Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/05/19

See below for an aviation forecast discussion for the 00Z TAFs.

&& .SHORT TERM...(This evening through Friday) Issued at 415 PM CDT Thu Apr 4 2019 Highlights of the short term forecast include low clouds and fog tonight and a warmer day Friday. Broad surface pressure falls are ongoing over the Northern Plains this afternoon and associated south-southeast flow is allowing for seasonably-notable moisture advection with dewpoints approaching 40 F in central and northeast SD as of mid afternoon. A strong low-level inversion is present thanks to warm air advection aloft and this scenario is generating extensive stratus. Ceilings may lift slightly through this evening in northeast SD in response to small increases in temperature-dewpoint deficits in the boundary layer owing to diabatic heating. However, maintenance of the inversion and moisture advection regime will allow for overall persistence of the low cloud regime in northeast SD and will likely promote at least patchy fog development. Rapid-refresh guidance through the 19 UTC HRRR suggests dense fog development is possible, as well, so later forecasts will monitor observational trends which could require issuance of a Dense Fog Advisory in some locations. Meanwhile, a surface warm frontal zone is approaching the Missouri River valley as of 20 UTC with rapid erosion of stratus along its interface where the boundary layer becomes well-mixed through a deeper layer. Rapid-refresh guidance also captures this trend well and suggests that low clouds will be favored east of Mobridge and Pierre tonight, though some fog development is possible near the edge of the stratus bank where the mixing regime typically favors its formation. HRRR guidance suggests that scenario could even impact parts of north central SD such as around Mobridge. Note we do have a low-grade, low-PoP for light showers in the forecast late tonight in far northeast SD and west central MN out of respect to advancing midlevel warm air advection. Cumulus fields which have been deepening in the well-mixed boundary layer over the western Dakotas could support isolated high-based showers being maintained into parts of the area tonight, but confidence in that is low and thus this forecast release is dry until late tonight. On Friday, mean middle and upper-level ridging will be in place across the area and the air mass will be warmer in the wake of tonight`s warm frontal passage. This should support highs ranging from the upper 50s in the norther parts of the SD James River valley to the 65-70 F range along and west of the Missouri River valley. .LONG TERM...(Friday night through Thursday) Issued at 415 PM CDT Thu Apr 4 2019 A mid level trough will bring showers and a few thunderstorms to the region Friday night into Sunday. Models indicate as much as 1000 J/kg MUCAPE during this time period, but low and deep layer shear do not support organized severe convection. An upper level ridge builds in early next week, keeping the forecast area dry. Temperatures look to remain mild through early next week, with highs mainly in the 50s and 60s. A deepening upper level low is forecast to eject off the Rockies into the Central Plains by mid week. There is still considerable uncertainty on the track and strength of this system, although it does look like there is a potential for widespread QPF of 0.5 to 1 inch. Temperatures may be cold enough for snow to mix in on the northern end of the system, especially during overnight and morning hours. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 648 PM CDT Thu Apr 4 2019 VFR conditions start things off at KPIR/KMBG, and unless some fog forms across the Missouri River valley overnight, things should stay VFR throughout the TAF valid period. Sub-VFR cigs/visbies start things off at KABR/KATY. The latest short range guidance seems to hint that either the low clouds will stick around overnight (continued sub-VFR), or if the clouds clear off and conditions go VFR later this evening, that would be a short-lived, as conditions will be favorable for fog (sub-VFR) formation overnight into Friday morning. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...Dense Fog Advisory until 10 AM CDT Friday for SDZ007-008-011- 019>023. MN...None. && $$ UPDATE...Dorn SHORT TERM...CJS/BIS LONG TERM...Hollan/BIS AVIATION...Dorn
Area Forecast Discussion
National Weather Service Columbia SC
1049 PM EDT Thu Apr 4 2019 .SYNOPSIS... A warm front will approach the region tonight and move into the area Friday. This will result in widespread showers. The showers will diminish friday afternoon and Saturday as low pressure moves northeast of the area. Another low pressure system will approach the region early next week resulting in numerous showers and thunderstorms at times especially Monday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... IR satellite imagery shows extensive cloud shield over the central Gulf States and much of the Southeastern US. Network WSR-88D imagery also shows large area of rain moving through GA and toward the forecast area. Over the next couple of hours expect the rain to move into the majority of the forecast area and with good isentropic ascent and plenty of moisture overnight expect moderate rain with some potential for some locally heavy rain. Expect convective potential to remain south of the area overnight with thunderstorm potential in the forecast area too low to include through daybreak. With the clouds and rain overnight expect low temperatures in the low to mid 50s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Friday...Deep moisture and isentropic lift Friday morning as warm front and upper level trough approaches. High resolution models suggest the heaviest rain will be from 12z to 15z...then decreasing from southwest to northeast as upper level trough moves through and low to mid level isentropic lift shifts northeast of the area. The GFS suggests some locally heavy rain possible across the north central Midlands associated with low level convergence. As warm front moves into the area and becomes stationary, the southern CWA becomes weakly unstable. Can`t rule out a thunderstorm mainly in the afternoon as coverage becomes scattered. Mid 70s for max temperatures south to mid 60s north of the front. Friday night...Surface ridge to the north builds south and front shifts south of the area. Pops should be low as air mass stabilizes and moisture becomes shallow. Areas of fog possible late at night. guidance temperatures look good. Saturday/Saturday night...Front lifts slowly back north as low pressure system develops in the Plains. Moisture and weak instability confined to the CSRA and southeast Midlands, so low chance pops mainly in the afternoon in those regions. Dry north of CAE. Temperatures max out in the 70s with scattered to broken clouds in the afternoon. Isolated showers mainly in the evening then patchy fog late. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Highly amplified upper trough and surface low will be off to the west to start off the week. ECMWF may be more progressive than GFS which shows a cut off low in the Deep South toward midweek. But models in much better agreement, showing trough moving through Tuesday, then east of the cwa Wednesday. Numerous showers and thunderstorms remain possible Monday, with scattered activity Tuesday. Isolated activity by Wednesday. Temperatures during this period will be above normal through this period with highs in the 70s and 80s and lows in the 50s to lower 60s. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Deteriorating conditions will occur tonight. Low-level wind shear will be an issue. Moisture will be on the increase in the onshore flow ahead of the approaching warm front. Followed the GFS LAMP for the timing of lowering ceilings. The high-resolution models and radar trends indicate rain spreading into the area from southwest to northeast during the 06z to 10z timeframe. The GFS LAMP and HRRR support conditions lowering into the IFR category in rain and fog 10z to 12z. A strong low-level jet will be associated with the system. Followed the NAM and included low- level wind shear in the terminal forecasts. There may be enough instability for thunderstorms but stronger convection closer to the Gulf Coast will likely limit the instability farther north. The thunderstorm chance was too low to include in the terminal forecasts at this time. EXTENDED AVIATION OUTLOOK...There will be periods of MVFR or IFR conditions through Tuesday associated with a frontal system in the region. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service State College PA
1125 PM EDT Thu Apr 4 2019 .SYNOPSIS... Low pressure will approach from the Mississippi Valley tonight and will pass south of Pennsylvania Friday night. A ridge of high pressure will build into the region this weekend. Another area of low pressure will track west of Pennsylvania early next week, with the trailing cold front likely coming by Tuesday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Mid clouds thickening late this evening as WAD increases from the Ohio Valley. Development of fgen forcing and influx of meager Gulf of Mexico moisture overnight will start very light rainfall for much of the area after midnight and into the pre dawn hours of Friday. Question is ptypes, and given wet bulb potential at the surface with very low dewpoints over the north any chances for freezing rain Friday morning. Model forecast soundings suggest predominant ptype to be snow/sleet across the northeast quarter of central PA. Soundings transition generally from SN/IP to rain by 15z, with little if any indication of fzra via manual examination. HRRR agrees with this, going from a period of snow to plain rain over the northeast quarter. NAM12 indicates a snow, sleet freezing rain mix, but examination of soundings via BUFKIT indicate any patchy freezing rain would be after minor accums of snow and sleet (perhaps 1-2") with pretty inconsequentual trace of fzra in some spots if it occurs. So, through collaboration with BGM, opted against any headlines and will continue to mention in HWO, and mentioned slight chance of fzra northeast. The tree limbs and cold car roofs are the most likely places which could see a thin ice coat. In and of themselves, the amount of sleet and snow are going to be sub-advisory. It is still early April and we go through a little light frozen precip at this time of year. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... Rain ongoing over all the area at sunrise, with a mix in the NE third/higher elevs there. It should go to all rain as the strong April SS works it`s magic and stops any threat for freezing/frozen stuff by mid morning over all but the extreme highest elevations N of IPT. The main push of moisture and lift will be gone by noon in the west and 2-3PM east. But, low clouds/crud will linger and keep the temp from getting anywhere near normal maxes. Some light rain/dz could also linger into the evening in the central and wrn highlands. Expect highs only in the upper 30s NE and 40s elsewhere. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... Fair and much warmer conditions are expected this weekend, as high pressure builds into the state. Increasing April sun angle and daylight hours will help push temperatures 10-15 degrees above normal both Saturday and Sunday. The bulk of med range guidance points toward showery and mild weather early next week, as next area of low pressure tracks west of Pa through the Grt Lks, with the trialing cold front coming through late Monday or early Tuesday. A fairly significant cool down appears likely by midweek, as upper troughing works into the northeast CONUS. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... VFR ongoing this evening will persist into the early overnight hours before conditions deteriorate over the west and north. Mid-deck already developing over the SW where virga will continue to gradually work down to the surface over the next couple of hours with reductions beginning as rain begins after midnight. The precip spreads north and northeast overnight, and UNV and IPT may be cold enough for a little PL or even SN at the very onset, but any ZR or extended period of PL will be confined to the north of IPT and east of BFD. Most of the terminals will experience a very cold rain and gradual decline into IFR for the daytime on Fri. MDT and LNS may have only brief forays into MVFR with just light rain, with a period of restrictions possible early Fri and then again Fri afternoon. Precip tapers to drizzle Fri night then ends by Sat morning. Ceilings remain low through 12z Sat followed by improving conditions as high pressure builds in for the weekend. Rain may arrive again late Sun. .Outlook... Sat...Ceiling restrictions early, then improving conditions with no sig wx. Sun-Mon...Restrictions possible with rain/showers. Tue...No sig wx. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo/DeVoir SHORT TERM...Dangelo LONG TERM...Fitzgerald/Gartner AVIATION...RXR
Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
944 PM CDT Thu Apr 4 2019 .UPDATE... The short term forecast is in good shape with just a few tweaks to the wx and sky grids. A weak backdoor front continues to progress southward through the FA at this hour. At present time it appears to be near and along a Graham to Hillsboro to Palestine line. No precipitation is expected with this frontal boundary as large scale subsidence in the wake of an upper trough has been efficient at keeping any upward vertical motion nil. This front will usher in higher dewpoints and this should set the stage for some fog near and east of this boundary The boundary shouldn`t make too much more progress and should stall not too far from its current location. Short term model guidance, though sometimes overly aggressive with its visibility output, appears to be keying in on areas near and north of I-20 and east of I-35 for the greatest widespread fog potential. This seems reasonable given that light morning rains may help to promote a more favorable radiation fog regime. I`ve beefed up the coverage of fog in the aformentioned area and would not be surprised to see some pockets of dense fog develop. At this time, I have no plans to post any dense fog headlines, but one may be needed at some point early Friday morning. For now, will highlight this threat in the HWO and graphics. Elsewhere patchy fog will be possible with unfavorable conditions for fog across the Big Country where dewpoint depressions are large. A deck of low clouds continues to invade East Texas this evening and have increased sky grids to account for what appears to be some nocturnal cool air stratocumulus. It appears plausible that this deck of clouds will continue to spread southwestward with time and I`ve increased sky grids across the Brazos Valley. Otherwise, the rest of the forecast appears in fine shape and no other changes were needed. Bain && .AVIATION... /Issued 638 PM CDT Thu Apr 4 2019/ /00 UTC TAF Cycle/ Concerns---Ceiling and visibility trends Friday morning at all TAFs. A cold front continues to slide through Metroplex TAFs as of 2330 UTC. Northeasterly winds initially will gust to near 15 knots, but these speeds will be short-lived and in general winds will be near or under 10 knots. The front will arrive at Waco near 0200 UTC and will usher in northeasterly winds near 10 knots. The main concern during the overnight period will be a threat for IFR ceilings and visibility. At this time, it appears that the Metroplex will have the best opportunity for poor flying conditions as BR develops to the north of the terminals and sags southward. Confidence is medium in this threat and we`ve relegated this potential to a TEMPO group. It is possible that the urban heat island effect may keep cigs/vsby MVFR, but after close examination of guidance and coordination with ZFW...felt it was necessary to include at least a decent chance for IFR during the Friday morning push. VFR will prevail around 1600 UTC Friday with a return to south flow appearing likely thereafter. At Waco, the potential for IFR vsby is more uncertain, but non- zero. For now, it appears more likely that a ribbon of IFR cigs will overspread the terminal during the pre-dawn hours. We will monitor trends in short term guidance over the next few hours, however, to determine if IFR vsbys are more appropriate. Similar to the Metroplex, VFR with southeasterly winds are anticipated during the mid to late morning time periods and beyond. Bain/Sellers && .SHORT TERM... /Issued 304 PM CDT Thu Apr 4 2019/ /Through Tonight/ A cold front is making its way across North and Central Texas this afternoon, ushering in northwesterly winds and drier air. Despite what is technically a cold front passing through, there has been little impact on temperatures this afternoon, with most observation sites making it into the upper 70s and lower 80s today. Cloud cover has been on the decrease as drier air has moved in, making for a nice sunny afternoon for most of our county warning area except for the northeast where cloud cover has been slower to exit. Skies should remain mostly clear through most of the overnight, with low temperatures dropping into the 50s. Winds will come around out of the northeast, but will remain light. Mostly clear skies and light winds will allow for excellent radiational cooling. With temperatures forecast to drop to near the dewpoint by early Friday morning, patchy fog may develop, and in fact this is shown by some of the high-resolution guidance, with the NAM and RAP being the most aggressive. Some of the ensemble guidance such as the HREF and SREF are less aggressive however. For now, will mention patchy fog in the weather grids, with the most coverage expected east of Interstate 45, but trends will need to be monitored through the evening and overnight hours. While dense fog does not appear likely, it may be worth allowing a little extra time on the morning commute Friday, just in case. Godwin && .LONG TERM... /Issued 304 PM CDT Thu Apr 4 2019/ /Tomorrow into Next Week/ Main concern in the extended period continues to be the potential for heavy rain and severe weather, primarily Friday night into Saturday (but potentially lingering into Saturday night or even Sunday). Until then, the day tomorrow should start with a weak front settling across our southeastern counties. Light winds and moist surface conditions may support fog development overnight into the morning hours, especially near the front where T/Td spreads will be lowest. Diurnal mixing of the boundary layer will erode the fog through mid morning, yielding some sunshine in most locations. Expect temperatures to warm accordingly, reaching the upper 70s and 80s. Our weather begins to become unsettled Friday evening and night as a shortwave trough approaches the southern Plains within broader cyclonic flow. In response, low-level moisture returns in earnest overnight Friday, especially across Central Texas and western North Texas. Amplifying warm advection and isentropic ascent may yield a few elevated storms ahead of the shortwave trough Friday night, and these may be accompanied by a hail threat, given steep mid-level lapse rates and strong convective layer flow. Towards daybreak then, focused surface convergence and ascent along the shortwave impulse should drive a complex of thunderstorms, perhaps in the form of a broken line, into portions of western north Texas. Damaging winds would likely be the primary threat, but we will have to closely monitor the magnitude of returning boundary- layer moisture. If sufficiently high during the morning, this moisture could yield more surface-based development, with a higher potential for damaging winds and perhaps a few embedded tornadoes. Regardless, this complex is forecast to quickly lift east/northeast across parts of our area through the morning. A second area of a few strong/severe storms and heavy rainfall may develop across Central Texas during the morning and afternoon hours, as a secondary surface trough/front closer to the Texas coast may focus strong ascent just to its north. Questions remain regarding the amount of surface-based buoyancy that will develop here, but heavy rain and all severe hazards could be a possibility as well. Guidance remains unsurprisingly dispersed on where this band of convection will establish, but these trends will need to be monitored given some focused potential for at least minor flooding issues. Rain/storm timing behind these two rounds remains nebulous, at best, owing to brief subsidence behind the initial systems and the potential for convective overturning. With that said, a secondary impulse will approach our area late Saturday into the overnight hours, and low-level moisture will not be scoured by the prior system. In turn, another round of showers and thunderstorms, perhaps accompanied by localized flooding and severe weather, may develop late Saturday into early Sunday, most likely east of the I-35 corridor. However, if the broader trough axis and low-level moisture plume shifts far enough east with the earlier round of convection, most heavy rain/storms could miss North/Central Texas to the east/southeast entirely. These details will slowly be refined as the event approaches. Conditions gradually dry from west to east on Monday once the the trough shifts east and heights build over our region. Temperatures will warm through Wednesday, with downslope flow helping a few spots perhaps touch 90 across western North Texas. A front then may bring a slight cooldown for the latter portion of the week. Picca && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 59 79 62 76 63 / 0 5 50 80 30 Waco 58 82 63 76 62 / 0 5 50 80 40 Paris 55 76 59 71 61 / 0 5 20 80 60 Denton 53 79 60 76 61 / 0 5 50 80 30 McKinney 55 78 61 74 61 / 0 5 40 80 40 Dallas 60 80 64 76 63 / 0 5 50 80 40 Terrell 57 80 63 75 62 / 0 5 40 80 50 Corsicana 60 79 63 73 63 / 0 5 40 80 50 Temple 59 81 63 76 62 / 0 5 50 80 40 Mineral Wells 55 80 60 76 58 / 0 5 70 70 20 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 24/79
Area Forecast Discussion
National Weather Service Wilmington NC
939 PM EDT Thu Apr 4 2019 .SYNOPSIS... A wave of low pressure will bring showers on Friday followed by weak high pressure over the weekend. A storm system will bring showers and thunderstorms to the Carolinas next Monday into Tuesday. A front will move off the coast early Wednesday, though temperatures will remain slightly above normal. && .NEAR TERM /THROUGH FRIDAY NIGHT/... As of 939 PM Thursday...Winds increasing and veering in the low levels per recent VWP data. Mosaic radar shows a leading edge of of rainfall moving across eastern Georgia approaching western SC. Based on this and recent HRRR forecast reflectivity depictions, some downward adjustments may be needed between 6z and 12z in pop values, delaying best rain chances and onset times a few hours later, leading moreso into daybreak Friday. As of 300 PM Thursday...Satellite imagery shows a healthy mid level system crossing into the Mississippi Valley. Despite its appearance the system has little to no surface reflection. Even so it will spread moisture/clouds across the area from west to east tonight and then rain chances to follow. Although rainfall a near certainty area- wide this still looks like a low QPF event. This seems plausible given the low amplitude aloft and poor surface and low level reflection all keeping overall forcing weak. Dry air moves in from west to east Friday evening/night ending rain chances, partially clearing skies, and possibly allowing for some fog if wind grows light enough. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 PM Thursday...Weak shortwave and associated precip will be well off the coast Saturday morning. A weak surface low will follow, moving off the northeast NC coast Saturday morning leaving light NW winds across the forecast area. Saturday through Saturday night should be precip-free as a weak ridge slides overhead. Models are showing a weakness that tries to top the ridge Sunday afternoon, which may lead to a few showers for late in the weekend. Otherwise, temps will be 6-8 degrees above normal in southwesterly flow. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 300 PM Thursday...Ridge sfc-aloft will move offshore Monday, and moisture ahead of upstream trough axis will make its way into the CWA by 00Z Tuesday. Showers with a few thunderstorms will be possible Monday through Tuesday night until the surface front clears the area around 12Z Wednesday. Max temps Monday near/around 80, and will only cool a few degrees behind the front with lack of much significant cool advection. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... As of 00Z...VFR conditions thru atleast 06Z. Expect conditions to deteriorate from generally west to east during the pre-dawn Fri hours. At the moment, a blanket of high level clouds are strewn across the FA. Will see a drop to mid-level cloudiness after 04Z and a further decrease to MVFR thresholds late in the pre-dawn Fri hrs. By daybreak and thru the remainder of the TAF Issuance period will indicate MVFR/IFR conditions from both low clouds and reduced vsby from stratiform light to moderate rains and fog. Models are indicating even a shot for LIFR conditions between 14z and 20z and at press time will determine if it`s feasible to include. Extended Outlook...The mid-level short wave trof will exit the FA by sunset Fri leaving enough low level moisture for MVFR/IFR clouds and/or reduced vsby from fog/dense fog Fri night thru Sat morning. VFR conditions to occur during the weekend except for MVFR/IFR from fog and/or low clouds both late Sat night and Sun night respectively. Sub VFR conditions from increased pcpn chances to occur late Sun night thru Tue in response to a low pressure system. && .MARINE... As of 745 PM Thursday...Weak ESE swell of 2 origins propagating ashore in 12 and 8 second intervals, phasing on occasion to produce a rideable wave of good form. Light SE chop tonight will turn moderate into Friday as winds amp up a little. Rain into Friday will begin to restrict long range visibility to 1-3 nm in rain at times. As of 300 PM Thursday...High pressure sliding off the coast will bring an increase in southeasterly winds tonight. The approach of a weak system on Friday will veer flow slightly and also bring another increase in wind speed. A few 6 ft waves could materialize along the very outer fringes of mainly NC waters but at this time it looks too marginal for an Advisory. Additional veering and abating winds/seas behind the weak system Friday night. Weak low pressure will move off the northeast NC coast Saturday morning. Although winds will be northerly to start the day, speeds should be on the order of 10 kt in a weak pressure gradient. Weak high pressure will slide across the waters through the day, with winds becoming variable for a time Saturday afternoon, before shifting to the south late. The overall pressure field will remain relatively weak through Sunday, and the center of high pressure north of the waters will maintain a southeast wind direction on Sunday. The gradient over the waters will begin to tighten Sunday night, and moreso Monday as a frontal boundary crosses Tennessee. Southwest winds will increase into a 15-20 kt range, and will also see shower and possible thunderstorm activity increase Monday into Tuesday ahead of the front. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...Bacon/Colby SHORT TERM...CRM LONG TERM...CRM AVIATION...DCH
National Weather Service Wilmington OH
803 PM EDT Thu Apr 4 2019 .SYNOPSIS... As a low pressure system moves eastward from the central Plains, moisture will increase throughout the Ohio Valley tonight, with rain expected. Chances for rain will end on Friday, as high pressure moves into the region for Saturday. Precipitation chances will increase again on Sunday and Monday, as an area of low pressure moves through the Great Lakes. && .NEAR TERM /THROUGH FRIDAY/... Strong east winds on the north side of the warm front will continue through about midnight and then relax. Current placement of the warm front is just south of the forecast area, probably skimming our southern counties. Most prominent delineation of the front is the wind shift, though readings around or in the low 70s south of the front are notably cooler by around 10 degrees when you hit the Ohio River, and another 10 degrees (around 50) towards the I-70 corridor. The strongest winds appear to be south of the axis of increased dewpoints just north of the I-70 corridor to about the Ohio River where ENE winds sustained at 15-20 mph are found, occasionally higher and also with some gusts. Tried to slow the incoming rain by a little bit but then blended in to the daybreak forecast. This ultimately lowered the chances of rain given the showery nature of the incoming rain and the potential for hit-and-miss pockets overnight and early Friday. Lowered tonight`s lows by a degree or so but thought the temperature forecast was well in hand. Strength of the boundary layer moisture transport with this system remains unimpressive. While PWAT remains <1", there is still high confidence in rain occurring in most locations (high PoP) but lower confidence in significant amounts (low QPF). HRRR runs continue to trend to a spotty showery nature. There remains better forcing ahead of the strongest part of the mid level shortwave in sern CWA overnight. Behind the shortwave, as the overnight hours progress, the temperature gradient at the surface should relax -- min temps are expected to range from the mid 40s to lower 50s. && .SHORT TERM /FRIDAY NIGHT/... The axis of the shortwave will be just about to exit the ILN forecast area at 12Z on Friday morning, which should herald the end of widespread precipitation once it has passed. Behind the wave, however, there is still the issue of a weak (and further weakening) surface low, which will be moving into the ILN forecast area through 18Z. Weak boundary layer warm advection ahead of this low may be enough to spark some light showers or drizzle, in a near-surface air mass that will be about as close to saturated as anything is going to get with this particular system. For that reason, some low-end PoPs were extended a little further into the day on Friday. However, once this low has washed out, any remaining precipitation chances should end by afternoon. With the Thursday frontal boundary having largely washed out, temperatures on Friday will have much less of a gradient, ranging from the upper 50s to middle 60s. Some models did suggest some slightly warmer conditions, but with BKN to OVC low level clouds expected for at least the first half of the day, this temperature forecast will be kept a little more conservative. High pressure on Friday night will bring a weakening of the winds and a clearing of the skies, with min temps in the middle to upper 40s. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Ridging over the area at the beginning of the period will move off to the east as a trough developing in the central part of the country moves east. An initial short wave lifting out of this trough will result in showers spreading across the region late Saturday night into Sunday. There will then be an increasing chance of thunder Sunday afternoon into Sunday evening with the probability then decreasing as the short wave moves east of the area. Additional showers as well as some thunderstorms will occur as the trough and associated cold front moves through later Monday into Monday night. Temperatures will be above normal over the weekend into the beginning of next week with Sunday and Sunday night expected to be the warmest stretch of the period. Sunday night lows will end up being close to the normal high for this time of year. High pressure will build in behind this front resulting in dry conditions with temperatures closer to normal. The next chance of showers will move in on Thursday as a closed low tracks through the mid Mississippi Valley. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... ENE winds 15kt will persist for a few more hours and then relax behind the upper level shortwave as the gradient loosens ahead of an approaching surface low. VFR conditions will prevail until some showers push in from the west late this evening and overnight. VSBYS will remain VFR and only see a brief drop to 5 miles or less, then be followed by cigs lowering beneath 3kft towards daybreak Friday. High end MVFR cigs will prevail tomorrow and could see a period where they drop below 2kft, particularly in the later morning to the west and afternoon in the east. OUTLOOK...MVFR conditions are possible Sunday and Monday, with a chance for thunderstorms on both days. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hatzos NEAR TERM...Franks SHORT TERM...Hatzos LONG TERM... AVIATION...Franks
Area Forecast Discussion
National Weather Service San Francisco Bay Area
846 PM PDT Thu Apr 4 2019 .SYNOPSIS...Scattered light rain showers are possible overnight, mainly in the North Bay. Widespread light to moderate rain is forecast to develop in the northern portion of the area on Friday morning and spread south through most of the rest of the region by early afternoon. Unsettled weather may persist into the first half of the weekend, with drier and warmer weather expected by Sunday. Another chance of rain will develop by Monday night, followed by cooler weather for the remainder of next week along with gusty northwest winds at times. && .DISCUSSION...As of 8:45 PM PDT Thursday...KMUX radar is currently detecting isolated light showers, mainly offshore. Latest HRRR model indicates that shower activity will increase overnight, but primarily over the North Bay, as a weak shortwave trough ripples through the moist westerly flow aloft. GOES-West satellite imagery shows a more organized system over the Eastern Pacific approaching 130W and rapidly approaching our coast. Models had previously forecast this system to be a low-end Atmospheric River event with heavy rainfall potential. But recent models have backed off considerably on the strength of this system, as well as rainfall amounts and wind speeds. Based on latest model output, this system will generate a period of light to moderate rainfall on Friday as it moves quickly through our area. Widespread rain will develop in the North Bay and as far south as the SF Peninsula during the morning commute, and then spread south through most of the remainder of our forecast area during the late morning and early afternoon hours. Rainfall amounts on Friday are forecast to range from 0.25-0.75" in the North Bay, with a quarter inch or less expected elsewhere. Southerly winds may gust as high as 30 mph, but for the most part winds are not expected to have much impact. After the Friday system passes, a moist zonal flow will persist across the Eastern Pacific and into California into the weekend. This moist flow will maintain widespread cloud cover through at least Saturday. However, forcing will be weak or lacking and so continued precipitation after Friday will likely be scattered and light. The NAM is by far the most bullish with precipitation after Friday, as it develops widespread light rain across our area late Friday night into Saturday morning, with scattered showers into Saturday afternoon. Most other models forecast only spotty precipitation on Saturday. Moist westerly flow will persist into Sunday but by then the models begin to build a low amplitude ridge which should keep our area mostly dry. The upshot is that we can expect lots of clouds over the weekend, especially on Saturday, but mostly dry conditions after Saturday morning. The building ridge over the weekend will result in warming temperatures with widespread low to mid 70s forecast by Sunday when we should see at least some sunny breaks. A shortwave trough is forecast to bring a quick shot of rainfall to primarily the northern portion of our area sometime between late Monday and Tuesday. Otherwise, the longer range models agree that we can expect mostly dry conditions next week, with cooler temperatures and brisk northwest winds at times. In fact, the latest GFS indicates the potential for strong and gusty northwest winds along our coast for Tuesday afternoon and evening. && .AVIATION...As of 4:50 PM PDT Thursday...for 00Z TAFs. A mix of mid and high clouds continue to impact area terminals this afternoon ahead of an approaching front. Models have backed off significantly with respect to the precip associated with this system. Therefore the TAFs have been adjusted and rain chances have been pushed back and scaled down. Rain showers are expected to begin impacting the North Bay tonight into Friday morning while terminals around the San Francisco Bay will begin seeing showers Friday morning around 15z-17z. Monterey Bay area terminals will likely only see hit or miss showers. Light to moderate west to southwesterly wind will ease this evening becoming light and locally variable to southeasterly overnight. Moderate and gusty southwesterly winds expected Friday morning as the front pushes inland. Confidence is low with respect to the timing of the rain. Vicinity of KSFO...MVFR/VFR cigs will prevail through much of the forecast period. Moderate south to southwesterly winds will ease this evening becoming light and locally variable to southeasterly overnight. Light rain will return to the region Friday morning then taper in the late afternoon. Moderate and gusty southwesterly winds expected Friday morning as the front pushes inland. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR cigs will prevail through tonight with MVFR cigs anticipated Friday morning with the potential of showers in the vicinity as the front moves inland. Showers will taper in the afternoon. Winds light to locally breezy. && of 2:38 PM PDT Thursday...Southerly winds will increase slightly tonight into Friday in advance of an approaching weather system. Southerly winds may become locally gusty Friday and even into Saturday. Light to moderate west to northwest swells will continue through Friday, then transition to a larger, long period northwest swell on Friday night and into the weekend resulting in hazardous conditions for small craft vessels. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...None. $$ PUBLIC FORECAST: Dykema AVIATION: CW MARINE: RGass Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Tallahassee FL
805 PM EDT Thu Apr 4 2019 .UPDATE... No significant changes to the previous forecast appear necessary. The mention of heavy rain for the western half of the area for the remainder of the overnight hours into Friday still looks on track. Satellite imagery shows a messy and complex convective evolution with a couple of mesoscale convective systems (MCS`s) approaching the area. The first is already moving into our coastal waters currently, and it is probably producing localized winds near 50 knots well offshore along with the possibility of waterspouts. However, SPC mesoanalysis indicates that surface based instability remains confined to mainly offshore and perhaps along the immediate coast, so the severe threat with this first MCS will likely remain mostly offshore. It may skirt the immediate coast around St Joseph State Park eastward to the Apalachicola and Saint George Island area later this evening, so those areas still bear watching. For late tonight into Friday morning, a second MCS stretching from south-central Mississippi to central Louisiana will also approach the area. Several HRRR runs have shown the potential for some west- east training with this activity shortly after sunrise Friday. This bears watching, and if there is a flash flood threat with this system, then the most vulnerable time frame would be around sunrise through the remainder of the morning hours Friday. Confidence is still not high enough on this scenario to introduce a flash flood watch, but it does continue to bear watching. At this time, the most impacted area would mainly be across the Florida panhandle west of Tallahassee should this scenario occur. && .PREV DISCUSSION [743 PM EDT]... .NEAR TERM [Tonight and Tomorrow]... Two upper level disturbances will impact the local weather through the next 24 to 36 hours with varying impacts. The first system will move through this afternoon and into the evening as residual convection and a mesoscale convective system (MCS) rotates through the area. Severe potential appears to remain low through the remainder of the evening as this system moves east. However, still can`t rule out some isolated strong wind gusts up to 50mph. The bigger threat with this wave will be heavy rainfall at times, but even with that, we should be able to handle 2 to 3 inches of rain possible overnight due to the very dry soils in place. A stronger wave will move through after midnight and through the early morning hours of Friday. The severe potential with this wave is a little bit higher as better shear and upper level support is expected. However, we`re likely to be somewhat stable across the region, especially in our inland counties so the severe potential will likely remain confined to near the coast, as outlined in SPC`s Day 1 outlook. The last thing we want to mention is the potential for flooding rains, and possibility of a few strong/severe storms on Friday. A frontal boundary is expected to stall across the region tomorrow morning and into the afternoon and will serve as a focus for convection across the area. Weakening flow aloft that is nearly parallel to the stalled front/boundary could allow the training of some storms tomorrow. Please see the hydrology discussion below for more information on the flooding rain threat. As for the severe potential, SPC has placed the majority of the region in a marginal risk for severe storms. The primary threats tomorrow reside in isolated hail and some damaging winds in the strongest storms. However, given the decreasing shear profiles through the day, widespread severe weather is not expected. .SHORT TERM [Friday Night Through Saturday Night]... While the stronger shortwave will be east of the CWA by Friday night, another wave will move through tomorrow night, but will be much weaker. This will allow for PoPs to continue into the short term. Southerly low level flow will continue through the weekend with showers and thunderstorms each day. The better chances are during the day, but not negligible overnight. While rain is expected in the short term, precipitation amounts will be more limited than what will occur in the near term. Highs will be in the low to mid 80s with lows in the 60s. .LONG TERM [Sunday Through Thursday]... A deep trough over Texas will begin to approach our area Sunday night, bringing heavy rain by Monday with some lingering showers Tuesday. There is enough CAPE and shear that the potential for severe thunderstorms cannot be ruled out. A cold front is expected to move through the region Thursday going into Friday, but guidance is not consistent on intensity. High temperatures will stay near or above 80, cooling slightly on Monday before warming back up. Lows will be in the upper 50s to low 60s. .AVIATION... [Through 00Z Saturday] Conditions will continue to deteriorate tonight as a batch of rain moves into the region. Late tonight IFR CIGs are likely. Rain may be heavy at times. Lightning will be mainly offshore tonight. Tomorrow scattered thunderstorms are expected mainly in the AL and GA counties. It is difficult to predict the timing of TS tomorrow since this isn`t a clean frontal passage. .MARINE... Southerly winds will persist into next week. Strong to severe storms are expected tonight into Friday. Convection will be more limited over the weekend and another system will move through Monday into Monday night. .FIRE WEATHER... A wet pattern will be in place through early next week. Widespread rain is expected tonight and tomorrow. No fire weather concerns. .HYDROLOGY... A strong shortwave will bring the potential for heavy rain tonight into Friday. Generally two rounds of storms are expected this evening/tonight with more scattered storms tomorrow. The overall forecast is for 3-4.5 inches of rain across the Florida Panhandle and 2-3.5 across southeast Alabama and the far southwest portions of Georgia. Elsewhere amounts should be limited to less than two inches. That said, localized higher amounts of 6-8 inches of rain cannot be ruled out, particularly across the Florida Panhandle. These higher amounts could lead to localized flash flooding. A flash flood watch is borderline at this point and given the uncertainty in the higher amounts and isolated area, will hold off on a flash flood watch at this time. While convection will be more scattered in nature this weekend, another cold front will bring additional rainfall on Monday which will need to be watched closely, particularly based on the amounts that fall tonight/tomorrow. With the event tonight/Friday and another round of widespread showers and thunderstorms early next week, these amounts could push some rivers into action stage. .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 61 79 62 84 61 / 70 70 20 20 10 Panama City 63 74 64 76 64 / 80 70 20 20 10 Dothan 61 78 63 81 62 / 80 80 30 40 30 Albany 60 78 63 82 62 / 80 80 30 40 30 Valdosta 60 78 62 83 61 / 60 70 20 30 30 Cross City 62 80 62 84 63 / 30 30 10 20 10 Apalachicola 63 75 64 77 64 / 60 50 10 20 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until midnight EDT /11 PM CDT/ tonight for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton. GA...None. AL...None. GM...None. && $$ UPDATE...DVD NEAR TERM...Dobbs SHORT TERM...Fieux LONG TERM...Fieux/Skeen AVIATION...McD MARINE...Fieux FIRE WEATHER...McD HYDROLOGY...Fieux
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday) Issued at 339 PM CDT Thu Apr 4 2019 An upper level shortwave continues to move east of the forecast area per the 20Z water vapor imagery and profiler data. Further west, an upper trough axis was noted off the west coast with a shortwave lifting northeast towards the Pacific Northwest. In between these features was a low amplitude ridge over the Rockies. At the surface, weak ridging had set up over the western central plains as an inverted trough moved into the Ozarks. However this ridge had already begun weakening. For tonight and Friday, the weather is expected to generally be dry with no obvious forcing as the upper level ridge moves out over the plains. The bigger concern is what to do with the stratus and possible fog overnight and Friday morning. NAM forecast soundings tend to show the stratus hanging around and limiting how dense any fog may get. But the RAP soundings do not hold onto the stratus overnight suggesting there is some potential for dense fog. Earlier mixing across central KS has not cleared out the low clouds across eastern KS. So the NAM may be onto something. For now have kept a mention for patchy to areas of fog in case the low clouds break up enough. But overall guidance keeping visibilities above 1 mile adds some uncertainty in there being widespread dense fog. Lows tonight are forecast to only fall back into the mid 40s since there is not a lot of cold air expected to move in. Models suggest better mixing of the boundary layer on Friday. As long as we see some sunshine by the afternoon, think highs could make it into the lower 70s. .LONG TERM...(Friday night through Thursday) Issued at 339 PM CDT Thu Apr 4 2019 For Friday night and the weekend, models prog upper level energy to lift across the forecast area with the best dynamics impacting northeast Kansas Saturday afternoon and Saturday evening. The GFS wants to develop some light precip late Friday night, but confidence in this is low given the NAM and ECMWF tend to keep things dry and there isn`t an obvious lead shortwave lifting out ahead of the main shortwave. So I just have some slight chance POPs for Friday night. The better chances will be Saturday afternoon and evening where POPs are in the 60 to 70 percent range. There is progged to be some modest instability with the wave but mid level temps are not all that cold and as a result lapse rates are forecast to be only around 6 C/km. Additionally deep layer shear looks to be on the modest side with 0-6KM shear values of 30 to 40 KT. So the severe risk looks to be muted on Saturday. By Sunday a second piece of energy is progged to move through the plains and kick the initial wave to the east. However the dynamics with this wave look to move mainly south of the forecast area. However a frontal boundary with some frontogenesis should move through the area. Because of this have continued with some chance POPs through the day Sunday. There does not appear to be a lot of cold air advection behind the front. So highs on Saturday and Sunday are expected to be in the upper 60s and around 70. Lows should also be on the mild side with readings in the lower and mid 50s. For Sunday night through Tuesday night, upper level ridging is expected to move across the area bringing a dry period to the forecast. The GFS does hint at a weak backdoor front moving into the area on Tuesday. There is not a lot of confidence in this solution as the mean westerlies look to remain across the northern plains and the ECMWF/Canadian fail to bring any boundary this far south. So have highs in the lower and mid 70s for Monday and Tuesday. Lows are expected to fall into the upper 40s. The next upper wave is forecast to move through the central plains Wednesday and Thursday. At this time the models tend to track the surface low pressure system along the NEB and KS state line with some decent spread in the ensemble solutions. So have some chance POPs beginning Wednesday afternoon and continuing through Thursday. The current operational solutions would minimize chances for snow on the back side of the system. But this could change if later runs trend south. Something to keep an eye on in any case. For now have a modest cool down for temps on Thursday with highs in the 50s until the uncertainty diminishes. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 631 PM CDT Thu Apr 4 2019 Stratus was holding on over TOP terminals into the evening hours. CIGS could lift slightly into the early overnight hours but fog is then looking likely to develop around 08Z, especially near TOP sites. Current thinking is that IFR vis and CIGS will be possible from around 08Z to 14Z at KTOP and KFOE, with MVFR vis at KMHK. Fog is expected to dissipate mid-morning and CIGS will lift by midday Friday. Otherwise, surface winds will remain light with a ridge near the area. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...Wolters AVIATION...Teefey