward the east southeast. Convection on Sunday will be driven largely by diurnal heating and sea breeze interactions. Therefore, greatest chances will be over the central portion of the forecast area. The high will build further to the east on Monday as a cold front approaches from the northwest. Subsidence from the ridge will help to minimize convective chances. The east coast sea breeze should be dominant Monday, which will have best convective chances further inland. Temperatures will trend near seasonal levels this period. .AVIATION... [Through 00Z Wednesday] Showers and storms ending earlier than last night and just have VCSH for SGJ and SSI this evening. Otherwise, VFR ceilings expected to prevail tonight but some chance of flight restrictions for vsby and ceilings for GNV and VQQ tonight based on the recent rainfall and latest guidance. Due to the uncertainty, just included TEMPO MVFR for this potential after 06Z. An early start to convection is likely again on Tuesday as activity generally moves west to east, first affecting GNV and then the rest of the TAFs. Started VCSH at GNV close to sunrise, and then late morning and aftn for the rest of the TAFs. Included TEMPO TSRA for GNV where highest chance of convection are expected, but PROB30 TSRA groups for rest of the TAFs. Winds will be light southwest 5-10 kt tonight, settling down a bit overnight. Winds expected to become breezy from the southwest about 8-13 kt on Tuesday. .Marine... High pressure will be southeast of the region this week. The high will be centered more to the east over the weekend. Rip Currents: SE GA: Moderate Today, Low Tuesday NE FL: Moderate through Tuesday && .PRELIMINARY POINT TEMPS/POPS... AMG 74 92 74 92 74 / 20 50 10 50 0 SSI 78 92 78 91 78 / 20 40 20 40 10 JAX 75 93 75 94 75 / 30 40 20 50 10 SGJ 76 93 76 93 75 / 30 40 20 50 10 GNV 74 92 74 92 73 / 20 70 40 60 10 OCF 75 92 74 92 74 / 20 70 30 50 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. &&
Area Forecast Discussion
National Weather Service North Platte NE
654 PM CDT Mon Jul 18 2022 .SHORT TERM...(This evening through Tuesday night) Issued at 327 PM CDT Mon Jul 18 2022 The CAMs, ECM and the RAP continue to show isolated thunderstorms this evening. The latest model runs suggest the Cheyenne divide would be the most favored location for storm development and this is consistent with a surge of hot dry west winds moving through that area this afternoon. Moisture aloft is good with PWAT around 1.3-1.4 inches and winds aloft weak, 20-30kt at h500-300mb. The 20-30% h850- 700mb shown in the RAP and the HRRR wind gust product suggest gusty winds are likely and the RAP sounding near Ogallala would suggest more- the potential for damaging wind gusts. The RAP models shows the CAPE, less than 1000 J/KG, forming at the top of the mixed layer- 500mb. The forecast this evening is guarded with isolated dry thunderstorms and gusty winds. The deterministic models are cooler and windier Tuesday. The prospect of 100s across swrn Nebraska appears low at this point. The short term model blend plus bias correction was the basis for highs in the upper 80s northwest to upper 90s southwest. This forecast is slightly cooler than the guidance blend and the NBM 50th percentile. .LONG TERM...(Wednesday through Monday) Issued at 327 PM CDT Mon Jul 18 2022 There is not much change in the extended forecast today. An upper level ridge of high pressure centered over NM will drift very slowly west and be located over AZ Thursday. The ridge will then build north and east through KS next weekend. The models suggest another major heat wave could develop across Nebraska Saturday, followed by a back door cold front Sunday. The models suggest h700mb temperatures peak around 17C Saturday, slightly cooler than what was predicted today. The GFS, which has shown the best skill predicting heat waves, indicates highs in the 90s and low 100s Thursday and Friday, then cooler Saturday. The forecast leans toward the slower ECM which maintains the heat through Saturday. Rain chances are just isolated through Friday. Chances POPs are in place Saturday night. It is important to note WPC suggests less than 1/10th on inch of rainfall across wrn and ncntl Nebraska. This is consistent with the GFS and ECM which show just isolated rain totals across the region. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 651 PM CDT Mon Jul 18 2022 VFR conditions are expected through the forecast period. Isolated convection approaching OGA is expected to dissipate prior to arriving into the LBF airspace. Strong southerly winds are likely to continue overnight with gradual veering to the northwest behind an approaching frontal boundary by Tuesday morning. Cannot rule out some LLWS at LBF though the greatest potential for this should remain confined to VTN. Gusty afternoon winds are likely Tuesday with peak speeds nearing 25 to 30 knots. && .FIRE WEATHER... Issued at 327 PM CDT Mon Jul 18 2022 Little or no rainfall is expected across western and north central Nebraska during the next 7 days. Critical or near critical fire weather conditions are underway this afternoon across parts of western Nebraska. There is a chance for isolated dry thunderstorms across western Nebraska this evening. Gusty winds will likely accompany the thunderstorms. A strong cold front will move through the region tonight. Very dry air and strong northwest winds Tuesday will lead to critical fire weather conditions across the Sandhills and parts of the Panhandle. Elevated fire weather conditions are likely across western Nebraska Wednesday through Saturday. The concern is humidity below 20 percent. Wind speeds during this time are generally expected to remain light at speeds of less than 15 mph. && .LBF WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 8 PM MDT this evening for NEZ210. Heat Advisory until 9 PM CDT /8 PM MDT/ this evening for NEZ004>010-022>027-035>038-056>059-069>071-094. Red Flag Warning from 1 PM to 8 PM CDT Tuesday for NEZ206. Red Flag Warning until 7 PM MDT Tuesday for NEZ204. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...NMJ FIRE WEATHER...CDC
National Weather Service Morristown TN
926 PM EDT Mon Jul 18 2022 .UPDATE... EVENING UPDATE. && .DISCUSSION... A few spotty showers remain this evening across northeast TN and southwest VA. Last few runs of the HRRR have shown additional isolated showers, and perhaps a storm, developing to our west across middle TN and then moving into the area overnight. This additional development is in response to the upper trough axis swinging into and across the area. Areas that saw rain today will likely see patchy fog overnight but there is uncertainty on how widespread it will be due to current cloud cover. Will send new zones to get rid of afternoon wording and will update HWO to remove strong storm wording. SR && .AVIATION... 00Z TAF DISCUSSION. Showers and storms have mostly exited our area. A mix of VFR and MVFR conditions can be expected over the next few hours as clouds thin from the earlier showers. Then, mostly VFR conditions are expected until late tonight/early tomorrow morning when MVFR and near IFR conditions are expected due to low CIGs. It`s hard to tell how widespread fog will be due to the remaining cloud cover and light winds but do expect some areas of patchy fog with MVFR visibilities. Also, a few isolated showers and storms are possible overnight at CHA. VFR conditions will return at all sites by late morning/early afternoon. Addition isolated showers and storms are expected tomorrow afternoon through evening. SR && .PREV DISCUSSION... /ISSUED 747 PM EDT Mon Jul 18 2022/ SHORT TERM (Tonight and Tuesday)... Key Messages: 1. Numerous showers and thunderstorms will continue through the evening with more isolated to scattered coverage focused on southern areas on Tuesday. 2. Isolated damaging wind gusts and localized flooding remain of concern through the evening hours. 3. Temperatures will be fairly close to normal with milder conditions expected on Tuesday. This Evening/Tonight Currently early this afternoon, a mid/upper shortwave is centered near the Ohio River Valley with a weak surface front. A downstream jet is also noted from Ohio into the Great Lakes. These features are the focus in the near-term period with upper divergence and strong southerly flow at and below 850mb supporting continued convection that is already ongoing in western areas. These features continue to advance towards the region with the consensus remaining that the frontal boundary will wash out to our west. Nevertheless, numerous convection will continue through much of the evening hours with a gradual decrease overnight. Deep-layer shear of 20+ kts is notable for this time of year, but thermodynamics in the mid-levels do seem to be an inhibiting factor. Overall instability is fairly marginal at generally near 1,000 J/kg. With the somewhat organized/linear nature of some cells, locally damaging wind gusts remain of concern. Additionally, with PWATs of near 1.7" and fairly uni-directional flow throughout much of the layer, there remains a concern for locally heavy rainfall largely via training convection. Luckily, many areas haven`t been too wet in recent days, but there are certainly some localized places with lower flash flood guidance. Given all of these factors, similar messaging will be kept to be focused on the early portions of the overnight hours. Tuesday During the day on Tuesday, the shortwave trough will be nearly centered with our region, and better moisture will be focused closer to Georgia and southwest North Carolina. Overall, dynamics/forcing for convection will largely be to our south and east. However, lapse rates may end up being slightly better than today due to the height falls with a focus more on southern areas where these values and moisture look to be better. With the limited upper support and comparable instability in these areas, mainly isolated to scattered coverage is expected. With the troughing remaining in place, temperatures will still be warm but fairly mild for this time of year. BW LONG TERM (Tuesday Night through Monday)... Key Messages: 1. Another hot spell in store for the coming weekend. 2. "Cold" front moves through Wed night into Thu for increased coverage of showers and thunderstorms. Otherwise typical summertime trends with regards to rain chances through Friday. Discussion: The big story for the long term period will be the strong ridge building across the southern US Friday into the weekend, sending high temperatures back into the upper 90s for most locations on Saturday and Sunday. Before we get to the weekend however, shortwave troughing will be lingering over the southern Appalachians Tuesday night into Wednesday. This will be kicked off to the east coast on Wednesday by a stronger upper low that will be moving into the Great Lakes region on Wed. This feature will push a cold front into the forecast area Wed night into Thu. Locally, the presence of the upper trough, as well as isentropic ascent ahead of that cold front, will keep some chances for showers and even some thunderstorms in the forecast Tue night through Wed. Limited it to chance levels, which may be generous, as brief upper ridging will lie between the exiting upper trough and the low moving into the Great Lakes. This should work to suppress convection a tad, but think there will be some convection present on Wed. Better rain chances exist on Thu with the passage of the front, with widespread convection likely. As the front pushes further into the southeast US the low will be lifting out into New England. There was some concern it may stall just to our south, allowing for more rain chances on Friday. But this seems to be the outlier scenario now and have a dry forecast in on Friday. As the upper low lifts into New England, a western ridge centered over the Four Corners region will begin to expand in earnest across the I-40 corridor from Texas through Tennessee. By Sat morning most guidance has a strong, albeit relatively flat, upper ridge centered over the Tennessee valley. The eastward expansion of the ridge on Friday will push highs back into the low to mid 90s throughout much of the lower elevations of east TN, but expect areas in the vicinity of the I-40 corridor and points south to see upper 90s for both Saturday and Sunday as the ridge peaks overhead. Have dry conditions on Saturday with the ridge overhead, but Sunday through Monday present an opportunity for some MCS activity to make it in from the NNW. Flat ridging, even with H5 heights of 594 dam or more, will leave a chance for convection to fire along the H85 thermal gradient from Nebraska eastward through the Ohio river valley. The GFS is more bullish on rain chances than the ECMWF but hard to ignore that even the stronger ridge on the ECMWF doesn`t suppress convection completely. CD && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 71 87 72 93 75 / 50 40 30 30 50 Knoxville McGhee Tyson Airport, TN 70 87 71 91 74 / 40 20 20 30 50 Oak Ridge, TN 69 87 71 91 73 / 40 20 20 30 50 Tri Cities Airport, TN 67 83 67 88 70 / 60 30 10 30 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service San Francisco Bay Area
551 PM PDT Mon Jul 18 2022 .SYNOPSIS...Monsoonal moisture is moving northward from Southern California into Central California. With mid-level moisture and instability present, we have a slight chance of thunderstorms for southeastern Monterey County and the southern portion of San Benito County. In addition, the monsoonal moisture will bring an increase in mid level clouds today and Tuesday. Very slight cooling trend this week with continued warm to hot conditions across the interior. Potential for sneaker waves and dangerous rip currents this afternoon through Wednesday evening. && of 03:15 PM PDT Monday...As discussed in the morning update, monsoonal moisture moving into Central CA has introduced some thunderstorm activity in our CWA. Thus far, we`ve had one thunderstorm in SE Monterey County (about 30 miles SE of King City) that did produce a couple of lightning strikes. This line of convection continues to move northward and it looks like another cell is developing in southern San Benito County. On satellite, there`s some rotation hugging the San Luis Obispo coastline and that is feeding the convection into our region. Currently, radar is showing a diminishing trend with the current convective showers, but we have extra eyes on shift right now in case additional cells pop up. Mid level moisture and instability looks to linger in those areas of SE Monterey and S San Benito counties through about 8 pm tonight. The HRRR shows that there could be a few intermittent cells that pop up between now and then, but they should be brief. The hi-res NAM is indicating that the convective line in SE Monterey County moving into southern San Benito County will persist through around 5 pm. Have kept the mention of thunderstorms through 8 pm tonight to cover both models. So could we get thunderstorms on Tuesday afternoon as well? Not very likely. Hi-res models along with the regular NAM show that the instability and moisture will be better aligned in the Central Valley and eastward into Nevada. Besides thunderstorms, the synoptic pattern over our CWA won`t be changing a whole lot this week. Our region will still be influenced by the high pressure over the desert SW while a cut off low spins out over the Eastern Pacific Ocean. That low is forecast to nudge closer to the coastline towards the end of the week which will allow for a slight cooling trend. In general, expect warm to hot conditions across the interior (peaking in the mid 90s to low 100s) while areas closer to the coast are more normal from mid 60s right along the coast then ranging up to 70s into the 80s around the SF and Monterey Bay shorelines. Should only see slight fluctuations in those temperatures through the week, but no significant swings on the thermometer...just very gradual cooling. To learn more about the Beach Hazards expected through midweek, please refer to the Beaches section below. && of 5:30 PM PDT Monday...For the 00Z TAFs. VFR. Upper level clouds moving up from Southern California have reached the Monterey Bay. Associated convection has eased significantly with no lightning detected for the last couple of hours. Moderate west to northwesterly winds will persist through this evening becoming light and variable overnight. The exception remains, KAPC and KSTS that will remain light out of the south to southwest. Stratus will return to the coast and high confidence of IFR cigs to KSNS, KMRY and medium confidence of IFR cigs at KOAK. Clearing will be around 16-17z Tuesday morning. Vicinity of KSFO...VFR. Moderate and locally gusty northwesterly winds around 20 kt with gusts to 25 kt will persist through this evening. Winds will diminish overnight becoming light and variable with the exception of KSFO that will remain steady around 8-10 kt at KSFO through the morning. Marine layer remains shallow, so low chance of stratus intrusion overnight for KSFO and higher chances for KOAK with borderline MVFR/IFR cigs. If they do form over KOAK, clearing would be around 16z. KSFO Bridge Approach...Similar to SFO. Monterey Bay...VFR with moderate northwest winds through this evening. Upper level clouds will persist through this evening. However convection has diminished from earlier this afternoon. IFR/LIFR cigs will return late tonight into early morning and will clear by 17z. && .BEACHES...Have issued a Beach Hazards Statement for now through Wednesday evening. A long period southerly swell arrives this afternoon. This long period swell will result in increased risk of sneaker waves and strong rip currents for south facing beaches. Strong currents also possible for west facing beaches. Individuals going to the coast should use caution and are advised to remain off of exposed coastal rocks and jetties. This situation will also bring dangerous swimming and surfing conditions along with the potential of some beach erosion. && of 05:20 PM PDT Monday...Winds in the northern outer waters continue to generate steep waves around 8 to 10 feet due to strong northwest winds. Winds and wind-driven seas start to diminish but will still be locally breezy near coastal jets and the outer waters. A long period southerly swell at 18 to 20 seconds has also arrived to our waters and will slowly diminish throughout the week. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tday...SCA...SF Bay until 9 PM SCA...Pt Arena to Pt Reyes 0-10 nm until 9 PM SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM SCA...Mry Bay from 9 AM SCA...Pigeon Pt to Pt Pinos 0-10 nm from 9 AM SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 PM && $$ PUBLIC FORECAST: Bingaman AVIATION: CW MARINE: McCorkle Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Shreveport LA
859 PM CDT Mon Jul 18 2022 ...New UPDATE... .UPDATE... Issued at 805 PM CDT Mon Jul 18 2022 The region is in the midst of a heat wave that looks to continue over the next week. Shreveport hit a high of 102F earlier which marks the 15th time this summer reaching triple digits. This evening, at the mid-levels, a 500mb ridge is centered over the Four Corners region and extends eastward into the southern Plains. A layer of very dry air from 500mb into the upper levels is in place across the southern Plains and Arkansas and is sliding southward into the ArkLaTex. At the surface, high pressure is centered southeast of the area over the Gulf of Mexico with a frontal boundary extending from North Texas northeastward into central Arkansas. Skies are clear or mostly clear this evening with a few high level clouds passing. Overnight, the deep layer of dry air in the mid to upper layer of the atmosphere will continue to advect southward across the area. This will contribute to clear skies overnight. While recent hourly runs of the HRRR have shown developing convection in central Arkansas making a close approach to El Dorado and Monroe as it moves over the ArkLaMiss through midnight, that is considered to be an outlier based on recent trends and given the drier air advecting in aloft. Thus, no showers or thunderstorms are expected through this period. Winds will continue to be south-southwesterly at 5-10 mph overnight. One additional consideration this evening is fire weather. Coordination with the Texas A&M Forest Service (TFS) earlier today has led to adjusted Red Flag Warning criteria for our Texas counties. The new adjusted criteria is RH values <25%, winds >15 mph, temps >100F, and critical or extreme fuel dryness. With locations in NE Texas in a critical fuel dryness level it looks like they will hit all of the criteria tomorrow afternoon except for RH values which will be in the 25-30% range. Given RH values are marginally close to hitting Red Flag Warning (RFW) criteria, we will need to monitor this closely in upcoming forecasts with an RFW possible. Thanks to our western neighbor WFO Fort Worth-Dallas for the coordination on this earlier this evening. For temperatures, lows tonight are closest to the National Blend of Models, ranging from the mid to upper 70s across much of the area. Population centers that are urban heat islands will struggle to drop below 80 tonight. Northeast Texas, portions of SW Arkansas, and McCurtain County have an Excessive Heat Warning (heat indices tomorrow afternoon of 110F+) in effect with all other locations under a Heat Advisory (heat indices tomorrow afternoon of 105-110F) at this time. /04-Woodrum/ && .SHORT TERM... (This evening through Tuesday Night) Issued at 235 PM CDT Mon Jul 18 2022 Upper-level ridge centered across the Four Corners region to continue to intensify with the ridge axis to extend eastward into Texas and across the ArkLaTex into Mississippi by Tuesday night. Subsidence associated with the upper-ridge will maintain the ongoing hot pattern. Afternoon high temperatures on Tuesday are forecast to range from around 100 degrees across north Louisiana to around 107 degrees across the I-30 corridor. The combination of heat and humidity will drive heat index values into advisory criteria across much of the region with portions of southeast Oklahoma and adjacent areas of northeast Texas and southwest Arkansas forecast to climb into excessive heat warning criteria as heat index values surpass 110 degrees. Aside from the heat headlines, the short term will be characterized by mainly dry conditions with south winds averaging around 10 mph on Tuesday with slightly lesser wind speeds overnight. Overnight low temperatures to average in the upper 70s to around 80 degrees both nights. /05/ && .LONG TERM... (Wednesday through next Sunday) Issued at 235 PM CDT Mon Jul 18 2022 Wednesday will see the apex of this first phase of the blazing heat wave, with the latest model guidance projecting nearly all area sites to be blistering above 100 degrees during the afternoon hours. The orientation of the upper level ridge will continue to see the warmest sites in southeast Oklahoma and northeast Texas, with current estimates aiming at scorching highs of 106. The Excessive Heat Warning in effect for Tuesday will most likely need to be continued into Wednesday, if not also expanded. Thursday will see a very slight relief as the aforementioned ridge backs off just enough to the west to allow for a return of PoPs consistent with a slight chance of showers and thunderstorms across our easternmost zones of north central Louisiana during the afternoon. Highs throughout these eastern zones may "only" reach the mid to upper 90s, with sites westward likely just hitting the century mark again. Calling this a break from the sweltering warmth would technically be accurate, for while it won`t feel much cooler, it will be the relatively cool day in the forecast period, as Friday will see the ridge build back in into the weekend, with the ovenlike heat returning in force, at least matching Wednesday`s highs with increasingly coalescent temperatures through the weekend and into early next week. /26/ && .AVIATION... (00Z TAFS) Issued at 638 PM CDT Mon Jul 18 2022 VFR conditions will prevail across the terminals throughout the TAF period as high pressure dominates the weather pattern. Winds will be south-southwesterly at 5-10kts overnight increasing to 10-15kts by 15z Tuesday. /04-Woodrum/ && .PRELIMINARY POINT TEMPS/POPS... SHV 82 103 80 104 / 0 0 0 0 MLU 78 99 79 101 / 10 10 0 0 DEQ 78 105 79 105 / 10 0 0 0 TXK 82 105 82 105 / 10 0 0 0 ELD 77 99 78 99 / 10 10 0 0 TYR 81 105 79 105 / 0 0 0 0 GGG 80 104 79 104 / 0 0 0 0 LFK 77 101 77 102 / 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...Heat Advisory until 7 PM CDT Tuesday for ARZ072-073. Excessive Heat Warning until 7 PM CDT Tuesday for ARZ050-051- 059>061-070-071. LA...Heat Advisory until 7 PM CDT Tuesday for LAZ001>006-010>014- 017>022. OK...Excessive Heat Warning until 7 PM CDT Tuesday for OKZ077. TX...Heat Advisory until 7 PM CDT Tuesday for TXZ126-136>138-149>153- 165>167. Excessive Heat Warning until 7 PM CDT Tuesday for TXZ096-097- 108>112-124-125. && $$ SHORT TERM...05 LONG TERM....26 AVIATION...04