Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/18/18

Area Forecast Discussion
National Weather Service Wakefield VA
759 PM EDT Sat Mar 17 2018 .SYNOPSIS... Low pressure moves across North Carolina overnight. High pressure builds into the area Sunday, then moves offshore Sunday night. A trio of low pressure systems are expected to impact the region Monday through Wednesday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Initial (light) pcpn moved off the coast earlier this eve. Sfc warm front tried to move N into far SSW areas of FA this eve...but stopped just before it did so. Now...the RAP indicates that boundary slowly settles back S overnight as sfc lo pres tracks along it (across NC). Area of SHRAs/ISOLD tstms moving through srn WV/far SW VA attm. Near term models and trends suggest that that area will be tracking ESE overnight. Would rule out a rumble or two of thunder (from potential ISOLD elevated stms) far SW and over NE NC...otherwise bulk of any tstms should remain S of the FA. Will carry highest PoPs (50-60%) across far srn VA and into NE NC...tapering to 10% or less NE quarter of the FA. A gradually lowering of the PoPs begins later tonight as lo pres exits the NC coast (S of HSE). Lows from the l30s N to the u30s- around 40F far S and SE. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Dry with near seasonable temps Sun as weak high pres moves across the area. Mstly sunny. Highs 50-55 along the coast, 55-60 west of the bay. The high moves off the coast Sun night. Mstly clr except for some incrg clouds across the piedmont. Lows in the 30s. The high pushes farther offshore Monday and will be quickly followed by overrunning pcpn leading to a weak or in-situ CAD setup across the region during the aftrn. Meanwhile, a potent s/w races eastward from the southern plains in the morning into the TN Valley by late in the day. Cut back pops a bit through 18Z and confined them to the wrn and srn most zones due to weak upslope flow. Light rain expected to break out and overspread areas west of the bay in the aftrn. QPF amounts during Monday generally aob one tenth inch. Highs 45-50 ern shore and through the 50s west of the bay. A widespread rain is expected Mon night as the s/w reaches the mts by 12z Tue. Categorical pops all areas with some mdt rainfall psbl aftr midnight. Lows mid 30s north to mid 40s south. A sfc low organizes over the Carolinas Monday night before emerging off the mid-Atlantic coast and deepening Tuesday morning. Will carry likely to categorical PoPs Tues morning as the best lift shifts east by 18Z. Chc pops west with likely east Tue aftrn. Highs 40-45 north, 50-55 se coastal areas. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The first few days of Spring will be more like Winter as deep/anomalous trough sets up invof ern CONUS. Using a blend of WPC/GFS/ECMWF the extended periods. Initial lo pres pulls slowly away from the coast Tue night...w/ trailing upper level system diving through the region Wed (w/ secondary lo pres developing invof SE VA-NC coasts). Partial thickness scheme gives rather hi potential for mixed ptype (SN/RA over many inland locations...mainly Wed/Wed eve). Way too soon to speculate on if/any accums. Drying out/chilly Wed night-Thu...remaining so through Fri. After that...the next lo pres system expected to approach from the W by Sat (bringing at least increasing cloudiness). Lows Tue night in the l-m30s inland...u30s/around 40F far SE VA-NE NC. Highs Wed in the u30s inland...l40s coastal SE VA-NE NC. Lows Wed night in the u20s W to the m30s right at the coast. Highs Thu ranging through the 40s. Lows Thu night in the u20s W...m30s at the coast. Highs Fri around 50F W...m-u40s elsewhere. Highs Sat in the l50s inland...m-u40s at the coast. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... VFR conditions continue across the region at 00Z with sct/bkn mid and high clouds and mostly light winds that vary from NW to NE. A stationary frontal boundary lies just south of the CWA border. A shortwave is moving through KY and bringing an area of showers which is generally riding along the frontal boundary from eastern KY into southwestern VA. The showers are expected to mostly affect the extreme southern portions of our CWA but scattered showers may also get into central and SE VA during the overnight hours. An isolated tstm is also possible especially for NE NC. The shortwave should push off the coast by sunrise Sunday and take any showers/tstms along with it. Expect mostly VFR conditions for Sunday. Outlook: Another window of flight restrictions late Mon thru Wed as a trio of low pressure systems impact the area. Rain for the most part may mix with or change to wet snow by Wed at RIC/SBY. && .MARINE... Current observations show E/SE winds of 10 to 15 knots over a majority of the waters this afternoon. Seas average 2 to 3 feet and waves average 1 to 2 feet or less. A surface low is expected to move across portions of southern VA and NE NC later tonight. As the low moves off the coast NC coast late tonight into Sunday morning, will see a bit of surge in NNE winds to ~15 knots. Still am not anticipating SCA headlines due to very limited cold air, but would not be surprised to see a few gusts in excess of 20 knots. Winds diminish to 5 to 10 knots or less Sunday afternoon while shifting to the east and then to the south Sunday night. Conditions become much more unsettled Monday night through at least midweek as the next low pressure system approaches from the TN Valley, then is progged to re-develop as a coastal low off the Mid- Atlantic coast Tuesday. The first low pushes off to the NE Tuesday afternoon and evening with yet another low expected to develop off the SE Coast and then rapidly intensify while pushing NE off the Mid- Atlantic coast Wednesday night. Still looking as though strong SCA conditions appear Monday night through Wednesday with a period of Gales even a possibility Tuesday night and again Wednesday into Wednesday night depending on the exact track of these systems. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...None. && $$ SYNOPSIS...ALB/MPR NEAR TERM...ALB/MPR SHORT TERM...JDM/MPR LONG TERM...ALB AVIATION...MPR/JEF MARINE...AJB/LKB
Area Forecast Discussion
National Weather Service Bismarck ND
944 PM CDT Sat Mar 17 2018 .UPDATE... Issued at 942 PM CDT Sat Mar 17 2018 Clearing across central ND persists. Used a blend of the last two HRRR iterations for sky grids, which is similar to the RAP/NAM in filling in this clear area with clouds between 06-09Z. No other changes at this time. UPDATE Issued at 640 PM CDT Sat Mar 17 2018 Sky cover was adjusted with a rather large hole in the stratus deck over portions of western and central ND currently. This hole will fill in this evening along with fog developing. Temperatures were adjusted upwards with cloud cover tonight keeping values from dropping too much. Otherwise edits to the forecast were minor. && .SHORT TERM...(This evening through Sunday) Issued at 243 PM CDT Sat Mar 17 2018 The main focus for the short term is fog tonight and mixed precipitation developing afternoon tomorrow. Tonight, warmer and more moist air starts to be advected in. Low stratus is already forming across southwest North Dakota in response to this return flow. Low stratus will continue to develop and overspread most of western and central North Dakota tonight. An upslope component to the winds will further aid in the development of stratus and eventually fog late tonight. Fog may become dense in some of the valleys later tonight. Tomorrow, the next storm system approaches North Dakota. Several small upper level waves will rotate around the main upper level circulation currently located in the Pacific Northwest. One such wave will swing through southwest North Dakota Sunday afternoon. This will combine with developing frontogenesis to spark an area of precipitation oriented southwest to northeast across western North Dakota. The evening hours on Sunday will see a period where there is support for banded precipitation with frontogenesis, an upper level jet streak and fairly steep mid level lapse rates. The period of highest precipitation rates will be late Sunday afternoon and Sunday night. With temperatures in the critical threshold of mid 30s there could be mix of rain, freezing drizzle and snow Sunday afternoon and evening. .LONG TERM...(Sunday night through Saturday) Issued at 243 PM CDT Sat Mar 17 2018 The focus in the extended will be the Sunday and Monday period. There continues to be some uncertainty in the snow amounts, however, we are seeing convergence on a location of highest accumulation. It appears west central North Dakota, locations generally between Bismarck and Dickinson, will see the highest accumulations. There appears to be a good chance for at least four inches over west central North Dakota for Sunday night and Monday. We continued the Special Weather Statement, with headlines possible later tonight/tomorrow. Tuesday through Thursday will see a building ridge across the Northern Plains which will suppress precipitation, but another rather robust negatively tilted upper low is forecast to move from the northwest US into the Northern Plains by Friday. This will provide another opportunity for precipitation, both rain and snow. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 942 PM CDT Sat Mar 17 2018 Widespread MVFR cigs remain over much of western and central North Dakota. There remains a large hole in the stratus across central North Dakota, but this should fill in after 06Z-09Z. IFR/LIFR cigs and vis overnight into Sunday morning as stratus lowers and fog develops. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AJ LONG TERM...AJ AVIATION...NH
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
321 PM MDT Sat Mar 17 2018 .SYNOPSIS... Looks like a windy week ahead for the Borderland as several impulses pass through. The first one is an upper trough passing across northern New Mexico Sunday. This will bring strong winds of 25 to 35 mph to the area, along with blowing dust. Monday through Wednesday will be quieter with no significant winds, though temperatures will be cooler. Then Thursday through the weekend, strong winds will develop again as a series of upper troughs move across northern New Mexico and the central Rockies. Winds will be mostly 20 to 30 mph each day, with some blowing dust. Temperatures will warm to well above normal. && .DISCUSSION... What do you know-it`s March and it`s windy. This week is looking windy for the majority of the time as several upper troughs sweep across the CWA. In the short term, an upper low continues to churn over the Pac Northwest. Ahead of it, a shortwave trough is passing through central New Mexico as we speak, with a plume of moisture associated with it. This plume is mostly higher level moisture as PWs are only around .3 to .4 inches. NAM and HRR both showing some convection developing over northern Mexico and move into west Texas tonight. Kept a low POP in for Hudspeth, but HRRR continues to show showers into El Paso county too. Mid level winds on satellite look pretty stout, though some CU and maybe TCU are forming over northern Mexico. will have to watch this over the next several hours. Sunday...upper trough swings across northern New Mexico. Moderate lee side cyclogenesis develops over SE Colorado, with surface trough down across far eastern New Mexico. Gradient and model lower level winds of 30-35 mph suggest lower rung wind advisory. Will issue NPW shortly for Sunday afternoon and early evening. Could be some dense blowing dust, though relatively early fropa and cold advection may help knock the dust down earlier than usual. Front could produce a few showers over the Gila as it moves through Sunday morning. Monday through significant weather as we sit in zonal flow under a low amplitude ridge. Temperatures will be on the cooler side, just below normal. Thursday through the weekend...returns to more winds as large Pacific low drags a series of troughs onshore. Increased southwest flow will induce lee side cyclogenesis over SE Colorado again. Expect breezy afternoons each day as surface pressure gradient tightens, though at this time winds look to remain below advisory level. Plenty of time for changes though. Warm advection from southwest flow will push temperatures well above normal, with warmest temperatures of the season likely. && .AVIATION...Valid 18/00Z-19/00Z... VFR conditions will continue thru the TAF period. However some reduction in visibility will be possible after 18Z due to localized BLDU. Expect P6SM FEW-SCT100 SCT-BKN250 with SW winds continuing. Expect winds 12 to 15 knots gusting 20 to 25 knots through 18Z. After 18Z look for increasing SW winds of 25 to 30 knots gusting 35 to 40 knots. && .FIRE WEATHER... An approaching upper disturbance will bring stronger winds to the area tonight and Sunday. However, temperatures will be a few degrees cooler Sunday, resulting in min RH values above critical thresholds through the day tomorrow. Mainly dry conditions will be the rule with this system with the exception of some isolated thunder over far eastern Hudspeth county tonight and a few stray showers over northwestern fire zones early Sunday. Warm conditions will return during the week ahead with a continuation of dry surface conditions. Lowland Min RH values will run between 10 and 15 percent through the week. This combined with increasing winds Thursday into the weekend could result in critical fire weather conditions across the region later in the extended period. && .PRELIMINARY POINT TEMPS/POPS... El Paso 51 65 42 64 / 0 0 0 0 Sierra Blanca 48 66 38 63 / 10 0 0 0 Las Cruces 44 62 35 62 / 0 0 0 0 Alamogordo 45 62 36 60 / 0 0 0 0 Cloudcroft 33 42 24 44 / 0 0 0 0 Truth or Consequences 42 60 34 61 / 0 0 0 0 Silver City 36 50 30 56 / 0 10 0 0 Deming 42 60 32 62 / 0 0 0 0 Lordsburg 39 58 32 60 / 0 10 0 0 West El Paso Metro 50 64 41 63 / 0 0 0 0 Dell City 46 68 37 66 / 0 0 0 0 Fort Hancock 50 69 41 66 / 10 0 0 0 Loma Linda 47 61 38 60 / 0 0 0 0 Fabens 48 67 40 65 / 0 0 0 0 Santa Teresa 47 64 39 63 / 0 0 0 0 White Sands HQ 47 63 38 62 / 0 0 0 0 Jornada Range 43 62 32 62 / 0 0 0 0 Hatch 43 63 32 64 / 0 0 0 0 Columbus 45 63 36 63 / 0 0 0 0 Orogrande 48 64 38 62 / 0 0 0 0 Mayhill 39 52 31 53 / 0 0 0 0 Mescalero 38 51 30 52 / 0 0 0 0 Timberon 38 50 29 50 / 0 0 0 0 Winston 36 52 31 56 / 0 10 0 0 Hillsboro 40 56 33 60 / 0 0 0 0 Spaceport 41 61 32 61 / 0 0 0 0 Lake Roberts 34 49 28 56 / 0 10 0 0 Hurley 36 53 29 58 / 0 10 0 0 Cliff 32 55 24 58 / 0 10 0 0 Mule Creek 33 52 24 58 / 0 20 0 0 Faywood 38 55 31 59 / 0 10 0 0 Animas 39 60 33 63 / 0 10 0 0 Hachita 40 60 32 62 / 0 0 0 0 Antelope Wells 41 63 33 64 / 0 0 0 0 Cloverdale 39 57 35 61 / 0 0 0 0 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...Wind Advisory from noon to 8 PM MDT Sunday for NMZ402>417. TX...Wind Advisory from noon to 8 PM MDT Sunday for TXZ418>424. && $$ Hefner/Laney
Area Forecast Discussion
National Weather Service Goodland KS
603 PM MDT Sat Mar 17 2018 .SHORT TERM...(This evening through Monday night) Issued at 315 PM MDT Sat Mar 17 2018 Tonight-Sunday...some mid and high clouds move into the area from the southwest with possibly a thick deck of cirrus toward sunrise. The latest high res guidance is showing stratus moving southwest into parts of our area with sharply reduced visibilities, starting around 07z-08z and continuing through mid morning Sunday. Have added areas of fog accordingly. Southeast winds 5 to 15 mph tonight with lows in the upper 20s to mid 30s. On Sunday mid level dry slot moves into the area from the southwest and should help in preventing any thunderstorm activity til perhaps the very late afternoon and closer to sunset when low pressure emerges over southeast Colorado associated with a larger upper trough. Enough moisture may be present to generate showers and thunderstorms generally west of a line from about Yuma to Colby and Oakley initially, slowly expanding in coverage though sunset. Winds increase into the breezy to windy category from the southeast during the day. High temperatures in the low to upper 60s. Sunday night-Monday night...models maintain a forecast track taking the center of the storm system east along the Kansas/Oklahoma border through Monday morning. Showers and thunderstorms increase in coverage through midnight with a change over to snow from west to east as colder air filters in behind the storm. North winds increase into the 15 to 30 mph range with higher gusts, strongest winds generally along and west of the CO/KS border. This will likely produce some reduced visibilities in snow and blowing snow. For Monday the storm system is well east of the area but we`re under the impact of an upper trough which will contribute to additional snow or a mix of rain and snow in the morning. Question is will temperatures warm enough in the afternoon to completely change the precip type to liquid or like on Friday keep temperatures under the stronger dynamics favorable for snow. I trended temperatures down a few degrees prolonging potential for snow but it may not be enough. Right now the afternoon has mainly rain as precip type. Currently have high temperatures in the upper 30s to low 40s. Winds will continue from the north in the 15 to 25 mph range with higher gusts. Precipitation comes to an end from west to east by midnight as drier air moves in. Little if any additional moisture is expected. Low temperatures look to range from the upper teens to low 20s west, low to mid 20s east of the CO/KS border. Right now total snowfall accumulations range from a trace to 3 inches, highest in Yuma county. ECWMF/SREF/GFS/NAM 24 hour snowfall amounts are quite a bit higher. Experimental HRRR snowfall amounts similar to current forecast. CIPS analogs also show high probabilities of 2 inch amounts with very little support for anything over 4 inches. Am hesitant to make any adjustments up or down from current forecast given at least continuity between model runs and neighboring offices. Still have time to adjust if need be. .LONG TERM...(Tuesday through next Saturday) Issued at 145 PM MDT Sat Mar 17 2018 Upper ridge over the Great Basin Tuesday will move east and amplify as it approaches the Plains on Thursday. A fast moving, weak shortwave trough will come through on Friday as the ridge moves east. Models have gone dry with this system, apparently due to a lack of moisture. So, the extended period is currently dry. Temperatures will start near normal on Tuesday and warm to much above normal by Thursday and Friday, then cool off a bit for Saturday behind a cold front associated with the shortwave. Only hazardous weather potential will occur on Friday, with critical fire weather conditions possible due to low humidity and gusty westerly winds. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 600 PM MDT Sat Mar 17 2018 VFR conditions will generally prevail through the 00Z TAF period, aside from a short period of MVFR/IFR stratus possible at the KMCK terminal Sunday morning, primarily between 12-16Z. Somewhat breezy SSE winds (15-20 knots with gusts to 25-30 knots) are expected to prevail at the KGLD terminal overnight through Sunday morning, strengthening to 20-25 knots with gusts up to 35 knots during the afternoon. Winds are expected to back from SSE to SE very near the end of the TAF period at KGLD. At KMCK, expect ESE winds at 8-13 knots overnight/Sunday morning to veer to the SE at 15-18 knots with gusts up to 25-28 knots by early afternoon (~18Z). By the end of the 00Z TAF period, winds at KMCK will back to the ESE and strengthen to 20-25 knots with gusts up to 30-35 knots. && .FIRE WEATHER... Issued at 315 PM MDT Sat Mar 17 2018 Critical/near critical fire weather conditions are possible Sunday afternoon as relative humidity values below 20 percent and south to southeast winds gusting 20 to 25 mph combine generally along and south of a line from near Flagler to Cheyenne Wells to near Tribune. Critical and near critical fire weather conditions remain possible Friday afternoon as relative humidity values in the 10-15 percent range combine with west and northwest winds gusting to 30 mph along and south of a line from Flagler to Burlington to Russell Springs. Critical fire conditions are possible Saturday afternoon from Flagler to Tribune and points west. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...99 LONG TERM...ERRYK AVIATION...VINCENT FIRE WEATHER...99
Area Forecast Discussion
National Weather Service Wilmington NC
1041 PM EDT Sat Mar 17 2018 .SYNOPSIS... Mild temperatures will prevail tonight ahead of an approaching cold front, that will cross the coast early Sunday. Lingering clouds and slightly cooler temperatures will be featured on Sunday. A warming trend can be expected early next week as a storm system approaches. Periods of rain and showers Monday night through Wednesday, may transition to light snow Wednesday night before drier air sets in Thursday. Accumulations are not expected because of the relatively warmer ground. A low pressure system will approach the coast next weekend. && .NEAR TERM /THROUGH SUNDAY/... As of 1000 PM Saturday...Concern overnight involves a potent shortwave evident on WV imagery moving overhead the Appalachians, and how its interaction with a surface cold front will impact convection overnight. Latest regional mosaic shows an area of strong to severe thunderstorms cresting the TN/NC/SC mountains and moving quickly to the ESE. This is in response to the aforementioned shortwave, and Although SPC has dropped the SLGT risk to our north, the MRGL risk has been expanded to include the extreme northern tier of the CWA. While the potential exists for thunderstorms overnight, it appears the severe risk is low due to the elevated nature of instability. Latest RAP soundings show 600-1000 J/kg of MUCape for parcels near 900mb, enough to sustain convection, but a stable surface layer should preclude any of the strong winds aloft from mixing down. However, there is a small area, mostly from Lumberton to Wilmington, where the high-res guidance suite, including the RAP, HRRR, NSSL WRF, and ARW, all paint some convection moving across beneath the upper vort and along the front. This is due to a ribbon of the slightly better instability correlating with higher moisture content and stronger forcing. Have increased POP to mid-chc northern tier and schc along the SC/NC border, but again, the severe threat looks minimal. Cannot rule out an elevated hailer, but the primary threat will be briefly heavy rain and some lightning, focused from about 2am near Lumberton, to 7am near Wilmington, and then moving offshore. A weak surface wave beneath the potent vort will exit offshore very late tonight or early on Sunday, and this will act to pull the cold front to the south. Behind this front temps will drop quickly and some stratus will develop, but exactly where this front settles will determine the sharp temperature gradient due to much warmer (cooler) temperatures on the south (north) side. Have tried to show this with upper 40s by daybreak Sunday far northern tier, while remaining in the mid 50s near the South Santee River. Relevant portion of previous discussion below: As of 344 PM Saturday...Southwest winds will veer around to the north behind front as it drops south through the area early Sun morning. Any lingering chc of pcp through the morning will lead to drying by Sun afternoon. Pcp water values up near 1.4 inches ahead of the front will drop to near a half inch air mass clears out in drier northerly flow as high pressure builds in. Max temps on Sunday will be near 60 over SE NC, but will reach closer to 70 in NE SC. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 344 PM Saturday...ECMWF/GFS both show an upper low across the Central Plains Sunday night. The upper low is progged to translate across the MS Valley during Monday evening. At the surface, a cold front will be aligned south of the forecast area at the onset. In the meantime, an area of isentropic lift and increasing low-level theta-E advection will bring rainfall chances back into the area Sunday night. Mentioned a slight chance of thunderstorms as well with some elevated instability present late Sunday night into Monday morning, primarily for SC zones. By early Monday evening both GFS/ECMWF position a surface low across TN with the warm front returning north across the area with decent rainfall chances continuing. Included thunderstorms during this time frame as stability decreases across the area. The ECMWF tracks the low a little further south, but given either solution our rainfall chances will be on the high end across the forecast area. Blend of MAV/MET numbers appears reasonable through the period. Would not be surprised to see the convective risk areas shifted a little farther north for Monday, but the bulk of the instability will likely stay farther south. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 344 PM Saturday...Low pressure pulling off the coast will bring a lull Tuesday, before another low develops and brings periods of showers Tuesday night through Wednesday, changing over to snow or a rain/snow mix Wednesday evening. Forecast low temperatures and thermal profiles, depict a brief period of frozen precipitation is possible across much of the area. Sharp mid- level drying will end PCPN prior to daybreak Thursday. Significant accumulations are not expected due to warmer ground, but a "Frost` advisory, or `Freeze Warning` may be needed very early Thursday, favored over interior SE NC, but could reach into parts of NE SC. Did not include thunder this period because of stable/cooler low levels, but elevated instability will exist to some degree. QPF Tue- Wed night averages to 3/10" to 5/10". && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... As of 23Z...Frontal boundary extends from the Outer Banks to western VA into eastern TN early this evening. As the boundary moves into the area overnight and early Sunday morning a few of the terminals may experience scattered showers and possibly an isolated thunderstorm. Best chance at KFLO and KLBT in the 06-08Z range and 08-10Z at the coastal terminals. A round of stratus in the wake of the front may cause IFR CIGS for a few hours in the morning before a drier column takes hold and clearing occurs thereafter. Extended outlook...Periods of MVFR Sunday through Wednesday. Chances for convection increasing Monday through Tuesday. && .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 1000 PM Saturday...Front to the north will waver in the vicinity until a shortwave and weak low pressure move along it and offshore by the morning. This will drag the front southward and turn winds to the N/NW. However, this is not likely to occur until first thing Sunday, and most of the local waters will remain entrenched in gusty SW winds of 15-20 kts through the overnight, persisting seas at 3-5 ft. Relevant portion of previous discussion below: As of 344 PM Saturday...Winds will veer around toward daybreak quite rapidly to the W-NW and then N, with speeds increasing after a brief reprieve back to 10-15 kts. Seas will basically be in the 2 to 4 ft range, but expect a few 5 fters in the outer waters off of Cape Fear heading out toward Frying Pan Shoals. Looks like seas should remain below any criteria for SCEC or SCA. SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 344 PM Saturday...Weak high pressure across eastern NC at the beginning of the period will shift eastward Monday morning. A stalled front south of the waters will begin to lift north as another area of low pressure takes shape across the MS Valley. The initial easterly wind will veer to a southeasterly direction Monday morning. Additional veering is expected as low pressure moves across NC Monday night. Thus a stronger southwest fetch will develop with Small Craft Advisory conditions possible overnight Monday. Seas will be highest in the southwest fetch late Monday night. LONG TERM /TUESDAY THROUGH THURSDAY/... As of 344 PM Saturday...This is shaping up to be a difficult marine period, as a series of strong low pressure systems impact the coast. Gusty SW winds 20-25 KT Tuesday and Tuesday night, will shift to north equally strong, if not stronger Wednesday as N and NW winds kick up in a cold air surge. Gusts to near Gale force are not out of the question Wednesday over the outer waters, with current numerical wave guidance at FPSN7 assigning 7 feet Wednesday. Very cold temperatures will greet mariners early Thursday, in a moderate, but biting, offshore wind. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...JDW/RGZ SHORT TERM...SRP LONG TERM...MJC AVIATION...SRP MARINE...
Area Forecast Discussion
National Weather Service Lincoln IL
915 PM CDT Sat Mar 17 2018 .UPDATE... Issued at 900 PM CDT Sat Mar 17 2018 Drier air is beginning to filter in across central and southeast Illinois from the north in the wake of the system that passed through the Midwest earlier today. While the arrival of this drier air and departure of forcing with the system has ended the precipitation risk, tonight`s forecast is still a little tricky. Skies across the forecast area have started to clear from the north, and this clearing should continue to expand southward overnight. The ground surface is wet across most of the area due to precipitation that occurred over the past 24 hours. This fact, combined with light winds and clearing skies would seem to be a good setup for fog later tonight. Most of the high resolution guidance suggests light fog development later tonight, with pockets of locally dense fog. Guidance generally suggests the thickest fog will be over southwest portion of the forecast area, which will also be one of the last areas to clear. Would generally expect areas that clear sooner to have thicker fog since they have longer for radiational cooling and associated saturation to occur. Going forecast already had mention of patchy fog and see no reason to deviate from this right now. Plan to update forecast for the latest hourly trends (mainly sky cover). Can`t rule out the need for stronger fog mention or possibly an advisory before morning, but confidence is not high enough to adjust at this time. && .SHORT TERM...(This evening through Sunday) ISSUED AT 303 PM CDT Sat Mar 17 2018 Ridging at the surface and aloft over the Plains this afternoon, keeping a northerly component in the winds over the forecast area. Cooler air filtering into the region, but the stubborn stratus associated with the low passing through the Midwest into IN this afternoon is slow to erode. HRRR slowly progresses this shield of clouds to the south tonight, eventually moving to mostly clear for Central IL by morning. Concerned that the dry air is a little further to the north than prev addition to the fact that there is not significant llvl flow to change the airmass quickly. Lighter winds in the overnight combined with llvl moisture still trapped in the low levels may slow the progression of the low clouds to the southwest. There is currently a good 30 mile or so lag of the dry air behind the clearing line to the north/northeast. With that in mind, have put patchy fog in the forecast after midnight for where the clearing is anticipated. Should the delay last longer, there is a potential for some of that fog to become dense...but guidance winds stay up just enough to drop confidence in that for now. Tomorrow, mild temps with highs in the 50s. The swath of low clouds holding just to the southwest with light easterly winds attempting to advect some of that drier air in at the surface. How far south those clouds get will greatly impact temperatures particularly SW of a line from Macomb to Decatur. .LONG TERM...(Sunday night through Saturday) ISSUED AT 303 PM CDT Sat Mar 17 2018 Overnight Sunday into Monday...lows drop only to the low to mid 40s as increasing clouds once again inhibit cooling in the overnight hours. Next system for Monday/Monday night went with a more southerly solution this run, with the GFS and ECMWF keeping the associated precip well south of the NAM solution. Given the erratic nature of the solutions out of the models at this point, keeping the slight chc/chc pops across the northern tier for now. Rain for Monday and Monday night is expected, before briefly changing over to snow on its departure to the east on Tuesday. Models are relatively consistent in suggesting that this wave will shift us back to a busier and more progressive northwesterly flow pattern aloft. Several waves suggested in this pattern, but the GFS is pretty robust with the development of a surface ridge, inhibiting precip development (Wed night in particular). Low confidence dry forecast through the middle of the week once the northwesterly flow kicks in. The next major storm is taking shape going into next weekend, with precip starting on Fri. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 653 PM CDT Sat Mar 17 2018 Low-end MVFR CIGS will sink south of central Illinois this evening, providing a return to VFR conditions. However, expect at least MVFR fog to develop across the area later tonight. Once the fog burns off Sunday morning, VFR are expected. Light winds will prevail through the 00Z TAF valid time. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Bak SHORT TERM...HJS LONG TERM...HJS AVIATION...Bak
Area Forecast Discussion
National Weather Service Jacksonville FL
902 PM EDT Sat Mar 17 2018 .UPDATE...The Atlantic sea breeze made it to the I-95 corridor and with the evening cooling and encountering the west wind is eroding this evening. Surface flow that was disrupted as a result of the sea breeze will veer back to the southwest late this evening and overnight. coupled with a weak surface winds, wet soils, and a pocket of dry air between 850 and 500mb will yield areas of fog across the region through mid-Sunday morning. SREF and HRRR do hint at patchy fog developing over the interior portions of SE GA and NE FL mainly west of highway 301 with lower clouds over the Suwannee Valley and interior SE GA. Current forecast has these trends and no updates this evening. && .AVIATION...VFR conditions through much of Tonight. Latest guidance suggests some low cloudiness and patchy fog could develop after 09z, and continued this potential for this in latest TAFs til about 12-13z. Would anticipate VFR conditions mid morning onward Sunday with light westerly surface winds with perhaps a seabreeze at St. Augustine and Saint Simon`s during the mid to late afternoon. && .MARINE...High pressure will shift S and E of the waters during the weekend. A series of low pressure systems will track to the north of the waters. This will maintain a southwesterly flow in the 10-15 kt range and 2-4 ft seas through the weekend. A stronger system will approach the waters late Monday and Tuesday resulting in increased southwest winds and seas as well as potential for scattered showers and thunderstorms. A strong cold front will move across the waters Tuesday night. Winds and seas expected to increase to advisor criteria Tue-Wed. Rip Currents: Low risk expected with offshore flow through Sunday. && .PRELIMINARY POINT TEMPS/POPS... AMG 59 81 60 76 / 10 10 70 60 SSI 60 76 60 71 / 10 10 60 80 JAX 58 81 60 81 / 10 10 40 70 SGJ 57 79 58 78 / 10 10 20 60 GNV 56 82 58 80 / 10 10 20 50 OCF 56 82 58 81 / 10 10 10 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Cordero/Shuler/McGinnis
National Weather Service Jackson KY
1051 PM EDT Sat Mar 17 2018 .UPDATE... Issued at 1051 PM EDT SAT MAR 17 2018 The forecast was updated to remove any last mention of thunderstorms and to account for ongoing rain showers that will be moving across the eastern third of the forecast area over the next hour or two. The rest of the forecast was in good shape with the latest obs used to establish new trends. The night shift will need to issue one more update early in their shift once the last of the ongoing rain showers finally exit the area. UPDATE Issued at 900 PM EDT SAT MAR 17 2018 Now that the severe weather threat has ended across the area, the severe thunderstorm watch has been cancelled. The forecast and the hazardous weather outlook products have both been updated to reflect this changes. Also updated the precipitation forecast for the rest of tonight based on current radar trends and the latest run of the HRRR model. Now have thunderstorms moving out of the area between 2 and 3Z and precipitation overall moving out of eastern Kentucky between 4 and 5Z. Will need to issue another update toward the end of the shift to get rid of any remaining evening wording and for areas where the ongoing precipitation will have already ended for the night. UPDATE Issued at 735 PM EDT SAT MAR 17 2018 Have updated the grids with the latest obs to establish new trends. Will leave the severe thunderstorm watch and zone forecast text product as is until we cancel the watch this evening after the severe threat has finally ended. It does appear that the severe weather threat will end across our area well before the midnight EDT expiration time of the watch. It also appears that we may be able to take precipitation out of the area a bit faster than the inherited forecast has been indicating, but will continue to monitor current radar trends and the latest model data to before making that determination. && .SHORT TERM...(This evening through Sunday night) Issued at 520 PM EDT SAT MAR 17 2018 A cold front was bisecting the forecast area from east to west late this afternoon, with a low pressure system tracking along the front from central into eastern KY. Showers and thunderstorms have quickly developed along the front. The regime will shift southward this evening. There is good speed shear in place, and dry mid levels with steep lapse rates. The severe weather parameter which is looking puny is the moisture. Strong heating has mixed drier air to the surface with dew points only in the 30s and 40s over most of the southern portion of the area late this afternoon. Can not rule out severe weather in places where higher dew points linger or redevelop, but for much of the area late afternoon conditions don`t look all that favorable. Freezing level and wet bulb zero height are quite low, which favors large amounts of small hail. Any large hail would probably need to come from storms with significant rotation. Storms should taper off from northwest to southeast this evening after cold fropa. Surface high pressure passing to our north will provide fair weather Sunday into Sunday night. Another low pressure system heading east from the southern plains will pull the front back north toward KY as a warm Sunday night. Showers could make a return to our southwest counties by dawn, but will more likely hold off until the daytime on Monday. .LONG TERM...(Monday through Saturday) Issued at 520 PM EDT SAT MAR 17 2018 Model solutions are in decent agreement, sufficient enough to pick out the main features of concern through the extended. Flow aloft amplifies with time but remains fairly progressive, with implications that our generally unsettled pattern will continue with only one relatively short period of fair weather from Thursday through at least part of Friday. Consequently our weather is active straight out of the gate as a mid level low, upper level wave moves into the region Monday. Additional shortwave disturbances follow Tuesday into Wednesday before exiting to our east by Thursday. Solutions differ on timing another shortwave disturbance into the region by the end of the period, with the 12Z GFS bringing our next weather maker into the area by late Friday into Saturday. The 0Z ECMWF and 12Z Canadian hold off on this system until beyond the end of the period, and seem to suggest a deeper, more organized storm system. Closer to the surface, a low pressure system will pass through the Tennessee Valley Region Monday/Monday night. Instability is marginal but may be enough to kick of a thunderstorm or two late Monday into Monday night. Shortwave disturbances following in the wake of the initial low will be responsible for the redevelopment of another surface low or two over the southern Appalachians through Tuesday and Wednesday. If enough cold air manages to be drawn southward into the region from the north, sensible weather may feature a wintry mix of rain and snow showers for a period of time late Tuesday night into Wednesday morning, particularly across the higher terrain. However, details remain a bit too sketchy to provide any specifics for now. Drier conditions will work into the area by Wednesday night and Thursday as ridging moves in from the west. Fair weather should continue through much of Friday before the next potential weather maker moves in from the west by late week or early into the weekend. Comparing models favored a slower arrival of the precipitation for the end of the extended and would not be surprised if Friday winds up dry in the end. But should not discount the GFS solution totally based on its recent very good performance with the last few systems to affect our area. Otherwise, near normal temperatures initially will cool to well below normal for the mid week time frame. Temps then rebound for the end of the week and following weekend. | && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 735 PM EDT SAT MAR 17 2018 Showers and a number of thunderstorms will continue to move across eastern Kentucky this evening. Based on the latest upstream radar trends, it appears that the showers and storms will be ending at LOZ, SME, and SYM by 1Z or so this evening, by 2 or 3Z at JKL, and between 4 and 6Z at SJS. Any storms may produce MVFR conditions at any given airport this evening. It appears that SJS and JKL will have the best chance of seeing a shower or storm to begin the TAF period. Will continue to monitor the ongoing showers and storms and will update the TAFs as necessary as the rain moves off to our east. Conditions should begin to improve VFR at the TAF sites between 13 and 17Z on Sunday. Cloud cover should progress from OVC to BKN to SCT during that time as well, with clear to mostly clear skies expected by Sunday afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...HAL LONG TERM...RAY AVIATION...AR
Area Forecast Discussion
National Weather Service Louisville KY
734 PM EDT Sat Mar 17 2018 ...Updated Aviation Discussion... .Mesoscale Update... Issued at 720 PM EDT Sat Mar 17 2018 Storms have pushed into eastern Kentucky and the air mass over central Kentucky has stabilized, so our portion of Severe T-storm Watch 10 has been cancelled. There were a few reports of small hail, but nothing severe that we are aware of. The remainder of the night should be dry as we are into northerly low-level flow and cold advection. Last set of updates was issued a few min ago. Issued at 550 PM EDT Sat Mar 17 2018 Convection is already on a downward trend after getting a few sub- severe reports from Marion County eastward to Lincoln. The main boundary of concern runs from near Greensburg to Stanford, and that will be the main focus of any remaining SVR threat. Will start peeling off the western/northwestern layer of counties from WW 10 this hour, with the rest of central KY likely to come down next hour. Issued at 433 PM EST Sat Mar 17 2018 Storms have developed along a well defined surface boundary stretching across central KY in an environment characterized by 1000- 1500 J/Kg surface based instability coincident with 50-55 knots of effective bulk shear. Given strong speed shear with height along with some veering with height, supercell structures (some splitting) are possible. The main concern is large hail given freezing levels around 8K feet and -20C heights around 18 K feet. A damaging wind threat will also exist given steep low level lapse rates with a 20 degree T/Td spread at the surface. There is a possibility that storms could congeal, and if a cold pool is established the wind threat would increase. An isolated tornado can`t be ruled out, however low level surface winds aren`t overly backed to promote horizontal streamwise vorticity ingestion. In addition, LCL`s are in the 1000-1200 M range. Latest mesoanalysis shows effective SRH values around 50-100 M2/S2 along the boundary so there is some localized enhancement of the environment along the front. Severe Thunderstorm Watch #10 was just issued and expires at Midnight EDT. However, expect storms to move east of our area by around 6-7 PM EDT. && .Short Term...(This evening through Sunday night) Issued at 215 PM EDT Sat Mar 17 2018 As of 2 PM, a surface analysis showed an area of low pressure centered near Owensboro, Kentucky. GOES-East mesoscale visible imagery depicted an arch of enhanced cumulus denoting the warm front location that was along an Owensboro-Elizabethtown-Lexington line. South of that boundary, spring-like weather prevailed with mostly sunny skies, breezy southwest winds, and temperatures in the 70s. Northward, across southern Indiana, lower clouds and easterly flow prevailed and readings were in the 40s. Across the forecast area, there is about a 30-35 degree temperature gradient. A pool of near-60 degree dewpoints lie across south-central Kentucky, contributing to about 500 to 1000 J/kg of surface-based CAPE, per recent RAP mesoanalysis and GOES-East CAPE derived product. Aloft, the presence of a passing shortwave is providing modest deep-layer shear, on the order of 40 to 50 kts. In the next 3-5 hours, a brief window of opportunity exists for strong to marginally severe thunderstorms where the axis of instability remains as the surface low tracks east through central Kentucky providing the necessary lift to initiate convection. The available hi-res models show the area where the risk exists is from around Lexington southward toward Lake Cumberland, and as far west as Glasgow, Campbellsville, and Springfield Kentucky. The latest SPC Day 1 outlook nudged the marginal/slight risks westward from the early morning issuance. The main hazards for any storm that does develop is large hail (quarter sized) thanks to the lower freezing levels (8-10 kft), steep low-level lapse rates, and drier air aloft. If storms organized into small clusters, a damaging wind threat also exists. The main time frame is from around 3-4 pm through 7 pm as the storms develop and quickly move eastward into eastern KY/TN. The surface low moves east of the area this evening and drags the cold front back through the area. There is a drizzle / light shower chance across the northern areas and northern Bluegrass later this evening, then temperatures tonight will fall into the upper 30s to lower 40s with mostly cloudy to overcast skies. On Sunday, seasonable readings are expected as high pressure builds into the region. Drier air working in from north will erode the cloud layer initially over southern Indiana and north central Kentucky, where a mostly to partly sunny day is expected. Further to the southwest, across south-central and west-central Kentucky, the effects of that dry air are limited and time-height cross sections show more moisture lingering, so a mostly cloudy to overcast day is forecast. The clouds will impact high temperatures, and southern Indiana may end up slightly warmer than south-central Kentucky by a few degrees. Most areas will range from 55 to 60. The next weather system is quick to move into the region as the upper level pattern remains quite progressive. Showers are likely Sunday night, especially after midnight across south central and central Kentucky. Lows will fall into the 40s. .Long Term...(Monday through Saturday) Issued at 220 PM EDT Sat Mar 17 2018 An unsettled weather pattern is in store for the upcoming work week across the lower Ohio and Tennessee Valleys. The progressive but active pattern could bring both spring and winter weather to the area. The 17.12z models are in reasonable agreement showing a compact shortwave tracking across the Tennessee Valley Monday. At the surface, a low pressure looks to organize and track across middle TN during the afternoon and evening hours. This setup will put a warm front somewhere along the KY/TN border or into south-central KY. The best dewpoint surge, instability, and potential severe weather threat continues to be across TN/AL/GA. However, a time-trend analysis over the last several model runs shows a slight northward jog in the surface low and shortwave, and if this trend continues, portions of south-central KY could be under a threat for stronger to severe storms Monday afternoon/evening. Further north, a frontogenetical band of rain is likely to setup across southern Indiana and north central Kentucky. As temperatures cool behind the front Monday night and Tuesday morning, a brief changeover to wet snow is possible but at this time, the colder air lags the precipitation enough to preclude much if any snowfall accumulation. The Tuesday-Wednesday period has more uncertainty and lower confidence. The potential phasing or not of the upper level energy and the southern stream system could spread light precipitation across portions of eastern and central Kentucky. It does appear to be much colder with highs in the 40s, and potentially staying stuck in the 30s. For now, continued with a model consensus but will need to watch this period for the potential for light snow accumulations across the Bluegrass. The remainder of the work week looks more benign with high pressure and seasonably cool temperatures. Toward next weekend it appears another system may track through the Midwest and OH Valleys and bring chances for showers and thunderstorms to the area. && .Aviation...(00Z TAF Issuance) Issued at 733 PM EDT Sat Mar 17 2018 Scattered storms have now pushed east of the region, with the frontal boundary that they initiated on also sinking south of the TAF sites. Therefore, we`ll stay dry the rest of this forecast cycle, with steady NW winds slackening and becoming light and variable later tonight. The biggest concern will be low ceilings already working into the region from the north, and expected to persist for much of the overnight. Have the TAFs mostly going into the low MVFR range below fuel-alternate, but can`t rule out some brief IFR at HNB or LEX around Midnight into the pre-dawn hours. Covered this potential with a TEMPO. Ceilings should improve close to sunrise at SDF/LEX/HNB, but expect them to persist at BWG well into the afternoon on Sunday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Mesoscale...BJS/RAS Short Term...ZT Long Term...ZT Aviation...BJS
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1044 PM EDT Sat Mar 17 2018 .SYNOPSIS... A warm front lingering across the area will push southward as a cold front tonight and early Sunday morning. A strong area of low pressure will affect the area Monday night and Tuesday. High pressure will build in from the northwest late next week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 1030 PM Sat...High pressure remains centered off the SE coast with a frontal boundary bisecting the region, roughly from Ocracoke to across the Pamlico River. Convection becoming enhanced across north-central NC along the sfc front as upper level dynamics improve with an approaching shortwave trough. SPC has lowered the severe risk to marginal across the area for the overnight as the MCS moves into the region. The primary severe threat remains to be for damaging wind gusts and large hail. The sfc front will slowly push S across the CWA overnight with only far southern areas remaining in the warm sector as the convection moves across the area. Latest update from the HRRR shows the convection entering NW portions of the CWA around 1 am and pushing off the coast around 6 am with greatest coverage across northern areas. Temps will remain mild south of the front, generally in the 50s to lower 60s but will cool into the 40s after the front pushes through and southern area will likely not drop into the 40s until late tonight. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... As of 3 PM Sat...The cold front will continue to push through the southern areas early Sunday morning, as low pressure and shortwave push further offshore. Could still see some lingering showers along the coast early, but that should taper off Sunday morning with skies becoming mostly sunny from north to south. Low level thickness values and N/NE flow support highs 50-55 degrees across the NE counties and 55-60 degrees across the SW. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... As of 330 AM Saturday...A strengthening closed mid- level low will lead to rapid strengthening of a surface low that will move across Tennessee and intensify off the NC coast early Tuesday at about 995 mb. Widespread showers will enter the region Monday afternoon with the heaviest precipitation Monday night. With strong low-level wind fields and backed SE flow, there would be some concern for strong storms, but instability appears to be limited to offshore areas at this time and will continue to carry showers. A unsettled pattern looks to continue Wednesday into Thursday as deep moisture swings through the area with deep mid-level trough and strong shortwave energy. Thermal profiles from both the GFS and ECMWF continue to support a rain/snow mix Wednesday night with light rain possible Thursday. Have PoPs in the slight chance to low chance range at this time, but with models showing a bit better agreement, may be to raise those PoPs on later updates. Drier air returns Friday with weak surface ridge building in from the northwest. Temperatures will show wide variation through the extended period with highs well into the 70s Tuesday in the S/SW flow ahead of the strong low, dropping into the lower 30s by Thursday morning behind the low with the possible light rain/snow mix. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... Short Term /through Sunday/... As of 8 PM Sat...Pred VFR expected this evening with light SW winds at the terminals. After midnight through roughly 6 AM, the models continue to indicate the potential for organized strong convection and sub VFR conditions moving east along a southward moving cold front which is currently stalled across the northeastern portion of Eastern NC. The front will move south of the area late tonight with a period of IFR ceilings expected in the northerly post frontal flow from 6 AM through 11 AM with conditions improving to VFR around 2 PM Sunday as drier air filters into the area. Long Term /Sunday through Thursday/... As of 145 PM Saturday...High pressure will bring drier air and VFR conditions from Sunday afternoon through about midday Monday. Deep moisture associated with the next system will lead to widespread showers Monday night and Tuesday with MVFR/IFR conditions expected along with gusty SW/W winds. With lingering precipitation associated with a strong upper-level feature, some MVFR ceilings with showers are possible into Wednesday, then VFR conditions prevail on Thu as high pressure begins to build into the area. && .MARINE... Short Term /through Sunday/... As of 9 PM Sat...A front continues to bisect the waters and latest obs show SW winds 15-25 kt with gusts as high as 30 kt south of Cape Hatteras, and E/NE 5-15 kt north. Seas continue around 2-4 ft north but have built to 4-7 ft to the south where stronger winds have occurred this evening. The front will push southward overnight and is progged to be across the far southern waters late tonight with N/NE winds becoming 10-15 kt behind the front. NNE surge 15-25 kt will develop behind the front Sunday. Seas expected to subside to 2-5 ft late tonight but build back to 3-6 ft Sunday with the N/NE surge. Continue SCA for the waters south of Oregon Inlet and Pamlico Sound into Sunday. Long Term /Sunday night through Thursday/... As of 330 AM Saturday...N winds at 15-20 knots initially on Sunday will become E/NE 5-15 knots Sunday night through Monday with seas subsiding from 3-5 feet to 2-3 feet Monday as weak high pressure settles over the waters. By Monday night, SE winds increase to 15-20 knots with seas building to 4-6 feet. Winds will veer to SW then W Tuesday into Wednesday with seas building to as high as 9 feet in the central waters by Wednesday morning. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory until 8 PM EDT Sunday for AMZ152-154. Small Craft Advisory until 5 PM EDT Sunday for AMZ156-158. Small Craft Advisory from 6 AM to 5 PM EDT Sunday for AMZ135. && $$ SYNOPSIS...CQD NEAR TERM...SK/CQD SHORT TERM...CQD LONG TERM...CTC AVIATION...CTC/SK MARINE...CTC/SK/CQD
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1002 PM CDT Sat Mar 17 2018 .DISCUSSION...See updated information for land areas below. && .UPDATE...The earlier scattered convection over our region has come to an end, with our local radars now back in clear air VCPs as of 945 PM. We have updated the forecast to remove POPs for the rest of the evening. The next upstream shortwave trough will be approaching the Lower Mississippi Valley overnight. High resolution guidance and most of the deterministic model guidance are in agreement that most of the ascent with this next feature will remain to our west through 12Z, though there is some indication that isolated light showers could develop over our western zones late, so will leave only 20 percent POPs in place across this portion of the area during the overnight hours. The main impact overnight looks to be development of patchy to areas of fog, especially south of the U.S. Highway 84 corridor, where the NAM-12, RAP, and HRRR are all indicating development overnight, not to mention >60% SREF probabilities of visibility less than 1 mile. We have included areas of fog vs. patchy over the central and southern zones in the latest update (keeping patchy mention for now in the north). The overnight shift will monitor observations closely for dense fog development. All other forecast elements look on track. /21 && .PREV DISCUSSION... /issued 623 PM CDT Sat Mar 17 2018/ DISCUSSION...Updated for latest aviation discussion below. AVIATION... 00Z issuance...Expecting mostly VFR conditions this evening with some MVFR ceilings possible from convective blow off clouds to the west of Mobile. As showers and storms come to an end this evening we should see a general increase in ceiling height through about midnight or so. Thereafter ceilings will lower as low stratus and fog are possible through early morning. Chances for showers and storms will increase as we head through the morning hours. 05/RR PREV DISCUSSION... /issued 420 PM CDT Sat Mar 17 2018/ NEAR TERM /Now Through Sunday/...A cold front will move into the Tennessee Valley this evening then slowly sink southward and stall across south central Mississippi and Alabama on Sunday. South of the this front, a very moist airmass will remain in the place with dewpoints in the mid 60s. This afternoon daytime heating is generating scattered showers and isolated thunderstorms across portions of the area. These will continue through early evening before dissipating tonight as the boundary layer cools. Although an isolated shower is possible overnight, most areas will remain dry. The increased moisture and light winds will allow for at least patchy dense fog to develop late tonight into Sunday morning. Lows tonight fall into the low 60s inland to mid 60s along the coast. A shortwave is expected to generate showers and storms across eastern Texas this evening which may congeal into an MCS and move eastward along the stalled front overnight. Depending on how well developed the convection becomes, it could act to enhance thunderstorm development on Sunday. Meanwhile, the airmass along and south of the stalled front is expected to become moderately unstable by tomorrow afternoon with MLCAPE values around 1000 J/Kg. In addition strong deep layer shear of 50 to 60 knots is expected. As a result, any cells that develop near or just south of the boundary will be capable of becoming severe with damaging winds and large hail. An isolated tornado is also possible due to the enhanced shear near the front. This is where the Storm Prediction Center has outlined a slight risk of severe storms, roughly north and west of a line from Leakesville to Evergreen to Greenville. /13 SHORT TERM /Sunday night Through Tuesday night/...An upper level shortwave over the Great Plains pushes east into the Mississippi River Valley Sunday night into Monday morning. Ahead of this system, onshore flow will continue to pump Gulf moisture into local area and convection will likely be ongoing along and south of a quasi-stationary front draped across the Mid South. Despite the loss of diabatic heating after sunset, an EML overspreading the region from the west will maintain at least a modest amount of elevated instability throughout the night, with MUCAPE remaining around 1500 J/kg per latest guidance. Thus, expect storms to continue during the overnight hours Sunday night into Monday. Effective bulk shear around 50 knots and mid-level lapse rates increasing to around 7.0 C/km (courtesy the aforementioned EML) will support the chance for some strong to possibly severe thunderstorms capable of producing large hail and gusty straight- line winds. The ingredients for strong to severe storms linger throughout the day Monday as the upper trough and attendant surface low continue to push east into the Tennessee Valley. The return of daytime heating results in further destabilization of the warm sector, with guidance continuing to suggest upwards of 2500 J/kg SBCAPE developing during afternoon hours. Strengthening 850 mb flow supports effective bulk shear values around 50 knots, meaning storms that are able to form will have the chance to organize and become strong to severe. However, there is some uncertainty regarding convective initiation Monday afternoon, as some high- res guidance suggests warm 850 mb temperatures maintaining a capping inversion over our area through much of the day, and the best forcing to overcome this cap would stay primarily to our north in closer proximity to the surface low and upper shortwave. Due to this uncertainty, have kept the best chances for strong to severe thunderstorms on Monday over the northeastern portion of the local area, where the best forcing will likely be realized before the cold front eventually sweeps through. There is a marginal risk across the remainder of the area, as any storms that are able to form will be capable of organizing and becoming strong to severe as well. The primary threats will be large hail and damaging straight-line winds. Please see the Storm Prediction Center website ( or our homepage ( for the latest information regarding severe weather potential Sunday night and Monday. The cold front passes through Tuesday morning, effectively ending rain chances and ushering in cool and dry air to finish off the short term period. Tuesday night lows will be much cooler as a result, dipping into the low 40s across the area. /49 LONG TERM /Wednesday Through Saturday/...A deepening upper longwave trough over the eastern CONUS pushes east over the Atlantic Ocean through the long term, with dry deep-layer northwest flow setting up over the local area as an upper ridge builds to our west. Will see cool and dry conditions beneath mostly clear skies Wednesday through the remainder of the week as a result. Highs reach the mid and upper 60s each day and lows dip into the upper 30s to low 40s each night. /49 MARINE...A predominantly light to occasionally moderate south to southwest flow is expected to continue over the coastal waters through Monday as Atlantic high pressure continues to ridge west across the eastern Gulf and a frontal boundary remains nearly stationary well to the north of the marine area. A stronger cold front approaches the marine area Monday night and is expected to move east across the coastal waters Tuesday with winds shifting to the northwest and increasing, along with building seas. /13 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at:
Area Forecast Discussion
National Weather Service Phoenix AZ
817 PM MST Sat Mar 17 2018 .SYNOPSIS... The approach and passage of a weather system will lead to breezy to windy conditions over much of the region today and tonight as well as a chance of showers...mainly east of the Lower Colorado River Valley. There will be some cooling as well with highs in the 60s on Sunday. Below normal temperatures through Monday should warm back into the 80s for the middle of next week. Another weather system will provide an opportunity for rain and cooler temperatures late next week. && .DISCUSSION... Upper level low tracking into the Southwest this evening, currently making its way across the Sierra Nevada. Ahead of it, nice little baroclinic leaf developing. Unfortunately the inflection point is near the Grand Canyon and well north of our forecast area. In general, the system seems to be under-performing. Winds are not quite as strong as anticipated and appears most of the lifting will be further north. HRRR for most of the afternoon and evening has been underwhelming showing scant precipitation and weaker wind fields. Adjusted pops down just a bit but still a chance for some light rain (this was never going to be a big producer, more the higher pop/low qpf scenario). Will continue the WI.Y across far southwest Imperial County. Winds have been in a bit of a lull there but are showing some increasing trends. For the early to middle portion of next week, high pressure aloft will build back over the desert southwest allowing for dry conditions and a sharp warming trend. High temperatures will climb back into the mid to upper 70s by next Tuesday and then into the middle 80s over the warmer deserts next Wednesday. We will see periods of mainly high clouds spreading through the ridge resulting in partly to mostly cloudy skies Tuesday into Wednesday, but the high cloud cover will not keep temperatures from reaching into the 80s. For the latter part of next work week - Thursday into Friday - operational GFS and ECMWF as well as GEFS ensembles continue to paint a picture that suggests another Pacific low will move inland and across the area, bringing another chance of showers to the lower deserts. Confidence in exact timing is low still, but somewhere in the Thursday/Thursday night time frame seems like the best bet for rain in the greater Phoenix area. NAEFS POP trend still looks to be decent with numbers that are a bit overdone but not too much. Expect quite a bit of cloud cover along with temperatures cooling back into the 70s with the passage of this next system. && .AVIATION... South-Central Arizona including KPHX, KIWA, and KSDL: Latest trends and guidance are looking less impressive with this system. Winds speeds have been paired back a bit and the TEMPO of ceilings around 5kft was removed. Still a chance the ceilings materialize in the 10-13Z window but not confident enough anymore to carry in the TAF. Southeast California/Southwest Arizona including KIPL and KBLH: Gusty westerly winds will continue this evening then slacken overnight. Little indication of significant dust at this time though always a potential with higher winds. Area METARs reporting clouds/cigs in the 7-8kft range and they should remain there for a few more hours before decreasing behind the passing front. Lighter winds with few clouds Sunday. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Monday through Friday... Very dry conditions together with a warming trend across the region will predominate through Wednesday. A weather system on Thursday will bring a chance of light rain from SE CA to AZ. Seasonably warm daytime temperatures early in the weak will increase to the mid 80s by Wednesday and then drop back down into the upper 70s on Thursday. Min RH`s in the 8-15% range through Wednesday are expected to jump up to the 20-25% with Thursday`s system. Very breezy to windy southwesterly winds gusting to 20-25kt from SE CA to SW AZ will also accompany the system on Thursday. Generally fair overnight recoveries should improve to fair to good by Thursday. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory until 5 AM PDT Sunday for CAZ562. && $$ DISCUSSION...Iniguez/CB AVIATION...Iniguez FIRE WEATHER...Sawtelle
Area Forecast Discussion
National Weather Service San Angelo TX
704 PM CDT Sat Mar 17 2018 .UPDATE... We have cleared our counties from the severe thunderstorm watch. With the loss of daytime heating, the atmosphere is becoming more stable. Will keep a slight chance of showers and storms in the grids until midnight, with a few lingering showers between Ballinger and southern Taylor county. 08 && .PREV DISCUSSION... /issued 637 PM CDT Sat Mar 17 2018/ UPDATE... A few strong storms lingering across the eastern counties with one severe storm currently exiting San Saba County. Will keep the thunderstorm watch going a little bit longer, but expect the remainder of the storms to weaken as we head toward sunset. 08 AVIATION... /00Z TAFS/ VFR expected for the next 24 hours. Main concern for TAFS will be stronger winds tomorrow. Thunderstorms have moved east of TAF locations this evening, so expecting VFR to continue. Will see winds weaken after sunset mainly southeast overnight. Dryline and Pacific front early Sunday will shift winds to the west to northwest with gusts of 30 to 35 kt possible. 08 PREV DISCUSSION... /issued 325 PM CDT Sat Mar 17 2018/ SHORT TERM... (Tonight and Sunday) Complicated surface pattern this afternoon with the stationary frontal boundary south of the Big Country, with a dryline extending south across the Hill Country. As the back edge of the mid and high clouds exited, temperatures and instability climbed and convection developed. Storms should end before 00Z and take most of the precip with it. High res models such as TTU WRF and the HRRR show an fast morning area of high based showers moving across the area late tonight into Sunday morning, with global models showing drier conditions. Not really accounted for in the forecast at this point, and will not add at this point, but will need to be watched to see if a little light rain will need to be added to the forecast for late tonight. Critical fire weather conditions still the main problem for Sunday and Monday, as gusty west and northwest winds develop behind a dryline and pacific front. Temperatures will soar behind the dryline with strong downslope flow, with readings near 90 in some locations. LONG TERM... (Sunday Night through Friday) As mentioned, fire weather the main concern for Monday in the wake of the cold front. Temperatures will be cooler, with highs in the 60s and 70s. Dry air mass will allow for some decent radiational cooling Monday night, with lows around 40. Gradual warmup for the remainder of the week FIRE WEATHER... Critical fire weather conditions the main forecast concern. With a lack of recent rainfall, ERC values are starting to climb across the area. Winds will shift to the west and start to increase behind the dryline on Sunday afternoon, but highest winds will wait until late afternoon as the pacific front moves into the area. With humidity values falling into the 10 to 15 percent range, west winds of 20 to 25 mph at the 20 foot level will create dangerous fire weather conditions mainly west of an Abilene to San Angelo to Ozona line. Wind speeds will continue Sunday Night, and humidity recovery will be very slow. Max humidity values Sunday Night will only reach into the 30 to 40 percent range for many locations. As as get into the day Monday, wind speeds will continue to be high and humidity values will quickly drop below 20 percent as temperatures begin to climb. Will be cooler on Monday than we see on Sunday, but critical fire weather conditions will still develop. A Fire Weather Watch has been issued for all of West Central Texas. Wind speeds will finally begin to ease and humidity values increase by early Monday evening. && .PRELIMINARY POINT TEMPS/POPS... Abilene 55 85 49 69 / 10 10 0 0 San Angelo 57 87 47 74 / 10 10 0 0 Junction 57 89 46 77 / 20 10 5 0 Brownwood 56 87 47 73 / 20 20 0 0 Sweetwater 55 83 47 69 / 10 10 0 0 Ozona 56 86 46 71 / 10 10 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 9 PM CDT Sunday for Coke-Crockett- Fisher-Haskell-Irion-Jones-Nolan-Runnels-Sterling-Taylor-Tom Green. Fire Weather Watch from Monday morning through Monday evening for Brown-Callahan-Coke-Coleman-Concho-Crockett-Fisher-Haskell- Irion-Jones-Kimble-Mason-McCulloch-Menard-Nolan-Runnels-San Saba- Schleicher-Shackelford-Sterling-Sutton-Taylor-Throckmorton-Tom Green. && $$ 99/99
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Sunday) Issued at 300 PM CDT Sat Mar 17 2018 An upper-level ridge is currently progressing across the Central Plains with a surface high pressure centered in SD and IA. Residual moisture in the form of stratus is present over northeast KS. Diurnal mixing on the southwest periphery of the stratus is slowly eroding the clouds towards the northeast. These clouds along with light northerly winds is keeping the temperatures in the upper 40s to mid 50s. The surface ridge orientated north to south slides through the area today and tonight keeping winds light and gradually veering overnight. Areas that receive minimal heating this afternoon but clear out this evening could have enough radiational cooling to support fog towards sunrise. The next midlevel low tracks over CO and NM tomorrow forcing a northward moisture flux. The surface front is currently over northern TX so modification of the post frontal air mass in OK and KS will be difficult given the short amount of time before the systems arrives. A more modest moisture transport appears to occur around the 800-700 mb layer beneath a modest EML. This moisture should be in place once the lift increases Sunday evening and contribute to marginal elevated instability. A narrow corridor of surface dew points in the upper 40s advects northward ahead of the surface cyclone into central and southwest KS by Sunday afternoon. It appears convection could initiate in the vicinity of the surface cyclone and then weaken as it progresses eastward given the narrow zone of positive buoyancy. Therefore only expected some embedded thunder within the large scale precipitation shield that is forecasted to move through portions of eastern KS. .LONG TERM...(Sunday night through Saturday) Issued at 300 PM CDT Sat Mar 17 2018 There is still slight discrepancy regarding the track of the midlevel low pressure Sunday night. The overall consensus is for the low to pass over the OK/KS state line, which places the upper- level divergence and PVA along and south of I-70 Sunday night into Monday morning. The expected rainfall will also be partially dictated by the northward extent of the moisture advection. The GEFS shows more spread in the QPF especially for northern KS, which is likely due to the southward shift and track discrepancy. This has caused a southward shift in the heaviest axis of rainfall and an overall reduction in forecasted QPF for the area. Another weaker shortwave ejects out of the Rockies over SD/NE Monday night into Tuesday. This may support additional precipitation mainly along and north of I-70 Monday night. Cooler temperatures advecting southward and the lack of diurnal heating may support a rain-snow mix. The QPF expected during this time frame is fairly minor so do not expect many impacts at this point. The series of shortwave troughs tracking over the Northern Plains and Upper Midwest eventually deepen the longwave trough over the eastern US. This keeps our region in the northwest flow aloft until Thursday. An approaching shortwave trough embedded within the southwest flow aloft will drive warm air advection precipitation across the region starting Thursday night into Friday. The strength, track, and timing of this shortwave is not certain, but it could support a surface cyclone in the region. Temperatures will moderate through out the week with highs in the 60s and 70s and lows in the 40s by Friday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 629 PM CDT Sat Mar 17 2018 Difficult forecast with MVFR cloud clearing line recently stalling in TOP/FOE vicinity. HRRR and RAP seem to have the best handle on this shallow cloud, but still vary notably in its evolution. At this point have kept it a few more hours but northeast winds at cloud level could easily keep a BKN deck in place much of the first half of this forecast. Will also need to watch BR/FG potential with light winds and crossover temps expected to be reached, with more concern at MHK, but at this point expect enough mixing to keep limiting BR in check. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sanders LONG TERM...Sanders AVIATION...65
Area Forecast Discussion
National Weather Service Tucson AZ
831 PM MST Sat Mar 17 2018 .SYNOPSIS...A weather system will bring a chance of valley rain and mountain snow late tonight into Sunday morning. Expect cooler temperatures Sunday and Sunday night before high pressure brings a warming trend the first half of the new week. Another system will brush by mainly north of the area later in the week. && .DISCUSSION...Shortwave trough axis is now located across central California with the associated cold frontal band now just pushing into Arizona across the lower Colorado River Valley. Latest IR satellite shows mostly clear skies from Tucson westward with some residual cirroform cloudiness east of Tucson. There is not a lot of cloud coverage with the cold front upstream of our area near Yuma but as the front pushes to the east it will pickup a bit of Gulf of California moisture. This moisture combined with weak forcing and ascent with the front are expected to result in a few showers on Sunday morning. Latest HRRR runs and 00Z NAM are certainly not too excited about shower coverage Sunday morning with the HRRR consistently not depicting much of anything. Will not make any changes to the forecast at this time, but if anything our PoPs might be a touch too high. Bottom line is this is really a minor system with precipitation amounts generally under 0.05" in the valleys with slightly higher amounts in the mountains. Just made some minor changes to tweak for latest trends in sky cover overnight, otherwise the previous forecast remains unchanged. && .AVIATION...Valid through 19/06Z. Approaching trough will result in increasing cloud cover late tonight along with VCSH around KTUS Sunday morning. Looks like best chance of rain will be centered on 14Z plus/minus a few hours, with showers exiting the region before 18Z. Any rain that occurs at KTUS will be light with no restrictions to vsby and only a brief drop in cigs to around 8kft. KOLS/KDUG likely too far south to see any rain but will likely see an increase in clouds. Expect southwest winds around 10-15 kts to become westerly Sunday with afternoon gusts of 20-25 kts possible mainly east of KTUS. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Isolated showers expected late tonight into Sunday morning but any rain/snow will be light. Mostly clear skies and dry weather are expected from Sunday night through mid/late week. Another trough will approach the region on Thursday bringing the next opportunity for rain to the area. As for winds, expect the strongest winds of the week to be the rest of today into early Sunday morning. Afternoon breeziness is expected each day Monday through Wednesday with typical diurnal patterns expected. Gusty southwest winds should return next Thursday and Friday. && .PREV DISCUSSION...Winds picking up this afternoon ahead of a storm system digging into the region from the northwest (below advisory levels but gusty). Most of the action will be north of our area with this system as it pushes across the region over the next 36 hours. The associated cold front currently near far western Arizona looks just a tad slower, and should push across SE AZ between 3AM and early afternoon. Some upslope and moisture increase ahead of the front, with a few orographically assisted light showers developing overnight. Our best rain chances will be immediately ahead of and with the front, which times out to between 5AM and 9AM MST for Tucson Metro. With little dynamics and a relatively poor moisture pool this far from the main system, storm totals will be on the light side. Say around .05 in valleys and 1/3 of an inch in mountains. Snow levels falling to around 5500-6000 feet behind the front with 1 to 3 inches of snow expected in the mountains. Solid cooling behind the system with daytime highs down 10 or 12 degrees tomorrow, and overnight lows dropping to around 5 to 8 degrees below average for mid March early on Monday morning. That means mid to upper 30s around Tucson, and mid 20s to lower 30s in colder valleys east and south of Tucson. Those colder valleys typically aren`t done freezing yet, and this year is no exception with a freeze just a few days ago (average last freezes in April for Santa Cruz, Cochise and Graham counties). Strong high pressure the first half of the new week. Temperatures will jump quickly back to 8-10 degrees above average by Wednesday. Basically some flavor of 80s just about everywhere. It looks like the storm track is going to have difficulty digging back into our neck of the woods, so a system pushing across western states the second half of the new week will probably remain north of our area. A glancing blow with gusty winds and some cooling, but best precip chances should be north of us. A common theme even in early portions of our transition season. We`ll see if we can get any moisture help off the Pacific, but trajectories aren`t as favorable this far south. && .TWC WATCHES/WARNINGS/ADVISORIES...None. $$ Lader/Meyer/Leins Visit us on Facebook...Twitter...YouTube...and at