Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/26/23

Area Forecast Discussion
National Weather Service Dodge City KS
428 PM CST Sat Feb 25 2023 ...Updated aviation section... .SHORT TERM...(This afternoon through Sunday Night) Issued at 1259 PM CST Sat Feb 25 2023 Water vapor satellite imagery and RAP upper air analysis at 18Z indicates zonal flow encompasses nearly the entire CONUS, while a potent cut-off low is moving inland over south-central CA. This lonely feature will move slowly east-southeast through early Sunday and gradually begin to open into a significant shortwave impulse. At the surface, weak high pressure over the Ozarks will slowly drift into Dixie Alley, leaving a somewhat nebulous pressure field across southwest KS with south winds generally in the 10-15 mph range. The only exception will be over far southwest KS (Elkhart and adjacent areas) where winds will be more southwesterly. Here, the stronger downsloping component will support much warmer afternoon temperatures, with highs in the mid 60s to near 70 while the rest of our CWA only reach the low to mid 50s. Tonight, high level cloud cover and non-zero winds will limit radiational cooling, with lows ranging from the low to upper 30s. Daytime Sunday, the aforementioned powerful upper level feature will pick up speed, and eject into the central plains Sunday afternoon/evening while opening fully and taking on a negative tilt. Rapid lee cyclogenesis across eastern CO will result in southerly winds increasing throughout our area, reaching the 20-30 mph range with gusts approaching 40-45 mph. Likewise, temperatures will soar into the upper 60s to low 70s for most locations Sunday afternoon. As the upper level impulse and associated surface trough move east, a N-S oriented dryline will sharpen somewhere between US-83 and US-283 southward into the OK and TX panhandles. Substantial convergence along this boundary aided by DPVA ahead of the upper level wave will result in thunderstorm development roughly in the 22-23Z time frame. Meager moisture ahead of the dryline will inhibit more robust destabilization, however short range guidance agrees at least 500 J/Kg of MLCAPE will develop amidst very strong bulk shear (50-70 kts). Given the strength of the wave, and a shear vector/boundary intersection angle around 45 degrees, fairly quick upscale growth into a fast-moving squall line appears the most likely scenario. Associated severe potential hinges somewhat on the amount of CAPE, but severe wind gusts (60+ mph) and perhaps severe hail (1+" in diameter, early in the convective evolution) are reasonably possible. This forecast thinking is in line with the latest SPC Convective Outlook, which forecasts a 15% chance of these severe hazards along and east of a Liberal-Garden City-Wakeeney line. Thunderstorm activity will hastily move east through Sunday evening, and be clear of southwest KS by midnight. Behind the squall line, significant gradient wind is expected as the surface low continues to deepen over northeast KS. The lack of boundary layer mixing will save southwest KS from the worst of it, but northwest winds sustained in the 25-35 mph range with gusts in the 45-50 mph range will be common. At the moment, high wind headlines are not anticipated, however they cannot be ruled out given the presence of additional pressure perturbations within the squall line`s cold outflow. .LONG TERM...(Monday through Saturday) Issued at 216 PM CST Sat Feb 25 2023 Strong northwest winds will be ongoing at the beginning of the long term period on the back side of the surface low, especially across locations closer to central KS, and will not begin to diminish substantially until Monday afternoon when the surface low has moved all the way into the Midwest. These winds will also do a poor job of cold advection, and afternoon highs will still reach the upper 50s to mid 60s. 12Z ensemble suite suggests upper level flow will trend west-southwesterly on Tuesday as the next upper level trough begins to build southeast from the Pacific Northwest. Lee cyclogenesis across eastern WY/CO and adjacent areas will result in another day of downsloping west-southwest surface winds, fostering an uptick in temperatures with highs in the low to upper 60s before a cold front passes through the area early Wednesday and sends temperatures back into the 50s Wednesday afternoon. Wednesday night into Thursday morning, EPS/GEFS ensembles agree the primary vorticity max within the upper level trough will dig into the Desert Southwest, drawing another cold front equatorward and giving southwest KS another shot of cold air. Roughly 2/3rds of the GEFS and EPS members suggest at least some precipitation is possible with this frontal passage, however confidence is low at the moment. Either way, temperatures will be well below average Thursday afternoon, with highs in the 40s. Friday through the end of the period, EPS/GEFS ensemble means diverge regarding the upper level pattern, rendering predictability low. For what it`s worth, the NBM suggests temperatures will rebound into the 50s both days, but forecast skill at that range is near zero. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 426 PM CST Sat Feb 25 2023 VFR conditions will prevail through tomorrow afternoon with high level cloudiness. Winds will be from the southeast this evening, shifting to more of a southerly direction overnight. Winds then shift to the south southwest by tomorrow afternoon and gust to around 30 knots. && .PRELIMINARY POINT TEMPS/POPS... DDC 36 69 37 62 / 10 60 60 0 GCK 35 71 34 60 / 0 30 30 0 EHA 39 71 32 62 / 0 10 10 0 LBL 37 73 33 63 / 0 40 20 0 HYS 30 68 39 59 / 0 60 80 0 P28 33 65 43 65 / 10 70 70 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Springer LONG TERM...Springer AVIATION...Hovorka_42
National Weather Service Sioux Falls SD
602 PM CST Sat Feb 25 2023 .SHORT TERM...(This Evening through Sunday Night) Issued at 336 PM CST Sat Feb 25 2023 Key Messages: 1. Fog is once again on the table for tonight across most of the area. 2. Rain remains on track for Sunday evening and night. The heaviest rainfall continues to look to fall over northwest Iowa. 3. Next chance for light precipitation comes on Tuesday evening along with below normal temperatures coming for the middle of next week. --------------------------------------------------------------------- Clear skies dominate the area this afternoon. Temperatures have warmed to the 20s and 30s. Winds continue to wane as as the low level jet weakens. With a weakening surface pressure gradient (SPG) and a strengthening nocturnal inversion this evening, winds will weaken to nearly calm. This will set the stage for another round of fog this evening and night. Latest HREF probabilities show a 60-80% chance for visibilities to drop below a mile across the majority of the forecast area. As such, have continued with fog chances in this forecast package. A bit of uncertainty exits in when the fog will burn off tomorrow morning. Warm air advection (WAA) will be strengthening overhead, making for a stronger inversion. This may keep fog from burning off as quickly as current thinking suggests. Will continue to monitor trends and make future updates. Low temperatures will fall single digits to along and north of I-90 to teens to low 20s south of the interstate. The main shortwave trough ejects into the Plains states from the Rockies on Sunday. WAA will further intensify ahead of the wave. This looks to push 925 mb temperatures to near zero degrees up to 7 degrees C. The NAEFS ensemble supports this as it shows 850mb temperatures warming to the 99th percentile of climatology. Mixing these warmer temperatures to the surface will result in highs in the 30s across most of the area. Highs up to the 40s are most likely across parts of northwest Iowa. Locations along highway-20 even have a shot to see highs peak around 50 degrees F if remaining snowpack and south/southeasterly winds don`t mitigate temperatures too much. Cloud cover will be increasing throughout the day as the main forcing for ascent associated with the wave arrives. BUFKIT soundings show dry mid levels Sunday evening as rain begins to work its way in to parts of northwest Iowa. This mid level dry air should diminish rather quickly as the dendritic growth zone (DGZ) saturates and precipitation wet bulbs quickly to the surface. The soundings also show minor instability during the onset of rain, indicating the possibility of a stray rumble of thunder. This instability will also quickly diminish as thermal profiles saturate to moist neutral as the previously mentioned mid levels saturate. In terms of rainfall amounts, latest 12z data has remained consistent in the highest amounts residing over parts of northwest Iowa. Amounts between a half an inch and and inch are still expected. Like the previous discussion mentioned, current guidance continues to keep the highest totals of an inch or greater southeast of the forecast area. Still seeing some variance in the specific track of the system in hi-res guidance as well as ensembles slightly vary in the storms track. Will continue to monitor trends and tweak QPF as new data comes in. Although temperatures will remain largely above freezing, easterly winds looks to back to out of the north as the system begins to exit the region Monday morning. With northerly flow in place, colder air will be advected into the forecast area. Hi-res guidance is starting to catch onto this as some members show freezing drizzle occurring over parts of southwest Minnesota. Given temperatures hovering around freezing at the surface along with temperatures above freezing aloft, do not think that any freezing drizzle that does fall will accumulate efficiently. Confidence is only moderate (~50%) in this potential but still high enough to continue in this forecast package. Should this occur, only a light glaze of ice would accumulate. Lows will fall to the 30s overnight. .LONG TERM...(Monday through Saturday) Issued at 336 PM CST Sat Feb 25 2023 Light precipitation will be exiting the region Monday morning as the previously mentioned system continues to pull away to the east. With the forecast area on the backside of the low, a stronger SPG will introduce gusty northwest winds within the cold advection regime. Despite the cold advection, highs look to remain near seasonable, predominately in the 30s. Gusty winds will finally wane as the SPG relaxes by Monday evening. Low temperatures look to fall to the teens and 20s overnight. The next chance for light precipitation comes Tuesday evening as a shortwave trough pushes off the Rockies. Medium range guidance struggles with the timing of this wave as the Canadian and Euro are in decent agreement but the GFS is faster with the wave. Ensembles are also in decent agreement in this wave producing precipitation Tuesday evening into Wednesday morning as the GFS, Euro, and Canadian ensembles show a 30-60% chance for receiving a tenth of an inch of precipitation or more. As of now, the highest probabilities are along and north of the highway-14. A much colder airmass looks to be in store for Wednesday in the wake of the previously mentioned wave. A strong surface high will be moving into the Northern Plains, bringing below average temperatures with it. Although highs look to hover near seasonable, lows will fall to the single digits and teens. This cold air looks to continue into Thursday as the previously mentioned surface high will be sliding off to the east. Highs in the teens and 20s are on the table with lows falling to the single digits and teens. This is supported by all the ensembles as they all show temperatures on the order of 10 to 20 degrees below average. A return to seasonable conditions looks to return for the end of next week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday Evening) Issued at 546 PM CST Sat Feb 25 2023 IFR-LIFR conditions in fog and/or stratus likely to be the biggest aviation impact this TAF period. RAP and other hi-res guidance, including HREF probabilities, continue to focus highest chances for low visibility at/around KFSD, so did introduce a period of 1/2SM FZFG 09Z-15Z, with potential for LIFR ceilings lingering for a couple hours beyond 15Z as surface winds begin to increase and lift the fog layer before dissipation. Lesser chances of seeing this impact KHON/KSUX, though KHON could see MVFR-IFR visibility at times. Light/variable winds which will aid in fog development will settle around to southeast late tonight/Sunday, with occasional gusts to around 20kt possible in the afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ SHORT TERM...Meyers LONG TERM...Meyers AVIATION...JH
Area Forecast Discussion
National Weather Service Grand Rapids MI
955 PM EST Sat Feb 25 2023 LATEST UPDATE... Update .UPDATE... Issued at 945 PM EST Sat Feb 25 2023 The only change to the forecast was to feature slightly colder overnight lows for tonight. The clearing skies and weakening winds have allowed for some better radiational cooling. Thus we lowered the low temperatures a few degrees...mainly southwest of Grand Rapids. We will have to monitor the freezing rain area Monday morning. The latest NAMNST, RAP and HRRR models are suggesting the Muskegon to Grand Rapids to Lansing corridor may end up with at least a few hours of freezing rain. && .DISCUSSION...(This evening through next Saturday) Issued at 141 PM EST Sat Feb 25 2023 - Freezing rain threat for Monday - Tranquil weather tonight and Sunday is followed by the focus of this forecast...the freezing rain potential for roughly the northern half of the forecast area on Monday. An occluding low combines with a retreating cold high to set up a period of overrunning warm air and surface cold advection on easterly winds. This will result in freezing rain and we expect some icing on trees and untreated roads Monday morning along and north of I-96. Confidence on location of the axis of heaviest icing potential is low at this time as there are still some differences between the colder ECMWF and warmer GFS. The ECMWF has less of a push of warm air as the primary surface low weakens more quickly and secondary redevelopment occurs to the east. The GFS has trended a bit in this direction today, so there are signs that the two are converging. The forecast from yesterday is largely carried over today with one to two tenths of an inch of icing north of I-96 with the axis of heavier icing from Big Rapids to Mount Pleasant. Upper limits from the the ECMWF would have over quarter an inch of ice in that area as well as some icing as far south as I-94 in the Jackson area. Skin temperatures will be marginal across central sections but cold enough across the northern forecast area to support ice accumulation on pavement. South of I-96 we expect mostly rain with close to an inch of QPF. This will cause some rises on local rivers and streams but at this point we do not expect river flooding. A weak low pushes an area of f-gen across Lower Michigan on Wednesday with some rain or snow, but marginal surface temperatures should mean travel impacts will be minimal. Colder weather follows for the end of the week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 629 PM EST Sat Feb 25 2023 The MVFR cloud deck will shift east of the TAF sites over the next couple of hours as some drier air works its way in from the west. Satellite trends show this decrease cloud cover near KBEH and KBIV. The moisture profiles through 00z Mon look dry. This will allow for VFR weather to prevail through then. The pressure gradient weakens during the day on the gust potential looks low especially in the afternoon. && .MARINE... Issued at 141 PM EST Sat Feb 25 2023 Winds and waves will increase overnight with conditions hazardous to small craft persisting into Sunday afternoon. After a brief lull we could see east gales on Monday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Small Craft Advisory until 11 AM EST Sunday for LMZ844>849. && $$ UPDATE...MJS DISCUSSION...Ostuno AVIATION...MJS MARINE...Ostuno
Area Forecast Discussion
National Weather Service Wichita KS
541 PM CST Sat Feb 25 2023 .SHORT TERM...(This evening through Monday night) Issued at 232 PM CST Sat Feb 25 2023 Bottom line up front: A warming trend begins tonight into Sun and then a chance of strong to severe storms with damaging winds for Sun evening/night. A return of SW surface winds and some light downslope flow will lead to a gradual warming trend beginning early this evening. Thick cirrus/stratus cloud cover over SE KS may lead to a slower retreat of the shallow cold across eastern KS. Still expecting the coldest temperatures in the early evening hours, with steady or slowly rising temperatures late tonight into early on Sun. Latest RAP is showing some low level moisture transport increasing with this warm advection late this evening, which may lead to increased isentropic lift for areas east of the KS Turnpike, for a shower chance late tonight or by early Sun morning. Think the short term models may be a bit fast with the low level moisture return, given that 50 degree dewpoints are still south of KDFW, so will make some adjustments to pops early Sun with a little slower arrival. This rapid warm up is associated with warm advection expected ahead of a vigorous shortwave, currently located over srn CA. This shortwave will race east across the southern Rockies into the Plains by Sun night. The GFS and ECMWF are similar in this shortwave taking on a negative tilt as it moves into KS, with cyclogenesis leading to a low pressure area developing over NW KS with some sort of dryline extending south across western KS from the low into OK and TX for Sun afternoon. The tight gradient ahead of this system, will require a wind advisory for portions of southern and southeast KS for Sun afternoon into early Sun evening, until the convection arrives. Models have been coming in a little slower with this system, which would suggest initial storm development will be west and southwest of our forecast area for Sun afternoon, with most of the area staying dry for most of the daylight hours, after the early morning shower chance. A weak elevated mixed layer, will keep the storms isolated initially over TX/OK, But as the cap weakens, expect widespread convection to rapidly develop into a squall line, as flow becomes more unidirectional, as the line eventually races east into the area for Sun evening. Some question on moisture quality and moisture transport this far north as well, with GFS showing MLCAPES only around 250-500 J/KG in southern KS. But impressive bulk shear will be associated with this system, with low level directional shear showing some turning with height, for early Sun evening before the directional shear becomes more unidirectional into late Sun evening. Starting to have some doubts on whether there will be any discrete storms with this system, even further south in OK. If (a big IF) a discrete storm can develop, it will probably be in northern OK, and areas SW of the forecast area. So thinking most of our convection will be a broken line of storms or a robust squall line, with some embedded strong to severe storms. Think the main strong/severe threat will be dime to quarter size hail and wind gusts of 55 to 70 mph, with greatest wind threat over southern KS. Given the 0-3km shear, could see a brief tornado or two develop along the leading edge of the Quasi Linear Convective System (QLCS), as it races east across the forecast area. The greatest threat of a QLCS tornado will be across southern KS, where some low level directional shear will be available. Current SPC day 2 looks reasonable with a slight risk for much of the area, and now an enhanced risk for extreme southern KS, mainly for the damaging wind threat. Once the convection becomes more widespread in the evening hours, higher than normal precipitable water values suggest a quick shot of much needed heavy rainfall for a good portion of the area as the system races east-northeast Sun night. A strong cold front on the backside of the system will sweep most of the convection to the east of the area late Sun night or early on Mon. Not expecting much a cool down behind the front, as downslope flow leads to another above normal temperature day on Mon. Ketcham .LONG TERM...(Tuesday through Saturday) Issued at 232 PM CST Sat Feb 25 2023 The start of the week looks dry, with slightly above normal temperatures. Another cold front looks to "backdoor" into the area either Wed night or early on Thu. This will push temperatures back below normal for the end of the week. Another quick hitting shortwave moves across the area for Thu and Thu night. As this system moves over the area, there is a slight chance of a mix of light rain/snow moving across the area. Lots of uncertainty with this system, as moisture is limited, and forecast trends of the medium range models is drier. If any precipitation occurs, think impacts will be minimal. Ketcham && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 541 PM CST Sat Feb 25 2023 MVFR stratus will prevail across most of south central and southeast Kansas thru the forecast valid period with a period of IFR possible. Stronger southerly winds will develop on Sunday afternoon in advance of a strong upper low/trof moving into the central/southern Rockies. While widely scattered very light rain is possible ahead of this trof, the more widespread showers and storms (some of which may be severe) will not move into central and southeast Kansas until late Sunday evening. KED && .FIRE WEATHER... Issued at 232 PM CST Sat Feb 25 2023 A tight pressure gradient on Sunday will lead to gusty south winds and a very high grassland fire danger across southeast Kansas. Questions remain on the extent of rainfall over Southeast Kansas early on Sunday which could create lower conditions should wetting rain begin earlier than expected. The grassland fire danger for Monday and Tuesday remain in question and will be highly dependent on the amount and extent of rainfall Sunday night. Most areas are expected to received significant rainfall which will keep fire danger in check. That said, winds will remain brisk and could dry out fuels enough to bring back very high conditions Monday afternoon and Tuesday. This will especially be true in areas where rainfall was limited. Ketcham && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 35 62 45 64 / 10 50 90 0 Hutchinson 33 62 43 62 / 10 50 90 0 Newton 33 60 44 62 / 10 40 90 0 ElDorado 36 60 46 62 / 10 40 100 0 Winfield-KWLD 37 61 46 65 / 20 50 90 0 Russell 28 68 40 61 / 10 40 80 0 Great Bend 29 65 40 62 / 10 40 70 0 Salina 30 63 43 62 / 10 40 90 0 McPherson 31 62 43 62 / 10 40 90 0 Coffeyville 40 60 48 67 / 40 50 100 0 Chanute 38 59 48 64 / 30 40 100 0 Iola 36 58 47 63 / 30 40 100 0 Parsons-KPPF 39 59 48 65 / 40 40 100 0 && .ICT WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 4 PM to 9 PM CST Sunday for KSZ071-072- 093>096-098>100. && $$ SHORT TERM...Ketcham LONG TERM...Ketcham AVIATION...KED FIRE WEATHER...Ketcham
Area Forecast Discussion
National Weather Service Lincoln IL
819 PM CST Sat Feb 25 2023 .SYNOPSIS... Issued at 254 PM CST Sat Feb 25 2023 Central Illinois will continue warming through Monday morning in advance of a strong storm system that will bring a chance for severe thunderstorms followed by gusty west winds. Warmer than normal weather is expected to continue through at least midweek when another system will near us to bring cooler temperatures and maybe a chance for winter precipitation to close the work week. && .UPDATE... Issued at 819 PM CST Sat Feb 25 2023 This evening high pressure is in place across portions of the mid Mississippi Valley and Ohio Valley resulting in light winds and fair weather across central Illinois. Except for a couple lingering patches of stratus over east central Illinois, low clouds have dissipated leaving thin cirrus in place for the rest of the evening and overnight. Temps are on track to fall into the mid to upper 20s north of I-72, and lower to mid 30s south where cirrus is a little thicker. && .SHORT TERM...(This evening through Monday) ISSUED AT 254 PM CST Sat Feb 25 2023 Thanks to the stratus, which stuck around considerably longer than guidance was initially suggesting, temperatures have remained cooler than forecast. The sun has come out for much of the CWA as of 230 PM, so a few degrees of warming may ensue before surface heating shuts off in a couple hours, though with temperatures in the mid to upper 30s it`s looking implausible that we`ll warm much above 40, especially southeast of I-55. Tomorrow, warm advection will overspread the region well in advance of a surface feature gradually taking shape across the Plains in the difluent left exit region of the upper jet. This system will have the potential to bring a couple hazards to central Illinois late Sunday night and Monday: * Severe weather: The first threat will be severe weather, the chances for which will be maximized during the 3 to 10 AM timeframe Monday morning as a squall line sweeps through the CWA in a semi-favorable environment for damaging straight line wind gusts. IVT values exceed 750 kg/m/s across most of the CWA and 1000 J/kg across the southeastern fringe as the ~70-75 kt southerly 850hPa LLJ moves overhead. The NAMNest suggests we`ll have several hundred J/kg of MUCAPE overnight Sunday night, possibly becoming surface based Monday morning in our eastern counties where the greatest threat for damaging winds is expected, depending on timing and precipitation ahead of the main line of strongly-forced storms with the occluded front. Still, given the possibility of heavy rain given the strong forcing with the front and abundant moisture present with ensemble guidance suggesting PWATS in the 1.1-1.3 inch range, even before dawn the storms could transfer higher momentum air to the surface via strong evaporational cooling. Mid-level lapse rates don`t look particularly impressive for a hail threat, but QLCS tornado potential is certainly nonzero as 0-3 km CAPE values briefly exceed 100 with the line of storms, especially in our northwest CWA nearer the triple point where shear will be off the charts; still, the biggest threat will be from downburst winds, particularly with any bowing line segments. Flash flooding potential looks minimal given the fast storm motion of 50 to 65 mph. * Strong gradient winds: Behind the cold front, the LLJ shifts east, but winds at 900mb rapidly veer to westerly and remain as high as 50-55 kt per GFS and NAM forecast soundings. The latest runs of the HRRR and NAMNest suggest surface winds behind the cold front will gust to 50 and 40 kt, respectively, while the momentum transfer technique from forecast soundings suggest gusts to 45 to 50 kt will be possible. This seems reasonable given the expected clearing and strong subsidence behind the occluded front, though it will certainly bear watching as even the deterministic models seem to be struggling with the orientation of the pressure field both with the cold front and well behind it on the south side of the low passing to our north. Depending on how rapid pressure rises are with the cold front (GFS is considerably stronger than the ECMWF with this), the strongest winds could occur right behind the cold front when subsidence should theoretically be maximized Monday morning, or the strongest winds could be later Monday morning/early afternoon if the gradient south of the low tends to be on the tighter end of guidance. An Advisory still looks likely, though there`s a 10-20% chance we could shake out with a Warning and a nonzero chance we could get by with no need for headlines with this one. Otherwise, Monday will be warm to start, with temps in the 60s for most on their morning commutes. NBM even suggests an 80% chance for highs of 65F or higher in Lawrenceville Monday morning, with 70F not out of the question depending on how much convection mitigates the effects of warm advection in the warm sector of the system. Winds should ease in the evening and especially Monday night as the gradient weakens, though temperatures by Tuesday morning are likely to be in the 30s (if not upper 20s in our northwest) given the cold advection behind the system. .LONG TERM...(Tuesday through Saturday) ISSUED AT 254 PM CST Sat Feb 25 2023 Sometime mid to late in the upcoming work week, another system is likely to pass somewhere through the TN or lower Ohio Valley to give us a shot of cooler air by the weekend and possibly some precipitation Thursday or Friday. Depending on how strong the low is, and hence how efficient cold air advection will be behind it, our precip may be wintry, and there are even a few members of the LREF grand ensemble (GE) that suggest we`ll have significant snow accumulations. The deterministic GFS, in its further north low track compared to its Canadian and European counterparts, shows a scenario that would yield such accumulations over at least a portion of our area which would receive a swath of banded snow in a broad deformation zone on the NW side of that feature. For what it`s worth, 13/100 GE members have more than 8 inches of snowfall accumulations at the arbitrarily chosen forecast point of Mattoon. By Friday and Saturday mornings, NBM suggests around a 20% probability for lows in the teens at Galesburg, and an 80-90% chance that temperatures will fall to sub freezing. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 508 PM CST Sat Feb 25 2023 VFR conditions and light southwest winds less than 10 kt will prevail overnight. After a period of very light winds Sunday morning, winds will set up out of the SSE/SE around 7 to 9 kt by mid to late afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Deubelbeiss SYNOPSIS...Bumgardner SHORT TERM...Bumgardner LONG TERM...Bumgardner AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service Indianapolis IN
928 PM EST Sat Feb 25 2023 .Forecast Update... Issued at 928 PM EST Sat Feb 25 2023 Small patch of low stratus over NW sections late this evening, beneath a shallow inversion, under the influence of broad surface high pressure, that extended from the South to the northern Plains. Meanwhile, cirrus was also moving overhead well in advance of the Pacific coast system. Temperatures were falling slightly faster than HiRes and with mainly only high clouds and light to calm winds, lowered overnight lows a degree to the upper 20s to mid 30s. && .Short Term...(This evening through Sunday) Issued at 316 PM EST Sat Feb 25 2023 * Warming trend back to above normal temperatures * Dry through the rest of the weekend .This evening and tonight... Latest surface analysis shows an area of high pressure centered over Southern Missouri slowly moving eastward resulting in light westerly flow across Indiana Saturday afternoon. GOES16 satellite imagery reveals an area of low stratus and cumulus clouds extending southwest from Michigan to Illinois and Indiana and slowly shrinking. Subsidence under the high has resulted in a strong low level inversion trapping moisture just above the surface. This area of lower clouds is evidence of the trapped moisture; however drying is taking place in this thin saturated layer as daytime mixing occurs. While clear skies remain over Indianapolis, 19z IND ACARS soundings still show the inversion in place just under 1 km agl. With high pressure remaining the dominant weather influence tonight, expect the inversion to persist into the overnight hours. RAP cross sections reveal low level moisture remaining in the boundary layer overnight, so would not be surprised to see continued lower clouds across Western and Northern Indiana through tonight. Temperatures overnight fall into the lower mid 30s across Central Indiana. With a small dew point depression at the surface, confidence further increases in lower clouds remaining where higher moisture remains trapped near the surface. Weak mid level shortwave also passes by to the north overnight, briefly increasing the surface pressure gradient and low level winds over the northern half of the state. Winds may pick up to 10 to 15 mph after 03z for the northern portion of the forecast area along with a slight increase in cloud cover. Overall, quiet weather persists across the state with lows dropping into .Sunday... Zonal flow pattern aloft transitions into ridging in response to a developing trough in the Plains on Sunday. At the surface, high pressure continues eastward with southerly return flow setting up across the region by Sunday afternoon. Warm air advection ahead of the developing Plains system already begins to influence the are tomorrow as temperatures aloft begin to climb above 0C and toward +10C by late Sunday night. Due to subsidence under the high, the inversion will likely persist through tomorrow as well, limiting afternoon mixing to under a kilometer. Limited mixing plus high pressure directly overhead will keep winds very light through the period as well. While a warmer airmass advects in aloft, those warmer temperatures will struggle to mix down to the surface due to the inversion. Still expecting highs to make it into the mid to upper 50s with abundant sunshine earlier in the day. High clouds stream in aloft during the later afternoon and evening hours and continue to lower Sunday night. With continued warm air advection and clouds, expect temperatures to remain elevated Sunday night in the 40s to near 50. && .Long Term...(Sunday night through Saturday) Issued at 316 PM EST Sat Feb 25 2023 Temperatures throughout the long term period will be above normal with highs oscillating from the 50s to 60s and lows from the 30s to 40s as a couple of systems move across the region. Models continue to be pretty consistent with this upcoming system leading to decent confidence at least with with precipitation and gusty winds. An upper low will move in from the southwest and southern plains reaching the Great Lakes region by early Monday. This system will bring precipitation chances starting in the SW as early Monday due to isentropic lift along the warm front moving northward. The surface low itself and the associated cold front will enter the forecast area Monday morning to early afternoon. The best chances for rain and storms will be from early morning Monday into midday with slight chances of thunder embedded during the daylight hours. Storm total QPF continues to be about half an inch to an inch which shouldn`t cause many issues in terms of flooding. The main story with this system will be the increased gradient winds set to move in along and behind the cold front. A LLJ, with a centroid of 60-70 kts at 850 mb will pass overhead which should mix down to the surface from prior to sunrise throughout the rest of the day with surface wind gusts potentially getting to around 50 mph at times and sustained winds near 30 to 35 mph. Within storms and showers themselves, some stronger to damaging winds could be embedded, especially across the SE midday if instability creeps in. This potential for damaging winds has prompted a risk of severe storms from SPC. Non-thunderstorm winds will drop some by monday night and will further weaken through the day Tuesday. Temperatures will dip some Tuesday behind the cold front but are expected to rebound quickly by Wednesday as southern to southwestern surface flow returns. There is a small chance of some precipitation in the far SE late Wednesday into Thursday from a wave but much of the moisture should keep to the south of the area. Otherwise, a surface high moving in behind the early week system should allow for a quiet midweek. At the end of the period, there remains quite a bit of variability between models thus leading to quite a bit of uncertainty. A low should move in from the plains, tracking somewhere between the Ohio and Tennessee Vallies, but the path and timing of the system remains highly uncertain. If it ends up further north, central Indiana could see precipitation for the end of the week and may potentially contain a mix of winter weather. But if it stays further south, the weather could stay dry but bring in slightly cooler temperatures to the area. && .Aviation...(00Z TAF Issuance) Issued at 522 PM EST Sat Feb 25 2023 Impacts: - MVFR ceilings possible at KLAF and KHUF this evening, otherwise, VFR flying conditions and WSW winds less than 10 knots expected through Sunday Discussion: GOES 16 visible satellite was showing shrinking stratus deck over the upper Wabash Valley. There is some concern that this could result in lingering MVFR stratus this evening for KLAF and KHUF. Otherwise, high pressure and fast WNW upper flow ahead of potent west coast system will result in passing cirrus. Meanwhile, modest surface pressure gradient will keep WNW winds less than 10 knots. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...MK Short Term...CM Long Term...KH Aviation...MK
Area Forecast Discussion
National Weather Service Jacksonville FL
657 PM EST Sat Feb 25 2023 ...New UPDATE, AVIATION... .UPDATE... Issued at 633 PM EST Sat Feb 25 2023 Lows tonight with generally upper 50s to lower 60s inland tonight with the middle 60s near the coast tonight. SREF and HRRR show best chance of localized dense fog will reside over the I-75 corridor during the pre-dawn through the early daylight hours. Boundary layer flow will trend west-northwesterly tonight and should keep the fog potential generally along and west of Highway-301 where again the fog may become locally dense along portions of I-75 near daybreak Sunday but confidence too low to warrant hoisting any Fog Advisory with the afternoon package. Low pressure over the northeast GOM will be southwest of the Big Bend region allowing a WSW surface flow to advect stratus in from the Gulf of Mexico. For the immediate coast, it looks the main convergent area along the coast that brought sea fog from south of Ponte Vedra to JAX beach will lift north and east toward the Savannah area tonight as weak warm front reforms. && .NEAR TERM...(through Tonight) Issued at 351 PM EST Sat Feb 25 2023 A stagnant weather regime will continue with surface high across the eastern GOMEX while a strong, supporting upper ridge is anchored over Cuba. Under the influence of this ridge, temperatures will continue to climb toward the mid to upper 80s and challenge daily record high temperatures again this afternoon. Temperatures will be mild once again tonight with lows in the upper 50s and low 60s (9-12 degrees above normal). There will be inland fog concerns again tonight as sea fog and low stratus across the Big Bend advects inland toward I-75. Flow will trend west-northwesterly tonight and should keep the fog potential generally along and west of Highway-301. Fog may become locally dense along portions of I-75 near daybreak Sunday but confidence too low to warrant hoisting any Fog Advisory with the afternoon package. && .SHORT TERM... (Sunday through Monday night) Issued at 351 PM EST Sat Feb 25 2023 Ridging aloft will stay situated over Cuba through the period as low level ridging/surface high shift eastward across the FL peninsula Sunday and then across the Bahamas Monday. As this unfolds, a weakening cold front will slide across the northern Gulf coast Sunday and slow as it approaches from the northwest Monday. Pressure gradients will tighten as the front nears leading to breezy southwesterly winds Monday afternoon. Expect a similar trend in fog advecting northeastward from the Big Bend Sunday night and likely progress further across NE FL as southwesterly flow ensues. Strong ridging will continue the anomalous heat through early next week with high temps reading in the mid to upper 80s, even at the coast due to the offshore flow. && .LONG TERM... (Tuesday through next Saturday) Issued at 351 PM EST Sat Feb 25 2023 A weakening front will sink southward and stall across the region Tuesday as it dissipates. A few sprinkles or an isolated shower will be possible along the decaying boundary. West-southwesterly flow will persist through Wednesday with low level ridge established over the Bahamas before shifting southwesterly Thursday ahead of vigorous and deepening low pressure system that is progged to track across the lower Mississippi Valley Thursday night into Friday. Based on the track, the area will be in be firmly in the warm sector Friday as the cold front trailing the strong surface low approaches. Showers and perhaps a few storms will be possible ahead of the front which is expected to press through either the afternoon or evening Friday. With dynamics lifting north, severe thunderstorm threat doesn`t appear to be very high with the cold front. Given the depth of the surface low, strong prefrontal winds are expected with gusts that could be up to 50 mph if the strength and track of the low holds. As the event nears next week, wind headlines are likely to be needed. Unseasonably warm temperatures will continue through next week ahead of the front with high temps continuing to challenge daily records. Despite the frontal passage, temperatures are still expected to be above normal next weekend however we will back away from the record- level warmth. && .AVIATION... (00Z TAFS) Issued at 633 PM EST Sat Feb 25 2023 VFR conditions will persist for most terminals tonight. The exception may be near the I-75 corridor toward daybreak where fog and stratus will be advected into the region. VSBYs near the I-75 corridor may drop below 2 miles at KGNV where have put 1 1/2 SM between 09-13z. Otherwise VFR conditions Sunday with a light west wind at 4 to 8 knots after 15z. && .MARINE... Issued at 351 PM EST Sat Feb 25 2023 Satellite continues to show a localized area of fog/low stratus right along the coast between Jacksonville Beach and south Ponte Vedra this afternoon. This fog has shown signs of lifting via satellite and webcams. Given these trends, the current Dense Marine Fog Advisory will be allowed to expire at 4 PM. Light offshore winds with an afternoon sea breeze are expected again Sunday as high pressure migrates eastward across southern FL. The only maritime concern Sunday will be the potential for another round of sea fog in the nearshore waters of northeast Florida. A weakening cold front will approach Monday and stall over the waters through Tuesday. Despite weakening, the front will strengthen winds and raise seas to hazardous levels for small craft, especially offshore, Monday into Tuesday. There will be a lull in the winds Wednesday before a potent cold front approaches late next week leading to a period of strong offshore winds and possible gales on Friday. Rip Current Risk: Low to moderate risk of rip currents is expected at area beaches Sunday and Monday. && .CLIMATE... Issued at 351 PM EST Sat Feb 25 2023 A table of daily high temperature records and year of occurrence for each of the climate sites is listed below for the next 5 days. DATE 2/26 2/27 2/28 3/1 3/2 ----------------------------------------------- JAX 88 86 87 88 86 (1962) (1962) (2017) (2017) (1997) CRG 85 85 87 87 84 (2018) (2022) (2021) (2017) (2012) GNV 88 87 87 87 88 (1971) (2011) (2021) (2017) (1918) SSI 83 81 85 85 84 (1972) (1971) (1962) (2018) (1971) AMG 82 84 85 86 85 (1996) (2021) (2017) (1997) (1976) && .PRELIMINARY POINT TEMPS/POPS... AMG 83 62 83 60 / 10 0 0 0 SSI 79 63 81 62 / 10 0 0 0 JAX 87 60 87 57 / 0 0 0 0 SGJ 84 62 84 58 / 0 0 0 0 GNV 86 58 86 55 / 0 0 0 0 OCF 86 57 86 55 / 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
618 PM CST Sat Feb 25 2023 .DISCUSSION...(This evening through Saturday) Issued at 249 PM CST Sat Feb 25 2023 KEY MESSAGES: - Another impactful storm system is expected late Sunday night and Monday. A period of moderate to heavy freezing rain at the onset could bring ice accumulations of around 1/4 inch to most of west central Wisconsin. Total precipitation amounts have trended up with a slight westward shift of the system, but a relatively sharp gradient from impactful amounts of precipitation to little or none remains from southwest to central Minnesota. - Low confidence continues with a midweek system that may bring another round of snow. After some morning clouds in Wisconsin, skies have cleared with a sunny day across much of the region. A band of high clouds across the northern half of Minnesota may drift over central parts of the state, but otherwise no concerns for tonight or Sunday. A cool day and light winds tonight should send us back into the single digits for lows. A vigorous and compact upper low over the coast of southern California will advance east to the southern Rockies Sunday afternoon, then begin to turn east northeast toward the mid Mississippi Valley Sunday night as it begins to encounter the strong southeast mid level ridge. The trend today has been to shift the track a little to the left, bringing a slight increase in QPF to eastern Minnesota and Wisconsin. However, there is still a ton of spread in ensemble guidance with QPF, owing to the fact there will be a relatively sharp gradient somewhere over the area. GEFS has a spread of about 2 inches across the eastern half of the area - 0.2" to 2.2" at EAU and 0.1" to 2.0" at MSP. This is very unusual for a storm system expected to begin within 36 hours, but the compact and potent nature of it means a lot can change with slight adjustments in track. 12Z hi-res guidance is mostly aligned with a farther west solution. The envelope of solutions should begin to narrow quickly, maybe as early as this evening. For now, the forecast follows close to the ensemble means which should minimize any adjustments one way or the other going forward. Precipitation will lift north rapidly late Sunday night, engulfing southern/eastern MN and WI by early Monday morning. Very warm air aloft will ensure no snow, and it should melt all hydrometeors completely to make sleet difficult to achieve too. What`s left is a surface temperature forecast hovering around freezing to determine if precipitation falls as plain rain or freezing rain. With a breezy east-southeasterly flow mostly originating from the current chilly airmass in place, not expecting temperatures to rise above freezing before precipitation begins across central MN and western WI. There may be a period of several hours freezing rain is occurring as precipitation rates increase into early Monday morning. This aspect of the forecast has remained pretty consistent and forecast ice grids remain near 1/4 inch across most of west central WI. Although temperatures near freezing, strong winds, and moderate to heavy rates are not efficient elements for a crippling ice storm, the consistency with the FRAM (freezing rain accumulation model) given all the above is such that a Winter Storm Watch is warranted. By late Monday morning, temperatures should rise to the warm side of freezing and end any further icing threat. By afternoon, the back edge of precipitation will clear from southwest to northeast and could mix with a little light snow before ending. With temps still above freezing, snow accumulation will remain light (if any occurs at all). Quick on the heels of the early week system, another will track east into the northern Plains Tuesday into Wednesday. This one won`t have as much moisture to work with and a narrower band of precipitation is likely on its northern half. There has been little consistency with the track, so confidence remains low. At this point, the system could drop a few inches of snow anywhere across the Dakotas, Minnesota, and northern Wisconsin. PoPs remain relatively low for now until greater consistency develops. High pressure builds in for the rest of the period and another shot of colder air will return late week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 602 PM CST Sat Feb 25 2023 Not much happening this TAF period, but trouble is looming just beyond the end of this period. Main concern is the threat for fog tonight. Models place the greatest fog threat from south-central MN up the MN Valley into west-central MN, so for us, MKT/RWF have the greatest potential for fog. Seeing enough short-term models showing fog developing at these two locations to hit the fog potential hard there. Everywhere else, the worst that can be expected with vis tonight is an MVFR in BR. Winds will go light and variable tonight, before setting up out of the southeast on Sunday. KMSP...Fog is not expected to be an issue tonight. For the end of the TAF, RAP forecast soundings do show IFR stratus possibly moving in as early as 3z Monday (10pm Sun), but kept it VFR for now with current thinking being that we will most likely have to wait for precip to arrive before sub-VFR probabilities really kick up. /OUTLOOK FOR KMSP/ Mon...MVFR/IFR with -RA. Chc -SN in aftn. Wind NE bcmg NW 10-15 kts. Tue...VFR. Wind W 5-10 kts bcmg S. Wed...MVFR likely. Chc -SN. Wind NNW 10-20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...Winter Storm Watch from late Sunday night through Monday morning for Dunn-Eau Claire-Polk-St. Croix. Winter Storm Watch from late Sunday night through Monday morning for Barron-Chippewa-Rusk. && $$ DISCUSSION...Borghoff AVIATION...MPG
Area Forecast Discussion
National Weather Service New York NY
751 PM EST Sat Feb 25 2023 .SYNOPSIS... Weak low pressure passes to the north Sunday, sending a cold front through the area in the evening. High pressure then builds into the area late Sunday night. A complex low pressure system will affect the area late Monday through Tuesday. High pressure briefly builds in for Wednesday with a frontal system moving through the area Wednesday night into Thursday. There is then the potential for low pressure to impact the area at the end of the week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A few flurries and/or a stray snow shower will be possible early this evening with a weak disturbance passing through. The biggest change though is some clearing across the Lower Hudson Valley. Latest HRRR and RAP13 show this and stay closed to these solutions through the first half of the night with skies clearing. However, reluctant to be too aggressive and allow some clouds to return toward daybreak with residual low level moisture. This part of the forecast will likely be in flux. This also resulted in knocking down lows a few degrees inland for starters. Temperatures will be close or just below normal with lows ranging from the upper teens inland to the mid and upper 20s at the coast. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... After the cold start, temperatures moderate on Sunday, with highs climbing back above average, into the mid-to-upper 40s. A weak low drops out of SE Canada and tracks through New England. The associated warm front lifts through the region in the morning, though limited moisture with the system will preclude the possibility of precipitation. SW flow increases into the afternoon with a 50 kt LLJ overhead at 850 mb. This should allow occasional gusts 25-30 mph to mix down to the surface during the afternoon. Cold front moves through in the evening, dry, and the flow veers NW in response. Generally stuck close to national blended guidance with this update. && .LONG TERM /MONDAY THROUGH SATURDAY/... A complex storm system will impact the area late Monday into Tuesday as a negatively tilted southern branch shortwave lifts up into the Great lakes Monday, with secondary low development off the Mid Atlantic coast. This is highly unusual scenario to bring a significant winter weather event to the area, since the inland surface low remains the deeper, primary low for much of the event. In addition, the secondary low and its circulation never really takes over as an elongated pressure trough extends back NW to the inland low. A big player here will be blocking by the northern branch due to low pressure over the Canadian Maritimes and the Davis Strait. The latter of which will keep a marginally cold airmass in place. The difficult part of the forecast is how far north the rain/snow line works inland. With a strengthening E/SE flow it would seem a safe bet for coastal zones to see the boundary layer warm enough for a changeover to rain. That being said, the changeover will work from south to north during the time of heaviest precipitation which occurs the first half of Monday night. For snowfall amounts, it now looks like inland areas will see 3-5 inches, dropping off to an inch or less across NYC and Long Island. There is the potential for coastal CT to see an advisory level snowfall of around 3 inches. But once again, not typical with this set up due to a prolonged easterly flow. In addition, there is some mid level warming that works in from the west, but its northeast extent will have a tough time getting into northern and far eastern sections of CT before the heaviest the precipitation exits. So there are a lot of moving parts here and confidence should increase over the next 24h with the thermodynamic structure of the storm. Surface temperatures for the event will also mainly be in the 30s to around freezing well inland. So not a dry, blowing around snow. In addition, east winds strengthen late Monday into Monday night with coastal areas possibly seeing gusts as high as 40 mph overnight. High pressure briefly builds in on Wednesday with a mostly sunny and dry day expected. Highs for the mid week period will be in the mid 40s to low 50s. A frontal system brings mainly rain chances to the area Wednesday night into Thursday. There is the potential for a more significant area of low pressure to impact the area at the end of the week, but much uncertainty remains with this system with global models presenting numerous scenarios. Temps cool down into the 40s for Friday and Saturday behind the frontal system, but a lot of this hinges on a late week storm track. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... High pressure will briefly build in tonight. Weak low pressure will then move across New England on Sunday. VFR cigs at the metro NJ terminals and MVFR to the east should clear out this evening at the NYC metros, and sooner than fcst per latest satellite trend. Push of drier air is not as great farther east, and cigs there should take longer to improve overnight and that improvement may not last as long. Expect MVFR cigs to redevelop daytime Sunday where skies clear out tonight, and these should last into at least early afternoon. Light SE-S winds this evening should become light SW/variable overnight, then pick up from the SW 10-15 kt in the afternoon, and WSW 15G20-25kt later in the afternoon. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... AMD likely to show improvement to VFR sooner than fcst this evening. OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY... Sunday night: VFR. Winds becoming NW10-15G20kt in the evening. Monday: VFR. Monday night into Tuesday morning: IFR or lower conds developing. Snow/wintry mix at onset for NYC/NJ metro and Long Island terminals in this evening with light snow accumulation possible, then rain overnight. KHPN, KBDR, and KGON transition to a wintry mix/rain with a few inches of snow accumulation likely. KSWF, mainly snow, with several inches of snow accum likely. Peak winds ESE G25-30kt for coastal terminals Mon evening. Tuesday afternoon: Conds improving to MVFR or VFR. Tuesday Night...VFR. NW 10-15G20kt. Wednesday...VFR. Wednesday night and thursday...MVFR or lower cond in rain. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ && .MARINE... Increasing SW flow on Sunday will lead to SCA conditions on the ocean, eastern Sound, and Peconic and Gardiners bays. Gusts 25-30 kt are expected beginning in the early afternoon on these waters, before subsiding early Monday morning. Seas 3-5 ft can be expected on the ocean during this time as well. Elsewhere, occasional gusts upwards of 25 kt are possible during the afternoon and evening Sunday. Confidence and coverage are too low to warrant an SCA at this time for these remaining waters, though remains possible with future updates. A complex storm system will impact the waters Monday night into Tuesday with the chance for an easterly gale on the ocean waters. A gale watch is in effect for the ocean waters Monday night. Wave heights are forecast to peak around 7-9 ft early Tuesday morning on the ocean waters. After a quiet Wednesday, there will be a few more chances at seeing at least SCA conditions on Thursday and Friday with the potential for several waves of low pressure to impact the region. && .HYDROLOGY... No hydrologic impacts expected through next week. && .TIDES/COASTAL FLOODING... E-SE gales ahead of approaching low pressure late Monday will bring potential for minor coastal flooding along vulnerable western Sound, NY/NJ Harbor, western Great South Bay, and Jamaica Bay communities with the Mon night/Tue AM high tides. Fortunately astronomical tides are running low, and 2 surge of 2 to 2.5 ft needed just for minor flood thresholds to be reached. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 11 AM Sunday to 4 AM EST Monday for ANZ332-340-350-353-355. Gale Watch from Monday evening through late Monday night for ANZ350-353-355. && $$ SYNOPSIS...DR/DW NEAR TERM...DR SHORT TERM...DR LONG TERM...DW AVIATION...BG MARINE...DR/DW HYDROLOGY...DR/DW TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Phoenix AZ
410 PM MST Sat Feb 25 2023 .UPDATE... Updated Aviation && .SYNOPSIS... A cold front will sweep across the area this evening and overnight. Gusty winds are anticipated ahead of the front across portions of southwestern Arizona early this evening. Shower activity is also expected along and behind the front, particularly across central Arizona through Sunday morning. Across the higher terrain east of Phoenix, light snow accumulations are likely above 4500 feet. Well- below normal temperatures in the wake of this system will linger through next week. Another chance of precipitation and windy conditions are possible midweek as a storm system moves through the intermountain West. && .DISCUSSION... Latest water vapor imagery reveals a vigorous low pressure system off the southern California Coast. Major impacts are anticipated near San Diego and Los Angeles today, however latest radar and visible imagery indicate moisture along a cold front is struggling to remain organized as it marches eastward through the peninsular ranges. Latest HREF indicates some potential for scattered showers across the Imperial Valley, though latest trends in the HRRR suggest this region will more or less be rain shadowed. Further east across southwestern Arizona, windy conditions have developed within a clear area where mixing has been enhanced. Latest ECMWF EFIs have trended steadily downward in this region, nevertheless observations continue to indicate gusts of 30-40 mph. Meanwhile, veering winds have been out of the south and southeast, which is generally unfavorable for blowing dust. Latest models remain in good agreement and indicate the low will open up and migrate eastward overnight. Consequently, IVTs will get a boost this evening as a stronger meridional flow develops between the Gulf of California and western Arizona. Precipitation will likely increase in coverage this evening across Yuma and La Paz Counties and NBM PoPs have increased to 80 percent in these areas. Latest CAMs suggest a line of showers will move steadily eastward and into central Arizona overnight. QPF from the ensemble suites have been consistent over the past few runs, generally indicating an average of one to two tenths of an inch of rain for the Phoenix area. Higher QPF is anticipated across the higher terrain east of Phoenix, where orographic lift will be maximized. Meanwhile, snow levels will plummet behind the front as the low moves eastward into northern Arizona Sunday morning. A Winter Weather Advisory remains in effect above 4500 feet, where 2 to 4 inches of snow is likely. HREF SBCAPE values suggest the possibility of increasing but meager instability associated with the cold pool across central Arizona, particularly after sunrise. A few rumbles of thunder cannot be ruled out, though the NBM generally indicates only a 10 percent chance of lightning. A few CAMS also suggest the possibility the instability may translate into the redevelopment of showers behind the front, mainly across central Arizona. Precipitation will generally taper off Sunday morning as a drier and subsident westerly flow overspreads the region. In the wake of the system, temperatures will struggle to reach the upper 50s across the Phoenix area despite mostly sunny skies. Some lingering breeziness is also anticipated with the ECWMF ensemble mean indicating widespread gusts of 20-25 mph. A longwave trough will remain situated across the western CONUS through much of next week. Temperatures will consequently remain below normal through at least next weekend. Ensemble suites are in good agreement the next anomalous low pressure system will impact the Desert Southwest midweek. There is considerable uncertainty with regard to the specifics, though a period of wet and windy weather appears increasingly likely. && .AVIATION...Updated at 2310Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: The largest weather issues through Sunday will include fropa with an abrupt wind shift tonight, scattered showers, and potential for MVFR cigs Sunday morning. A southerly cross runway wind with gusts up to 20kt may persist into the evening with low confidence on a steady direction. Wide variability (150v210) may be common before directions tend to back towards a SE direction mid/late evening. Confidence is good in timing fropa through the terminals during a 08Z-09Z time frame, where winds will shift abruptly to a SW or W direction. Along and behind the front, cigs should drop into a 040- 060 AGL with numerous showers. There is around a 50-75% chance of at least temporary MVFR conditions as visibilities may fall to 3-5SM and cigs as low as 2K ft. While the front and showers should clear the terminals by sunrise, lingering low clouds below 6K ft (and potentially still some MVFR) may linger through the morning hours. Winds may be highly variable and even briefing obtain an easterly heading for a few hours. Overall forecast confidence in details during the 12Z-18Z time is low. Confidence is much better than cloud decks will scatter and rise by early afternoon with westerly winds prevailing. Southeast California/Southwest Arizona including KIPL and KBLH: Gusty west winds this evening with lowered cigs and a few showers will be the primary weather issue through Sunday. A cold front has already passed the terminals, and wind gusts 25-30kt should steadily weaken through the evening as the pressure gradient relaxes. Cigs as low as 5K ft AGL will also lift and scatter through the evening and overnight as showers exit eastward. While some gusts 20-25kt may redevelop Sunday afternoon, skies will clear with far more tranquil conditions. && .FIRE WEATHER... A cold front will sweep across southeast California this afternoon and across Arizona tonight and Sunday morning. It will produce scattered to numerous showers but only for a relatively short time. Passage of the front through the Greater Phoenix area will be roughly between midnight and 4 A.M. Much more isolated showers may follow before clearing overspreads the region during the afternoon. The approach and passage of the front will lead to windy conditions as well, mainly Saturday afternoon into early Sunday, but not as strong as earlier this week. Dry weather and warmer temperatures are expected Monday and Tuesday with another system possibly affecting the region Wednesday and Thursday. MinRH today will range from 20-40% over the AZ districts and 40-70% over SE CA. Values Sunday increase by 5 to 15% Sunday over south-central AZ and decrease by 10-20% over SW AZ and SE CA. The higher terrain of south-central AZ declines 10-15% on Monday (little change elsewhere). Anticipate a temporary increase Wednesday over south-central AZ before drier air moves in Thursday with values of 15-25% most locations (30-50% higher terrain of south- central AZ). Little change Friday. Max RH values will remain good through Wednesday morning with values of 60-90% before declining 20-40% by Friday over SE CA and SW AZ and 10-15% over south-central AZ. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Wind Advisory until 8 PM MST this evening for AZZ530>536-538-539. Winter Weather Advisory from 2 AM to 2 PM MST Sunday for AZZ545- 557-558-563. CA...Wind Advisory until 7 PM PST this evening for CAZ561-569-570. Wind Advisory until 6 PM PST Sunday for CAZ562. && $$ DISCUSSION...Hirsch AVIATION...18 FIRE WEATHER...AJ
Area Forecast Discussion
National Weather Service Tulsa OK
951 PM CST Sat Feb 25 2023 ...New SHORT TERM... .SHORT TERM... (The rest of tonight) Issued at 951 PM CST Sat Feb 25 2023 Made another quick evening update to raise PoPs across NE OK. A couple clusters of showers and isolated thundershowers have developed, with the higher res EC outperforming the HRRR attm. Lacy && .LONG TERM... (Tomorrow through Saturday) Issued at 224 PM CST Sat Feb 25 2023 Showers and isolated may be ongoing Sunday morning primarily across NE OK otherwise extensive and cloud cover with isolated showers are possible through the day. Focus by afternoon will be on the developing storms across the TX Panhandle and monitoring their downstream environment into the forecast area. Better agreement exists today resolving the low level moistening ahead of the storms by Saturday evening. The influence of the shallow cold airmass remains intact through deep south TX with sfc ridging holding moisture return at bay. This does cast uncertainty on quality moisture return. However, the airmass south of the cold front and sampled by the 12z KCRP sounding is anomalously moist for the season and guidance trends are for a corridor of this favorably moist profile to be in place just ahead of the developing line of storms. Fcst soundings do maintain a notable capping inversion across the region, however expectations are the strong synoptic lift coupled with the mesoscale influence of the organized line of storms will be sufficient to maintain a zone of strong updrafts well into, and possibly through, the forecast area. Wind fields are intense with this wave and the lack of low level veering through the event maintains a favorable shear orientation for maintenance of the convective line. Convective models show a signal typically found with well developed inflow jets supporting the organized convective structure especially across the northern half of the forecast. Low level UH tracks also have reflections of curving to the north of the mean wind suggesting within the model a zone of favorable low level mesocyclones along the qlcs as it advances into NE OK Sunday evening. While a weakening trend is likely with eastern and southern extent the background wind fields will remain strong through the overnight hours and any deeper convection may maintain a wind threat through western AR. This wave will act to scour out the shallow cold airmass and the trailing airmass will be seasonably warm through mid week. The next wave and cold front may bring a slight chance of rain by mid week to southern area. A strong system is likely by late next week and this wave continues to have large variance amongst guidance. For now a broad chance of precip will be retained across the region as the forecast awaits better clarity. && .AVIATION... (00Z TAFS) Issued at 526 PM CST Sat Feb 25 2023 MVFR conditions are common across the area this evening. However, MVFR to IFR conditions will become more prevalent later tonight and into Sunday as moisture surges into the region from the south in advance of our next storm system. && .PRELIMINARY POINT TEMPS/POPS... TUL 43 61 46 70 / 40 30 100 0 FSM 47 63 49 72 / 20 30 80 0 MLC 45 64 46 73 / 20 30 90 0 BVO 39 58 44 70 / 30 30 100 0 FYV 45 60 45 68 / 30 30 90 0 BYV 45 61 47 68 / 40 30 100 0 MKO 45 61 46 70 / 40 40 100 0 MIO 41 59 44 67 / 40 30 100 0 F10 44 62 46 72 / 30 30 100 0 HHW 46 67 47 72 / 10 20 80 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...Wind Advisory from 6 PM Sunday to 6 AM CST Monday for OKZ054>076. AR...Wind Advisory from 6 PM Sunday to 6 AM CST Monday for ARZ001-002- 010-011-019. && $$ SHORT TERM...30 LONG TERM....07 AVIATION...10