Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/09/20

National Weather Service Albany NY
1036 PM EDT Wed Apr 8 2020 .SYNOPSIS... Weak high pressure will build in tonight, as clouds will increase ahead of the next system approaching from the west. A strong low pressure system and its cold front will bring showers, windy conditions and a chance of thunderstorms south of the Capital Region tomorrow. Much colder temperatures and windy conditions will persist Thursday night into Friday with accumulating mountain snowfall over the western Adirondacks and southern Greens. High pressure builds in Friday night into the weekend with fair and cool temperatures. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Clouds over the region are exiting and a zone of clearing will track through tonight. The zone of clearing and light winds will help temperatures fall to forecasted lows. Convection and convective debris will spread over the region later tonight and the leading edge of some rain will arrive just before daybreak in many areas. Just some minor adjustments to temperatures and sky cover through tonight. Previous AFD has a few more details and is below... The next potent short-wave will be approaching the western- central Great Lakes Region, and the Midwest tonight. Clouds will quickly thicken and lower with some isentropic lift ahead of the warm front to the system bringing some light rain predominately west of the Hudson River Valley prior to sunrise. The winds will be light to calm early, but then start to increase from the south to southeast at 5 to 15 mph shortly before sunrise. The winds should be strongest funneling up the Hudson Valley and in the confluent area of the Capital Region. Lows temps will be challenged by the clouds thinning, but then increasing. We tried to forecast mins close to the GFS/ECM/NAM MOS blend and have the lows between 2-5 am. Expect mid and upper 30s over the higher terrain, and upper 30s to lower 40s in the valley areas. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Tomorrow...A fairly dynamic wave and its associated cold front will impact the region in the late morning into the early afternoon. A deepening short-wave ahead the left exit region of a mid and upper level jet streak will impact the forecast area. Heights will be falling, and mid level lapse rates will be steepening, as the sfc low deepens to 980-985 hPa lifting north/northwest of Albany by 18Z. Some digging short-wave energy will allow for the trough to become negatively tilted. A couple of bands of showers and some thunderstorms could impact the region. The latest HREFS, 3-km NAMnest, 3-km ARW-WRF, and the 3-km HRRR are hinting at some elevated instability being over the area ahead of the cold front. MUCAPEs are in the 100-300 J/kg range especially closer to KPOU and the I-84 corridor. We are concerned a lack of heating or destabilization may inhibit deeper convection. The low-level winds are impressive, but a low-level inversion seen on the model soundings may inhibit strong or borderline severe winds making their way to the sfc. We are in decent agreement with SPC with the Marginal Risk grazing the southern 5 zones. We can not rule out a rogue isolated severe. Basically locations south of the Capital Region (We will break away these area in the HWO). We kept a chance of thunder in these areas, and went with slight chances over the Capital Region/Mohawk Valley/northern Catskills. We think these cells may fire along the prefrontal trough zone or just west of it. There may be a narrow cold frontal rainband that follows with the burst of strong cold advection. Some of the CAM`s and HREFS show this. Some of the wind gusts may flirt with wind advisory values, and bullet SPS statements may account for gusts 40-45+ mph. PWATs briefly rise above normal as some localized burst of rain are possible. Rain rates may briefly be about a quarter inch per hour. Along the triple point to the system, a secondary wave may form near Long Island or southeast New England. The trend will be for a dry slot to bust into the region from the southwest by the mid to later portion of the afternoon with brisk and cooler conditions. Expect west winds to increase to 15 to 30 mph with some gusts in the 30-40+ mph range. Max temps will be in the upper 40s to lower/spotty mid 50s in the valleys, and 40s to lower 50s over the mtns, but then fall off in the afternoon in the cold advection. Some of the showers will transition to snow over the western Adirondacks/southern Greens /2000-2500 ft range/ before nightfall. The NAM momentum transfer profiles indicate a few wind gusts may flirt with advisory levels at Albany prior to sunset. We will continue to monitor this. Thu night...A chilly cyclonic flow sets up over NY and New England, as a broad upper level trough will be over the Great Lakes Region, southeast Canada, NY and New England. Two low pressure centers will consolidate and merge near northern ME with wrap around moisture impacting the forecast area. Some moisture will be tapped from Lakes Ontario and Erie. We will likely see westerly upslope snows persists most of the night over the western Adirondacks/southern Greens with a few inches (a few localized 3" or so amounts are possible). Rain may mix with some wet snow in the Capital Region/Mohawk Valley towards sunrise. A coating to a few tenths may occur on the grassy surfaces in a few spots (better chance in the western Mohawk Valley). The winds will remain blustery overnight, and should crank up more towards day break. Lows will be in the mid 20s to around 30F over the mountains, and 30-35F in the valley areas. Fri-Fri night...Additional wet snow accums are possible Fri-Fri night over the western Adirondacks, and southern Greens. Another 1-3" may occur especially for the western Adirondacks. It is unclear if this will be occur over a 12-hr period, but some long duration tallies could be in a 2-6" before tapering FRI evening, but this is over several periods. The best would be northern Herkimer and extreme western Hamilton Counties. The winds will be blustery at 15-30 mph with some gusts in the 35-45 mph range. We may have to place a wind advisory for some locations on FRI (if widespread wind gusts of 46-57 mph are expected), as the 970 hPa cyclone spins over New Brunswick. The low-level wind fields are decent, but intervals of clouds with slight or low chances of light rain showers in the valley areas and the snow showers over the higher terrain /diurnal effects/ could prevent deeper mixing. We will leave this in the HWO for now. The upslope and lake enhanced snow showers should diminish Fri night with ridging building in from the south and west. Below normal temps for FRI with lower to upper 40s in the valleys, and 30s to lower 40s over the higher terrain. Expect 20s to lower 30s over Fri night with slowly diminishing winds. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Saturday-Saturday night, lingering cold cyclonic flow may favor lots of clouds to start Saturday, but rising heights and slow infusion of drier air from the west should allow for some clearing in the afternoon, especially in valley areas. Mainly clear and chilly for Saturday night. Highs Saturday in the 40s to lower 50s, except 30s across higher terrain areas. Lows Saturday night in the 20s to lower 30s, with some teens possible across portions of the SW Adirondacks. Sunday-Monday, remnants of upper level low, currently located off the southern CA coast, tracks across the southern Plains/MS Valley, and eventually into the Ohio Valley and eastern Great Lakes. Warm conveyor belt associated with system should move into the region late Sunday night into Monday, which is when highest probabilities for rain are indicated. However, some showers may develop ahead of the main forcing by Sunday afternoon, especially areas west of the Hudson River, where slight chance to low chance PoPs are indicated. There are some signals for briefly heavy rain to occur with this system late Sunday night into Monday morning, especially across the SE Catskills, mid Hudson Valley into NW CT and possibly the Berkshires, as a strong low level jet (at least +2-3 SD southerly component at H925 and H850) and PWAT`s of +1-3 SD cross this region. Can not rule out a few convective elements as well. In addition, with the strong low level jet, will have to watch for strong southeast winds across typically favored areas (within strong southeast low level flow regimes) of the Berkshires, Taconics and southern Greens late Sunday night through Monday morning. Highs Sunday mainly in the 50s for valley areas and 40s to lower 50s higher terrain, with some potential for even warmer max temps if thicker clouds/rain arrive later. Lows Sunday night mainly in the upper 30s to mid 40s. Monday highs could reach into the 60s in portions of the Hudson Valley and western New England, with mainly 50s elsewhere. For Monday Night-Wednesday, lingering showers could mix with snow across higher terrain areas by Tuesday morning in the wake of the storm system. However, main upper trough will remain to our west, with slow advancement toward the east Tuesday into Wednesday. Models exhibit uncertainty as to how this trough advances east, with some suggesting a gradual approach of the trough with some showers of rain/snow late Tuesday into Wednesday as it nears. Other models and some GEFs members suggest the possibility of a more organized storm system developing ahead of this trough within a strong low level baroclinic zone remaining nearby. For now, have indicated chance Pops for rain/snow showers Tuesday into Wednesday, but there is at least some possibility for a a steadier/heavier period of precipitation sometime in this time frame, some of which could be snow as colder air aloft works into the region. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Clouds exiting this evening and VFR conditions expected through about 10Z-12Z, when lower clouds and the leading edge of some rain moves into our region. Next system arrives tomorrow morning with a lowering and thickening of clouds once again. Light rain will begin around 12Z with ceilings trending down to MVFR. Periods of moderate to heavy rain are possible from 15Z to 19Z where ceilings and visibilities could periodically lower to IFR. A rumble of thunder cannot be ruled out with some of this activity. We only have enough confidence to add TS in a PROB30 for KPOU at this time, but it could extend northward to KALB and/or KPSF in later updates. Strong wind gusts could also occur in any periods of moderate to heavy rain. Rain will come to an end near or just after 19z as the cold front sweeps through. Prevailing VFR conditions return after 19Z. Winds will remain at less than 10 kT in variable directions early this evening, then light and variable at less than 6 Kt tonight. Wind will then pick up from the south to southeast Thursday morning at around 10 Kt with some gusts past 20 Kt, especially at KALB/KPSF. After the passage of the cold front, winds will shift to the west at near 20 Kt with gusts around 30 Kt. Outlook... Thursday Night: Moderate Operational Impact. Windy With Gusts To 30 kts. Chance of SHRA...SHSN. Friday: Moderate Operational Impact. Windy With Gusts To 38 kts. Chance of SHRA. Friday Night: Low Operational Impact. Breezy. Slight Chance of SHRA. Saturday: Low Operational Impact. Breezy. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: Moderate Operational Impact. Breezy. Chance of SHRA. Sunday Night: High Operational Impact. Breezy. Definite RA. Monday: High Operational Impact. Breezy. Definite RA. && .FIRE WEATHER... Weak high pressure will build in tonight, as clouds will increase ahead of the next system approaching from the west. A strong low pressure system and its cold front will bring showers, windy conditions and a chance of thunderstorms south of the Capital Region tomorrow. Much colder temperatures and windy conditions will persist Thursday night into Friday with accumulating mountain snowfall over the western Adirondacks and southern Greens. The RH values will increase to 85 to 100 percent Thursday morning, and will lower to 45 to 65 percent in the wake of the strong cold front. The RH values will be in the 65 to 90 percent range Friday morning. The winds will be light and variable direction at 5 mph or less early tonight and then will increase from the south to southeast at 5 to 15 mph Thursday morning. The winds will shift to west to southwest at 15 to 25 mph in the wake of the front with some gusts in the 35 to 45 mph range. Gusty west winds will continue Thursday night into Friday. A widespread soaking rain will occur with the frontal passage and surface low late Thursday morning into the afternoon. A few thunderstorms are possible south of Albany. && .HYDROLOGY... No widespread hydro problems are expected the next several days and at least through the weekend. High pressure will briefly build in through most of the night time period with dry weather. However, a strong front will bring more rain to the region on Thu. A quarter to a half inch of rain is expected Thursday with locally higher amounts. While this rainfall may cause some minor rises on rivers and streams, no widespread flooding is anticipated. Cloudy, blustery and cool weather, with more valley rain showers and mountain snow showers are expected for Thursday night through Friday night. Some light to isolated moderate amounts of snow are possible for the western Adirondacks and southern Green Mtns. Although most of the weekend will be dry, more rain looks to return for Sunday night through Monday. Another widespread soaking rainfall will be possible. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Wasula NEAR TERM...NAS/Wasula SHORT TERM...Wasula LONG TERM...KL AVIATION...NAS FIRE WEATHER...Wasula HYDROLOGY...Frugis/Wasula
Area Forecast Discussion
National Weather Service Birmingham AL
1007 PM CDT Wed Apr 8 2020 .UPDATE... Evening Update. && .SHORT TERM... /Updated at 0947 PM CDT Wed Apr 08 2020/ Quite a volatile atmosphere across Central Alabama. In fact, the airmass covers a large section of the central Conus. Severe thunderstorms that moved over the southern third of the area have since dissipated after producing large hail and damaging winds. The atmosphere in the south has been mixed up and this is where the most stable air resides at this time. Low level isentropic lift is already working the air in Central Alabama. The latest satellite imagery has low clouds and fog developing. Will mention some patchy fog, some of which could be dense at times. This will only occur ahead of the developing thunderstorms and will also provide a near surface stable zone. Concerning the severe potential overnight, we will continue advertising damaging winds, hail up to ping pong ball size and the outside shot at a tornado. This activity will be associated with an approaching cold front from the northwest. Timing remains about the same after 1-2 am and lasting until just after sunrise. MUCAPE values may be as high as 2500 with bulk shear of 50kts or so. There will be plenty of CAPE in the hail growth zone and 500 temps go down overnight. The mean relative humidity values do drop as the forcing approaches the I-20 corridor and therefore that seems like a reasonable break point for slight and marginal due to coverage. Additionally, the large scale forcing does skirt the northern areas and exits northeast by daybreak. 75 Previous short-term discussion: /Updated at 1002 AM CDT Wed Apr 08 2020/ Through this evening: Current satellite imagery & RAP mesoanalysis indicate a broad fetch of lingering low-level stratocumulus amidst southwesterly low-level warm/moist advection. Some patches of clearing can already be picked out, with storms already ongoing near the ArkLaMiss. Dewpoints in the mid 60s (mainly northeast) to low 70s suggest MLCAPE of 1,000- 1,500 J/kg as of ~10 AM , with diurnal heating into the upper 70s lower 80s increasing this to ~2,000-3,000 SBCAPE per our modified 12z RAOB. Focus for convective initiation is subtle, though with WAA and a diffuse theta-e boundary draped from northwest to southeast, thunderstorms that get going in the early afternoon could quickly strengthen to severe limits as eff. bulk shear runs ~50 kts via the H5 speed max aloft, and relatively unidirectional hodographs support robust/splitting updrafts. 500 mb temperatures range from -10 to -12 C, suggesting decently cooler air aloft despite effects from deep- layer ridging southward, as well as drier air near that layer. (This would favor wet-bulbing and potentially enhance buoyancy in the hail growth zone.) All things considered, 1-2" hail is possible in stronger storm cores this afternoon with expectation the most favorable zone for convective activity will stretch from northwest to southeast across the center of Central Alabama, generally along near the lingering/subtle surface boundary dividing the upper 60/lower 70 dewpoints. Damaging winds are also possible as stronger convective downdrafts tap into 800-1,000 J/kg DCAPE and likely cluster/cold pool with southeast progression later in the afternoon/evening. Severe weather timing still remains advertised from 1 PM to 9 PM with large hail and damaging winds the primary threats. 40/Sizemore .LONG TERM... /Updated at 417 AM CDT Wed Apr 08 2020/ Friday and Saturday: Cooler and drier air builds in as ridging slides across the Gulf States on Friday. Upstream, the cut-off low pressure system that has been hanging back over the Desert SW for several days gets picked up by the main upper level trough and slides eastward through the Great Plains. Rain chances could increase Saturday afternoon into the evening as a pre-frontal shortwave lifts out of the Western Gulf. Sunday: The trough is expected to swing through the region on Sunday, and will likely be the main story weather-wise for the next several days. A surface low develops and lifts northeastward into the Mid-MS Valley. This will be a highly dynamic system with strong low level and upper level jets, increasing the 0-6km shear to upwards of 70+kts. There will be plenty of forcing as the trough and low pressure system move through, so expect widespread showers and thunderstorms to develop. The biggest question right now is instability and timing. The Euro shows the warm front lifting well to our north, placing Central AL in the warm sector of the developing low. It also has a slower timing overall, which allows for more destabilization. However, the GFS is quicker and doesn`t lift the warm front as far north, which could limit how much instability we have. The GFS also continues to develop some convection along the coast, which could limit our instability as well. Overall, given the strong dynamics of this system and the thermodynamics currently shown in the model guidance, I`ll add mention for a slight risk of severe weather for Sunday with damaging winds, hail, and tornadoes possible. Exact timing remains uncertain as model guidance continues to flip back and forth. This has the potential to be a strong system, so it will need to be monitored closely. Monday and Tuesday: The trough is expected to move east of our area by Monday morning, and drier air builds in. Guidance hints at a secondary cold front moving through the region Monday night into Tuesday, but there shouldn`t be any precip along the boundary due to the lack of moisture return. 25/Owen && .AVIATION... 00Z TAF Discussion. A cluster of showers and thunderstorms will continue along and south of I-85 thru 02z, otherwise VFR conds will prevail thru 06z. A strong cold front will push thru Central Alabama between 08z and 15z. A line of strong to severe storms will accompany the cold front. The storms will not last for more than a few hours due to the quick movement of the cold front. Warm and moist southwest flow will bring widespread MVFR cigs to the area between 06z and 09z. The cigs will rise quickly several hours after fropa, with VFR conds at sites by 16z. North winds 10-15 kts will prevail after 15z with gusts to 18 kts. 58/rose && .FIRE WEATHER... A cold front will sweep through Central Alabama late tonight and Thursday morning. A line of strong to severe storms will accompany the frontal passage. The rain will not last for more than a few hours due to the quick movement of the front. Cooler and drier conditions will prevail Thursday and Friday. Rain chances return for the weekend as another system approaches. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 60 71 46 63 38 / 60 10 10 0 0 Anniston 64 73 48 63 39 / 60 20 10 0 0 Birmingham 65 74 50 64 42 / 60 10 10 0 0 Tuscaloosa 65 76 51 67 43 / 50 10 10 0 0 Calera 64 75 50 66 42 / 60 30 10 0 0 Auburn 63 77 52 66 42 / 30 30 10 10 0 Montgomery 68 80 54 70 44 / 20 30 20 10 0 Troy 68 81 55 70 45 / 10 30 20 10 0 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$
Area Forecast Discussion
National Weather Service State College PA
955 PM EDT Wed Apr 8 2020 .SYNOPSIS... Expect a short break from the mild spring pattern with noticeably colder conditions and gusty winds Thursday and Friday. A strong cold front will deliver much colder air on Thursday. It will be cold enought for scattered snow showers over the Allegheny Mountains Thursday night through Friday. Conditions will improve over Easter weekend with subsiding winds and moderating temperatures. Next week will start off wet. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A quiet evening with mostly clear skies throughout central PA. Clouds increase later tonight ahead of approaching secondary cold front. Showers associated with this front will reach my western zones before daybreak. Mins will range from the mid 30s north to the mid to upper 40s southeast. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... A strong cold front will sweep across the area tomorrow accompanied by gusty rain showers. A narrow ribbon of weak instability along/ahead of the front along with strong winds aloft will support marginal tstm wind threat primarily east of the I-81 corridor during the late morning to mid afternoon. Strong post-frontal winds are expected to drive much colder air into the region through late week. 35-45 mph gusts will impact the Lower Susq and a Wind Advisory has been issued from mid morning through the afternoon hours. Gusty winds will continue Friday as well accompanied by below normal temperatures, bringing a chilly bite to the air. Temp curve should be limited to non- diurnal tomorrow as strong CAA kicks in. Friday will be the coldest day with highs 10 to 20 degrees below average (mid 30s NW to upper 40 SE). Persistent and relatively cold cyclonic flow will change rain to snow showers over the Alleghenies with a few inches of accumulation likely over NW PA and favored upslope areas Thu night - Friday. Snow showers taper off Friday evening with gradually improving conditions into Easter weekend. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... The extended period begins cold as Canadian high pressures builds into the region Friday night, maintaining breezy conditions overnight that should prevent widespread frost from forming over the Lower Susq. High pressure crosses the area on Saturday with moderating temperatures (still below avg highs) and dry conditions. Temperatures continue trend warmer on Sunday with increasing clouds as high pressure slides off the East coast. Widespread rainfall expected to begin early next week with anomalous moisture flux spreading into central PA in advance of low pressure tracking northeast from the lower MS Valley. Showers remain possible on Tuesday with secondary cold front crossing the Appalachians, followed by another shot of colder air for midweek. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... As of 00z Thu, skies have cleared out at all airfields. Will maintain VFR conditions through at least 06z. HRRR model tracks remnant rain showers from MCS currently over IL into southwestern airfields by 08z and through the southeastern airfields by 12z. Confidence is low in whether this rain will hold together as it moves across the area late tonight. More well defined forcing for a narrow band of rain showers moves into northwestern airfields by 11z in the form of a strong cold front, with showers pushing through to the southeastern airfields by 16z Thurs. Ahead of this cold front, models indicate pockets of 35-40 kt LLWS from 09z to 15z as 50 kt southerly LLJ moves overhead. Behind the cold front, sfc winds shift to 250-280 degrees and low level mixing will allow for wind gusts of 30-40 mph Thurs afternoon. Scattered rain showers in post frontal airmass may mix with snow and graupel in central and northern airfields Thurs night. .Outlook... Fri...Low cigs/rain/snow showers likely NW 1/2. Gusty winds 25-35kt from 270-300 degrees subsiding Friday night. Sat...Low cigs psbl early then trending VFR. Light rain showers psbl late. Sun...VFR early. Chance rain showers by aftn. Strong/gusty southerly winds psbl Sunday afternoon depending on track/development of sfc low forecast to move east from the Mississippi Valley. Mon...Reduced cigs/vsbys in widespread rain. Strong/gusty southerly winds continue turning westerly late in the period. && .CTP WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 10 AM to 6 PM EDT Thursday for PAZ036- 056>059-063>066. && $$ SYNOPSIS...Gartner/Steinbugl NEAR TERM...DeVoir/Gartner SHORT TERM...DeVoir/Gartner LONG TERM...Jurewicz/RXR/Colbert AVIATION...Colbert
National Weather Service Eureka CA
332 PM PDT Wed Apr 8 2020 .SYNOPSIS...Dry weather is expected to persist for most of our region into next week. Above normal temperatures are expected in the interior, though somewhat cooler high temperatures will filter in toward Friday. Marine layer cloudiness will gradually expand along the coast through the end of the week, keeping conditions there seasonably cooler. && .DISCUSSION...Marine layer cloudiness dissipated fairly early this morning, with mostly sunny conditions for the vast majority of northwest California this afternoon. The lower atmosphere has become unstable enough over the mountainous terrain of southern portions of our area to allow for some decent cumulus growth there, aided by some mid-level moisture. However, there is a strong enough capping inversion to limit any shower development. Low pressure spinning over southern California is resulting in plentiful shower and some thunderstorms there, and will try to send a spoke of deeper moisture toward Lake County late tonight, but aside from a thickening of the clouds already passing by there, do not expect showers to make it that far north. That area of low pressure will continue to drift southeastward across the southwestern United States over the next couple of days, with generally drier and more stable air moving in. Another upper-level trough dropping in from the northwest will clip our area over the weekend, and with that there is a non-zero chance of isolated shower development over the interior mountainous terrain, but am skeptical there will be enough moisture, so we have not included it in the forecast at this time. To summarize, expect dry weather across our forecast area through at least the middle of next week. With that cleared up, our focus will be on coastal stratus and temperatures. An inverted surface trough will shift off the Mendocino coast tonight, allowing southerly winds to send marine stratus northward toward Cape Mendocino. Some stratus or fog may try to creep into the lower Eel River Valley tonight, but overall thinking it will turn out clearer than last night to the north of the cape. While coastal areas south of the cape may stay cloudy through much of the day on Thursday, stratus may start to creep around to Humboldt Bay on northward by the afternoon hours. Where stratus does not reach during the afternoon, it will be another mild day, especially farther inland. That said, high temps will start to take a step back through Friday as the marine layer deepens. At least overnight and morning low clouds will linger along the coast into the weekend. Northwest breezes will be found during the afternoon hours where clearing occurs. Temperatures will remain near or above seasonal averages through much of next week, with overall a fairly quiet and benign weather pattern persisting as strong upper-level high pressure remains anchored over the eastern Pacific. /AAD && .AVIATION...Low clouds and some light fog across portions of the coastal plain and interior valleys have dissipated nicely today courtesy of warmer temperatures and a shrinking marine layer. Expect low clouds to expand along portions of the coast again this evening and overnight, but they are expected to be less expansive than last night. However, a southerly surge of moisture is expected to commence along the coast S of Cape Mendocino by Thursday morning, expanding coastal cloudiness northward. High resolution HRRR guidance shows this surge continuing N around the cape by early afternoon with the potential for low ceilings by late in the forecast period. Mostly VFR conditions are expected to continue at KUKI through the period. Earlier model guidance suggested low-level winds would increase after midnight at KUKI with marginal potential for low- level wind shear, but this may be a bit overdone. /SEC && .MARINE...High pressure over the NE Pacific continues to promote a strong northerly wind regime over the northern CA coastal waters through the end of the week and beyond. Short period seas will continue to build today in response to the prolonged northerlies, with the worst conditions remaining over the outer waters. Increased offshore flow on Thursday may induce a brief weakening trend in the winds south of Cape Mendocino, but the steep short period seas will likely be enough to sustain the Small Craft Advisory through that time for the southern outer zone. Meanwhile, stronger winds and higher seas in the nearshore zones will generally be confined to the typically favored locations near and downwind of Point Saint George and Cape Mendocino over the next few days. The nearshore waters along the Mendocino Coast will remain a little more sheltered from the northerly wind-driven waves, and thus no advisory is anticipated for the southern nearshore zone at this time. /CB&SEC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until noon PDT Thursday for PZZ450-475. Small Craft Advisory until noon PDT Friday for PZZ470. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
925 PM CDT Wed Apr 8 2020 .UPDATE... Despite ample shear and a strongly unstable atmosphere, the lack of any sustained lifting mechanism prevented severe storm development this afternoon and evening. A few pulsey cells developed and dissipated, with radar imagery generally clear at this time save a few bat colonies and a weak shower in Dimmit County. HRRR continues to indicate that an isolated shower/storm may impact far southwestern portions of the area overnight, however generally most locations will remain dry until more widespread showers and storms are able to develop Thursday afternoon ahead of a cold front and upper level disturbance. Those storms will have the potential to become severe with large hail the primary threat followed by gusty winds and locally heavy rainfall. && .PREV DISCUSSION... /ISSUED 628 PM CDT Wed Apr 8 2020/ AVIATION... VFR conditions are expected overnight at all sites. Chances for thunderstorm development near the terminals this evening appears very low and so VCTS mentions have been removed. Around sunrise, some light fog will probably develop at AUS and SSF, and potentially at SAT, but won`t stick around long and MVFR visibility should be predominate. VFR conditions should return much of the daytime. As a cold front and upper level disturbance approach on Thursday afternoon, shower and storm activity is expected for the I-35 sites. There is much higher certainty in convective development occurring tomorrow than there was today. Although the best environment for strong storms should remain southeast of the terminals, the potential is there for a few large hail or gusty wind reports. VCTS is included in the TAF at this time, but will likely be upgraded to TSRA as confidence increases in subsequent forecasts. For the 30 hour sites, some of this activity may linger past 00Z on the 10th, but confidence is lower so have opted for VCSH for that period at this time. PREV DISCUSSION... /ISSUED 337 PM CDT Wed Apr 8 2020/ SHORT TERM (Tonight through Thursday Night)... While fairly quiet at the moment, there is some initial development of convection along the I-35 corridor as this is being typed. With a moist and unstable airmass in place in place, a eastward mixing dryline moving across the area aide in convection. High CAPE values of 3000-4000 J/kg are present with, now, little to no inhibition as destabilization is occurring with daytime heating. With continued development along the I-35 corridor, the potential for convection to become severe is justified. Day one of the Storm Prediction Convective Outlook has most of the area under a slight risk with large hail, potentially being greater than 2 inches in diameter, being the main threat with strong wind gusts. As convection continues into the afternoon and early evening, activity should move eastward and weaken after sunset. Tonight, convection decrease and becomes a non-threat. Temperatures and dewpoints remain relatively high, giving us another warm and muggy night with low temperatures in the low 70s. Early morning cloud return with possibly some areas of light fog. Tomorrow, with the moist and unstable airmass still in place, a cold front is progged to be draped across the Edwards Plateau. The dropping cold front will be aided by a short wave moving across South Central Texas. The front will provide better lift than what is being observed today, and coverage and intensity of convection could be greater and more widespread. An area of Slight risk covers the Hill Country and I-35, and a higher risk of Enhanced has been added to the area between Interstates 10 and 37, by the Storm Prediction Center with an initial threat of large to very large hail, then transitioning to a damaging wind threat should the activity become more linear. Meso models are currently showing initiation over the Hill Country and Edwards Plateau around 3 to 4 pm local, and moving into the I-35 corridor between 4 and 6 pm. Locally heavy rainfall is also a concern for these storm and areas could see up to 2 inches in a relatively short period. The Weather Prediction Center has the area highlighted enhanced for excessive rainfall for tomorrow. This means that there is a 5 to 10 percent chance that the rainfall exceeds the flash flood guidance and may be subject to flash flooding. Turn Around Don`t Drown. Tomorrow night, convective activity moves east and the severe threat diminishes with only some residual light showers. Low temperatures will be in the low 60s overnight. LONG TERM (Friday through Wednesday)... The first part of Friday should have most of the atmosphere worked over through either the post-frontal winds or the storms themselves. Thus Friday morning may begin uneventful. The Rio Grande Plains may still be able to see a rumble or two, as the frontal layer should be more shallow there. However, overrunning embedded shortwaves should enhance rain and storm potential as the day goes on and eventually expanding east across the whole area by early evening. QPF amounts are probably going to be lightest during this stormy period, but there should be enough instability out west for a few marginal hailstorms. Later in the night, surface winds begin to increase out of the east and southeast as the parent upper low gets closer to the Southern Plains. At this point the threat for locally heavy rainfall (generally 1-2 inches) may become cumulatively the more impactful time that runoff could cause flooding. Similar to the WPC day 2 outlook the area of runoff concern should be mainly eastern Hill Country, I-35, and the Coastal Prairies. Dynamics/shear will probably be stronger with this round of activity, but with a reduced amount of CAPE, so the magnitude of the severe potential may also match that of Thursdays event. By Sunday morning even the slower ECM/Canadian solutions pull the deeper convection west to east for all rains ending, by no later than midday. The rest of the forecast is for a cool and dry period late Sunday through next Wednesday as broad polar troughing over the Central US reinforces the front in the wake of the southern stream upper low. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 70 84 60 73 62 / 20 60 30 30 50 Austin Bergstrom Intl Airport 68 83 60 74 61 / 20 60 30 30 50 New Braunfels Muni Airport 71 85 60 73 62 / 20 70 30 40 50 Burnet Muni Airport 66 80 57 72 60 / 20 60 20 30 50 Del Rio Intl Airport 71 87 63 79 64 / - 20 20 40 60 Georgetown Muni Airport 66 81 57 73 61 / 20 60 30 30 50 Hondo Muni Airport 70 87 61 76 63 / 0 40 30 40 70 San Marcos Muni Airport 70 83 60 73 61 / 20 60 30 40 50 La Grange - Fayette Regional 70 86 62 74 63 / 20 70 50 30 30 San Antonio Intl Airport 72 89 61 73 63 / 0 70 30 40 60 Stinson Muni Airport 71 90 62 74 64 / 0 70 30 40 60 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...KCW Long-Term...Platt
Area Forecast Discussion
National Weather Service Little Rock AR
752 PM CDT Wed Apr 8 2020 .AVIATION...09/00Z TAF CYCLE Cannot rule out a few storms forming later tngt acrs parts of cntrl/srn AR as a CDFNT drops SWD thru the FA. Opted to go with a mention of VCSH/TS as overall coverage expected to be limited. Otherwise, VFR conds wl prevail. Sfc winds wl shift to the N/NW behind FROPA later tngt and linger into Thu. /44/ && .PREV DISCUSSION...(ISSUED 248 PM CDT Wed Apr 8 2020) Short Term...Tonight thru Friday... We are facing a high CAPE / weak shear type of thunderstorm environment this evening. Strong H5 low is off the southern CA coast, and has been ejecting some weak shortwaves to the east. Subtropical jet is streaming across Baja Ca, over TX, and across AR, while the polar jet is digging south out of Canada, dropping a trof over the Great Lakes region. Both jets are essentially converging on the midsection of the country, creating a somewhat unfavorable upper level environment for thunderstorm development. At the surface, a cold front is diving southward across the Plains, and will be pushing into Arkansas tonight. The front will be pushing it`s way into a very warm, humid and unstable airmass. Model soundings have been indicating maximum MLCAPE values between 2500-5000 j/kg across the eastern half of the state this afternoon into this evening. While some of this may a bit overdone, an 18Z sounding here at LZK has indicated a MLCAPE value of 3300 j/kg, so values upward of 4000 j/kg to the east do not seem unrealistic. There is not an excessive amount of CIN to overcome, so with the front pushing into the area, there would appear to be little to hold back thunderstorm development. The limiting factor, of course, will be the weakly sheared environment, in addition to the lack of upper level support - which may even contribute negatively to the environment. Midlevel lapse rates are very steep, and if any large storms are able to develop, there will be a risk for substantially large hail. My confidence in this scenario is only moderate at the moment, but the potential for large hail - larger than 2" probably - is certainly there. If a QLCS does develop, the inflow environment will also support the development of shorter-lived tornadoes along the line. It`s possible this may not happen in the LZK CWA, but again, the potential is certainly there. The NAM Nest and WRF NMM models have been more forthright in developing a QLCS after 00Z and bringing it down into the eastern half of the CWA, with the line moving down into SE Arkansas well after 06Z. The HRRR has been much more conservative, generally keeping most of the activity well to the east. However, the ESRL HRRR and more recent runs of the HRRR are trending more toward the NAM/WRF solution. They are certainly not in agreement, but this does add confidence to the forecast of strong thunderstorms tonight. Putting it all together, we are probably not looking at a high- impact widespread severe weather event. Most of the event will probably occur east of the LZK forecast area. However, there could certainly be areas of wind damage, large hail, and even a few tornadoes depending upon what sets up across the area tonight. The most likely scenario brings a QLCS thru the eastern CWA, which may not even be a continuous line. We also have to watch for any cells that develop ahead of the line, especially in this high-CAPE environment. With all that said, the cold front should sweep thru the area tonight and bring dry weather to the area for the remainder of the short term. Extended Term...Friday Night thru Wednesday... The extended period will remain unsettled through the extended period. Rain chances will begin to increase across the area on Saturday as an upper level low across the Four Corner`s Region and attendant cold front move eastward. Chances for rain will linger through the weekend and into early portions of next week as the low strengthens over the Natural State. Thunderstorms will be possible, some of which could become severe, especially across the southern portions of the state where the instability is more favorable for convection. Slight rain chances will linger through early portions of next week as mean troughing overcomes much of the CONUS, and small perturbations in the flow intermittently swing through the state. Temperatures will be much cooler through the extended, especially after the aforementioned cold front moves through on Sunday. && .LZK Watches/Warnings/Advisories...NONE. && $$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1000 PM EDT Wed Apr 8 2020 .SYNOPSIS... A series of weak disturbances will move across the area into Thursday with a mainly dry cold front pushing through the area late Thursday. Cooler high pressure fills in late in the week before a stronger frontal system impacts the region Sunday into early next week. && .NEAR TERM /Overnight/... As of 10 PM Wed...Line of bkn tsra continues to push sewrd through the FA. The convection has become sub severe, and only expecting some gusty winds and brief heavy rains, albeit still observing frequent lightning. Still have pops decreasing markedly after around midnight when storms should be moving offshore. Prev discussion... As of 630 PM Wed...We are watching several clusters of strong to severe thunderstorms in the nrn NC Piedmont, which are quickly charging sewrd towards the NC Coastal Plain, and will arrive in the next couple hours. If they hold together, they will present and damaging wind and large hail threat. Chc pops for thunder still in good shape through midnight. Prev discussion...As of 345 PM Wed...Upper level analysis shows deep northwesterly flow aloft with a weak mid- level shortwave diving out of the Ohio Valley. At the surface, weak and broad high pressure was situated over the Bahamas with a cold front stalled near northern Virginia. Earlier noted outflow boundary has thrown a wrench in the original forecast with dew points dropping into the low 50s inland, with resulting RAP analyzed CAPES struggling to reach 500 J/kg along southern portions of the CWA with even lower values north of Highway 264. This is despite nice warming into the low to mid 80s. 12Z CAM suite continues to advertise a band of showers and storms beginning to impact the region from north to south starting at 23Z, with the latest runs of the HRRR advertising that line being initiated by outflow from the current cluster of storms over the Central Appalachians. The near-storm environment will be characterized with CAPEs of 500-1000 J/kg and effective shear of 30-35 kt, coupled with straight hodographs, suggesting an isolated damaging wind threat or hail threat is possible. SPC has our northwest counties in a Slight Risk with a Marginal Risk elsewhere. Convective activity is expected to clear the Crystal Coast by around midnight with partly cloudy skies and light winds in its wake, although with mild airmass still in place lows will only fall into the low to mid 60s. Low dewpoint depressions suggest a patchy fog threat although confidence is low. && .SHORT TERM /THURSDAY/... As of 400 PM Wednesday...CAMS depict another band of showers and thunderstorms crossing our area from west to east as part of a decaying MCS cross the Ohio and Tennessee valleys overnight. Weak pre-frontal convergence is expected with light south/southwesterly surface flow. CAMs suggest a ribbon of ~1000 J/kg are possible right around daybreak with dew points in the low 60s. This, along with effective shear again around 30-35 kt, points to an isolated strong storm with damaging winds and some hail. Band will quickly clear the area midday with strong west/northwesterly winds developing in its wake with sustained 15-20 kts for the coastal plain and gusts up to 30 kts with deep mixing. Model guidance points to dew points falling into the upper 40s for the coastal plain although in cases of robust mixing this can be generous. Given this, there is concern with increased fire risk tomorrow afternoon with RHs around 30% and temperatures still climbing into the 80s in downsloping flow. No headlines necessary yet but next shifts will need to analyze further. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 330 AM Wed...A few showers and thunderstorms are possible Thursday ahead of a cold front that will cross the area later in the day. Drier and cooler conditions are then on tap for Friday into Saturday. The next storm system will impact the area Sunday into Monday with high pressure returning thereafter. Thursday night through Saturday...High pressure building into the area behind the front will keep dry conditions in place Friday and Saturday, with temps below normal both days. Efficient radiational cooling is expected Friday night, with lows dipping into the 30s, and the potential for frost away from the beaches Saturday morning. Sunday through Monday...Longer range guidance continues to converge on the solution of a potent H5 shortwave lifting from the south central US across the Midwest Sunday, with the associated complex surface low crossing the Tennessee Valley and riding up the Appalachian Mountains through Monday. This will likely result in a warm front crossing the area Sunday, with strong WAA on the back of a 50+ kt LLJ Sunday night into Monday. Given this wind profile and the potential for instability to quickly build, severe weather is a concern Sunday into Monday, as are strong gradient winds, especially along the coast. Details of the severe threat will be refined in the coming days, but currently carrying the threat for thunderstorms Sunday through Monday in the official forecast. Current expectation is that a cold front will move through Monday, with generally dry conditions behind it for Tuesday. However, upper level heights could continue to fall, and dry conditions are not a guarantee Monday night into Tuesday as broad lift could occur across the region. Regardless, much cooler temps are expected Tuesday through the middle of next week. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Short Term /through 18Z Thursday/... As of 630 PM Wed...Mainly clear skies prevail across the terminals today with only some light cirrus to speak of. Convection firing across the NC Piedmont will quickly move sewrd towards the Coastal Plain counties of NC, and may produce strong winds and breif reductions in vsby this evening, then move well away by midnight. Coverage is still uncertain enough to preclude explicit TEMPO groups this cycle, but will be amending if threat becomes more imminent. Will continuously carry and VCTS. Another round of showers and storms is possible ahead of an advancing cold front early tomorrow morning before sweeping offshore before midday. Strong and gusty westerly winds expected with this passage with gusts of 25-30 kt possible especially for coastal plain. Long Term /Thursday night through Sunday/... As of 330 AM Wed...VFR prevails through Saturday. A prolonged period of flight restrictions and LLWS is possible beginning Sunday as a strong frontal system impacts the area. && .MARINE... Short Term /Tonight and Thursday/... As of 415 PM Wed...Southwest to westerly winds prevail over the waters at 10-15 kts with a few gusts to 20 kt with seas 3-5 feet, except 2 feet to the north. Winds are weaker than expected with the passing outflow boundary earlier this morning, and therefore dropped the existing SCA. Cold front will approach and cross the waters tomorrow around midday with southwest winds 15-20 kt in the morning veering northwesterly at 15-20 kt in the evening, with seas in the outer southern and central waters reaching 6 feet by sunset. Long Term /Thursday night through Sunday/... As of 330 AM Wed...Winds shift abruptly to breezy NW behind the cold front, then gradually wane into Friday as cooler high pressure builds in. A strong frontal system will impact the area beginning Sunday, bringing the potential stronger winds. Seas subside gradually Thursday night into Saturday as the windswell fades. Seas increase quickly beginning later Sunday as the next strong frontal system begins to impact the area. && .TIDES/COASTAL FLOODING... As of 415 PM Wed...A perigean spring tide will bring elevated tidal levels today through the end of the week. Minor inundation of very low lying areas is possible around the times of primarily the evening high tide cycles, especially near inlets and along the beaches south of Cape Lookout tonight, then across all of eastern NC into late week. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Coastal Flood Advisory until midnight EDT tonight for NCZ195- 196-199. MARINE...Small Craft Advisory from 11 AM Thursday to 2 AM EDT Saturday for AMZ154-156. Small Craft Advisory from 2 PM Thursday to 2 AM EDT Saturday for AMZ152. Small Craft Advisory from 11 AM Thursday to 8 PM EDT Friday for AMZ158. && $$ SYNOPSIS...MHX NEAR TERM...TL/MS SHORT TERM...MS LONG TERM...CB AVIATION...TL/CB MARINE...CB/MS TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion
National Weather Service Nashville TN
1059 PM CDT Wed Apr 8 2020 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Updated suite of forecast products to include Severe Thunderstorm Watch 94, which includes southern and eastern portions of mid state region through 5 AM CDT Thursday morning. Like previously stated, leaned toward latest HRRR model reasoning. However, that reasoning showed convection dying off before reaching or even moving into Nashville Metro Area. It did not show this robust line of showers and thunderstorms that moved into the Nashville Metro Area within the last hour and is now progressing southeastward through I-40 Corridor of mid state region approaching 11 PM CDT. Additional convection noted to northwest and across southwestern Kentucky presently. This was the convection previously noted that would develop into a squall line of showers and thunderstorms that would move through mid state region in association with strong cold frontal passage, specifically through the Nashville Metro Area, around 1 AM CDT Thursday morning, i.e. around 09/06Z. It will be of keen interest if this present line of showers and thunderstorms progressing southeastward through mid state region will leave an atmosphere behind of it that will not be supportive of strong to severe convection. As usual, tweaked hourly temperature, dewpoint, and wind speed/direction grids. Current temperatures in line with forecasted lows. Remainder of forecast from Thursday onward continues to be on track. && .AVIATION... 00Z TAF DISCUSSION. A few showers and thunderstorms moving through Middle TN as of 00Z TAF time. Don/t think any of these will hit a TAF site. Will keep a VCTS for BNA and MQY. Might need to add this to CSV as well. Still expecting a screaming front/squall line tonight. Timing for CKV around 03Z...BNA/MQY around 05-06Z and CSV around 07Z. This should be a fast moving system and any storms will contain wind/hail. The good news is the storms should be fast moving and should only impact the TAF sites for an hour or two. CIGs and VISs will become MVFR before the front. After the storms move out MVFR CIGs will linger for a couple of hours before VFR conditions return. Southwest winds cactus with the front and switching around to the northwest post frontal with continued gusts. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......JB Wright AVIATION........12
Area Forecast Discussion...CORRECTED
National Weather Service Pueblo CO
352 PM MDT Wed Apr 8 2020 .SHORT TERM...(This evening through Thursday) Issued at 347 PM MDT Wed Apr 8 2020 Upper ridge building over Colorado today ahead of western U.S. upper low, keeping much of the region mild and dry, with only sporadic breezy winds at times over the plains and across the higher peaks. Cold front backs westward across the plains overnight, leaving a shallow cold air mass in place along and east of the mountains by early Thu morning. 12z/18z NAM soundings suggest stratus possible toward sunrise on the plains as winds turn ely, though HRRR runs have been less enthused about both the strength of the easterly component and amount of low level saturation expected. Leaned toward cloudier NAM at this point, though not expecting much fog/drizzle to develop, except near where the cloud edge intersects the higher terrain and Palmer Divide. On Thu, shallow cold air holds on across the plains, as lee-side surface low spins up along the NM border and resulting pressure gradient keeps an ely component to low level winds along and east of I-25. Blended model temps from the NBM looked rather warm over the plains, and shaded many areas downward several degf toward cooler MAV/MET guidance. Mountains and valleys will remain warm for another day, as clouds gradually increase ahead of slowly approaching upper low. By late afternoon, expect just some isolated showers to break out over the higher terrain as upward motion increases, with best chance of measurable precip over the higher peaks around Leadville, especially toward early evening. .LONG TERM...(Thursday night through Wednesday) Issued at 347 PM MDT Wed Apr 8 2020 ...Much cooler and unsettled weather expected on Sunday... Thursday night-Friday night...Models remain in decent agreement of northern stream upper trough digging across the central Conus on Thursday, which continues to translate across the eastern Seaboard on Friday, as a southern stream cut off low across southern California slowly meanders into the Desert SW. Models also continue to indicate a minor short wave ejecting across the Desert SW on Thursday, will continue to translate east across the southern Rockies Thursday night. With some increase in mid level moisture, steep mid level lapse rates, continued low level upslope flow and some diffluence aloft associated with the passing short wave, will see isolated to scattered showers over the higher Thursday afternoon spreading east across the immediate adjacent plains Thursday evening and out across the far southeast plains Thursday night. Snow levels are expected to remain high (aoa 9K feet) with local accumulations of 1 to 3 inches possible at the peaks through early Friday morning. Similar conditions can be expected for Friday afternoon and early evening, with isolated to scattered showers and a few possible thunderstorms over and near the higher terrain. Temperatures through the period look to be near to slightly above seasonal levels. Saturday-Monday...Again, latest models in decent agreement of the next northern stream system digging across the Intermountain West through the day on Saturday, with increasing westerly flow aloft keeping the southern stream cutoff low well south of the area across southern Arizona and southern New Mexico. Saturday looks to be the proverbial "warm before the storm" with westerly flow aloft leading to highs in the 60s and 70s across the plains, with 50s and 60s across the higher terrain, save for 30s and 40s at the peaks. Again, models indicating a few possible showers across the higher terrain Saturday afternoon, as the northern streams associated strong cold front remains lurking just north of the Colorado and Wyoming border Saturday evening. Well there are still some differences on timing and strength/amplitude of this system, general model consensus digs the strong northern stream through across the Rockies through the day Sunday, with secondary energy digging down the backside of the system on Monday. The system`s associated strong cold front blasts across eastern Colorado late Saturday night and early Sunday morning with widespread precipitation expected over and near the higher terrain through the day Sunday and Sunday night. Strong caa will likely lead to Sunday`s high temperatures across the plains being recorded early Sunday morning, with steady and cooling temperatures and gusty northerly winds expected through the rest of the day across eastern Colorado. Latest models indicating the potential for 3 to 6 inches of fluffy snowfall across the central and eastern mountains through Sunday night, with lesser amounts along the immediate adjacent plains. Overnight lows Sunday night look to be well below seasonal levels mainly in the teens across the lower elevations and single digits above and below zero across the higher terrain, with cold northwest flow aloft leading to highs on Monday well below seasonal levels in the 20s and 30s across the eastern plains. Secondary energy digging across the area on Monday will also lead to scattered to numerous snow showers again, especially over and near the higher terrain. Tuesday-Wednesday...A cool northwest flow pattern remains in the offing for Tuesday and Wednesday, with temperatures slowly warming though remains below seasonal levels. Pattern also supports daily chances of isolated to scattered showers, most numerous across the higher terrain. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 347 PM MDT Wed Apr 8 2020 At KALS, VFR the next 24 hrs, with s-sw winds increasing after 17z on Thu. At KCOS and KPUB, VFR much of tonight, then MVFR cigs develop 10z- 12z Thu morning behind a cold front, with lower cigs persisting through at least midday Thu. Winds will become northerly this evening behind a cold front, then swing around to the E-SE overnight into Thu morning. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MW AVIATION...PETERSEN
National Weather Service Raleigh NC
915 PM EDT Wed Apr 8 2020 .SYNOPSIS... A cold front will approach from the west late tonight, bringing showers and storms through Thursday morning. The cold front will cross the area Thursday, bringing strong gusty winds. Behind this front, high pressure will bring cooler and drier air for late Thursday night into Saturday. Rain chances return by Sunday and Monday as another storm system moves in from the west. && .NEAR TERM /THROUGH TONIGHT/... As of 915 PM Wednesday... What began as a couple of small storm clusters during the mid afternoon over north central NC grew upscale in the hours since, coalescing into a band of showers and strong storms which have impacted central NC since 20z with high winds of 40-60 mph, a lot of mostly small hail, and pockets of wind damage, feeding on steep low- (~8.5 C/km) and mid- (~7.0-7.5 C/km) level lapse rates, moderate MLCAPE near 1000 J/kg, and 40-50 kts of deep layer shear. This broad broken band of showers and storms now extends across the far S Piedmont across the Sandhills to the central/S Coastal Plain and central Coastal Area. Outflows have largely raced out ahead of this band but embedded discrete cells remain and will pose a continued risk for small hail and 35+ kt wind gusts for another couple of hours. A brief calm period will follow for much of the night with fair to partly cloudy skies. Based on the latest CAM output and extrapolation of upstream strong to severe convection over IN and the Mid Miss Valley, it still appears that showers and storms are likely to arrive in the NW CWA about 09z, crossing central NC over the ensuing 4-5 hrs. Lows in the upper 50s to mid 60s. -GIH Earlier discussion from 255 pm: We`ve been awaiting convective initiation thus far, given the formidable cap around 800 mb and dewpoints that are less than ideal, mostly in the 50s. But we`re finally getting some agitated cu across the W Piedmont and Sandhills where the CINH is finally dissolving and where dewpoints are generally a bit higher than in the NE CWA, a function of the old outflow generated from the early-morning MCS over OH/WV/VA. As strong heating continues to chip away at the cap and culminate in 1000-1500 J/kg of MLCAPE within 30-40 kts of effective bulk shear, we should see isolated to scattered convection develop over our far N counties, developing further on its western flank as it propagates to the ESE through early evening. Fat CAPE through the hail growth zone aloft (a result of steep lapse rates through the EML, evident in the 750-500 mb profiles in the 12z observed GSO sounding and in proximity forecast soundings) still suggests a large hail threat, with the wind profile indicative of possible splitting cells. Damaging wind gusts remain a threat as well, with RAP downdraft CAPE in the 800-1000 J/kg range. Once this activity exits the SE CWA, likely in the late evening, we should see several hours of dry weather and partly cloudy skies. Areas that happen to receive decent rainfall later today could see patchy fog development, but the presence of residual convective debris clouds to curb radiational cooling may limit the fog threat, despite light winds. Our attention then turns to what should be a band of strong to severe storms just ahead of the approaching cold front over the Ohio Valley and Mid Miss Valley tonight. Timing this convection (or its remnant MCV) east-southeastward brings it into the western CWA toward daybreak, so will trend pops up there very late tonight. Expect anomalously warm lows in the upper 50s to mid 60s. -GIH && .SHORT TERM /THURSDAY/... As of 315 PM Wednesday... ...Wind advisory may be needed for Thursday... The band of convection is expected to cross central NC during the morning, departing the Coastal Plain around noon or shortly thereafter. While there may be a few embedded strong storms, the unfavorable time of day and waning large scale forcing for ascent will reduce the threat of strong storms. The bigger story Thu may be the strong winds from the W and WNW near and just behind the front, with the potential to gust to 25-35 mph as strong winds at 925-850 mb are transported groundward. Will need to monitor high-res guidance and morning observations to see if a short-fuse wind advisory might be warranted. (See fire weather section below for fire concerns.) Otherwise, expect fair skies with scattered flat stratocu. Confidence in the high temp forecast is reduced by the likely initial delay of the coolest air by the higher terrain, as it appears that thicknesses won`t drop in earnest until well into the afternoon. Will go with highs from the mid 70s in the NW to the mid 80s SE. -GIH && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... As of 200 PM Wednesday... Thursday night through Saturday night: A large upper low will swing through SE Canada and the Northeast US Thursday night. Meanwhile at the surface, the cold front will continue pushing east of central NC. Expect lows in the mid 40s NW to low 50s SE in the wake of the fropa. Cold Canadian high pressure will build south into the Plains Thursday night and shift eastward into and over the mid-Atlantic on Friday/Friday night. Despite a shortwave aloft passing over the the area on the back side of the departing upper low, expect the weather to remain dry with NW flow and subsidence over the area. Expect below normal temperatures Friday and Friday night with highs in the upper 50s to mid 60s and lows in the upper 30s to low 40s. Temperatures should moderate some to near normal on Saturday and Saturday night as the surface high shifts east off the Atlantic coast and weak sub-tropical ridging aloft builds over the Southeast and mid-Atlantic. Highs in the mid 60s and lows in the mid 40s to around 50 degrees. Sunday through Tuesday: Little change in the forecast for the system moving into the area Sunday/Monday. The upper low should be sampled much better today, so expect model agreement to improve further in the next day or so. This low will slowing make its way through the Southwest by Saturday before getting caught in a deepening northern stream trough and swinging east through the southern Plains, then northeast through the MS Valley as a s/w trough Sunday/Sunday night. The wave will then lift through the OH Valley and into the Great Lakes and Northeast US Sunday night/Monday. At the surface, the low will strengthen as the it moves east through the Plains and MS Valley. The attendant cold front will push east Sunday night and Monday, though specific details regarding the timing of the front and the evolution/track of the low are still quite uncertain. Timing for best rainfall chances is still between 12Z Sunday and 00Z Tuesday. This system has the potential to result in some significant rainfall amounts across central NC. Regardless, expect some moderation in temperatures from Sunday to Monday and increasing moisture and cloud cover as return flow off the Atlantic and southerly flow from the Gulf ahead of the front advect warm, moist air into the region. Given the uncertainty and dependence on the timing and strength of the system, will not get into specifics regarding temperatures at this time. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 845 PM Wednesday... Storm clusters which impacted central NC since 20z with high winds, a lot of mostly small hail, and pockets of wind damage have congealed into a broad broken band of showers and storms, still impacting FAY and RWI but has pushed well SE of INT/GSO/RDU. Aside from the continued short-term storm threat at FAY, the other terminals will remain largely dry with VFR conditions and much lighter winds for much of the night. We`re likely to see areas of fog, although given the overspreading mid and high clouds, confidence in this occurrence is low. Another band of showers and storms will cross central NC late tonight through Thu morning, mainly 09z to 16z, and an hour or so of MVFR cigs/vsbys are possible at all sites during that time. VFR conditions will return from W to E between 13z and 16z. Attention will then turn to the strong gusty winds from the W or WNW at sustained speeds of 15-20 kts and gusts to 25-35 kts, dominating from late morning through the afternoon, which could generate mechanical turbulence and present difficulties in aircraft handling, particularly smaller aircraft. Looking beyond 00z Fri, the strong and gusty winds should subside by early Thu evening. VFR conditions will largely hold through early Sun as high pressure builds over the area. A storm system will approach from the SW from midday Sun through Sun night, bringing a high chance of stormy sub-VFR conditions. Improvement is expected Mon as the system exits to our E. -GIH && .FIRE WEATHER... Strong gusty winds from the W and NW are expected near and behind a cold front that will cross central NC Thursday. These winds, sustained at 15-20 mph with possible gusts to 25-35 mph, will occur in conjunction with falling relative humidities, likely bottoming out in the 25-32% range Thu afternoon as drier post-front air spreads into the area. The combination of strong winds and low RH will bring about concerns for adverse fire behavior, particularly in areas that don`t see much rainfall either today or early Thu. Will coordinate with forestry officials early Thu to address these concerns. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...KC AVIATION...Hartfield FIRE WEATHER...Hartfield
National Weather Service Charleston WV
1123 PM EDT Wed Apr 8 2020 .SYNOPSIS... A strong cold front crosses overnight. High pressure Friday and Saturday. Low pressure crosses Sunday/Sunday night, with a cold front Monday morning. Cooler with weaker systems next week. && .NEAR TERM /THROUGH THURSDAY/... As of 1120 PM Wednesday... Tornado Watch 93 issued for all but the northern tier of the forecast area, the northern extent of where the boundary indicated by the west-northwest to east-southeast oriented line of thunderstorms may get before the main line ahead of the cold front arrives. Surface based CAPE and effective bulk shear depict this most favored air mass for tornadic development nicely, as do the upstream warnings. Added severe weather wording to the forecast where the watch is until its 08Z expiration overnight. As of 825 PM Wednesday... Used mostly the HRRR to time PoPs associated with a cold front that will push through during the late overnight hours. The timing for the strongest thunderstorms midnight to 4 AM west to east, with a gradually weakening trend possible during that time on loss of CAPE, which may start out over 2 KJ/kg into southwest portions of the CWA, with elevated CAPE over 3 KJ/kg. Bulk shear values in the 0-6 km layer are forecast to reach 50 to 60 kts giving rise to strong rotating elevated updrafts, with large hail and damaging winds possible. The bulk shear will be longer lived, so the wind threat is likely to outlive the hail threat. An isolated tornado cannot be ruled out, especially as 0-1 km bulk shear increases to 40 kts and the LCL decreases to less than 1km immediately ahead of the cold front. Downward transfer of 50 to 60 kts aloft may also lead to a surge of strong wind gusts immediately behind the front. As of 620 PM Wednesday... The severe thunderstorms have weakened and moved south of the CWA. Therefore, the remainder of SVR Watch 87 has been canceled. As of 525 PM Wednesday... Dropped portion of SVR Watch 87 behind southward moving line. These leaves only SW VA in the Watch. As of 204 PM Wednesday... Latest radar mosaic shows a broken line of showers and thunderstorms have developed across the middle of our county warning area. Mesoanalysis indicates these storms may be associated with an outflow boundary from the earlier storms. Per SPC discussion, a Severe Thunderstorm Watch has been issued for portions of Northeast Kentucky, Southeast OH and Southwest Virginia as well as the southern third of West Virginia until 8 PM. Models indicate convection should wind down this evening with a brief dry period. A strong cold front is then expected to push southeast across the region later tonight with the possibility of additional strong and possibly severe storms. The front should be southeast of the area by sunrise on Thursday with high pressure building in. As a result, precipitation chances will end from the northwest during the day. Will keep chance pops in the northern mountains through the evening hours as cold west-northwest flow prevails. Would not be too surprised to see some snow across the highest elevations late. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 220 PM Wednesday... Additional shortwave will cross the area Thursday night into Friday, with another round of precipitation, and much colder air. Light snow showers will be likely, particularly across the higher terrain, where light accumulations will be possible. In addition, gusty winds on Friday will make it feel like it`s winter again, with wind chills in the 20s to lower 30s. High pressure will build in for Friday night into Saturday. With a clearing sky and calm winds taking hold, widespread frost is expected for Saturday. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 225 PM Wednesday... After a brief break in the precipitation, rain, along with warmer temperatures will return to the area for the start of the long term period. Good southerly fetch of moisture will create a good soaking rain for the area, but heaviest amounts look to lie to the south and east of CWA. System will lift to the northeast of the CWA at the start of next week, but mild, and somewhat unsettled weather will continue to linger. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... As of 825 PM Wednesday... A front stretched west to east across southern Ohio and central WV this evening, will move northward, as a warm front, ahead of showers and thunderstorms, associated with a cold front, approaching from the west. These showers and thunderstorms may be quite strong as they cross the area overnight, before weakening during the early morning hours, as they move through with the cold front. One last line of showers may move through after daybreak, before clearing takes place by afternoon, except northeast portions of WV. The best chance for the strongest thunderstorms will be HTS, with decreasing strength to the north and east. The timing for strong storms is 04Z-08Z from west to east, with diminishing strength as the storms move east. Ceilings will lower to MVFR as the thunderstorms move through, and may even dip briefly to IFR early Thursday morning, before mixing through and breaking out Thursday. Even in NE WV, CKB and EKN, where ceilings may persist throughout the day, they should lift above MVFR early Thursday afternoon. MVFR visibility is likely in showers and thunderstorms overnight, with brief IFR visibility in heavier thunderstorms. Light north surface flow will shift to south as the front moves north tonight. Strong wind gusts are possible in the thunderstorms overnight, mainly from the west to northwest. Gusty west to northwest winds will develop in the wake of the cold front Thursday, with peak gusts of 20 to 25 kts. Light west to northwest flow aloft this evening will become light to moderate south to southwest tonight, and then strong west as the cold front crosses overnight, and then moderate west first thing Thursday morning, remaining so for the balance of the day Thursday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Coverage of storms and associated lower conditions and wind could vary overnight. Gusty winds Thursday will fluctuate. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE THU 04/09/20 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EDT 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 CRW CONSISTENCY H H H M M H H M H M H H HTS CONSISTENCY H H M H M H H M H M M H BKW CONSISTENCY H H H H M M M M L M H H EKN CONSISTENCY H H H H M H L M M L M M PKB CONSISTENCY H H M L H M M M H M M H CKB CONSISTENCY H H H H M M H H H M H H AFTER 06Z FRIDAY... IFR conditions possible in showers and thunderstorms late Sunday into Monday. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...JSH/SL NEAR TERM...JSH/TRM SHORT TERM...SL LONG TERM...SL AVIATION...TRM
Area Forecast Discussion
National Weather Service Shreveport LA
937 PM CDT Wed Apr 8 2020 .SHORT TERM... Conditions this evening across the region remain very abnormally warm and humid, with the evening sfc analysis depicting a rather large tongue of higher theta-e air across much of Cntrl and Ern TX into LA/Srn and Ern AR well ahead of a cold front extending from extreme SE MO into Nrn and NW AR into SE OK into the Wrn sections of N TX. This front remains progged to enter the NW zones of McCurtain County OK/extreme NE TX by 06Z Thursday, before shifting S to near the I-20 corridor of E TX/N LA by 12Z, before reaching Cntrl LA into Deep E TX by mid to late morning before the bndry pulls up stationary during the afternoon. Convection along the front tonight remains confined to NE AR into the Mid-South region, although the CAMs and HRRR continue to suggest that a narrow band of convection may develop along the frontal zone across Ern/SE AR late tonight, with consistency in the runs indicating that any convection will remain E of ELD/MLU. Have kept a dry forecast tonight as any moisture will remain quite shallow and large scale forcing well to the NE of the region, although some stratus looks to pool along and ahead of the front late tonight mainly over portions of extreme Ern TX/N LA/Srn AR. Did bump min temps up a tad across the warm sector given the current dewpoint trends, and the expected stratus development as well as a thickening cirrus shield that will increase from the W overnight. Have also beefed up the sky conditions to mostly cloudy late tonight through Thursday especially for the increase in elevated cloud cover well ahead of the embedded shortwave energy that will eject E over the Srn Plains. Did trim back pops slightly across Lower E TX/Wrn LA as well given the consensus in the progs with the column having to saturate from the top down in the drier post-frontal air which will continue to deepen throughout the day. Zone update already out...grids will be available shortly. 15 && .PREV DISCUSSION... /issued 658 PM CDT Wed Apr 8 2020/ AVIATION... VFR conditions will continue this evening, with a sct cu field persisting across portions of extreme Ern TX/N LA/Srn AR, but low MVFR/IFR cigs are expected to develop by/shortly after 06Z Thursday over portions of Srn AR/N LA/extreme Ern TX, near and ahead of a cold front that will enter SW AR/extreme NE TX after 08Z, and shifts N to near the I-20 corridor of E TX/N LA around 12Z. These low cigs will quickly lift/scatter out with the fropa, with VFR conditions returning by mid to late morning as the front enters Cntrl LA into Deep E TX. The cirrus shield will increase and thicken from W to E late tonight/Thursday morning even in wake of the fropa, although some cu may linger across the W/SW sections of E TX. An approaching shortwave trough over WCntrl and Cntrl TX Thursday after will result in increasing convection near and S of the front as it becomes stationary, with some areas of elevated -SHRA with embedded deeper convection developing during the afternoon over Cntrl TX and will advance E and possibly affect the WSW sections of E TX between 21-24Z. Have added VCSH for the LFK terminal for mid-afternoon, with the elevated SHRA spreading E across much of Lower E TX and N LA during the evening. SW winds 4-8kts this evening will become NNE and increase to 10-15kts with gusts to 20kts with the fropa late tonight/Thursday morning. /15/ && .PRELIMINARY POINT TEMPS/POPS... SHV 67 78 54 69 / 0 10 40 10 MLU 66 76 52 66 / 10 10 20 10 DEQ 58 74 49 66 / 0 0 10 0 TXK 61 73 51 65 / 0 0 20 0 ELD 62 74 50 65 / 10 0 20 0 TYR 66 77 54 69 / 0 30 40 10 GGG 67 78 54 69 / 0 20 40 10 LFK 71 81 57 72 / 10 50 60 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 15