Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/01/22

Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
719 PM CDT Sat Apr 30 2022 .AVIATION...00Z TAFs Frontal boundary has moved south into the Hill Country but looks to have stalled and will drift northward during the overnight hours. Low level flow will be weaker than previous nights with southerly winds up to 20 knots. Scattered to broken cumulus/VFR conditions early this evening with MVFR ceilings expected to affect coastal regions by 04Z Sunday. These lower ceilings will gradually spread inland and reach LRD area by 08Z. SREF probabilities along with the HRRR show ceilings will likely lower to IFR over the inland coastal plains from 07-08Z with MVFR vsbys in fog through 14-15Z Sunday. MVFR ceilings will be prevalent elsewhere until 17Z for the coastal plains and a little later for the Brush Country. A few light showers could affect the Brush Country Sunday morning also. VFR conditions will occur through the rest of the afternoon with gusty southeast winds. && .PREV DISCUSSION... /Issued 326 PM CDT Sat Apr 30 2022/ SHORT TERM (Tonight through Sunday Night)... A boundary has pushed into the area this afternoon, stretching at time of writing from around Laredo to around Corpus Christi. The boundary hasn`t has much impact on our sensible weather, but has been a focus for just a few small showers mainly near the coast and offshore. Dont expect much out of this at the boundary continues to sink southward. Will have to keep an eye out though to the west for any potential mountain convection that develops this evening and into tonight. While convection will likely stay pretty close to the cold front draped across Central Texas, 850-300mb thickness contours tonight are aligned more northwest to southeast and could bring some convection down into the area. That said...only the FV3 meso model is really showing this scenario...other models either keep it along the front or far west of our area. Will carry some 20 PoPs west into the night for the small chance here. By tomorrow, a weak upper shortwave is progressing across the area, and with PWAT values at or above 1.5" the energy could be enough to trigger a few showers during the day. Will just stick with mainly 20 PoPs through the day though as the wave is pretty weak. A stronger wave will move mainly north of the area by tomorrow night, and could be a concern for showers and storms though the best chance will once again be north of the area as strong storms are expected to develop over West Texas ahead of a dry line, then push east in the late evening and overnight. Expect a mainly easterly movement, but can`t rule out some storms moving or developing into our northwest counties. Min temps continue elevated tonight and tomorrow night with abundant low level moisture. Expect lows mainly in the lower to mid 70s. Despite expected cloud cover, high temps tomorrow should reach into the lower 90s west and mid to upper 80s east. LONG TERM (Monday through Saturday)... Not too much change to the forecast for the upcoming week with continued breezy/windy, humid and hot conditions persisting. Models continue show a quasi-zonal flow aloft with upper low pressure systems remaining north of the region and high pressure remaining across Mexico well south of TX through mid week. Embedded short waves in the flow aloft are progged to bring isolated to scattered showers and thunderstorms into S TX Monday and again Wednesday night. By the latter part of the week, models indicate a mid/upper long wave trough digging southeastward across northern Mexico with the overall synoptic pattern becoming more amplified by Thursday/Friday and bringing additional rain chances to S TX. A short wave Monday morning will bring a chance of convection to the western half of S TX then dries out from west to east through Monday afternoon as weak ridging builds in behind the short wave. Tuesday looks rain free, humid and hot with heat indices around 105 across the Brush Country/Rio Grande Plains. Heat indices could reach 105 briefly each afternoon through the latter part of the week. As low pressure in the mid/upper levels moves across northern Mexico, an associated frontal boundary is progged to move across South Central TX Thursday with models indicating convection ahead and along the bdry. Models have been inconsistent from run to run and with each other with this feature. Some runs have brought the boundary into S TX either Thu, Fri or Sat or stall it north of the area before it retreats and washes out by the end the week. Given a southwest flow aloft ahead of the approaching long wave trough, feel the frontal boundary will not make it to S TX. That being said, an outflow boundary from convection farther north could move into S TX. Kept with the National Blend which shows increasing rain chances beginning Wed night into Thu across the western CWA then shows a slight chance across S TX Thu night through Fri night. The NBM progs the surface winds across S TX to back briefly to the east by Sat with no definitive boundary in the area. P-ETSS continues to forecast above normal tides through the period with water levels possibly reaching the dunes during times of high tide. Tide level trends will continue to be monitored for the potential for minor coastal flooding. MARINE... A mainly moderate onshore flow will persist tonight through Sunday night before increasing to more moderate to strong levels Sunday night. Moderate to strong onshore flow will persist through the week with advisory conditions possible at times. Isolated showers and thunderstorms are possible toward the end of next week. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 74 87 75 87 75 / 10 10 10 10 10 Victoria 71 88 73 87 72 / 10 10 10 10 10 Laredo 74 93 75 95 74 / 10 20 30 20 0 Alice 73 90 74 92 73 / 10 10 20 20 10 Rockport 75 84 76 85 76 / 10 10 10 10 10 Cotulla 72 92 73 92 74 / 20 30 40 40 10 Kingsville 74 89 75 90 74 / 10 10 20 10 10 Navy Corpus 75 83 75 82 76 / 10 10 10 10 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ TMT/89...AVIATION
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
644 PM CDT Sat Apr 30 2022 ...New AVIATION... .SHORT TERM... (Tonight through Sunday night) Issued at 132 PM CDT Sat Apr 30 2022 Two different weather features will drive the weather in the short term. The first of these is a cold front currently located from south of Rocksprings to Kerrville to Blanco to Georgetown. A prefrontal boundary moved through the morning and helped clear out much of the cloud cover a bit earlier than expected. The front itself had been making decent progress to the south and east through the morning, but has finally begun to slow down as expected. Most of the mesoscale models show the front becoming stationary very near where it is currently located before lifting back to the north late tonight. Some showers have already tried and failed to develop across Bell County to our north and additional showers and storms are expected this afternoon thanks to the ample heating the area is now seeing. The HRRR, depending on the run has shown isolated showers and thunderstorms along the whole length of the front in our area from the Rio Grande right through the Austin Metro area. This is supported by other models, with some like the Texas Tech WRF, lingering showers and storms late into the overnight in areas like Williamson and Lee Counties. In addition, the Texas Tech WRF and one or two of the other mesoscale models show additional shower and possibly thunderstorm activity across parts of the Rio Grande Plains overnight. Have lower confidence in this activity, but have maintained a 20 PoP out west to cover the chance given that the NBM picked up on this activity as well. Any storms that do develop this afternoon have a chance to become strong to severe. While shear is limited, which will likely lead to more pulse type convection (a storm forms, strengthens, then dies), there is plenty of CAPE around with anywhere between 1500 j/KG to 2500 j/KG along with fair lapse rates around 7 C/km. Large hail will be the primary hazard, with damaging winds secondary. One note, the HRRR does depict some afternoon development along the Serranias del Burro mountains later today. Typically when upper flow is more zonal and weak, like it is today, these storms tend to take a hard right turn and stay in Mexico. It may be a different story on Sunday. SPC has a band of Marginal Risk area across much of our CWA ahead of the surface boundary to account for the severe risk. As mentioned above the front draped across our area this afternoon will lift back north overnight as a warm front allowing Gulf moisture to surge northward. Some isolated showers/drizzle may be ongoing Sunday morning especially across parts of the Hill Country and Rio Grande Plains. By late in the day an upper level shortwave will approach West Texas and begin to interact with the dryline to produce thunderstorms from the Texas Panhandle down to the Big Bend. Storms should be firing in these areas west of Val Verde county by 4pm, with the activity working eastward by 6pm lasting into the overnight hours. Models show a bit of a mixed solution with how storms will evolve overnight. Most keep activity confined to Val Verde County and close to the Rio Grande, while a few (notably the NSSL WRF) bring a few isolated storms close to the HWY 281 corridor during the overnight hours Sunday into Monday morning. The best atmosphere will be along the Rio Grande and across West Texas where similar CAPE and lapse rates to today will be met with better shear (40-50 knots worth) which should help sustain storms longer tomorrow. There may also be some Serranias del Burro supercells again tomorrow, and with the upper flow turning more out of the southwest and increasing ahead of the main trough they should have a better chance at crossing into Kinney and Maverick counties late in the day. Models do show convective parameters decreasing the further east towards HWY 281 and I-35 corridor which supports the SPC updates to the convective outlook for their Day 2 which highlights Val Verde county with a Slight Risk, and generally a line from Leakey to Uvalde to Eagle Pass westward with a Marginal risk. Any storms that do form could produce a quick downpour either Saturday or Sunday with some areas picking up a quick 1/3 to 1 inch of precipitation while most of the rest of the area remains dry. Afternoon highs will range from the low 80s to near 90 each day - cooler where cloud cover sticks around and warmer in places that see more sunshine. && .LONG TERM... (Monday through Friday) Issued at 132 PM CDT Sat Apr 30 2022 Our stretch of active weather will look to continue into the month of May as several key features act to focus showers and scattered thunderstorms over the CWA this week. On Monday, remnant showers and thunderstorms from overnight convection may be moving through the CWA, generally from west to east by midday then through the eastern zones by mid afternoon. At this time, severe storms are not anticipated but SPC does have a Day 3 Marginal Risk for portions of the Southern Edwards Plateau and the western Hill Country. Primary threats would be large hail and damaging winds, but the threat appears to be highly conditional at this time. Once the 500mb shortwave moves through Monday afternoon, we should remain under largely west-southwesterly mid-level flow into the day on Tuesday. Our next weather maker should arrive by midweek, Wednesday/Thursday, as an upper-level low deepens over the central Rockies. This will act to send at least one and maybe even a couple of shortwave disturbances through South-Central Texas Wednesday and Thursday. Wednesday may provide the best threat for scattered thunderstorms as the southern branch of the 300mb jet sets up over central Texas, placing much of South-Central Texas within the favorable right entrance region. Model forecast soundings indicate rich boundary layer moisture with dewpoints surging into the mid to upper 60s and even some lower 70s sprinkled in over the Coastal Plains on Wednesday. One item of note is the very steep mid-level lapse rates depicted by the GFS Wednesday evening, which would be quite favorable for a severe threat, given modest instability and favorable deep-layer shear over the Hill Country and the Rio Grande Plains (30-50 kts). One more item of note is the fairly high PWATs that will be in place over much of the area by midweek. If storms can grow upscale, locally heavy rainfall is possible. Obviously, we`ll take pretty much anything we can get at this point, as much of the region remains within D2 to D4 drought. Beyond Thursday, the region may transition into a bit of a northwesterly flow regime, but models differ on the evolution of the pattern at this time. We should be able to keep rain chances in the forecast though through much of this upcoming week. && .AVIATION... (00Z TAFS) Issued at 629 PM CDT Sat Apr 30 2022 VFR conditions persist this evening as the front remains north of the aerodrome sites across the Hill Country and Southern Edwards Plateau. Isolated convection remains possible along the front but areal coverage and confidence is too low for inserting any VCTS within the TAF package at this time. The front lifts northward as a warm front overnight where some showers and isolated storm may also occur with the low-level moisture advection. Elected to keep VCSH in KAUS and KDRT where the greatest chance exists for any activity into and through the overnight. MVFR to IFR ceilings are expected to develop overnight and will continue through much of Sunday afternoon before improving to VFR levels into and through the afternoon hours. Isolated to scattered convection possible Sunday afternoon but confidence remains too low for VCSH or VCTS mentions. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 69 87 70 85 / 20 20 30 40 Austin Bergstrom Intl Airport 68 87 70 86 / 20 20 20 40 New Braunfels Muni Airport 69 87 71 87 / 20 20 20 30 Burnet Muni Airport 66 85 69 83 / 20 30 30 50 Del Rio Intl Airport 72 86 72 91 / 30 30 50 30 Georgetown Muni Airport 66 86 70 85 / 30 30 20 40 Hondo Muni Airport 69 89 71 87 / 20 20 40 50 San Marcos Muni Airport 69 87 70 86 / 20 20 20 30 La Grange - Fayette Regional 70 87 72 88 / 20 20 10 20 San Antonio Intl Airport 70 87 71 84 / 10 20 30 40 Stinson Muni Airport 72 89 73 89 / 10 20 30 40 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Treadway Long-Term...Morris Aviation...Brady
Area Forecast Discussion
National Weather Service North Platte NE
626 PM CDT Sat Apr 30 2022 .SHORT TERM...(This evening through Monday) Issued at 252 PM CDT Sat Apr 30 2022 All remaining precipitation has moved out of north central Nebraska this afternoon as the low pressure system becomes centered over Minnesota and Wisconsin and wrap around moisture becomes too far out of reach for central Nebraska. The tight pressure gradient will ease this afternoon and evening as the low moves out and high pressure begins to build in from the west. This will lead to a decrease in strong northwesterly winds starting in the Panhandle and moving east into north central Nebraska. Bufkit soundings along with the HRRR and NAMNST wind gusts show a decrease in strong wind gusts after sunset. Have decided to end the High Wind Warning at 03Z. Otherwise, mostly quiet weather is expected tonight with lows in the 30s. Some CAA may occur as northwesterly flow will continue on the far west side of the low pressure system, so used NBM 25th percentile for low temperatures tonight. Mild weather is on tap for Sunday as ridging develops over the Great Plains before the next disturbance moves east across the Rockies. Temperatures range from the upper 50s in northern Nebraska to the upper 60s in southwest Nebraska; about normal to the south, but below normal to the north. Low temperatures Sunday night will be in the 30s, with the coldest temperatures along the Pine Ridge. The weather pattern begins to change on Sunday night as the upper level disturbance advects across the Rockies and brings the next opportunity for precipitation. This is mainly expected to be in the form of rain, but some areas of the Panhandle and Sandhills may receive snowfall or a rain/snow mix. Some thunder cannot be ruled out either on Monday, especially in southwest Nebraska where there is more instability. There remains a discrepancy between models for snow amounts and location for Monday. The European Model, NAM, and NAMNST seem to set up a deformation band and accumulating snow over the Sandhills during the day on Monday. Soundings show sufficient lift in the dendritic growth zone. Dynamic cooling earlier in the day might keep temperatures cool enough for some accumulation but warmer temperatures at the surface may be a limiting factor for accumulating snowfall. Meanwhile, the GFS suggests snow along and east of the Pine Ridge on Monday morning. Elevation will help maintain cooler temperatures and snowfall. With both solutions this will be a heavy, wet snow likely mixed with rainfall much of the time. Snow ratios will be less than 10:1. Will continue to monitor for location and amounts for snowfall. .LONG TERM...(Monday Night through Saturday) Issued at 252 PM CDT Sat Apr 30 2022 Precipitation will move east out of the forecast area on Monday night as the upper low moves east out of the area. Temperatures will be below normal on Tuesday with highs in the upper 40s to mid 50s. That being said, the amount of snowfall that remains from the previous system may help lower temperatures in some areas. Once again, another upper level disturbance will move out of the Rockies and into the Great Plains on Tuesday night into Wednesday, bringing more opportunities for precipitation. A rain/snow mix may occur early on Wednesday on the Pine Ridge, and thunder is possible in the afternoon and evening. The possibility for rain and thunderstorms appears to continue through the end of the week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 619 PM CDT Sat Apr 30 2022 VFR conditions will persist through the forecast period. Strong northwest winds will gradually diminish through late evening. Expect winds to veer to northeast by early afternoon Sunday while remaining generally light though a gust of near 20 knots will be possible for VTN during a brief period around midday Sunday. && .LBF WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 10 PM CDT /9 PM MDT/ this evening for NEZ004>010-022>029-035>038-056>059-069>071-094. && $$ SHORT TERM...Meltzer LONG TERM...Meltzer AVIATION...NMJ
Area Forecast Discussion
National Weather Service Louisville KY
947 PM EDT Sat Apr 30 2022 .Mesoscale Update... Issued at 948 PM EDT Sat Apr 30 2022 The first wave of convection has stayed subdued as expected early this evening. However, we are starting to see a slow uptick in coverage and intensity as the stronger low level jet core overspreads the area, and the mid level cap starts to erode a bit. This trend should continue through the next few hours, with scattered to numerous thunderstorms expected overnight ahead of the approaching front. Although we have lost a bit of surface based instability, we still have modest to moderate MU CAPE values in the 1000-1500 J/KG range that should persist through the overnight. In addition, a second ML CAPE axis just ahead of the front should overspread the area again around and after Midnight. So, do think that an isolated damaging wind and hail threat will still exist with the strongest storms. Still think the overall tornado threat is low, but not zero as the initially more favorable low level wind field should veer with time and create an overall more unidirectional shear profile. Previous Update... Issued at 537 PM EDT Sat Apr 30 2022 Things are quiet across our CWA at this hour, however convection is beginning to fire off to our west along two distinct axes. The lead line of broken convection is currently stretching from the Ohio/Mississippi River confluence up through the lower Wabash River Valley. Oddly enough, this convection is embedded in an area of minimal instability, but appears to be driven/forced by the narrow low level jet axis and/or some differential heating. A look at satellite imagery also shows the convection embedded in/near a corridor of heavy cloud cover, which makes sense that it is more forced given the overall instability minimum between our unstable, but capped environment, and the main instability axis farther to the west just ahead of the main front. Overall, don`t expect this lead convection to do much as it enters our CWA over the next few hours. HRRR has picked up on this activity, but shows it mostly weakening later this evening (at least initially). Although there isn`t as much concern for the initial convection, there is some concern for what could occur between 00-09z as a stronger core of the low level jet ramps up (40-45 knots), and enough instability (1000-2000 J/KG of MUCAPE) lingers through much of the overnight. We will be holding onto 500-1000 J/KG or less of SB CAPE by this time so a widespread severe threat should be somewhat diminished, however overall coverage and intensity of actual storms may increase through 03 or 06z given the added forcing. So, think that an isolated wind/hail threat could still be on the table overnight. The overall shear profile does look to become more unidirectional with time, although can`t rule out a few supercells (perhaps a few splitters?) in that 00-06z time frame given a somewhat veered profile. The overall low level shear component is lacking a bit for a more concerning tornado threat later this evening, but it isn`t zero either. Will have to see how things evolve, and if the low level winds stay backed or veer pretty quickly to a more unidirectional overall profile. Did also want to mention that we do have a moderate amount of instability over our area right now, however we are capped just above 700 mb. Outside of the convection entering our CWA from the west, this should mostly keep our area in check until the cap erodes between 00-03z. That timing also lines up with the arrival of the LLJ/forcing which also makes sense. So, the bottom lines is that the severe threat should begin increasing by 8-9 PM EDT. && .Short Term...(This evening through Sunday) Issued at 330 PM EDT Sat Apr 30 2022 ...Possible Strong-to-Severe Storms Tonight... Synopsis...An upper-level low and associated occluded surface reflection will slowly transition from the High Plains to the Upper Midwest. This will push a cold front towards the lower Ohio Valley tonight, so expect storm chances to ramp up after sunset. Meanwhile, central Kentucky and southern Indiana have been in the warm sector this afternoon with a higher than previously thought warming and destabilization given the early dissipation of the cloud debris. Models are generally depicting the current state fairly well; however, they start differing once the front moves through our area with varying degrees of convective intensity as the storms move to the east. Although the aforementioned scenario is certainly plausible due to the lack of diurnal instability, the strongest outputs represent a more continuous threat thanks to a sustained LLJ intrusion. Rest of Today - Tonight...The rest of this afternoon should stay partly cloudy with a low chance of isolated showers to the north while temperatures and dewpoints top around the low 80s and 60s, respectively. Then, the cold front will be entering southern Indiana by 1/00Z and progressively move through the rest of the forecast area until right before sunrise tomorrow when most of the storms will be moving east of I-75. As mentioned in previous forecast packages, there is a possibility of strong-to-severe storms for tonight, mainly along and behind the frontal line. The main severe threat with the strongest cores is damaging wind, although hail is not out of question if discrete organized convection is realized and lasts long enough. The current reasoning for tornado risk is very marginal given the rapid near-surface destabilization. Forecast soundings favor a conditional chance of a brief spin-up in southern Indiana in the early evening given the low-level kinematic and thermodynamic parameters. Nonetheless, deep layer shear will lag behind the warm sector and the frontal line, which undermines a greater confidence on storm organization and updraft maintenance. Finally, there is a marginal risk of localized flooding concerns west of I-75 that overlaps with the better storm coverage and healthier rain rates. However, it is important to note that the lowest 1-,3-hr FFG is placed at this moment around the Cumberland and an small section of the Bluegrass area. Taking into account the moisture content and slow Corfidi upshear vectors, some instances of flash flooding might occur in the previously-mentioned areas should the frontal line maintains the strong convection. Tomorrow...Improving conditions area-wide as the post-frontal rain exits to the east after sunrise. Temperatures will stay a few degrees above normal even though not as warm as today, for example. Sunday afternoon will be rain-free, with mostly clear skies, and gusty westerly winds. .Long Term...(Sunday night through Saturday) Issued at 205 PM EDT Sat Apr 30 2022 ...Chance of strong/severe storms Tuesday... Synopsis: Expect an active stretch of weather this coming work week as several upper waves are progged to move through the area. Chances of showers will be present through much of the week with the best chances for thunderstorms Tuesday and Friday as cold fronts sweep through the OH Valley. Discussion: By Sunday night, clearing skies will prevail as the cold front pushes east to the Appalachians. Pleasant conditions will continue through Monday early afternoon as surface high pressure skirts across the OH Valley under brief upper level ridging. Expect morning lows in the upper 40s to low 50s Monday with afternoon temperatures rising into the mid to upper 70s for most, while some urban locations and areas along the KY/TN border peak around 80 under increasing mid to high cloud cover. Tuesday will be our next active weather day as a closed 5H low over the Central Plains and associated surface low advances NE into IN/OH. Rain showers with embedded thunderstorms will spread across the area as a surface warm front lifts northward through the Commonwealth accompanied by a 45-50kt LLJ and a moist atmosphere thanks to deep SW flow. There is potential for strong to severe storms Tuesday as models advertise ample instability with CAPE values around 1500 J/kg alongside modest shear and surface dew points in the mid 60s. Model disparity exists as to exactly when and where the cold front will reside by Tuesday evening, but will closely watch this system as new data becomes available. Wednesday will likely see residual light precip in the form of either light rain or light drizzle for some as the system exits to the NE, but dry conditions should prevail for the latter portion of Wednesday through Thursday late morning as brief low amplitude ridging moves through the area. A cooler air mass and cloud cover will also serve to quell temperatures a bit with afternoon highs only reaching into the upper 60s to low 70s. Forecast confidence decreases beyond Wednesday as models greatly diverge in their handling of another closed upper low that will traverse the Rockies and head toward the OH Valley. GFS and CMC show the system moving rather progressively and pushing to our NE by late Friday night. This would likely lead to a dry Saturday (though GFS soundings do show lingering low level moisture indicative of a drizzle scenario through the early morning hours). The Euro on the other hand has a much slower solution with the surface low lingering over the OH Valley throughout the weekend. Will go with a model blend for now with mention of chance showers for Saturday, but this will likely change over the coming days. && .Aviation...(00Z TAF Issuance) Issued at 749 PM EDT Sat Apr 30 2022 Numerous showers with a few embedded rumbles of thunder have arrived near the HNB TAF site at this hour. Expect coverage and intensity to increase at the rest of the TAF sites between 10 PM and 2 AM EDT tonight as a stronger low level jet overspreads the area and the main frontal boundary arrives. Will mention prevailing SHRA with some VCTS and TEMPO TSRA to cover that threat. Also expect a brief window for VFR/MVFR threshold ceilings as the front passes in the pre-dawn hours. This will be accompanied by a shift in surface winds from SSW to SW or even WSW. Any MVFR period will be brief overnight. Expect skies to quickly clear out and prevail VFR for the daylight hours of Sunday. Gusty SW winds between 20 and 25 mph will be possible at times. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Mesoscale...BJS Short Term...ALL Long Term...CG Aviation...BJS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
637 PM CDT Sat Apr 30 2022 .MESOSCALE DISCUSSION... Issued at 628 PM CDT Sat Apr 30 2022 While our tornado threat continues to decrease across the area following the northward passage of the warm frontal boundary, the threat for severe weather will continue in the watch area for for the next couple hours (especially east of the I-39 corridor). Skies have cleared south of the warm front and ahead of the approaching cold front and this has allowed surface temperatures to warm back into the lower 70s amidst lower 60s dewpoints. The net result being increasing MLCAPE values just ahead of the cold front to around 1,000 J/KG per SPC RAP Mesoanalysis. Continued lower level confluence associated with the approaching cold front will thus continue to maintain the line of northeastward moving convection for at least next hour or two as it moves into eastern IL. The KLOT VAD wind profile along with recent radar imagery suggests that quasi linear storm clusters will be the primary mode of convection as it approaches eastern IL. The main severe threat with this activity for the next couple hours will be damaging wind gusts and hail. It appears the storms may begin to diurnal weaken as the approach the IN state line in the next couple hours. For this reason, the SPC is not currently planning a new watch downstream into IN, but this will continue to be monitored. KJB && .SHORT TERM... Issued at 308 PM CDT Sat Apr 30 2022 Through Sunday night... A tornado watch was recently issued for much of my northern IL counties, with the exception of Lake and Cook in far northeastern IL. The watch will run through 8 pm this evening. Increasingly diffluent upper level flow associated with the exit region of a mid/upper level jet max continues to overspread the northward shifting warm sector early this afternoon. This is noted by the recent uptick in thunderstorm development across western parts of the area. Severe concerns with these storms over the next few hours will be hail and possible tornadoes, especially with any storms that are able to root themselves near the surface warm front, where increasingly backed surface flow (hence higher effective helicity) resides. However, the main negating factor to the overall tornado threat continues to be the extensive stratus deck that has overspread much of northern IL, and is limiting further destabilization. This may limit the overall tornado threat, especially with northeastward extent into the Chicago metro area. Nevertheless, we will need to continue monitoring the storms as the strongest ones will be capable of producing some hail. Damaging winds will also become possible with the stronger storms amalgamate into clusters as they migrate eastward late this afternoon. Expect the storms to end from west east early this evening. Sunday will be a cooler and breezy day as the occluded surface low gradually fills as it shifts into the upper Great Lakes. Expect highs mainly in the 50s. KJB && .LONG TERM... Issued at 159 PM CDT Sat Apr 30 2022 Monday through Saturday... Following what will be a rather quiet Sunday, there will be no shortage of rain chances next week with a couple of more storm systems on the horizon. Monday will begin on a tame note with just some mostly cloudy skies and morning lows in the 40`s. Temperatures will climb into the upper 50`s and 60`s by the mid-afternoon with the help of some height rises aloft. Meanwhile, a negatively tilted trough will move through the Plains and into the Midwest through the day on Monday. As the trough propagates into the Midwest late Monday, it`s forecast to lose out on a good amount of it`s amplitude resulting in the associated surface Low steadily weakening as it too inches into the Midwest Monday night. However, the near-storm environment remains as such that a few thunderstorms still appear likely, some of which could be on the stronger side. The rain will arrive Monday evening as shower pop up along the system`s warm front and will continue through most of Tuesday. The greatest chance for seeing a few thunderstorms will occur Tuesday afternoon and evening as the Low pressure center passes through the CWA. The greatest potential for a couple of stronger thunderstorms appears to exist south of I-80, but this could very easily change as any little shift in the storm`s track. Additionally, if the storm`s center were to pass through the CWA as guidance currently suggests, highs on Tuesday will range from the lower 50`s in the northern CWA to the upper 60`s further south. Wednesday will feature a pretty good deal of sunshine, something we will not be seeing much of next week. We`ll be getting some sufficient, but brief, dry air advection aloft with higher pressure setting in from the northwest. Despite the sunshine and drier air, cool northerly winds will have us finding ourselves in the upper 50`s and lower 60`s once again on Wednesday afternoon. Cloud cover will build through the latter part of Wednesday as more moisture is advected in on the lee side of an enclosing trough. This trough will provide us with our second storm system of the week come Thursday. The forecast for the this system has changed quite a bit since this time yesterday. Whereas the upper level trough was originally slated to be progress through the lower Midwest dragging the surface Low well to our south through the lower Missouri and Ohio Valleys, now guidance has the trough moving through the heart of the Midwest bringing the surface low pressure center much closer to the CWA. An incredibly saturated profile will result in widespread rainfall on the northern flank of the storm. However, no instability means the rain will be purely stratiform in nature and shouldn`t amount to anything more than light to moderate showers. The rain will arrive as early as early Thursday morning and last through roughly the first half of Friday. Highs for the latter half of the week will remain fairly steady with upper 50`s and lower 60`s in the forecast. This includes on Saturday when we will finally see some more sunshine and primarily dry conditions to kick off the weekend. Doom && .AVIATION... For the 00Z TAFs... A second line of thunderstorms is en route to the terminals, with the exception of RFD whose thunderstorm chances have just about dissipated for the night. These storms are expected to reach the Chicago terminals shortly after 00Z and be short-lived likely remaining in the vicinity for only an hour or so. Heavy rain, strong wind gusts, and small hail appear likely underneath these storms. Such conditions could easily pull visbys down into MVFR or even IFR territory for brief periods. The thunderstorm threat should conclude with the passing of this next line, perhaps with the exception of a stray light thunderstorm or shower trailing behind. Winds throughout this event have been troublesome teetering back and forth between SW and SE. Wind are expected to establish a SSE direction immediately ahead of the line of storms and veer west of south behind the line. From this point on, winds should hold steady at a SSW to SW direction for the remainder of the TAF period. Gusts of 15-20 kts will persist through the remainder of the evening and through the night. Near daybreak Sunday morning, cigs are expected to drop below MVFR thresholds and the SW winds will increase slightly as the morning progresses. Conditions are then expected to be rather consistent with breezy SW winds and MVFR cigs through the remainder of the TAF period. Doom && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...Wilmette Harbor to Michigan City IN until 9 PM Saturday. Small Craft Advisory...Winthrop Harbor to Wilmette Harbor until 1 AM Sunday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1037 PM CDT Sat Apr 30 2022 .SHORT TERM... (Through Late Sunday Afternoon) Issued at 238 PM CDT Sat Apr 30 2022 The primary concern for the short term is obviously the ongoing threat for severe thunderstorms ahead of the cold front late this afternoon/early evening. All CAMS show convection across east central and southeast Missouri into southwest Illinois to a greater or lesser degree this afternoon and evening. The HRRR and HiRes-FV3 are perhaps the most robust, showing several discrete cells this afternoon, growing upscale into a line. SPC mesoanalysis is already showing 2000+ J/Kg SBCAPE that`s uncapped or virtually so. This might be a bit overbaked the RAP dew points are a little high compared to surface obs. That being said, the MLCAPE is 1000-1500 J/Kg and is forecast to increase over the next 2-3 hours, most likely due to dew point pooling ahead of the front, and some slightly steeper low level lapse rates developing due to daytime heating. 0-6km bulk shear is 40-50kts, with 0-1km shear of 20- 25kts, and some low level curvature to the hodographs, so rotating storms look likely, and all severe weather types will be possible including damaging winds, large hail, and a few tornadoes. Consequently, a tornado watch was issued a short time ago for southeast Missouri and southern Illinois until 01Z. After the front moves through this evening, we should see a drier airmass move into the Mid Mississippi Valley for Sunday. It looks breezy again tomorrow behind the front, particularly across northern Missouri and central Illinois where the pressure gradient will be tightest. West winds of 15-20mph with gusts in excess of 30mph look likely up there with somewhat weaker winds further south. The west wind won`t promote strong cold advection, so highs on Sunday will be similar to today`s across most of the area, but northern Missouri into central Illinois will see cooler temperatures than today as they will be closer to the cold core of the low over the Upper Midwest. Carney .LONG TERM... (Sunday Night through Next Saturday) Issued at 238 PM CDT Sat Apr 30 2022 Monday through Saturday next week should continue the active weather pattern with a train of short waves moving from the Pacific across the CONUS. The first wave is actually moving across the Pacific Northwest at this time and it will be dug in over Colorado by Monday morning. The resulting lee-side cyclogenesis will turn the low level flow back to the south over the Mississippi Valley which will bring rich low level moisture back into Missouri and southern Illinois. Deterministic guidance shows moderate to strong low level moisture convergence Monday into tuesday as the wave moves east- northeast across the Midwest resulting another round of wet weather for that time period. Deterministic guidance is showing 1000+ J/Kg of MUCAPE hanging across southern Missouri and Illinois Monday night into early Tuesday morning with 30-40kts of 0-3km and 0-6km shear respectively. SPC is hinting that we could see some nocturnal severe weather due to these conditions, and this looks reasonable at the moment. CAPE increases pretty rapidly on Tuesday ahead of the front thats associated with our short wave, so the severe weather threat may continue for parts of southeast MO/southern IL into Tuesday until the front pushes through. Current indications are that we`ll have a respite in the wet weather on Wednesday behind the front, but the next short wave digs into the western Plains on Thursday to set up a very similar pattern for late- week as we will see Monday and Tuesday. According to the deterministic models, Thursday-Friday will be wet and stormy again, with a potentially dry day on Saturday. WPC cluster analysis is showing some variance with the timing and amplitude with both the late-week short wave as well as the upstream ridge following in its wake. This obviously lends some uncertainty to the timing of the rain and the strength of any potential convection. Temperatures through the period continue to look mild to a bit cool with highs strong low level mi mainly in the mid 60s to low 70s and lows in the mid 40s to mid 50s. Carney && .AVIATION... (For the 06z TAFs through 06z Sunday Night) Issued at 1035 PM CDT Sat Apr 30 2022 Cold front and precipitation has moved well east of the TAF sites. So dry VFR flight conditions for TAFs along I-70 corridor. However, ceilings will lower across portions of northeast Missouri and west central Illinois due to wrap around clouds on back side of system. MVFR flight conditions expected at KUIN between 12z and 20z Sunday. Otherwise, gusty west winds which will diminish by Sunday evening. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Spokane WA
353 PM PDT Sat Apr 30 2022 .SYNOPSIS... Some showers will linger into Saturday evening. Otherwise drier, warmer weather is expected on Sunday as a weather system pulls away from the area. More rain is possible on Monday. Some locations may reach 70 degrees for the first time this spring Wednesday or Thursday, before the next system moves in. && .DISCUSSION... Tonight and Sunday: Band of stratiform rain over northern Washington into the North Idaho Panhandle will continue to stretch and weaken into early this evening as a closed low over NW Oregon drops south and away from the area. Meanwhile a cluster of showers and thunderstorms over NE Oregon developed this afternoon in response to sun breaks destabilizing the atmosphere. Lightning has been on the decrease but the area of moderate to heavy rain continues and will be pushing in towards the Blue Mountains and Camas Prairie this evening as well as the Lewiston area. Rain cooled outflow wind gusts of 25-35 MPH are possible between 4-6 PM this evening in these areas. Isolated thunderstorms are possible as well. Some of this activity may impact the palouse as well but with the low dropping south and away from the area into the evening confidence is lower. This activity will diminish overnight into Sunday morning as the low drops all the way into central Nevada by 18z Sunday. Lingering boundary layer moisture over the northern valleys and Spokane/Coeur d`Alene area and some breaks in the clouds overnight may allow for patchy fog development by Sunday morning. A short wave ridge moves over the region on Sunday for warmer and drier weather. High temperatures will rise back up towards seasonal normals in the upper 50s to mid 60s. JW Sunday night through Saturday: The potential for precipitation continues into early next week, followed by a drier and warmer pattern before the next trough and precipitation chances arrive Thursday onward. The pattern will also favor some breezy conditions and temperatures pushing above normal, especially around mid-week. First between Sunday night and Monday the next low (currently coming into the Gulf of AK) makes it ways into the region, with the model tracking its center just to the south of our CWA before it moves toward the Great Basin and ridging starts in for Tuesday and Wednesday. The low will start to bring precipitation chances toward the Cascades late Sunday night, then across the rest of our region Monday. However the track of the low will keep the the highest PoPs over over the Cascades and central to southeast WA and lower ID. Some model indicate the risk for heavier precipitation amounts over southeast WA/lower ID into Monday afternoon/Monday night. The NAM holds the precipitation back longest. Overall ensembles suggest about a 60 to 90% chance of wetting rains (>=0.10" of precip) over the west and southern CWA through 12Z Tuesday. But the amounts the NAM suggests are no favored by the ensembles which keep the potential for >0.50" of rain just to the southeast of our region. Additionally the passing trough carries some instability, which leads to the potential for about 10-15% chance for t-storms over the north and eastern CWA for Monday afternoon/early evening. For Tuesday and Wednesday the area, for the most part, dries out as a ridge builds in. An impulse riding down the backside of the exiting long-wave trough will keep some limited shower chances alive over the eastern mountains Tuesday, but otherwise look for a mix of sun and clouds. Then from Thursday to Saturday the ridge axis starts to shift east and a trough approaches the coast. Models do not agree on how quickly it moves inland, with the ECMWF slower and drier than the GFS. However either way the door is opened for impulsing riding in ahead of the trough in the southwest, with a milder and more unstable and moist atmosphere. Thus PoPs increase across the region. Overall there are about 15-20% PoPs over the Basin/Valley areas and the mountains zone have about a 30 to 50% chance at this point. This also includes about a 10-15% chance of t-storms over northern WA/north ID for Thursday afternoon. Chances will also have to be monitored for Saturday. Temperatures warm to near normal early next week, then push above normal into the middle of the week before cooling again some toward next Friday and Saturday. Wednesday and Thursday continue to look like the warmest days, with highs in the upper 60s to mid- 70s outside of the mountains. /Cote` && .AVIATION... 00Z TAFs: Expect deteoriating conditions at KPUW/KLWS this evening as band of moderate to heavy showers approaches. A few thunderstorms may develop around the Blue Mountains as well with low confidence of any of the terminals receiving a thunderstorm. Latest guidance suggests these will impact KLWS beginning with westerly outflow winds followed by moderate to heavy rain showers. KPUW may be on the fringes of this activity but current radar trends and latest HRRR model suggests some showers over the area this evening. Meanwhile a combination of precipitation and winds shifting to an upslope west-northwest direction will lead to lowering CIGS. HREF guidance shows a 70% chance of CIGS lowering to IFR overnight. Elsewhere rain is coming to an end with afternoon CIGS rising to between 2000-5000 feet. Fog and stratus are likely for the northern valleys around Winthrop, Omak, and Colville Sunday morning as some clearing combined with a moist boundary layer allows for fog/stratus development. Some fog patches are also possible around Spokane and Coeur d`Alene but with less of confidence of clearing VFR conditions are forecast. JW && .PRELIMINARY POINT TEMPS/POPS... Spokane 37 61 41 61 40 64 / 20 0 0 40 20 0 Coeur d`Alene 38 60 40 63 42 61 / 30 0 0 30 30 10 Pullman 39 56 41 56 39 57 / 50 10 0 60 50 10 Lewiston 44 63 44 60 44 64 / 60 10 0 70 50 10 Colville 36 65 41 65 40 71 / 20 0 0 30 20 10 Sandpoint 38 61 40 62 42 61 / 30 10 0 30 20 10 Kellogg 37 58 41 62 42 56 / 40 10 10 40 40 10 Moses Lake 37 67 45 60 39 70 / 20 0 0 60 20 0 Wenatchee 39 68 47 56 42 67 / 20 0 10 60 20 0 Omak 37 68 46 64 43 73 / 20 0 10 60 20 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
Area Forecast Discussion
National Weather Service Paducah KY
1010 PM CDT Sat Apr 30 2022 .UPDATE... Issued at 1010 PM CDT Sat Apr 30 2022 During the last 30 minutes, the western two thunderstorm clusters were beginning to become more outflow dominated. Although more unidirectional, KPAH VAD wind profile still showing an impressive 50kt southwesterly flow in the 2-7kft layer. There is still some potential for sub-severe winds during the next hour or two. Overall, the severe potential has decreased enough to let the Tornado Watch #164 expire at 10 pm CDT. Will be monitoring for some low-end wind gusts and potential for isolated flooding potential with thunderstorm clusters through midnight. UPDATE Issued at 752 PM CDT Sat Apr 30 2022 Per coordination with the Storm Prediction Center and NWS St. Louis, keeping current Tornado Watch Number 164 in place from 8 pm through 10 pm, covering the same area. Minor wave and low level convergence over southeast Missouri still supporting some increase veering through 12kft, with persistent 35-45 knot winds just off the surface near 1kft off the surface per the KPAH VAD wind profile. Decent dry line west of the current convection should be the tail end of the activity in the watch area during the next two hours. && .SHORT TERM...(Tonight through Sunday night) Issued at 130 PM CDT Sat Apr 30 2022 The RAP did a good job depicting the corridor of drier air over our CWFA centered between two low trop moist axis to our east and west. Surface dew points have dropped into the 50s most of the area, with a lot of debris cloudiness over the west 1/2 of the CWFA. SPC just issued a mesoscale discussion for our area. But overall our thinking has not changed. While there is certainly a risk for a few severe storms, we are not expecting a big event. Better forcing for ascent with jet dynamics stay more to our north. Not much speed shear with flow at and above 700mb staying in the 40-45 kt range up to near the EL. The one area we continue think might have the best chance of isolated severe is SEMO, into briefly far west KY and the southern tip of Illinois. This is supported by higher probabilities seen across this area in the SSCRAM (RAP/HRRR), with the most likely hazards marginally severe hail and high wind. After 00z, the low level flow actually weakens with 40kts of S/SW flow dropping down to 25 kts or so. MLCAPES that peak 1500 j/kg or slightly higher in the aforementioned areas quickly diminishes south as well. So the window of opportunity does not seem all that long into the evening. For storm mode, mainly clusters, or short line segments. There could be a brief supercell storm or two, again in the favored areas mentioned. As the parent system to our north heads into Canada, and after the weak front moves across the area, our chance for convection will end from west to east tonight, with dry weather expected Sunday and Sunday night. It will be breezy and warm Sunday. .LONG TERM...(Monday through Saturday) Issued at 244 PM CDT Sat Apr 30 2022 The first of many 500 mb shortwaves will set the stage for a fairly active week as the chance for pcpn will be on the increase during the afternoon Monday, especially across southeast MO. The period with Categorical PoP does not begin until Monday night as showers and tstms will increase in coverage across the FA. Elevated CAPE will be the greatest across southeast MO and the Purchase Region of west KY where SPC currently has a marginal risk for severe weather. The main hazard will be the potential for some hail. Risk for showers and tstms then continues through Tuesday as a sfc low pressure moves across the Ohio Valley with a trailing cold front. A few strong to severe storms with strong winds and frequent lightning are possible as GFS BUFKIT soundings show CAPE values around 1500- 2000 J/KG and steep mid level lapse rates. High temps during this period will range from the mid to upper 70s for most locations. The risk for showers and storms may linger into Wednesday morning if the front remains close enough to the FA, especially near the TN border. However, the more likely scenario is for the front to stall far enough south allowing for dry air to build in as a sfc high pressure passes by to the north. Pncpn chances will gradually lower from north to south. Temps will also be a bit cooler with highs only near 70 degrees. Lower confidence once again begins Thursday as models differ in the timing of a sfc low pressure system that looks to move through the lower Ohio Valley. The 12z ECMWF/CMC are in better agreement compared to the 12z GFS which remains the big outlier with pcpn arriving early Thursday morning. While PoP chances are more likely across western counties in the afternoon, would favor the Thursday night into Friday time frame for when pcpn will be the most widespread across the area. At the moment, it appears the greatest instability will remain to our south with more organized storms; however, it will not take much of a shift north with the sfc low to bring the better parameters for storms into the PAH CWA. Too early to go into details for Saturday as it is unclear how quickly pcpn chances will diminish. High temps will range from the upper 60s to mid 70s during the period. && .AVIATION... Issued at 620 PM CDT Sat Apr 30 2022 For the 00z Sunday WFO PAH TAF issuance, kept VFR ceilings and visibilities in advance of the primary storm line. With the supercell over Wayne county MO, leaned to MVFR ceilings and visibilities for the KCGI TAF with the potential for some small hail near the airport within the first 1-2 hours of the forecast period. If the cell weakens significantly before 02z Sunday, will likely drop any mention from the TAF. Otherwise, tried to keep any VFR/MVFR visibilities limited to a 1-3 hour time period with the main convective activity, persisting it a little longer for the KEVV and KOWB TAF sites through at least 05z. Beyond that time, VFR conditions will dominate the rest of the forecast period for all TAF sites. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...Smith SHORT TERM...CN LONG TERM...DW/SP AVIATION...Smith
Area Forecast Discussion
National Weather Service Phoenix AZ
513 PM MST Sat Apr 30 2022 .UPDATE...Updated Aviation Discussion. && .SYNOPSIS... A progressive weather pattern will remain in place through next week with weather disturbances passing north of the region. This pattern will keep temperatures in the mid 90s each day, with mostly sunny skies. Breeziness is expected each afternoon while windy conditions are likely Sunday and Tuesday, with each passing disturbance. Seasonably dry conditions will continue and no rain is expected through the next seven days. && .DISCUSSION... Latest RAP streamline analysis reveals a short-wave ridge across the intermountain West and a closed low across the Pacific Northwest. Across the Desert Southwest, the ridge has helped to boost temperatures several degrees today with lower desert highs in the mid 90s. Meanwhile, dewpoints are considerably lower than they were this time yesterday, generally in the teens and 20s. The aforementioned low pressure system will dive southeastward into southern UT by early tomorrow evening. PWATs of 0.2-0.3 inches remain insufficient for precipitation, instead main impact across our area will be an increase in wind Sunday afternoon. ECMWF EFI anomalies are generally less than 0.5, nevertheless the ECMWF ensemble indicates gusts of at least 30 mph will be likely in the Valley ahead of the trough axis. Stronger gusts will be possible across the higher terrain north and east of Phoenix, resulting in a high fire danger. && .PREVIOUS DISCUSSION... Brief shortwave ridging returns on Monday before yet another shortwave passes by to the north on Tuesday. This system will likely lead to another period of breezy to windy conditions, but at this time most guidance shows speeds a bit lower than Sunday. WPC cluster analysis shows good agreement on the pattern progression heading into the middle to end of next week, with about 75% of guidance suggesting somewhat stronger ridging will set in. The other 25% still show a warm and dry pattern, but perhaps a bit cooler and windier with a weak trough along the west coast. NBM temperature guidance reveals very little uncertainty for the next 5 days with high temperatures in the middle 90s. It does suggest that high temperatures may climb a bit under the stronger ridging, but with more uncertainty as well. The NBM temperature probabilities of reaching 100 F in Phoenix never climb above about 10% in the next week, so our first such reading will likely wait a little longer than typical. && .AVIATION...Updated at 00Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Winds will be light to moderate, aob 10 kts with a few gusts into the teens through the early evening and follow typical diurnal patterns. With an ozone air quality alert through this evening, there may be some increased haziness that could impact slantwise visibility early in the period. By mid-late Sun morning S component crosswinds near 8-11 kts are expected. By late Sun morning to early afternoon windspeeds will increase with the SW- WSW switch with gusts of 20-25kt through Sun afternoon and early evening. Mostly clear skies with FEW high clouds to become clear by later this evening or tonight. Southeast California/Southwest Arizona including KIPL and KBLH: Light winds will increase somewhat this evening by around 02Z at KIPL with gusts of 20-25 kts followed by S wind by mid morning Sun. Then gusty W winds resume again by early Sun afternoon with gusts upwards of 25 kft. Lighter winds at KBLH will favor normal diurnal patterns through midday Sun. Then gusty SW winds develop by early afternoon with gusts near 25 kts. Mostly clear skies with FEW high clouds to become clear by later this evening or tonight. && .FIRE WEATHER... A progressive weather pattern will remain in place with a series of troughs passing north of the region. This will keep conditions dry with very little cloud cover and no chance of rain in the next week. As is typical for this time of year, breezy conditions will develop each afternoon, but the breeziest days are expected to be on Sunday and again Tuesday, with the passing of the next couple of troughs. Wind gusts these days could reasonably reach 25-35 mph, especially over the higher terrain north and east of Phoenix. With above normal temperatures in the 90s (low elevations) and Min RHs between 5-15% each afternoon, elevated fire weather conditions will remain a concern through the forecast. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Red Flag Warning from noon to 10 PM MST Sunday for AZZ133. CA...None. && $$ Visit us on Facebook, Twitter, and at DISCUSSION...Hirsch PREVIOUS DISCUSSION...Hodges AVIATION...Sawtelle/Heil FIRE WEATHER...Hodges/Benedict
Area Forecast Discussion
National Weather Service Shreveport LA
908 PM CDT Sat Apr 30 2022 .UPDATE... Frontal boundary along a line from near Prescott to Shreveport to Nacodoches gradually moving east. Despite MLCAPE values of 3500 J/kg and steep mid-level lapse rates, convection has dissipated across most of the region with the exception of portions of south- central Arkansas. Latest HRRR model suggests convection to reignite within the next few hours along the front as it shifts south of I-20. Therefore, only made minor adjustments to the watch at this time, removing counties that are now on the drier side of the boundary and leaving the remainder of the watch intact. /05/ && .PREV DISCUSSION... /issued 635 PM CDT Sat Apr 30 2022/ AVIATION... For the 01/00z TAFs, convection continues along a cold front from near ELD to SHV to near TYR, progressing eastward. The front is forecast to stall across east Texas and north Louisiana overnight before lifting northward on Sunday. VCTS conditions expected across SHV/MLU/ELD/LFK terminal sites through the evening with VCTS conditions continuing across LFK through late morning Sunday. Otherwise, could see tempo MVFR ceilings across mainly MLU/LFK around daybreak, improving to VFR by 01/18Z. /05/ /05/ PREV DISCUSSION... /issued 330 PM CDT Sat Apr 30 2022/ SHORT TERM.../Tonight through Sunday Night/ At 20z, a cold front was located from near Hot Springs, to Ashdown, to Pittsburg, to Athens. Scattered convection has repeatedly tried to develop along the front in Southwest Arkansas but has struggled. Latest radar loops are indicating signs of development farther southwest into Central and East Texas, which suggests convective initiation is underway. Latest mesoanalysis suggests the atmosphere is strongly unstable, with CAPE values in excess of 3000 J/kg. However, there is little in the way of large scale forcing at present. That should change over the next several hours as a weak axis extending southward from a deep upper trough over Nebraska and Iowa moves across the area this evening and tonight. Convective coverage should continue to increase along the front. Despite deep layer shear of only 20 to 30 kts, the strong instability and steep lapse rates should be more than sufficient to support a risk for severe weather posing a risk for large hail and damaging winds. Low-level SRH values are rather modest, but an isolated tornado cannot be ruled out. The convection and the front will continue southward across the area tonight, and the threat for severe weather should end with the frontal passage. After midnight, the risk for any additional severe weather should be limited to Deep East Texas and Central Louisiana where the front is expected to stall. However, what little large scale ascent we have should be diminishing, so the convection should also gradually weaking and decrease in coverage, especially during the early morning hours. However, rain chances will persist along the frontal boundary. The front will rapidly return northward Sunday morning, and a few isolated showers or thunderstorms will be possible across our southernmost zones where moisture availability remains high. Little to no effect on our temperatures will occur, as daytime highs will still climb into the mid 80s areawide on Sunday. Chances for more showers and thunderstorms return Sunday night and into Monday morning as a convective complex develops ahead of the dryline over West Texas and moves east-northeast across the Southern Plains and towards the ArkLaTex. CN LONG TERM.../Monday through Saturday/ Well the weekend cold front is lifting back northward early, but will quickly get another push into our area mid to late day Monday. A short wave over the plains states with the GFS is an open wave of 561dam and the ECMWF is closed low at 560dam. Typically a much slower trend going forward in time and not as progressive open waves with all the rings of isoheights aloft. The ECMWF is the more optimistic for rain for us during this timeframe while the GFS struggles with not much signal anywhere in the midSouth. A deeper upper low will be on approach from midweek. The long range models are in good agreement on position of a core low in the deepening pattern over the Rockies. Once again this feature will activate the lift aloft for the SPC day 6 to highlight for us a Slight risk potentially. By Friday 00Z on Thursday evening we have some timing differences on players, but not so much on QPF signal. This may be the most we see all week with a stronger frontal approach and then a bubble high of 1015mb over MO. Conversely the ECMWF is preceding much slower with the upper on GFS in the western Atlantic, while the ECMWF has the upper low still over KY/TN. Little difference for us in the four state area as we are on the drier side of either solution. Next Saturday looks good for us in either case with a 1019mb air mass over the corn belt and the ECMWF 1017mb over NB/KN. So the bottom line is little change for our work week with more of chance for rainfall than not until that sfc front eases in for late work week. Expect unseasonably warm temps to continue with mid to upper 80s for highs and about 20 degrees cooler by comparison for lows. Even behind this front next weekend, the air will just be cooling down briefly like it has been all Spring. We are seeing average temps warm quickly during May with the longer days. /24/ && .PRELIMINARY POINT TEMPS/POPS... SHV 64 86 67 85 / 50 10 10 30 MLU 64 85 66 85 / 60 20 10 20 DEQ 52 84 62 80 / 0 0 40 70 TXK 58 84 67 82 / 0 0 30 60 ELD 59 85 63 84 / 50 0 10 40 TYR 61 85 68 84 / 10 20 20 40 GGG 61 85 67 85 / 20 20 10 40 LFK 66 85 67 87 / 40 30 10 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 05/09/20