Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/23


Area Forecast Discussion
National Weather Service Charleston SC
1012 PM EDT Tue Mar 21 2023 .SYNOPSIS... High pressure will remain the primary feature across the region through the rest of the week. A cold front is expected to pass through on Saturday, followed by unsettled conditions early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... The lower levels of the atmosphere are starting to moisten as evidenced by the 00Z soundings from KJAX and KCHS, and the Satellite Layer Blended Percent of Normal imagery. KJAX PWat is 0.91 inches (close to normal) while KCHS PWat is 0.47 inches (around 35% of normal). Dew points are gradually climbing through the 40s in most places, and dew point depressions are shrinking. The increase in moisture and the isentropic ascent will continue to produce a further development of stratocumulus from the south and southeast, along with cirrus clouds coming in from the west. Recent temp trends support lowering temps even more across many parts of the Charleston quad-county region, where radiational cooling will persist longer. We now have min temps as cold as near 40 degrees in the Francis Marion National Forest to the lower and middle 50s along the barrier islands. Cloud cover will put a damper on the hourly decline, and temps look to hold steady or even rise, most notably northern sections where sky cover will transition from clear to mostly cloudy/cloudy. Previous discussion... High pressure will pull further into the ocean off the mid- Atlantic region within the zonal flow aloft. During this transition an inverted trough becomes better defined off our coast. This feature doesn`t move too much toward shore through the night, but it does allow for onshore moisture advection to combine with increasing isentropic ascent on the 290K and 295K surfaces to cause increasing stratocumulus from south-southeast to north-northwest. Condensation pressure deficits seem a bit too high for any showers over land, but we do show "silent" 10% PoPs over coastal Georgia late. The increase in cloud cover and warm advection will allow for a much warmer night when compared to the past two nights. But temps will still be a challenge, as there will be decent radiational cooling early on, especially north and northwest until the cloud cover increases. This allows us to lower some temps, most notably in the Francis Marion, which will take the longest for skies to become mostly cloudy. Once the cloud cover expands, temps will generally hold steady the rest of the night. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Wednesday and Wednesday night: Aloft, zonal flow will prevail ahead of an advancing and building ridge centered across the Gulf of Mexico. At the surface, the day will begin with high pressure centered just off the Mid Atlantic coast and a coastal trough paralleling the Southeast coast. As the high shifts a bit further east, the coastal trough is expected to draw closer to shore and even push onshore during the afternoon. For the past several cycles, several model solutions have been depicting showers breaking out across the forecast area and the adjacent coastal waters. These showers will be forced by convergence within the coastal trough and the presence of a well defined thetaE ridge that is poised to extend inland into the forecast area. Solutions such as the HRRR and the HREF mostly isolated and light, and this makes sense given the presence of impressive precipitable water values (1.2-1.3 inches) but the lack of any significant large scale forcing for ascent. All of this to say, we have introduced a 20 percent chance of showers across much of the forecast area that roughly spans from the mid morning hours through the late afternoon. Shower activity should come to an end quickly through the evening and the rest of the overnight is expected to be dry. Temperatures are expected expected to warm considerably from previous days, though exact values will be tricky given the presence of cloud cover. Where more cloud cover is expected, highs should top out in the low to mid 70s which is basically from along the Savannah River eastward. Areas further to the west, and especially along and south of I-16, highs could reach the upper 70s. Thursday through Friday: Upper ridging will build across the region Thursday and persist through Friday. At the surface, high pressure over the Atlantic will extend westward into the forecast area providing a nice setup for warming conditions. The main forecast issue for the end of the week will be temperatures. Look for low to mid 80s on Thursday with mid to upper 80s being more common on Friday. The immediate coastline will be several degrees cooler each day thanks to what should be a progressive sea breeze each afternoon. Expect breezy conditions each afternoon overall, with the strongest winds expected Friday. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... The long term period will begin with a cold front quickly approaching the forecast area from the west Friday night and crossing the area on Saturday. The timing of this front has shown some run to run variable, with the overall trend showing a slightly later passage. The later this front arrives, the more time there will be for destabilization and the chances of thunderstorms will increase. Therefore, we have added in a slight chance of thunderstorms for Saturday. Also of note, model soundings show a nice increase in mid-level flow which would yield deep layer shear on the order of 50 knots. So, though there are lots of details to still iron out, we can`t completely rule out a low end severe threat. The front will move offshore Saturday night and then Sunday should be a relatively quiet day. As we move into early next week, model guidance now shows a front lifting into the area and producing unsettled conditions. Overall forecast confidence is quite low at the end of the forecast period. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Cloud cover will increase and eventually lower and thicken as a coastal trough offshore draws closer to the terminals. We have VFR at all sites tonight into the middle of Wednesday afternoon, followed by MVFR ceilings, especially at KCHS and KJZI. All sites have some chance of showers after 15Z Wednesday, and for now we have VCSH until radar trends become better defined. Extended Aviation Outlook: Brief MVFR conditions and light rain showers could impact the terminals Wednesday evening. Otherwise, VFR conditions should prevail. Breezy conditions are expected Thursday afternoon, and especially Friday into Saturday. In addition, can`t rule out a thunderstorm as a cold front crosses on Saturday. && .MARINE... Overnight: A 1032 mb high offshore the Delmarva will pull east, while an inverted trough sharpens across the immediate coastal waters. Typically this feature has a difficult time penetrating the cooler shelf waters, which will result in E and NE winds around 15 or 20 kt. There will be some gusts around 25 kt on the Georgia waters early on, but they look to be infrequent. The favorable onshore fetch will yield elevated seas as high as 4 or 5 feet within 20 nm and up to 6 feet further out, and we have a Small Craft Advisory on the Georgia waters 20-60 nm out. Wednesday through Sunday: Relatively light east to northeast flow will prevail Wednesday as a coastal trough lifts through the local waters. Behind the trough, winds will turn southerly to southwesterly Wednesday night and continue through Friday and into the weekend. Wind speeds will begin to increase Thursday, and especially Friday into Saturday as a cold front approaches from the west. In fact, conditions will increasingly become supportive of Small Craft Advisories Friday through Saturday for at least a portion of the local waters. Conditions should then improve into Sunday after the front moves through. Rip Currents: The combination of onshore winds, some swell energy, and favorable astronomical factors will continue to produce a Moderate Risk of rip currents at all beaches Wednesday. An elevated risk of rip currents is possible again on Thursday though overall conditions will be less supportive than in days past. && .TIDES/COASTAL FLOODING... One more round of minor coastal flooding will be possible with the Wednesday evening high tide around Charleston. The astronomical high tide will actually be at its peak (6.22 ft MLLW) Wednesday evening, and winds (though weaker) will still be easterly or northeasterly. High tide will likely peak right around the 7 ft MLLW threshold and a Coastal Flood Advisory could be needed. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ374. && $$ NEAR TERM... SHORT TERM...BSH LONG TERM...BSH AVIATION... MARINE... TIDES/COASTAL FLOODING...
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
805 PM CDT Tue Mar 21 2023 ...New UPDATE Marine... .UPDATE... Issued at 758 PM CDT Tue Mar 21 2023 Winds have diminished along the coast and will cancel the SCA for the near shore waters early. Winds are at SCEC levels over the offshore buoys, but the seas are still elevated and winds should pick up a little bit tonight as the low level jet increases to 30 knots. Sensors along the coast show vsbys have lowered to 2-3 nm. Will issue a Marine Weather Statement to cover the lower visibility in fog. With strong low level flow, not expecting the fog to become dense, but there could be some patchy dense fog at times during the overnight period. && .SHORT TERM... (Tonight through Wednesday night) Issued at 342 PM CDT Tue Mar 21 2023 Key Messages: - High rip current risk continues tonight, becoming moderate Wednesday. - Warming trend through Wednesday. An upper level short wave that brought cloudy skies and drizzle/light rain/patchy fog to South Texas, will exit to the northeast of the area by early evening. The RAP and HRRR indicated that light precipitation will continue across the Victoria Crossroads through early evening. Thus, kept a slight chance through 01Z for the northeastern CWA. Mid/upper level ridging will take place through tonight bringing drier mid/upper levels across S TX. Given the drier airmass aloft and continued low level moisture, fog will be possible tonight. However, winds will remain elevated, keeping the fog light and patchy. The upper level ridge will also lead to warmer temperatures with less clouds/more sunshine for Wednesday. Gusty southerly winds this afternoon, will decrease tonight, but remain around 5 to 15 mph overnight. Southerly winds are expected to strengthen Wednesday, especially across the Coastal Bend, in response to a tightening pressure gradient across S TX as low pressure deepens across W TX and northeastern Mexico. The combination of long period swells and a new moon will maintain a high risk of rip currents tonight. As winds become more southerly across the gulf and swell periods decrease, so will the risk of rip currents on Wednesday with the rip current risk expected to be moderate. && .LONG TERM... (Thursday through next Monday) Issued at 342 PM CDT Tue Mar 21 2023 Key Messages: -Winds could reach advisory conditions over the Coastal Plains and Coastal Bend Thursday ahead of the cold front -Chance of showers and thunderstorms Friday morning into the early afternoon hours -Fire weather conditions could develop Thursday morning in the Rio Grande Plains ahead of the front High pressure will remain over the Gulf of Mexico Thursday while a trough approaches the state from the west. This will allow the pressure gradient to tighten and create windy conditions across the area. Moderate to strong winds, RH values in the 30% range, and dry fuels may lead to brief elevated fire weather conditions Thursday morning into the early afternoon hours. Additionally, winds may reach advisory levels across the Coastal Plains and Coastal Bend, so will need to continue to monitor and issue a Wind Advisory in a later forecast package should this trend continue. The trough will travel eastward across the Plains and into the Great Lakes region Friday through Saturday, and will eject a weak front into South Texas during the day Friday. The front is not expected to bring too much in the way of rainfall to South Texas, with highest PoPs existing in the northern tier counties and into the Victoria Crossroads (20-30% chance). There is a slight chance of thunderstorms, though with SBCAPE on the lower side, expecting storms to be elevated in nature. Conditions will dry out in the wake of the front; however, onshore flow will return Saturday afternoon with PWAT values quickly rebounding to 1.5" by Sunday. A mid-level shortwave will allow for a slight chance of showers on Sunday and Monday. Another mid-level trough will move across the Rockies and into the Plains early next week; however, models remain pretty varied on timing and strength. && .AVIATION... (00Z TAFS) Issued at 655 PM CDT Tue Mar 21 2023 Low stratus/IFR ceilings have persisted over the central coast northwest toward BEA, while ceilings have lifted to low MVFR over the Victoria Crossroads. Weak low level warm air advection, with assistance from a weak mid level disturbance, will keep isolated to scattered light showers/MVFR vsbys going through mid evening from the northern Coastal Bend into the Victoria Crossroads. Low level southerly flow will increase to 30-40 knots during the night and spread westward into the Brush Country. Expect MVFR ceilings will return to the eastern Brush Country by 03Z and into the western Brush Country (LRD/COT) by 08Z Wednesday. IFR ceilings will be prevalent over the coastal plains from 06Z-15Z with patchy fog/MVFR vsbys possible. Improvement to VFR will occur from 17-19Z over the Brush Country as clouds scatter out, while ceilings will lift to VFR over the coastal plains by mid afternoon Wednesday. Gusty south-southeast winds are expected from 16Z through the afternoon over the coastal plains with gusts over 30 knots at CRP in the afternoon. && .MARINE... Issued at 342 PM CDT Tue Mar 21 2023 Patchy light rain is expected to continue through early evening, then slightly drier conditions filter into the area overnight with the precipitation exiting to the northeast. Winds are expected to decrease tonight with wind speeds dropping below advisory levels. However, seas will remain around 7 feet across the offshore waters through mid morning Wednesday. Therefore, have extended the Small Craft Advisory for the offshore waters until 10 AM Wednesday. Moderate to strong onshore flow and elevated seas will continue through early Friday morning with periods of Small Craft Advisory conditions possible through the week. Chance of showers and slight chance of thunderstorms on Friday as a cold front approaches the coast. Brief offshore flow may develop Friday night if the front pushes into the waters with weak to moderate onshore flow returning by Saturday afternoon. Another cold front may push through the waters Monday into Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 68 81 69 83 / 0 0 0 0 Victoria 67 80 68 82 / 20 0 0 0 Laredo 70 90 71 95 / 0 0 0 0 Alice 66 84 67 91 / 0 0 0 0 Rockport 66 77 67 78 / 10 0 10 0 Cotulla 68 88 70 95 / 0 0 0 0 Kingsville 68 83 68 89 / 0 0 0 0 Navy Corpus 68 76 70 77 / 10 0 0 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk until 7 AM CDT Wednesday for TXZ345-442- 443-447. GM...Small Craft Advisory until 8 PM CDT this evening for GMZ231-232- 250-255. Small Craft Advisory until 10 AM CDT Wednesday for GMZ270-275. && $$ SHORT TERM...TE LONG TERM....HA AVIATION...TMT/89
Area Forecast Discussion
National Weather Service Dodge City KS
505 PM CDT Tue Mar 21 2023 ...updated aviation section... .SHORT TERM...(This evening through Wednesday night) Issued at 357 PM CDT Tue Mar 21 2023 The mid afternoon water vapor loop and RAP analysis continued to reveal a rather perturbed west-southwest flow pattern across much of the CONUS. One embedded shortwave trough raced across Kansas earlier today which was located near St. Louis, MO as of 20Z. A weak surface low within the broader leeside trough pushed east into central Kansas, but afternoon surface observations were showing this weak surface low slowly dissipating as a new leeside low was developing across southeast Colorado. Tonight, the new southeast Colorado surface low will also push quickly east across Kansas through Wednesday morning as another in the series of low-amplitude shortwave troughs races across the Central Plains. In addition to this, a shortwave trough across Wyoming will move east tonight across the southern Dakotas, which will push a polar front south across Nebraska, reaching north central Kansas late tonight into early Wednesday morning. The strength of this cold frontal push into Kansas early Wednesday morning will be key to the remainder of the day forecast across our northern counties -- particularly the I-70 corridor. The latest forecast now calls for much of Trego and Ellis County remaining just north of this polar front all the way through the afternoon and early evening Wednesday...with areas of fog and low stratus through the late morning hours. The much more significant Southwest CONUS storm and associated intense jet streak out ahead of it...will favor eastern Colorado for the strongest low level response in terms of northward advancement of the polar front as a warm front. In fact, the latest 18Z NAM model that rolled in now has the front as far south as Jetmore at 21Z...keeping I-70 much cooler in the afternoon than our new going forecast of around 70 for Wakeeney and Hays. There is big temperature bust potential up along I-70 and even farther south toward Scott City to Larned line. Southwest of the front, the warm and windy forecast remains on target. That said, we will keep the High Wind Watch going for the western six counties (along/west of Highway 25), as 80% confidence for warning criteria being met is not there with this latest forecast update. The best forecast is peak wind gusts in the 50 to 55 mph range, but gusts up to 60 are still in question...at least enough to not warrant an upgrade to a warning. We will keep the "patchy" blowing dust going in the forecast for areas greater than 40 mph wind gusts and "areas" blowing dust for areas generally greater than 50 mph wind gusts, which matches fairly well with WFO AMA, PUB, and GLD (thanks for the collaboration). The Wednesday storm will rapidly shear out across Colorado and lift northeast across the Dakotas Wednesday night with trailing southwest to northeast upper level jet remaining in place all the way down to Baja Mexico where the next shortwave disturbance will be advancing from (see the Long Term section for discussion on this system). A lot going on...except for precipitation, unfortunately. .LONG TERM...(Thursday through Tuesday) Issued at 357 PM CDT Tue Mar 21 2023 As mentioned in the last paragraph of the Short Term section, a trailing upper level jet streak will extend down into Baja in the wake of Wednesday Night`s storm. This will result in only a modest cold front passage with fairly weak winds poleward of the front, as yet another surface low develops along the front. In fact, there may be more than one sub-synoptic scale surface low along the front from the Red River northwest up into the western Oklahoma Panhandle by late Thursday afternoon. This setup will keep our southwest Kansas region in the cooler airmass with northeasterly winds much of the day. As the next shortwave trough within the larger scale southwest flow pattern approaches Thursday Night, mid level frontogenesis will increase in the 800-600mb layer across southwest Kansas. This will favor at least light accumulating precipitation for our region. As a result, 12-hr POPs have been bumped up to 40 percent or slightly higher over a larger area of southwest Kansas for the Thursday Night and also Friday periods. The latest ECMWF deterministic model valid 18Z Friday shows a little more concentration and favorable shape/positioning of the mid level potential vorticity anomaly -- which would focus frontogenesis in the 800-700mb layer squarely across southwest and west central Kansas. All that said, the mid level wave will remain open, at least at 500mb and will also be moving fairly quickly during the day Friday, so while there is hope for widespread accumulating precipitation, the quantity of precipitation will likely be in the 0.20 to 0.35 inch range for much of the forecast area. This is suggested by the latest EPS means as the latest EPS 12Z run has a pretty nice greater than quarter inch signal across much of southwest and west central Kansas. The latest thermodynamic soundings for late Thursday Night and Friday suggest a cold rain event, although some wet snow cannot be ruled out before ending and/or in small regions of stronger mesoscale upward vertical motion. The Thursday Night into Friday storm system will eject northeast quickly and another one will be developing out across the southern Rockies/Southwest late in the weekend. NBM POPs continue to increase as confidence and model support increase (both deterministic and ensemble). This late weekend storm system looks colder, so probability of type being snow is better than the Thursday Night/Friday system. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 502 PM CDT Tue Mar 21 2023 GOES16 Day Cloud Phase Distinction product is showing areas of thin mid water cloud overspreading the west central and far south west central Kansas counties – and none of this will impact local terminals Tonight. Light and variable winds will continue to be the rule as well before a frontal boundary slides south into the area overnight, stalling probably south of Hays based on some of the models. Additionally, some lower ceilings might occur based on Hires Ensemble forecast for cigs < 1000 ft , but the probabilities are not very high, (mainly in the 50-60 percent range). And even at that, it’s likely to be limited in duration as the warm front redevelops, spreading north early Wednesday. Details on the ceilings levels at Hays will be tough to pinpoint now and may still be a challenge to forecast Tonight. && .PRELIMINARY POINT TEMPS/POPS... DDC 40 78 40 62 / 0 0 0 0 GCK 38 78 39 59 / 0 0 0 0 EHA 47 75 42 64 / 0 0 0 10 LBL 46 76 42 66 / 0 0 0 0 HYS 38 70 35 56 / 0 0 10 0 P28 47 82 48 66 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from 1 PM CDT /noon MDT/ to 8 PM CDT /7 PM MDT/ Wednesday for KSZ043-061>063-074>076-084>086. High Wind Watch from Wednesday afternoon through Wednesday evening for KSZ061-062-074-075-084-085. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...99
Area Forecast Discussion
National Weather Service Lincoln IL
832 PM CDT Tue Mar 21 2023 .SYNOPSIS... Issued at 832 PM CDT Tue Mar 21 2023 Breezy and damp conditions will prevail across central Illinois tonight with temperatures remaining nearly steady in the upper 30s and lower 40s. Warmer weather will arrive on Wednesday as highs climb well into the 50s. && .UPDATE... Issued at 832 PM CDT Tue Mar 21 2023 A few light showers linger along/northeast of a Bloomington to Mattoon line this evening as the short-wave trough responsible for the rain pushes eastward into Indiana. Based on radar timing tools and latest HRRR data, it appears the showers will end within the next 1-2 hours...followed by cloudy and mostly dry conditions through the night. A second short-wave trough further upstream across the Plains will arrive by Wednesday morning, but its associated showers will hold off until after sunrise. Low temperatures tonight will drop just a degree or two from current readings into the upper 30s and lower 40s. Thanks to continued brisk S/SE winds gusting 15-20mph, wind-chill values will dip into the 20s. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 357 PM CDT Tue Mar 21 2023 An upper level shortwave will continue to produce rain especially from near I-72 and southward this afternoon into evening, then depart quickly to the east this evening. However, warm, moist advection will continue behind this feature, and could continue to bring scattered showers through the night, although with less distinct lift and therefore lighter amounts likely. Another shortwave looks to bring another more distinct region of showers crossing the area sunrise to noon or so Wednesday, tracking roughly along I-72, and have higher chance PoPs for that. After that, a surface low will take shape in eastern CO and head eastward, with the attendant warm front lifting into central IL. Showers could continue through the day Wednesday, but thunderstorm activity looks minimal during the afternoon with stronger instability developing to the southwest behind the warm front. Subtle warm advection at the surface, southerly winds, and cloud cover look to bring mild temperatures overnight tonight, dipping to near 40 at midnight and then subtly rising the remainder of the night. Highs Wednesday should peak in the early evening behind the warm front, reaching lower 60s in the south, but likely remaining in the 50s for northern portions of the forecast area. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 357 PM CDT Tue Mar 21 2023 Main forecast concerns... 1. Thunderstorms, possibly severe, late Wednesday night 2. Heavy rainfall Thursday evening to Friday evening 3. Thunderstorms continuing into Thursday afternoon or evening Late Wednesday night the surface low approaching from the west arrives in west central IL, with several hundred J/kg elevated CAPE possible, and could result in some strong thunderstorms mainly with a potential for isolated hail north of I-72. Behind the low, a cold front will sag southward through the area Thursday, shifting precipitation chances southward through the area and possibly stalling out in southeast IL Thursday night into Friday as another low tracks out of the southwest along the front. Heavy precipitation could result especially from I-70 southward, where somewhere in the neighborhood of 3 inches could be common for Thursday-Friday night totals. To the north, amounts should taper off, being generally under an inch north of I-72. Severe thunderstorm potential looks rather low Thursday but not out of the question, with the front sagging through the area and limited instability of a few hundred J/KG CAPE. Friday evening, a potent low looks to finally arrive in southern IL. This will likely provide some more severe thunderstorm potential and heavy rain, but it is unclear how far north the track of this low will go. A few additional disturbances could track through the area over the weekend into early next week, but do not appear to be as strong/wet as late this week. Temperatures look to fluctuate near normal values in the Thursday through early next week period, with no snow forecast. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 640 PM CDT Tue Mar 21 2023 An upper-level wave is currently triggering an area of light rain across central Illinois...primarily along/east of a KPIA to KDEC line. The rain will persist at the E/NE terminals for a couple more hours followed by mostly dry conditions across the board for the remainder of the night. MVFR ceilings will lower to IFR by 02z-03z, then remain IFR for the rest of the 00z TAF period. S/SE winds will gust to around 20kt tonight, then gusts will increase to 20-25kt east of I-55 by Wednesday afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SYNOPSIS...Barnes SHORT TERM...37 LONG TERM...37 AVIATION...Barnes
Area Forecast Discussion
National Weather Service Lubbock TX
640 PM CDT Tue Mar 21 2023 ...New AVIATION... .SHORT TERM... (This evening through Wednesday) Issued at 309 PM CDT Tue Mar 21 2023 Early afternoon visible satellite imagery shows generally clear skies overhead with high clouds to our southwest and west over New Mexico. Temperatures at 2 PM are on track to hit forecasted highs in the 70s over much of the area, with breezy southwesterly winds at 20- 25 mph gusting to 30 mph through sunset. High clouds to our west will move over the area tonight, acting as a blanket and keeping low temperatures in the upper 40s and 50s. An upper low currently (2 PM) noted on upper-level water vapor and RAP analysis entering the west coast will continue its trek east and open into a trough. As this trough moves east, a lee cyclone over eastern Colorado will strengthen, bringing breezy westerly winds for tomorrow. Something that may help to tame winds some will be the potential for high clouds over the area during the day on Wednesday. These clouds may also knock temperatures down a few degrees compared to what is currently forecasted in the 80s. Clouds or no clouds, we will probably still climb to around 10 degrees above normal. These dry, breezy, and warmer-than-normal conditions will bring increased fire weather concerns and the potential for blowing dust tomorrow afternoon. Thus, a Fire Weather Watch has been issued for much of the area for tomorrow afternoon and early evening. More will be discussed about fire weather concerns in the Fire wx section of this discussion. GKendrick && .LONG TERM... (Wednesday night through next Monday) Issued at 309 PM CDT Tue Mar 21 2023 By Thursday morning, troughing will be established to our west over the Great Basin. Weak surface troughing will remain positioned across the forecast area with a dryline bifurcating the forecast area keeping surface moisture confined to the far southeastern Texas Panhandle and portions of the Rolling Plains. This is where some morning fog may be possible as Gulf of Mexico air continues to advect into the region. As the trough approaches the forecast area a surface low will emerge from southeastern Colorado and bring a Pacific cold front through the forecast area. This will bring some breezy westerly winds and drier air to locations on the Caprock which may allow for elevated fire weather conditions. East of this front, the northeast to southwest oriented dryline should remain in place across the eastern portions of the forecast area. Model guidance may be a bit aggressive with moving moisture out of the forecast area therefore as the cold front overtakes the dryline thunderstorm initiation is expected to occur within our forecast area with storms then quickly moving to the east and out of our area of responsibility. Depending on how quickly these storms exit the forecast area a severe weather threat may be possible across the eastern Rolling Plains but the greatest severe weather threat will remain east of our forecast area. Our upper-air pattern will remain nearly zonal through the remainder of the forecast period which will keep our forecast area quiet. Behind the front on Friday winds will be gusty out of the west during the day but gradually diminish during the afternoon hours as the core of the 700 mb jet moves east of the forecast area. While high temperatures will be cooler on Friday (mainly in the 60s) very dry surface air will combine with the strong winds leading to near-critical fire weather conditions area wide. Fire weather will also be the main concern through the rest of the weekend as the dry surface air remains in place although wind speeds won`t be quite as strong but still breezy. Another cold front is expected to drop south into the forecast area early next week dropping temperatures a bit more but with dry air remaining in place this will be a dry frontal passage. Fire weather concerns may persist through the middle of next week as well as dry surface air remains in place. /WI && .AVIATION... (00Z TAFS) Issued at 640 PM CDT Tue Mar 21 2023 Continued VFR. Outside chance tonight for some LLWS at all the terminals, although this remains marginal overall so will omit mention from the TAFs. Else, gusty SW winds of 20-30 knots will taper around sunset and then resume by late morning. && .FIRE WEATHER... Issued at 309 PM CDT Tue Mar 21 2023 A strengthening lee cyclone over eastern Colorado will bring breezy downslope winds to the region, resulting in warming and drying of the near-surface layer. This will allow for highs to be 10-15 degrees above normal, resulting in the potential of mixing up to 650 mb where 35+ kt winds will exist. Something that will help to reduce mixing, and warming to a lesser extent, is an expected high cloud layer over the region. However, there is disagreement in regard to how dense high clouds will be, with global data having thicker clouds than higher-res data. Nevertheless, warmer than normal conditions, min RH 12-18%, and winds 20-30 mph, along with drying fuel (ERCs exceeding the 70th percentile over the northern South and Rolling Plains and southern TX Panhandle) will still bring critical fire weather to much of the forecast area. Therefore a Fire Weather Watch is in effect for tomorrow afternoon into the early evening hours. GKendrick A Pacific cold front will move east through the forecast area on Thursday bringing breezy westerly winds to locations on the Caprock as well as drier surface air. This may lead to a period of elevated fire weather concerns across the western South Plains and far southwestern Texas Panhandle during the afternoon and early evening hours. More widespread critical fire weather conditions will be possible Friday and persist through the weekend as very dry surface air remains in place. Westerly winds will be strongest on Friday with sustained winds around 30 mph leading to RFTI values of 5-7 across a large portion of the forecast area. Wind speeds will diminish some for Saturday and Sunday but with sustained winds remaining around 20 mph RFTI values of 3-5 will continue to be possible. && .LUB WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Wednesday afternoon through Wednesday evening for TXZ021>037-039>042. && $$ SHORT TERM...10 LONG TERM....58 AVIATION...93
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CDT Tue Mar 21 2023 ...New UPDATE... .UPDATE... Issued at 747 PM CDT Tue Mar 21 2023 Light rain is slowly spreading across Middle Tennessee this evening. The 00Z sounding from OHX shows the results of considerable moisture advection the past 12 hours, with PWAT having jumped from 0.15" at 12Z to 0.70" now. The surface map shows a warm from extending across the Tennessee Valley, with existing showers all occurring north of the front. The latest HRRR shows at least scattered showers lasting through the night and tomorrow morning across Middle Tennessee, although QPF values remain relatively low. No forecast changes are planned this evening. && .SHORT TERM... (This afternoon through Thursday) Issued at 145 PM CDT Tue Mar 21 2023 Not a half bad day across Middle TN, though clouds continue to pile into the area ahead of our next weather maker. Radar across the mid- state has had these light returns all morning and into the afternoon hours. However with 30 deg dew point depressions across the area, rain is finding difficult to reach the ground. This will change as we move into the late afternoon hours. Heavier precip being shown across West TN will finally make its presence felt in our northwest counties over the few hours and this will spread across the rest of the area this evening. Rains will last through mid- afternoon tomorrow on the Plateau with expected rainfall totals averaging around 0.5". This current weather system will get completely out of here by sunset tomorrow and without a frontal passage, along with a strengthening upper ridge to our southeast, we are going to warm up considerably on Thursday. Many spots will be pushing 80 degrees. && .LONG TERM... (Thursday through next Tuesday) Issued at 145 PM CDT Tue Mar 21 2023 In any other forecast package, I`d be telling you that this Thursday warmup would be setting the stage for a classic spring-time severe weather threat. While a few strong storms and potentially even some marginally severe storms will be possible Friday evening, I`m still not completely sold on widespread severe chances with this next system -- but I am seeing a couple of things in forecast soundings that I`m paying more attention to. First, there`s more dry air aloft ahead of what looks to be a line of storms Friday evening. This could go towards intensifying updrafts, which has not been shown in previous model runs. Lapse rates are better than they have been, as well. CAPE is still not impressive. A few hundred J/Kg is still the best I see, but with the proximity of the surface low to Middle TN, we could get some frontogenetical forcing to help overcome a lack of instability. With that said, a line of thunderstorms is likely to move into the area Friday evening and right now, I like areas west of I-65 (and even better south of I-40) for a chance of strong to marginally severe storms. Biggest concern will be damaging straight line winds and maybe even some hail. Rainfall totals on the order of 1 to 2 inches will be possible, with higher amounts in our northwest counties. If it so happens that these totals come with just the line on Friday evening, some localized flooding will become possible, as well. The catch with this is the inconsistencies of QPF setup in the models during the day Friday. A couple models have showers and maybe few storms up in the LBTL area Friday afternoon, but many leave the entire mid-state dry due to atmospheric capping ahead of the front. It`ll be close, but if we can spread out the rainfall amount over 12 hours instead of 2-3 hours, flooding concerns should be pretty limited. What this does mean is my PoP forecast consists of a pretty tight gradient across the area on Friday. Coordination with HUN/MRX allowed me to eliminate some of the stray WPC QPF across the south and east during the 06-18Z time frame on Friday. (Deep breath) Storms should exit Middle TN Friday night and in their wake, we don`t get a big cool down (break for celebratory cheers). Temperatures should remain the 70s Saturday and Sunday, making for a very nice weekend. Models have been decently in agreement with rain chances returning Sunday night, but the evolution of this system is still quite in disarray. For now, we`ll carry a decent chance for just rain Sunday night into Monday morning. && .AVIATION... (00Z TAFS) Issued at 643 PM CDT Tue Mar 21 2023 Showers will impact Middle Tennessee terminals overnight and through Wednesday morning. Showers will slowly end from west to east Wednesday afternoon. Cigs will decrease to MVFR Wednesday morning with temporary reductions in visibilities with heavier showers. MVFR cigs may improve to VFR at the end of the forecast period, but will likely wait until after the taf period. Winds will be southerly for the forecast period. Winds will increase to around 10 kts by mid morning with some gusts to around 20 kts from late morning through the afternoon. && .PRELIMINARY POINT TEMPS/POPS... Nashville 49 65 56 79 / 90 80 0 0 Clarksville 47 65 57 78 / 90 60 10 10 Crossville 42 57 49 74 / 90 90 10 0 Columbia 47 64 54 78 / 80 90 0 0 Cookeville 45 60 53 76 / 90 90 10 0 Jamestown 42 57 50 75 / 90 90 0 0 Lawrenceburg 47 62 54 78 / 80 90 10 0 Murfreesboro 47 62 54 79 / 80 90 0 0 Waverly 45 65 57 77 / 90 60 0 10 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.......Rose SHORT TERM...Unger LONG TERM....Unger AVIATION.....Reagan
Area Forecast Discussion
National Weather Service Pocatello ID
119 PM MDT Tue Mar 21 2023 .SHORT TERM...Tonight through Wednesday night. A warm frontal boundary will approach from the south and expect snow to move south to north overnight tonight into Wednesday. A winter weather advisory is in effect for the Bear River Range where over 6 inches is expected through Wednesday night. Elsewhere 3 to 6 inches is possible in mountains with locally higher amounts far east at pass levels and 1 to 3 inches in Snake Plain. Expect a change to rain in magic valley Wednesday afternoon and a change or mixed precipitation American Falls to Pocatello. Snow levels reach valley floors again late Wednesday. Temperatures tonight will be near normal under cloud cover and remain well below normal Wednesday with highs in the 30s and 40s. GK .LONG TERM...Thursday through next Tuesday. A cold upper level trough remains anchored over the Western US through the period. Weather is expected to remain cool and unsettled. Models swing a series of shortwaves through the trough Friday and through the weekend, but are rather inconsistent with the timing. The wave on Friday appears the most consistent among deterministic models. The 06Z GFS/ECMWF ensembles are comparable with the shortwave, though the GEFS is slightly faster in timing. Winds will still be gusty on Friday and there may be some issues with blowing snow across the Snake Plain and Eastern Magic Valley. The weekend will still be dominated by a broad upper trough with fairly disorganized snow showers. Some convective instability is noted in the models, particularly in the afternoon, which may lead to some thunder or at least some enhanced showers with some graupel. Another upper low is seen in model forecasts early next week, leading to a continuation of unsettled weather. Hinsberger && .AVIATION...We sit between two systems today: a shortwave departing to the east, and a second that will lift across NV today. Current guidance shows improvements in ceilings this afternoon in wake of the departing wave. The second wave will draw in some snow late tonight, with best chances of onset as early as 06Z-07Z at PIH and BYI, and around 10Z to 12Z at DIJ and SUN. While NBM MOS is favoring MVFR conditions for the event, HRRR VIS guidance is indicating a band of VIS < 1SM surging northward with the snow around 09Z to 13Z. Interestingly, NBM MOS and HRRR are supporting fog development around DIJ this evening. Hinsberger && .PIH WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from midnight tonight to 6 AM MDT Thursday for IDZ060. && $$