Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/08/16


Area Forecast Discussion
National Weather Service Wakefield VA
1009 PM EDT Fri Oct 7 2016 .SYNOPSIS... Hurricane Matthew is forecast to lift along the Southeast coast through Saturday night. A cold front will cross our region Saturday night and steer Matthew east and away from the coast through Sunday. Cool high pressure then builds in from the northwest early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Latest IR satellite imagery depicts warming cloud tops over the local area, downstream of Hurricane Matthew. This matches well with diminishing light precip. Model soundings and RAP guidance indicates some drier air working into the low levels this evening, which has helped erode the light rain. Have trended POPs westward tonight, but will keep chance POPs into central Virginia though around 08/06Z. Rain chances begin to increase from SW to NE after 06Z as the moisture from Matthew begins to edge north. Will have likely pops or better (>55%) along/south of the I-64 corridor by 12Z Sat. Mostly cloudy/overcast through tonight with lows in the 60s to near 70. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Hurricane Matthew slides N/NE along or just off the NC/SC coasts Sat into Sat night with widespread rainfall occuring across the FA. With the storm staying south of the local area, the main land impacts from Matthew will be heavy rain/gusty winds SE and tidal flooding along the coast. Refer to the Tides/Coastal Flooding section below for more on that. The heaviest rainfall continues to be expected Sat aftn into early Sun morning across SE VA into NE NC, where a flash flood watch remains in place. Will add another row of counties to the north of the previous watch (which will now include the lower Peninsula). Storm total QPF amounts have changed very little with the most recent model runs, and therefore will continue to show 1-2" across far southern VA, 2-4" of rain across the Tidewater/SE VA and 3-7" across NE NC with locally higher amounts possible near the Albemarle Sound. The rain will end from west to east late Sat night/Sun morn, except lingering until late Sun aftn along the SE coast, as a cold front crosses the area. Clouds will decrease from west to east on Sunday as well. Winds will be strongest over SE portions of the FA beginning Sat eve, spreading NE into areas adjacent to the Ches Bay/lower Eastern Shore coastal waters on Sunday. Peak wind gusts are expected to reach 35-45 mph...and up to 50 mph VA Beach/Outer Banks Currituck. Will go head and issue a Wind Advisory for the VA Tidewater into NE NC this afternoon. This will likely need to be extended northward along the Ches Bay/lower VA Eastern Shore by Sat morn. High pressure begins to build into the area Sunday night thru Monday for dry wx all areas and a mainly clear sky (some additional clouds linger along the coast). A tight pressure gradient will linger Sun aftn into Monday, especially along the immediate coast where winds will remain elevated. Highs Sat upr 60s NW to mid 70s SE. Lows Sat night in the mid 50s to mid 60s. Sunday/Monday highs in the 60s to near 70. Please refer to the National Hurricane Center for the latest information on Matthew. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... The long term period Monday night through Friday will be mainly dry and relatively uneventful. A strong surface high will be firmly in control on Tuesday extending from a center near Maine with a ridge reaching southwest into the Gulf Coast States. Tropical Cyclone will be weakening well to the east of Florida. The high retreats around midweek and a cold front moves through from the west around Thursday. High temperatures in the upper 60s to lower 70s warm to the mid to upper 70s Wednesday and Thursday then cools a few degrees on Friday. Low temperatures in the mid 40s in the Piedmont to the mid and upper 50s southeast Tuesday morning will range through the 50s to near 60 Wednesday through Friday mornings. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Onshore flow persists over the region with a weak coastal trough located over the coastal plain. Light rain/drizzle continues across southern Virginia into northeast North Carolina. Expect the TAF sites to remain dry for the next several hours. Northeast winds have diminished at or below 10 knots. MVFR/locally IFR conditions over the Piedmont into central Virginia will push eastward overnight tonight, reaching all but KSBY by 09-11Z Saturday. Scattered light rain or drizzle possible through the overnight, but the best coverage expected over the Piedmont. For Saturday, Matthew continues to lift slowly along the Southeast coast as high pressure retreats northeastward. Widespread precip is expected to reach northeast North Carolina and southeast Virginia early Saturday morning, and overspreading the area through mid to late morning. Heavy rainfall is expected across the southeast local area, reducing visibilities to IFR at times. Ceilings expected to be MVFR all sites (late Saturday for KSBY). Northeast winds increase to 15 to 20 knot with gusts to 30 knots southeast Virginia/northeast North Carolina. Elsewhere...10 to 15 knots. OUTLOOK...Rain continues Saturday night which will be heavy at times mainly southeast portions. Periods of IFR will be possible. The weather improves slowly from northwest to southeast Sunday with rain ending southeast portions in the afternoon. High pressure and fair weather returns Sunday night through mid week. && .MARINE... Latest position of Hurricane Matthew has it just E of KJAX at of 21z. On the latest NHC forecast track, expect Matthew to lift off to the N/NE along or just off the FL/GA coast early tonight, and to the GA/SC coast by late tonight. With the storm staying south of the local area, the main land impacts from Matthew will be heavy rain SE and gusty winds/tidal flooding along the coast (See coastal flooding section below). Onshore E-NE flow will continue tonight as the inverted coastal trough pivots offshore this evening. SCA for New Point Comfort to Little Creek drops off early this evening, with winds briefly diminishing early tonight as gradient slackens. SCA flags mainly for hazardous seas continue flying through the night along the coastal zones and the mouth of Chesapeake Bay. Seas 4-6ft (highest south), waves 2-3 ft, except 3-5 ft in the mouth of the Bay. Seas ramp up a bit late across the southern waters, as wind wave from Matthew arrive late tonight. Seas quickly ramp up well offshore late tonight and Saturday. Seas Saturday increase to 6-8ft over southern waters by late tomorrow morning. Matthew will lift NNE to a position along and just off the NC/SC coast on Saturday and Saturday night, with dangerous navigating conditions across the waters through the weekend w/widespread rainfall and gusty winds across the marine area. Given that Matthew is expected to stay to the south, strongest winds are expected after sunset Saturday night and through Sunday in strong cold air advection behind strong cold front, as strong 1030+mb sfc high pressure builds over the upper midwest into the interior northeast. Deterministic models and their member ensembles show a likely period of gales over most of the marine area late Saturday night through early Sunday night on strong NNE winds. Winds average 25-30kt over northern waters to 30-35kt S Sat night and Sunday. Gusts to 35-45kt possible, and potential for a period of low end Storm (in excess of 45kt possible) s of Cape Charles. Have not gone with any storm mention at this point with lower probabilities indicated. However, did issue a Gale Watch for all zones starting Saturday night, again with a high likelihood of gale conditions across much of the waters. For the sake of simplicity at this stage, have run through midnight Sunday/early Monday, but latest ECMWF indicates Gale may linger over far southern areas into Monday morning. After Gales come down, SCA conditions should persist for much of early next week for the ocean for hazardous seas, with a NE wind gradually diminishing as high pressure builds into the region from the north as coastal trough remains aligned offshore. && .TIDES/COASTAL FLOODING... Tidal departures continue to trend downward w/most sites now just below minor flood thresholds with the exception of near Jamestown, which is currently dropping below minor thresholds at this hour. Advy for Jamestown area has been allowed to expire. A continued modest improvement is expected tonight/overnight into Saturday before anomalies trend back up later Saturday and Sunday, and another round of Coastal Flood headlines are likely to be needed. Regardless of the track of Matthew, strong northerly winds are expected to develop late Saturday into Sunday night with tightening pressure gradient between high pressure to the north and the tropical cyclone Matthew to the south. Latest ESTOFS/ETSS each depict the potential for 2.0-2.5ft tidal anomalies late Saturday night into Sunday from the lwr Bay to coastal se VA/ne NC. This has the potential to produce high end minor to moderate coastal flooding from the lwr Bay to the nrn Outer Banks. High seas will build to 8-10ft nearshore by Saturday night...have issued High Surf Advisory for VA Beach/Northern OBX. Will likely need to add Eastern Shore Atlantic coastal zones with forecast issuance late tonight or tomorrow, with seas likely building across northern zones later Sun into Monday. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...Flash Flood Watch from 4 AM EDT Saturday through Sunday afternoon for NCZ012>017-030>032-102. Wind Advisory from 6 PM Saturday to 2 PM EDT Sunday for NCZ012>017-030>032-102. High Surf Advisory from 8 PM Saturday to 6 AM EDT Monday for NCZ102. VA...Flash Flood Watch from 4 AM EDT Saturday through Sunday afternoon for VAZ087-092-093-095>098-524-525. Wind Advisory from 6 PM Saturday to 2 PM EDT Sunday for VAZ087- 092-093-095>098-524-525. High Surf Advisory from 8 PM Saturday to 6 AM EDT Monday for VAZ098. MARINE...Gale Watch from Saturday evening through Sunday evening for ANZ630>638-650-652-654-656-658. Small Craft Advisory until 6 PM EDT Saturday for ANZ634-650- 652-654-656-658. Small Craft Advisory until midnight EDT tonight for ANZ632. && $$ SYNOPSIS...JDM NEAR TERM...JDM/SAM SHORT TERM...JDM/MAS LONG TERM...MAM/LSA AVIATION...SAM/LSA MARINE...MAM TIDES/COASTAL FLOODING...
Area Forecast Discussion...Updated
National Weather Service Billings MT
905 PM MDT Fri Oct 7 2016 .UPDATE... Shower activity is decreasing across the area but a few light showers should be expected. The HRRR has followed this trend and backed off the amount of activity it was progging compared to earlier runs. Winds at KLVM are weakening as the leeside trough is pulling a bit eastward. No updates. dlb && .SHORT TERM...valid for Sat and Sun... A zonal flow regime aloft will spread periods of clouds across the area through the weekend, but downslope winds with this pattern will produce mainly dry and warmer conditions. Tonight...Pacific jet supports a disturbance crossing the area this afternoon through late tonight. Residual low level moisture combined with a strong fetch of moisture with the jet stream will bring isolated to scattered showers to western and northern zones. Any precipitation will be light with this activity. Stronger winds off the surface should limit any overnight fog formation tonight. Lows tonight will be in the 35 to 45 degree range overnight. Saturday/Sunday...Jet stream shifts just a bit north of the area for more sunshine this weekend. Winds on Saturday look fairly light out of the south, but increase on Sunday out of the west at 10 to 20 mph. These stronger downslope winds will boost temperatures from the 60s Saturday to the mid 70s on Sunday. Looks like next cold front arrives Monday afternoon. Chambers .LONG TERM...valid for Mon...Tue...Wed...Thu...Fri... Only minor changes to the extended forecast this afternoon. Model agreement through the period appears to be greatly improved from 24hrs ago. That said ensemble spreads for temps increase significantly after midweek. Temps will trend downward Monday and Tuesday...as quick moving clipper system pushes through the region. Warmup for Monday will be limited by FROPA...especially for northern tier, where temps will struggle to reach 60s. Highs in the 40s are expected for Tuesday. This system will bring precip chances across the region...as northerly flow produces shallow upslope on north facing slopes of the Beartooths and Pryors, and some degree of low level of frontogenesis over the plains. Ridging builds into the area by Wednesday...beginning a warming trend. The ridge remains in control over the region into Thursday. Weak shortwaves begin to break down the ridge Thursday afternoon...with flow becoming more zonal by Thursday night. Dry conditions should limit any development to western high terrain through the day Thursday...but did extend pops across the region for Friday...with stronger energy...and improved moisture availability. Highs will climb back into the mid 60s for Thursday and Friday....with Friday looking to be the warmer day with support of downslope winds. AAG && .AVIATION... VFR conditions will prevail across the area tonight through Saturday. A few showers will move across the area during the night, but should not lower conditions. Gusty WSW winds at KLVM will diminish overnight. Arthur && .PRELIMINARY POINT TEMP/POPS... Sat Sun Mon Tue Wed Thu Fri ----------------------------------------------------------- BIL 044/066 048/075 049/065 036/044 036/057 044/065 049/067 11/B 00/U 01/N 22/W 00/U 00/B 12/B LVM 043/068 047/074 047/065 037/051 036/060 041/065 045/064 21/N 10/N 11/N 22/W 10/B 02/W 22/W HDN 042/067 044/078 044/067 036/045 034/057 041/065 047/068 11/B 00/U 01/B 22/W 00/U 00/B 12/B MLS 039/061 045/077 045/062 035/044 033/055 041/064 047/070 21/U 10/U 01/B 22/W 10/U 00/B 11/B 4BQ 041/065 044/078 044/072 036/044 034/059 041/067 046/073 11/B 10/U 01/U 22/W 00/U 00/B 11/B BHK 034/058 041/074 044/063 032/042 030/052 038/062 044/070 10/U 10/U 01/B 32/W 10/U 00/B 11/B SHR 040/066 043/076 045/072 037/046 034/060 041/067 045/068 11/U 00/U 01/U 22/W 10/U 00/B 12/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$ weather.gov/billings
Area Forecast Discussion
National Weather Service State College PA
1131 PM EDT Fri Oct 7 2016 .SYNOPSIS... Rain will begin over the western highlands this evening as a a cold front moves in from the west tonight. The front will pass through the region during the day Saturday. Cooler and drier weather is expected into early next week before a new but mainly dry cold front approaches Thursday. Hurricane Matthew will remain off the southeastern US coast and not directly impact our weather. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Tropical plume of moisture lifting into southwest PA ahead of 5h shear axis lifting northward is bringing light showers from the Laurel Highlands to the North Central Mountains late this evening. The eastern periphery of this activity is just light sprinkles and cuts off over northern portions of the central mountains. Deep layer moisture will continue to slowly increase overnight as southerly flow aloft between approaching Glaks trof and offshore ridge directs it northward. Forcing remains rather weak...and so showers will be most favored over the higher terrain...but expect a gradual eastward progression to shower chances as 1 to 1.5" PW increase late tonight into Saturday morning. Expect increasing low clouds and fog after midnight in the NW two-thirds of the area. Steady rain will likely take all night to get past UNV and may not get to IPT before sunrise. The cold front should be almost to Warren Co by sunrise. The QPF from the SREF plumes is very widely dispersed, but the median & mean look close and also close to the oprnl models. Up to an inch is possible in the Alleghenies, esp the Laurels. Muggy and mild overnight in the east. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... The front will move across the area Saturday as a weakening feature. The band of rain before the front is likely going to weaken as the front nears, with little moisture left for the front to lift as it goes by. After a very dismal start to the day - the NW will brighten nicely during the morning. It will take much of the aftn for the rain to push east of the central mtns, and another few hours to clear out. If the clearing happens before sunset, the high ambient moisture may lead to very a foggy Sat night. If clearing happens later, widespread fog is not likely. But, it will almost certainly happen in ye olde valleys of the north and west. Maxes in the 60s will be just a shade above normal. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Any lingering showers will exit eastern Pennsylvania Saturday night. Cold, dry air will advect into the area behind the front. High pressure will build in behind the front and bring a period of tranquil but cool weather that will last into the midweek. The cold air will continue to filter in as the northwesterly flow continues into Monday morning. This cold air advection could allow for the first real chance for widespread frost of the season Sunday night into Monday morning. Models continue to show 850 temps nearing zero with anomalously dry air and light wind setting in. The main area of concern in through the Northern half of Central Pennsylvania. The only possible complication in the medium range could be for the potential of low clouds returning in a developing maritime flow by later Tuesday into Wednesday. The next front is made to approach later Wednesday into Wednesday night, with another chilly chunk of air expected to follow for the last days of the work week. The GEFS and EC have significant timing and placement differences for any significant confidence. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... A plume of tropical moisture streaming up the Appalachian Mountains is supporting a band of steady rain tonight from KBFD to KJST. The moist southeast flow ascending the higher terrain of Central Pa is already resulting in IFR cigs in the vicinity of KBFD/KJST at 0330Z. Model soundings and latest HRRR support the idea of IFR cigs also developing at KAOO and KUNV overnight. The lower elevation airfields further east are likely to experience a dry night. However, MVFR cigs appear possible late tonight associated with moistening southeast flow. Not giving much credibility to the HRRR producing fog at KMDT/KLNS after midnight, given the amount of high clouds and substantial dwpt depressions going into the evening. Low cigs and showers appear likely across the Central Mtns into early Saturday afternoon associated with slow moving cold front, then some modest improvement is possible late in the day, as drier air arrives. Across the eastern airfields from KIPT south through KMDT/KLNS, it looks like MVFR conditions will predominate for much of the day, with morning cigs in the 1-3KFT range, followed by scattered rain showers with arrival of front in the afternoon. Outlook... Sun...No sig wx expected. Mon...AM fog possible KBFD. Tue-Wed...Patchy AM fog possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo/DeVoir SHORT TERM...Dangelo LONG TERM...La Corte/Ceru AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
651 PM CDT Fri Oct 7 2016 .UPDATE... 00Z Aviation Update Below. && .AVIATION... The main cold front has caught up with the earlier wind shift this afternoon, and is now located just south of a DRT-SAT line. Scattered SHRAs and TSTMs will continue south of DRT over the next hour or two. IFR/MVFR ceilings prevail over the Hill Country early this evening, and HRRR guidance suggest these ceilings will remain over this region into the late evening and not impact AUS or SAT. HRRR and NAM12 BUFR soundings do suggest BKN MVFR ceilings developing up the Rio Grande at DRT later this evening, and have included mention in the DRT 06Z-12Z. N winds at AUS/SAT/SSF gusty through the evening hours, with gusts 18-22 kts possible, before settling down after midnight. Similar gusts from the NW at DRT but may diminish sooner. && .PREV DISCUSSION... /ISSUED 235 PM CDT Fri Oct 7 2016/ SHORT TERM (Tonight through Saturday Night)... The cold front continues to push into South-Central Texas this afternoon. At 2 PM the initial wind shift was located near the I-10 corridor with the actual cooler temperatures lagging a bit farther behind. Scattered convection continues as well along the boundary and this will continue through the early evening hours with the best chances of showers and storms moving south and southwest over the next several hours as the front continues to move. Things will clear out after this evening with partly to mostly cloudy skies continuing. Lows tonight will be much cooler, bottoming out in the middle 50s to middle 60s. Tomorrow should be mostly quiet with partly to mostly cloudy skies continuing. Highs will top out in the upper 70s to upper 80s. LONG TERM (Sunday through Friday)... A surge of drier air is expected to move in from the northeast on Sunday. This push of dry air will be funneled to the southwest between surface high pressure in the Central Plains and the surface low associated with Hurricane Matthew just off the coast of the Carolinas. Dewpoints on Monday morning will likely be 40s across much of the area. This will lead to the coolest night of the year so far with lows Monday morning in the upper 40s for some of the area. With the dry air in place, we should see high diurnal ranges in temperatures Monday through Wednesday with cool nights and warm afternoons in the middle 80s. Moisture values will increase slightly by the end of the forecast period leading to lows back into the lower to middle 60s. No rain additional rain is expected through next Friday. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 61 84 62 84 52 / - 0 - 0 0 Austin Bergstrom Intl Airport 58 84 59 83 49 / - 0 - 0 0 New Braunfels Muni Airport 62 85 61 85 51 / 10 0 - 0 0 Burnet Muni Airport 57 80 58 80 50 / - 0 - 0 0 Del Rio Intl Airport 64 80 65 84 60 / 20 10 - 0 0 Georgetown Muni Airport 59 82 57 82 49 / - 0 - 0 0 Hondo Muni Airport 63 87 63 87 53 / 10 0 - 0 0 San Marcos Muni Airport 62 83 61 83 51 / 10 0 - 0 0 La Grange - Fayette Regional 62 86 61 83 52 / - 0 - 0 0 San Antonio Intl Airport 65 85 63 84 53 / 10 0 - 0 0 Stinson Muni Airport 66 86 65 86 54 / 10 0 - 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Mesoscale/Aviation...Runyen Synoptic/Grids...Treadway
Area Forecast Discussion
National Weather Service Omaha/Valley NE
631 PM CDT FRI OCT 7 2016 .SHORT TERM...(Tonight through Monday) Issued at 250 PM CDT Fri Oct 7 2016 The main forecast concerns in this period are potential for patchy frost tonight...mainly in our northern zones - and precipitation chances from Sunday night into Monday. Water vapor and IR satellite imagery early this afternoon in combination with recent RUC model initializations showed fairly quiet weather in our area behind the system that moved through yesterday. A 100 knot jet max at 300 mb was noted over the Pacific Northwest ar 12z, associated with a disturbance there. There was also a disturbance noted moving into southern California. At the surface...high pressure was noted over the region. That high pressure will move east/southeast tonight. By sunrise Saturday, the axis of the high should extend from western Oklahoma into southeast Minnesota. Our area will be in southerly return flow, which is expected to develop latest in our far northern counties. Will mention some patchy frost mainly there, and also in parts of western Iowa north of Interstate 80. Southerly flow should bring in some warmer air for Saturday, and with lots of sunshine we look for highs in the upper 60s and lower 70s. A weak cold front will try to push into our area from the north Saturday night but then start to lift back north Sunday. Highs Sunday should be in the lower 70s at most locations. Southerly flow will strengthen a bit Sunday night into Monday, bringing in a little more low level moisture and some instability. Some energy aloft associated with a weak trough will move in from the west/southwest, so some isolated showers and thunderstorms appear possible. .LONG TERM...(Monday night through Friday) Issued at 250 PM CDT Fri Oct 7 2016 At the start of this period, there will be a blocking ridge in the mid troposphere from just off the Pacific Northwest coast up into the Yukon. That should help funnel some colder air from Canada down into the Northern and Central Plains for Wednesday and Thursday. The mid level ridge should break down by late in the week...with temperatures moderating back closer to normal by Friday. Opted to go with a dry forecast for Monday night but there may be some isolated activity ahead of the front. Will keep an eye on that for later forecasts. Did include some low rain chances later in the week (Tuesday night into Wednesday) and then again from Thursday into Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 629 PM CDT Fri Oct 7 2016 VFR conditions under clear skies are forecast through Saturday afternoon. Low level wind shear is likely at KOFK from 09Z to 15Z when southwest winds average 40kt at FL020. Light winds overnight will become south to southwest at 12kt by 18Z. && .OAX Watches/Warnings/Advisories... NE...None. IA...None. && $$ SHORT TERM...Miller LONG TERM...Miller AVIATION...Dergan
Area Forecast Discussion
National Weather Service Buffalo NY
416 AM EDT Sat Oct 8 2016 .SYNOPSIS... A cold front will move across Western NY this morning with a few scattered showers. A plume of sub-tropical moisture will bring steadier rain to Central New York and the eastern Lake Ontario region. All of the rain will end from west to east later today with the passage of the cold front. Much cooler air will then move into the region for Sunday and Monday. A few scattered lake effect rain showers are possible Sunday southeast of the lakes. High pressure will then bring a return to dry weather for the first half of next week. && .NEAR TERM /THROUGH TONIGHT/... Radar imagery showing a band of steady, moderate rain moving north through the Finger Lakes and spreading into the eastern Lake Ontario region early this morning. This area of rain is in association with a narrow plume of sub-tropical moisture and associated modest 30 knot low level jet extending well north of Hurricane Matthew. Short term high resolution guidance such as the HRRR is handling this scenario well, and suggest the steadier rain will last across Central NY and the eastern Lake Ontario region through mid to late morning before becoming more intermittent in nature. Meanwhile a few scattered showers are also found upstream across southern Ontario just ahead of a surface cold front. These scattered showers will cross Western NY this morning as the cold front approaches, but coverage and amounts will remain very sparse compared to points farther east. As the cold front catches the plume of sub-tropical moisture across the eastern Lake Ontario region, it will force additional showers to develop during the midday and early afternoon hours. Much drier air will advect into the region behind the cold front, with a return to sunshine this afternoon across Western NY. Clouds will be slower to clear east of Lake Ontario, but even here a few breaks in the clouds may develop late in the day. High temperatures will reach the mid 60s in most areas through the first half of today, then begin to pull back later this afternoon as moderately strong cold advection develops behind the front. Any breaks in the clouds this evening will gradually fill in again overnight as chilly northwest flow becomes established and promotes lake effect and upslope cloud development. Lake induced equilibrium levels rise to around 8K feet, only marginally supportive of any lake effect rain showers. Further limitations will be a short northwest fetch, limited background synoptic scale moisture, and a stout inversion above 8K feet. Thus expect just a few scattered showers overnight. Off Lake Erie any showers will be directed across the Chautauqua Ridge. Showers off Lake Ontario will be found from the Rochester area east to Oswego County and southward into the Finger Lakes. Steady cold advection will bring lows into the mid 40s on the lake plains by daybreak Sunday, with lows around 40 across the interior Southern Tier and Lewis County. && .SHORT TERM /SUNDAY THROUGH WEDNESDAY/... On Sunday, an upper level trough will be crossing the lower Great Lakes with cold air advection in place behind the associated surface cold front. 850 mb temperatures will drop to about 0C by Sunday morning, which will warrant a weak lake effect response in the short northwest fetch and limited synoptic moisture. Widely scattered rain showers will develop southeast of Lake Ontario and Lake Erie in the northwesterly flow. As the upper level trough pivots across the region during peak diurnal heating, the resultant steepening lapse rates across the region and an upstream Georgian Bay connection may help scattered rain showers develop across the Niagara Frontier and drop southward across western NY as the flow pivots more northerly behind the trough passage by Sunday afternoon and evening. Showers will taper off Sunday evening in the increasing subsidence and drier air behind the trough passage, with some lingering scattered lake cloudiness. Normal high temperatures for this time of year are in the low 60s, and we will finally see a day close to, if not slightly below, normal this fall as high temperatures top out in the upper 50s to near 60. High pressure will build across the lower Great Lakes through Sunday night, giving way to clearing skies and diminishing winds. Low temperatures will bottom out near freezing in the interior portions of the Southern Tier and the North Country, while the lake plains remain more mild in the upper 30s to lower 40s. High pressure will then remain over the lower Great Lakes and into New England through Monday night. Any lingering lake effect cloudiness from Sunday will be a distant memory by Monday as abundant sunshine will prevail across the region. Highs on Monday will remain near normal in the upper 50s to lower 60s under the surface high. Another chilly night will be in store Monday with more optimal radiational cooling conditions in place. Tuesday and Wednesday will both be fantastic days across the region with building warmth and just some increasing mid and high level cloud cover. The surface high will slide off the New England coast, as deep southwesterly flow develops over the Great Lakes. The result will be the return of warmer air, pushing 850 mb temperatures back to around +10C and giving daytime highs in the mid to upper 60s. 850 mb temperatures push just a bit higher on Wednesday (to around +11/+12C) resulting in afternoon highs in the upper 60s to low 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Global models are in good agreement with the timing of a weak trough that tracks from high plains to the upper Great Lakes on Wednesday, and lifts across Ontario by Wednesday night. The weak, positively tilting trough will drag a weak surface cold front across the region Wednesday night into Thursday, which will result in some widely scattered showers with the frontal passage. A large surface high will the build across the region for the end of the week and into the weekend resulting in more near-normal temperatures and fair weather. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... A narrow plume of tropical moisture will continue to stream northward through the Finger Lakes and Central NY through this morning with periods of rain and associated MVFR and brief IFR VSBY. A cold front approaching from the west will bring a few scattered light showers to Western NY this morning, then sweep east with rain ending from west to east during the day. CIGS are already deteriorating to MVFR and IFR across the Southern Tier, and these lower CIGS will continue to spread north and east through this morning. High resolution model guidance suggests a subtle IFR event at KBUF and KIAG as the cold front approaches and picks up moisture off Lake Erie, producing a plume of IFR stratus northeast of the lake. During the afternoon CIGS will improve following the cold frontal passage as dry air sweeps into the area, with conditions returning to VFR from west to east. Tonight a northwest flow of chilly air will allow some lake effect and upslope clouds to develop, with these clouds reaching a maximum of coverage around daybreak Sunday. CIGS will be a mix of lower end VFR and MVFR in the lake effect clouds. A few widely scattered lake effect showers are also possible southeast of the lakes overnight. Outlook... Sunday...areas of MVFR with a chance of lake effect rain showers southeast of the lakes. Monday through Wednesday...VFR. && .MARINE... A cold front will move across the Lower Great Lakes today. Southerly winds ahead of the front will continue to produce Small Craft Advisory conditions this morning at the northeast end of Lake Ontario. Winds will become westerly behind the front this afternoon, with Small Craft conditions developing on the rest of Lake Ontario and also Lake Erie. Winds will diminish later this evening on Lake Erie, while Small Craft advisory winds and waves continue on Lake Ontario through early Sunday morning. Another brief period of stronger winds and waves may develop on Lake Ontario Sunday night as northeast winds increase. High pressure will then bring a return to lighter winds for the first half of next week. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...Small Craft Advisory from 2 PM this afternoon to 11 PM EDT this evening for LEZ040-041. Small Craft Advisory from 2 PM this afternoon to 8 AM EDT Sunday for LOZ042>044. Small Craft Advisory until 8 AM EDT Sunday for LOZ045. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...HITCHCOCK SHORT TERM...CHURCH LONG TERM...CHURCH AVIATION...HITCHCOCK MARINE...HITCHCOCK
Area Forecast Discussion
National Weather Service State College PA
525 AM EDT Sat Oct 8 2016 .SYNOPSIS... A cold front will move through the area today. Cooler and drier weather is expected into early next week before a new but mainly dry cold front approaches Thursday. Hurricane Matthew will remain off the southeastern US coast and not directly impact our weather. && .NEAR TERM /THROUGH TONIGHT/... Though the center of Hurricane Matthew will not come close to central Pa, the storm is being generous in sharing some of its deep tropical moisture that will continue lifting north into the region ahead of an approaching cold front. Water Vapor loop shows the storm spinning off the Ga/Sc border with the moisture plume surging northward up through Pa into upstate NY. HRRR timing shows the band of rain marching steadily east today with the highest chances for rain early over my western zones, moving into my central zones by mid to late morning and finally into my eastern zones by early to mid afternoon. The front will lag this rain so even behind the main band of rain, we will stay vulnerable to scattered showers over most of the area well into the afternoon. I used a model consensus for QPF which shows amounts around 1/3 inch over eastern areas, building up to a little over an inch in the Laurel Highlands. Highs today will rise into the low to mid 60s, which will be very close to normal for early October. Skies will become clear to scattered from west to east later today and overnight. It should stay a bit on the breezy side so I didn`t include any fog at this time. But if the winds drop off, Sunday could start rather gloomy. Overnight lows will drop to around 40 over the north, to around 50 in the southeast. && .SHORT TERM /SUNDAY/... Short range guidance suggests the cold front will hang up just off the coast Sunday. Some guidance shows the chance of rain lingering over my far sern zones. I used the normally wet SREF pops which in this case, keeps the region dry tomorrow. The upper shortwave could trigger a light shower over the NW mountains as well, but MOS pops are very low there as well so I chose to mention just a sprinkle, and no measurable rain. Highs Sunday will range from the mid 50s to low 60s, averaging about 4-8 deg below normal. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... High pressure will build into the region to start the new work week and bring a period of tranquil but cool weather that will last into the midweek. Monday morning will start on the chilly side with perhaps the first widespread front of the season over much of northern Pa. as models advertise 850 temps nearing zero with anomalously dry air and light surface wind setting in. The next front is now delayed until Wednesday night into Thursday, with another chilly chunk of air expected to follow for the last days of the new week. Pretty uneventful overall. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... 09Z TAFS sent. A plume of tropical moisture streaming up the Appalachian Mountains is supporting a band of steady rain early today from KBFD to KJST. The moist southeast flow ascending the higher terrain of Central Pa is already resulting in IFR cigs in the vicinity of KBFD/KJST at 0330Z. Model soundings and latest HRRR support the idea of IFR cigs also developing at KAOO and KUNV overnight. The lower elevation airfields further east are likely to experience a dry night. However, MVFR cigs appear possible late tonight associated with moistening southeast flow. Not giving much credibility to the HRRR producing fog at KMDT/KLNS after midnight, given the amount of high clouds and substantial dwpt depressions going into the evening. Low cigs and showers appear likely across the Central Mtns into early Saturday afternoon associated with slow moving cold front, then some modest improvement is possible late in the day, as drier air arrives. Across the eastern airfields from KIPT south through KMDT/KLNS, it looks like MVFR conditions will predominate for much of the day, with morning cigs in the 1-3KFT range, followed by scattered rain showers with arrival of front in the afternoon. Outlook... Sun...No sig wx expected. Mon...AM fog possible KBFD. Tue-Wed...Patchy AM fog possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...La Corte AVIATION...Fitzgerald/Martin
Area Forecast Discussion
National Weather Service Duluth MN
403 AM CDT SAT OCT 8 2016 .SHORT TERM...(Today through Sunday) Issued at 403 AM CDT Sat Oct 8 2016 At 403 AM, skies were clearing across portions of the Northland. After a night of cloudy skies, skies were clearing in the Brainerd Lakes Area, and along the North Shore of Lake Superior. Temperatures ranged from the lower 30s in the southwest to around 40 in portions of northwest Wisconsin. The main focus for this weekend will be cloud cover and temperatures. The clouds should continue to decrease from west to east across the Northland today, although more high clouds will spread in from the west. The result will be a partly sunny sky for most areas, although areas of clouds will linger in some locations. High temperatures will definitely be on the cool side, with highs ranging from the mid 40s to the lower 50s. We should see areas of frost early this morning, especially along and south of the Highway 2 corridor. It looks like we will see another night of frost and freeze conditions tonight, as temperatures fall into the lower 30s. Some typically colder locations could see temperatures drop into the upper 20s. As a result, we may need frost and/or freeze headlines once again for the upcoming night. Southerly winds will bring warmer air back into the Northland on Sunday. Temperatures will generally be in the 50s under partly sunny skies. .LONG TERM...(Sunday night through Friday) Issued at 403 AM CDT Sat Oct 8 2016 The main concerns for the long term include temperature trends and the potential for rain and thunderstorms Tuesday and Tuesday night. A quasi-zonal flow will continue to build across the Northern Plains Sunday night. Surface high pressure will depart to the east overnight with a south to southwesterly return flow developing. A positively tilted longwave trough will dig across the Rockies and into the Great Plains Monday afternoon. An elongated surface low will develop in the lee of the Rockies in response to falling heights and approaching cyclonic vorticity with a cool front advancing east across the Dakotas and Canadian Prairie Provinces. The southwest flow will pull two separate moisture streams northward into the region ahead of the system. Even with meager moisture, there should be sufficient lift along and ahead of the front for showers and a few thunderstorms late Monday night through Tuesday. Colder air will return behind the front beginning Tuesday morning in the northwest, with temperatures dipping below normal once again through Wednesday. High pressure will build across the region Tuesday night and Wednesday leading to fairly quiet conditions. Quiet weather will continue Thursday and Friday as another round of quasi-zonal flow returns. Temperatures will trend gradually warmer, back to near or slightly above normal, by Friday. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 102 AM CDT Sat Oct 8 2016 Elongated trough of low pressure remained in place over the area early this morning. Cyclonic flow and weak cool air advection will continue through early evening with VFR/MVFR ceilings expected until around 14Z. With gradually warming surface temperatures after sunrise, expect MVFR ceilings to develop at remaining airports thanks to weak instability and low level moisture. The ceilings will gradually increase as temperatures warm through the day for most sites. A few rain showers may pass over the terminals at times during this forecast period, especially INL between now and sunrise. Low-level wind shear is a concern at DLH/HYR/BRD as surface winds continue to decouple. KDLH VAD wind profile indicates 500 meter winds of 310 at 32kt, which is right on the threshold for LLWS. RAP 925 wind speeds suggest the highest wind speeds will rotate through the trough and out of the terminals by mid- morning. && .PRELIMINARY POINT TEMPS/POPS... DLH 48 33 52 45 / 10 0 0 0 INL 45 26 52 46 / 30 0 0 0 BRD 48 30 56 48 / 0 0 0 0 HYR 49 30 56 44 / 0 0 0 0 ASX 51 34 54 44 / 10 0 0 0 && .DLH Watches/Warnings/Advisories... WI...Frost Advisory until 9 AM CDT this morning for WIZ001>004- 006>009. MN...Frost Advisory until 9 AM CDT this morning for MNZ018-025-026- 033>038. LS...Small Craft Advisory until 10 AM CDT this morning for LSZ121-140- 141-146>148. && $$ SHORT TERM...DAP LONG TERM...Huyck AVIATION...Huyck
Area Forecast Discussion
National Weather Service North Platte NE
309 AM CDT Sat Oct 8 2016 .SHORT TERM...(Today and tonight) Issued at 309 AM CDT Sat Oct 8 2016 Today and Tonight...sfc low pressure across northeast WY is progged to move east along the SD-Neb border this morning and drop a back door cold front into Ncntl Neb this afternoon. This could hold highs in the 60s across Nrn Neb while Cntl and Swrn Neb rise into the 70s. The forecast uses the bias corrected RAP and LAV data which was cooler than the MET MAV EKDMOS and ECS guidance across northern Neb. It also captures the cooling effect of the snow cover across the Sandhills which still lingered in some areas Saturday afternoon. The cloud cover on satellite across MT and the Dakotas is forecast to move east and remain north of Nebraska. Generally clear skies are expected today and tonight. Low pressure will deepen across the Nrn High Plains tonight producing south winds across Wrn and North Central Neb. A blend of the MET MAV EKDMOS and ECS guidance plus bias correction suggested lows in the 30s to near 40. .LONG TERM...(Sunday through Friday) Issued at 309 AM CDT Sat Oct 8 2016 Zonal flow to prevail across the central Plains which will induce a the development of a surface trough off the Lee of the Rockies. Southerly flow will increase as a result and lead to breezy...but warm conditions. The latest medium range guidance indicates widespread 70s for highs. There remains a disorganized area of low pressure that moves from the southern Rockies out onto the southern Plains...which may spark off an isolated shower or thunderstorm to our south and southeast. Weak instability is in place across our southern zones and with forcing for ascent arriving from the south, it is possible that our far southeastern zones see a thunderstorm during the afternoon and evening hours. The next system of interest rapidly advances from the Pac NW across the northern Rockies and making the northern plains by 00Z Wednesday. In advance of the shortwave the models suggest southwesterly downsloping winds...which will help boost high temperatures into the 80s Monday afternoon for most locations. The shortwave will force a cold front across the CWA early on Tuesday. A stark cooldown is forecast for mid-week with highest in the 50s /north/ and lower 60s /south/. The front arrives when the troposphere is moisture starved, thus at least initially, rain chances are slim. The models continue to advertise sufficient saturation when the large scale forcing associated with the shortwave trough arrives. Will maintain slight chance to lower end chance pops Tuesday evening into early Wednesday for much of the forecast area. Beyond early Wednesday the forecast is dry as forcing for ascent is largely absent save for an unorganized shortwave passing in the southern stream late week. Temperatures will warm once again late week as thermal advection and rising heights build east from the Rockies. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1115 PM CDT Fri Oct 7 2016 VFR conditions currently prevail across western and north central NE and this is expected to continue through the TAF period. Winds have lessen from earlier with the latest sfc plot showing several sites with calm to light and variable winds. Elsewhere, winds have stayed up in the far southern portions of the forecast area with speeds of 5-8 kts still being observed. Latest satellite imagery reveals mostly clear skies with a few high clouds coming in from the northwest. The main concern this package is LLWS conditions. Low-level wind shear conditions are expected to develop near midnight as southwest low level winds develop across southwest NE to north central NE. Wherein for these terminals the height of the top of the shear layer is expected to be about 1000 feet with a forecast wind speed of 40 kts. Thus LLWS was added to the KLBF given this combined with light to calm/variable winds that are expected. Not anticipating LLWS conditions across the remainder of the local forecast area so LLWS was left out of the KVTN TAF at this time. This continues to be supported by guidance, however, this will continued to be monitored. LLWS conditions are expected to diminish before mid morning. Light southwest winds in the morning hours will shift over the course of the day becoming northerly by early afternoon. Winds are expected to stay under 10 kts sustained across much of the area tomorrow. Winds will become easterly by the evening. && .FIRE WEATHER... Issued at 300 AM CDT Sat Oct 8 2016 Dry air in the lower and mid levels of the troposphere will combine with warm temperatures to create near RFW criteria RH across southwest Nebraska today and for much of the sandhills and southwest Nebraska on Monday. Wind speeds are forecast to remain well below criteria, but early Tuesday a cold front is slated to arrive, which will provide for a distinct wind shift and increase in speeds. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...Jacobs AVIATION...ET FIRE WEATHER...Jacobs
Area Forecast Discussion
National Weather Service Marquette MI
513 AM EDT Sat Oct 8 2016 .SHORT TERM...(Today and tonight) Issued at 511 AM EDT SAT OCT 8 2016 WV imagery and RAP analysis indicated a mid/upper level low just nw of James Bay with troughing into the wrn Great Lakes. At the surface, brisk wrly flow prevailed between the low near James Bay and a ridge from Saskatchewan through srn MN. Radar and sfc obs indicated sct lake effect rain showers over ern lake superior and some lighter pcpn into the nw cwa supported by moderate instability with 850 mb temps around -3C and lake temps in the 10C-14C range and a moist 850-700 mb layer. Otherwise, IR loop showed mostly cloudy skies across the area. Today, 850 temps remaining around -2C will continue to provide enough instability for sct -shra for locations favored by wrly flow. As the low level winds gradually veer to the nw with high pres building into the nrn Ontario, look for greater pcpn coverage into the ern cwa this afternoon. Over the rest of the area, Fall-like conditions with highs from the upper 40s west to the lower 50s east under mostly cloudy skies are expected. Tonight, winds will diminish and continue to veer to the north as the high builds closer to the region. Even though inversion heights drop slightly, 850 mb temps remaining in the -2C to -4C range will bring sct -shra into much of n cntrl upper MI. Wet-bulb zero heights suggest that the pcpn will remain as rain. Mostly cloudy skies should keep temps from falling off too far, but mins in the lower 30s are still expected over the inland west half with readings in the upper 30s to lower 40s near the Great Lakes. .LONG TERM...(Sunday through Friday) Issued at 253 AM EDT SAT OCT 8 2016 The start of the long term begins 12Z Sun with a SFC high over the area and 850mb temps around -3C. Should see some isolated to scattered lake effect rain showers mainly Sun morning, but can`t rule out precip sticking around into Sun afternoon over the east. The high moving through will switch winds around to the south from west to east, ending the precip in that order. Upper ridging will also moving in later in the day, bringing a warmer airmass along with it. The SFC high will continue to shift east while a SFC trough moves toward the area from the west Sun night and Mon. 850mb temps increase to around 12C by Mon afternoon. The parent upper trough for this system will be over the Pacific NW on Mon, with potential for some weak shortwaves and associated scattered showers to move into the area late Mon into Tue. Main precip threat comes Tue night into Wed morning as the upper trough approaches and the SFC trough/cold front move through. Have high chance to likely PoPs during that time period. May need higher PoPs behind the cold front as models indicate 850mb temps dropping a few degrees below 0C through Thu, but models vary in the magnitude and duration of the colder air, as well as with wind directions. Models do agree on a warmup late this week into the weekend. Overall stuck close to blended guidance. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 142 AM EDT SAT OCT 8 2016 Strongest winds over 30 kts at times will be at CMX through Sat afternoon. Expect lake effect rain showers tonight in westerly flow at CMX. Overall tonight conditions will be MVFR due to the lower cigs at CMX as upper level disturbance moving through enhances the lake effect rain. Will be borderline low VFR/high MVFR at both KIWD and KSAW through most of this forecast period. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 511 AM EDT SAT OCT 8 2016 West winds to 30 knots are expected today that will gradually veer to the northwest. Winds will diminish to under 15kt late tonight into early Mon as high pres moves across. SW winds will increase to 30 kts later Mon and Mon night ahead of another low pressure system then shift to the northwest to 20-25 kts behind the system on Tue/Wed. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Titus AVIATION...07 MARINE...JLB
Area Forecast Discussion
National Weather Service Phoenix AZ
145 AM MST SAT OCT 8 2016 .SYNOPSIS... Scattered light showers will return to parts of Arizona today with more thunderstorms and brief local heavy downpours and gusty winds late this afternoon and evening. Dry conditions will return next week with temperatures hovering well above average throughout much of the week. && .DISCUSSION... Both WV imagery and objective analysis indicates a jet streak punching into NW Mexico early this morning with attendant downstream difluence and ascent spreading into southern AZ. However, backed lower/middle tropospheric winds have been slower in advecting sufficient moisture towards central AZ with deeper 6-7 g/kg mixing ratios and theta-e advection still languishing in SE AZ. Both 21Z and 03Z SREF probabilities have retreated from more bullish numbers advertised yesterday; and most high resolution model output only briefly develops showers within the forecast area bounds before lifting activity north (and most concentrated through Gila County and northern edges of Maricopa Co). Still, with the good ascent structure entering the region and moisture not far away, feel some measure of showers are still possible through central AZ this morning, though pared back POPs somewhat to account for less overall coverage. While the reflection towards morning showers has waned somewhat in model output, the propensity towards more extensive deeper convection this afternoon has grown in high resolution models. There is fair evidence that thicker high clouds will at least partially clear today allowing better sfc insolation and MLCape around 1000 J/kg throughout SE AZ. SSEO members, complimentary WRF high res windows, and HRRR output all suggest fairly concentrated thunderstorm activity erupting through Pima and southern Pinal counties by mid afternoon. Instability may be more muted with notable Cinh further north into Maricopa County, however substantial DCape in excess of 1000 J/kg would support more organized outflows. Typical best performing convective models are not overwhelmingly in agreement regarding expansive well organized outflows and SSEO neighborhood probabilities for stronger wind gusts remains low, though conceptually one would expect some isolated strong outflows and blowing dust. Kept this mention in the forecast, though the window in time and space for greater impacts would likely be much less than is typical during warm season convective events. Whatever convective activity does manage to survive into the forecast area should gradually wane this evening with the loss of daytime heating, and propagate into far eastern AZ as the supporting shortwave lifts into the four corners. Flow aloft on Sunday will gradually become more anti-cyclonic and subsident though enough residual moisture may linger over higher terrain of eastern AZ to support and isolated shower in parts of Gila County. Otherwise, clearing and increasing heights aloft will support afternoon highs near or warmer than experienced on Friday (i.e. mid to upper 90s). Medium range operational models and NAEFS members remain in very good agreement advertising a high amplitude blocked northern stream throughout North America coincident with a more progressive southern stream flow flanked equatorward by an expansive east-west oriented subtropical ridge along the far southern tier of the United States. Locally, Monday and Tuesday will be characterized by dry subsident flow, H5 heights in a 585-588dm range, and afternoon H8 temperatures hovering around +20C to +22C. Resultant highs will favor +5F-10F above average with readings flirting with the 100F threshold across parts of SE CA. At some point during the middle of the week, a fast moving shortwave will dampen heights and temperatures aloft slightly, though enough spread among forecast models exists to precluding pinpointing which exact day may be notably "cooler". In reality, this "cooling" only represents shaving 2F-5F from early week temperatures closer towards the seasonal normal before readings rebound back into an above average range for the end of the week under stronger ridging aloft. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Thickening mid/high clouds will continue overnight with some scattered showers possibly developing after 12Z. Cigs, even with showers, will remain AOA 8kft. Showery activity ends after 17-19Z as gusty easterly winds develop. Additional showers possible later Saturday afternoon, even a low chance of TS (not included in TAF). More likely would be outflow winds from distant storms - will be monitoring for future inclusion in TAFs. Southeast California/Southwest Arizona including KIPL and KBLH: Winds will remain light and out of the north at KBLH and out of the northwest at KIPL. Skies will remain mostly clear today with a gradual increase in cloud cover through tomorrow morning. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Monday through Friday: Dry southwesterly flow aloft will continue to spread across the region and continue into the end of next week. Minimum humidities will be in the 15-30 percent range across the region on Monday. Thereafter, humidities will remain low, near the 10-25 percent range. Overnight recovery will be good to excellent. Although conditions will be dry, winds will remain on the light side, with the exception of a few periods of breeziness up to 20 mph on Thursday in southeast California and on Friday in southwest and south-central Arizona. High temperatures over the deserts will stay in the 90s during the period and generally be above seasonal normals. Warmest western deserts may be near 100 degrees on Monday. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures today. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...MO AVIATION...Hernandez FIRE WEATHER...Hernandez
Area Forecast Discussion
National Weather Service Wilmington NC
1028 AM EDT Sat Oct 8 2016 .SYNOPSIS... The center of Hurricane Matthew will move very near the coast of South Carolina this morning, and should barely miss Cape Fear this evening as the storm turns east and moves out to sea. Life threatening flash flooding, damaging winds, and storm surge flooding are expected. Behind Matthew, Canadian high pressure will bring the coolest air of this Fall season, with dry weather expected through Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Saturday...Entire Forecast area is under a flash flood warning now with very impressive rainfall totals rolling in. Saturated ground and tropical storm force gusts have combined for a number of downed tree reports and numerous power outages. Watches and warnings continue as before. Latest HRRR guidance has center of Matthew about 50 NM directly south of Cape Fear at 7 PM this evening. Previous discussion follows: Hurricane Matthew will continue to move north-northeastward along the South Carolina coast this morning, turning more east- northeastward toward Cape Fear this evening. Tremendous moisture content in the atmosphere (precipitable water values 2.6 to 3.0 inches) is not only a record high for October, but likely is in the top few events for all of recorded history here! An exceptionally high risk for flash flooding exists as an additional 7-10 inches of rain is expected to fall today, making storm totals near 15 inches in spots. Referencing values on the NOAA Precipitation Frequency Atlas, 45-day rainfall totals (Sep 1 through Oct 15) are probably going to be in the 50 to 100 year average return interval after Matthew is done with us. Matthew should soon lose its symmetry as a tropical cyclone as wind shear increases and begins to tilt the upper portion of the circulation northeastward (downshear). The southern half of the circulation also continues to ingest rain-cooled air off Georgia and South Carolina, and this should continue to concentrate heavy rainfall more preferentially in the northwestern quadrant of the storm where the flow is onshore from the high heat content of the Gulf Stream. Tropical storm force winds will continue to spread northward along the coast this morning, but I fear there is a surprise waiting for us late this afternoon into this evening. For several days the GFS model has been indicating as the center of Matthew passes south of Cape Fear, rain-cooled air across interior North Carolina would get pulled south behind the storm. As lapse rates steepen in the lowest 1500-2000 feet of the atmosphere, winds of 60-80 mph may get transported down through this mixed layer to the surface. For many locations north of Myrtle Beach this may be the strongest winds we see from the entire event, and could pose quite a shock as the system will seem to be on its way out to sea by then. After a foot of rain, gusts this strong would almost certainly uproot trees causing power outages and blocked roads. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 300 AM Saturday...With Matthew pulling off to the east and the coolest airmass of this Fall season building in, we should have two days of crisp, dry weather with dewpoints plunging into the 40s. Highs both days should run within a few degrees of 70 with overnight lows in the 40s or lower 50s. There is actually a lot of spread among various models with lows Monday night/Tuesday morning. We`re not quite as cold as the 00z GFS, although I`m trending the forecast in that direction. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 320 PM Friday...The extended still looks very uneventful as the mid level pattern will show a some amplitude early with a mostly zonal flow developing late. Early on a modest ridge moves across the Tennessee Valley and eventually dampens. This will allow a very cool airmass to advect in behind Matthew. Guidance has cooled considerably since this time as has the official forecast. The airmass modifies later in the week with another front expected to move across late Thursday or early Friday. No pops in the forecast. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... As of 12Z...Needless to say, not a good aviation day. Look for increasing winds as the center of Hurricane Matthew drives up the coast. Winds will gust to near hurricane strength by mid morning south continuing through the afternoon hours. Ceilings will bounce around but will be predominately IFR, as well as the visibilities in heavy rain. Winds will shift rather abruptly this evening as the low moves east, still gusting over 50 kts. EXTENDED OUTLOOK...VFR possible MVFR for the inland terminals during the pre-dawn Sun hours. MVFR possible IFR for the coastal terminals during the pre-dawn Sun hours. All terminals should become VFR during or by daylight Sun morning. The Winds will remain gusty with a slow diminishing trend during the day on Sunday. VFR Sunday night thru Tuesday. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Saturday...Impressively high seas this morning as Matthew churns up the coast. We are seeing around 20 ft out at 41013 and 13 ft at the 41110 near-shore buoy. Winds are gusting at tropical storm force throughout the waters. Hurricane warnings continue over the waters as before. Previous discussion follows: As Hurricane Matthew moves northward along the South Carolina coast today and then turns northeastward toward Cape Fear this afternoon, marine weather conditions will remain exceptionally hazardous. Winds will increase to the 45-60 knot range with higher gusts south of Cape Fear today. Seas from 10-20 miles from shore should increase to 12-18 feet. As Matthew`s center moves toward Cape Fear this evening, cooler air lurking over interior North Carolina will be pulled southward. Steep lapse rates within this cooler air should transport down 55-65 knot gusts to the surface, leading to a second period of very strong winds. This could be the strongest portion of the storm for the Brunswick County beaches and Cape Fear area. Offshore wind directions developing overnight should begin to smooth out the sea state, although very large backswell will continue to make marine conditions very hazardous. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 300 AM Saturday...As Matthew moves eastward and away from the Carolinas, Canadian high pressure over the Great Lakes will push the coolest airmass of this Fall season southward. Strong northerly offshore winds Sunday will only slowly diminish in speed Monday, likely keeping conditions too rough for small craft, especially with considerable backswell still moving in from the east. LONG TERM /TUESDAY THROUGH WEDNESDAY/... As of 320 PM Friday...Rugged conditions will continue for the marine community through the period. A broad surface trough will be aligned offshore with strong high pressure building in from the northeast. These features coupled will keep a good 20-25 knots across all waters Monday scaling back slowly Tuesday and Wednesday. Significant seas will go from 6-10 feet Monday to 3-6 feet Wednesday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Hurricane Warning for SCZ053>056. Flash Flood Watch through late tonight for SCZ017-023-024-032- 033-039-053>056. Tropical Storm Warning for SCZ017-023-024-032-033-039. High Rip Current Risk until 8 PM EDT this evening for SCZ054- 056. NC...Hurricane Warning for NCZ105>110. Flash Flood Watch through late tonight for NCZ087-096-099- 105>110. Tropical Storm Warning for NCZ087-096-099. High Rip Current Risk until 8 PM EDT this evening for NCZ106- 108-110. MARINE...Hurricane Warning for AMZ250-252-254-256. && $$ SYNOPSIS...TRA NEAR TERM...REK/TRA SHORT TERM...TRA LONG TERM...SHK AVIATION...DL MARINE...REK/TRA/SHK
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
610 AM CDT Sat Oct 8 2016 .SHORT TERM...(Today and tonight) Issued at 309 AM CDT Sat Oct 8 2016 Today and Tonight...sfc low pressure across northeast WY is progged to move east along the SD-Neb border this morning and drop a back door cold front into Ncntl Neb this afternoon. This could hold highs in the 60s across Nrn Neb while Cntl and Swrn Neb rise into the 70s. The forecast uses the bias corrected RAP and LAV data which was cooler than the MET MAV EKDMOS and ECS guidance across northern Neb. It also captures the cooling effect of the snow cover across the Sandhills which still lingered in some areas Saturday afternoon. The cloud cover on satellite across MT and the Dakotas is forecast to move east and remain north of Nebraska. Generally clear skies are expected today and tonight. Low pressure will deepen across the Nrn High Plains tonight producing south winds across Wrn and North Central Neb. A blend of the MET MAV EKDMOS and ECS guidance plus bias correction suggested lows in the 30s to near 40. .LONG TERM...(Sunday through Friday) Issued at 309 AM CDT Sat Oct 8 2016 Zonal flow to prevail across the central Plains which will induce a the development of a surface trough off the Lee of the Rockies. Southerly flow will increase as a result and lead to breezy...but warm conditions. The latest medium range guidance indicates widespread 70s for highs. There remains a disorganized area of low pressure that moves from the southern Rockies out onto the southern Plains...which may spark off an isolated shower or thunderstorm to our south and southeast. Weak instability is in place across our southern zones and with forcing for ascent arriving from the south, it is possible that our far southeastern zones see a thunderstorm during the afternoon and evening hours. The next system of interest rapidly advances from the Pac NW across the northern Rockies and making the northern plains by 00Z Wednesday. In advance of the shortwave the models suggest southwesterly downsloping winds...which will help boost high temperatures into the 80s Monday afternoon for most locations. The shortwave will force a cold front across the CWA early on Tuesday. A stark cooldown is forecast for mid-week with highest in the 50s /north/ and lower 60s /south/. The front arrives when the troposphere is moisture starved, thus at least initially, rain chances are slim. The models continue to advertise sufficient saturation when the large scale forcing associated with the shortwave trough arrives. Will maintain slight chance to lower end chance pops Tuesday evening into early Wednesday for much of the forecast area. Beyond early Wednesday the forecast is dry as forcing for ascent is largely absent save for an unorganized shortwave passing in the southern stream late week. Temperatures will warm once again late week as thermal advection and rising heights build east from the Rockies. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 609 AM CDT Sat Oct 8 2016 VFR is expected all areas today and tonight. A weak cold front...currently draped across the Dakotas...will drift into Ncntl Neb this afternoon and Wrn Neb tonight. No significant high or low clouds are expected along the front. && .FIRE WEATHER... Issued at 300 AM CDT Sat Oct 8 2016 Dry air in the lower and mid levels of the troposphere will combine with warm temperatures to create near RFW criteria RH across southwest Nebraska today and for much of the sandhills and southwest Nebraska on Monday. Wind speeds are forecast to remain well below criteria, but early Tuesday a cold front is slated to arrive, which will provide for a distinct wind shift and increase in speeds. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...Jacobs AVIATION...CDC FIRE WEATHER...Jacobs
Area Forecast Discussion
National Weather Service Marquette MI
741 AM EDT Sat Oct 8 2016 .SHORT TERM...(Today and tonight) Issued at 511 AM EDT SAT OCT 8 2016 WV imagery and RAP analysis indicated a mid/upper level low just nw of James Bay with troughing into the wrn Great Lakes. At the surface, brisk wrly flow prevailed between the low near James Bay and a ridge from Saskatchewan through srn MN. Radar and sfc obs indicated sct lake effect rain showers over ern lake superior and some lighter pcpn into the nw cwa supported by moderate instability with 850 mb temps around -3C and lake temps in the 10C-14C range and a moist 850-700 mb layer. Otherwise, IR loop showed mostly cloudy skies across the area. Today, 850 temps remaining around -2C will continue to provide enough instability for sct -shra for locations favored by wrly flow. As the low level winds gradually veer to the nw with high pres building into the nrn Ontario, look for greater pcpn coverage into the ern cwa this afternoon. Over the rest of the area, Fall-like conditions with highs from the upper 40s west to the lower 50s east under mostly cloudy skies are expected. Tonight, winds will diminish and continue to veer to the north as the high builds closer to the region. Even though inversion heights drop slightly, 850 mb temps remaining in the -2C to -4C range will bring sct -shra into much of n cntrl upper MI. Wet-bulb zero heights suggest that the pcpn will remain as rain. Mostly cloudy skies should keep temps from falling off too far, but mins in the lower 30s are still expected over the inland west half with readings in the upper 30s to lower 40s near the Great Lakes. .LONG TERM...(Sunday through Friday) Issued at 253 AM EDT SAT OCT 8 2016 The start of the long term begins 12Z Sun with a SFC high over the area and 850mb temps around -3C. Should see some isolated to scattered lake effect rain showers mainly Sun morning, but can`t rule out precip sticking around into Sun afternoon over the east. The high moving through will switch winds around to the south from west to east, ending the precip in that order. Upper ridging will also moving in later in the day, bringing a warmer airmass along with it. The SFC high will continue to shift east while a SFC trough moves toward the area from the west Sun night and Mon. 850mb temps increase to around 12C by Mon afternoon. The parent upper trough for this system will be over the Pacific NW on Mon, with potential for some weak shortwaves and associated scattered showers to move into the area late Mon into Tue. Main precip threat comes Tue night into Wed morning as the upper trough approaches and the SFC trough/cold front move through. Have high chance to likely PoPs during that time period. May need higher PoPs behind the cold front as models indicate 850mb temps dropping a few degrees below 0C through Thu, but models vary in the magnitude and duration of the colder air, as well as with wind directions. Models do agree on a warmup late this week into the weekend. Overall stuck close to blended guidance. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 741 AM EDT SAT OCT 8 2016 Strongest winds to near 30 kts will be at CMX through this afternoon. Expect sct/isold lake effect rain showers today in westerly flow at CMX where mainly mvfr cigs are expected today. As winds veer nrly tonight and somewhat drier air moves in, expect VFR cigs. The wind direction will be less favorable for lake effect pcpn at IWD and SAW where vfr or high end mvfr cigs should prevail. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 511 AM EDT SAT OCT 8 2016 West winds to 30 knots are expected today that will gradually veer to the northwest. Winds will diminish to under 15kt late tonight into early Mon as high pres moves across. SW winds will increase to 30 kts later Mon and Mon night ahead of another low pressure system then shift to the northwest to 20-25 kts behind the system on Tue/Wed. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Titus AVIATION...JLB MARINE...JLB
Area Forecast Discussion...Updated
National Weather Service Phoenix AZ
555 AM MST SAT OCT 8 2016 .UPDATE...Updated aviation discussion. && .SYNOPSIS... Scattered light showers will return to parts of Arizona today with more thunderstorms and brief local heavy downpours and gusty winds late this afternoon and evening. Dry conditions will return next week with temperatures hovering well above average throughout much of the week. && .DISCUSSION... Both WV imagery and objective analysis indicates a jet streak punching into NW Mexico early this morning with attendant downstream difluence and ascent spreading into southern AZ. However, backed lower/middle tropospheric winds have been slower in advecting sufficient moisture towards central AZ with deeper 6-7 g/kg mixing ratios and theta-e advection still languishing in SE AZ. Both 21Z and 03Z SREF probabilities have retreated from more bullish numbers advertised yesterday; and most high resolution model output only briefly develops showers within the forecast area bounds before lifting activity north (and most concentrated through Gila County and northern edges of Maricopa Co). Still, with the good ascent structure entering the region and moisture not far away, feel some measure of showers are still possible through central AZ this morning, though pared back POPs somewhat to account for less overall coverage. While the reflection towards morning showers has waned somewhat in model output, the propensity towards more extensive deeper convection this afternoon has grown in high resolution models. There is fair evidence that thicker high clouds will at least partially clear today allowing better sfc insolation and MLCape around 1000 J/kg throughout SE AZ. SSEO members, complimentary WRF high res windows, and HRRR output all suggest fairly concentrated thunderstorm activity erupting through Pima and southern Pinal counties by mid afternoon. Instability may be more muted with notable Cinh further north into Maricopa County, however substantial DCape in excess of 1000 J/kg would support more organized outflows. Typical best performing convective models are not overwhelmingly in agreement regarding expansive well organized outflows and SSEO neighborhood probabilities for stronger wind gusts remains low, though conceptually one would expect some isolated strong outflows and blowing dust. Kept this mention in the forecast, though the window in time and space for greater impacts would likely be much less than is typical during warm season convective events. Whatever convective activity does manage to survive into the forecast area should gradually wane this evening with the loss of daytime heating, and propagate into far eastern AZ as the supporting shortwave lifts into the four corners. Flow aloft on Sunday will gradually become more anti-cyclonic and subsident though enough residual moisture may linger over higher terrain of eastern AZ to support and isolated shower in parts of Gila County. Otherwise, clearing and increasing heights aloft will support afternoon highs near or warmer than experienced on Friday (i.e. mid to upper 90s). Medium range operational models and NAEFS members remain in very good agreement advertising a high amplitude blocked northern stream throughout North America coincident with a more progressive southern stream flow flanked equatorward by an expansive east-west oriented subtropical ridge along the far southern tier of the United States. Locally, Monday and Tuesday will be characterized by dry subsident flow, H5 heights in a 585-588dm range, and afternoon H8 temperatures hovering around +20C to +22C. Resultant highs will favor +5F-10F above average with readings flirting with the 100F threshold across parts of SE CA. At some point during the middle of the week, a fast moving shortwave will dampen heights and temperatures aloft slightly, though enough spread among forecast models exists to precluding pinpointing which exact day may be notably "cooler". In reality, this "cooling" only represents shaving 2F-5F from early week temperatures closer towards the seasonal normal before readings rebound back into an above average range for the end of the week under stronger ridging aloft. && .AVIATION... South-Central Arizona Including KPHX, KIWA, and KSDL: Expect thickening and lowering clouds this morning as an upper low moves slowly east across the area...with cigs to lower to around 10k feet by 14z or so. As supported by a variety of local models, isolated showers have begun to percolate over the greater Phoenix area and thus have updated TAFs to include VCSH. Showers should persist on and off into the afternoon, then decrease into the evening. Thunder remains a possibility with better chances in the afternoon but we have already seen an isolated storm this morning mainly west of KPHX. Confidence in areal coverage and timing issues still a bit low and will hold off for now on updating TAFs to mention thunder. Cannot rule out a storm affecting KPHX or one of the other TAF sites this morning. Lowest cloud decks mid morning thru afternoon should be 7-8k feet unless more rain than expected occurs leading to lowered bases/cigs. Clearing to take place this evening with cloud decks becoming few-sct for the most part. Winds to favor the east to southeast next 24 hours with little chance of a westward swing later this afternoon, and we should see some gusts over 20kt during the mid morning to early afternoon time frame as well. Southeast California/Southwest Arizona including KIPL and KBLH: No threat of precip next 24 hours and most cloud decks to be aoa 15k feet today. By early evening skies to become clear or mostly clear. Winds to favor the north-northeast next 24 hours at KBLH and during the afternoon at KIPL, with speeds mostly below 10kt. Aviation Discussion not updated for amended TAFs. && .FIRE WEATHER... Monday through Friday: Dry southwesterly flow aloft will continue to spread across the region and continue into the end of next week. Minimum humidities will mostly be in the 15-20 percent range across the deserts each day with the western deserts and southeast CA lowering to 10-15 percent Tuesday and Wednesday. Overnight recovery will be good to excellent. Although conditions will be dry, winds will remain on the light side each day with only typical afternoon local breeziness. High temperatures over the deserts will stay in the 90s during the period and generally be above seasonal normals. Warmest western deserts may be near 100 degrees on Monday. && .SPOTTER INFORMATION STATEMENT... Spotters should follow standard reporting procedures today. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook...Twitter...and at weather.gov/phoenix DISCUSSION...MO AVIATION...CB FIRE WEATHER...Hernandez/CB
Area Forecast Discussion
National Weather Service Blacksburg VA
945 AM EDT Sat Oct 8 2016 .SYNOPSIS... A cold front will cross east through the Ohio Valley today and through the Mid Atlantic region tonight as Hurricane Matthew moves northeast along the Carolina coast. High pressure will build in Sunday and remain over the much of the eastern United States through Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 945 am EDT Saturday... Around 8 am/12z this morning, Hurricane Matthew was about 20 miles SSE of Charleston, South Carolina and moving northeast around 12 mph. The NHC track still has the hurricane moving northward today along the South Carolina coast, then turning right tonight into Sunday morning. The northwest edge of the large shield of rain associated with Hurricane Matthew will advanced into the foothills and Piedmont of Virginia and North Carolina today. Meanwhile, a cold front to our west continue to move east today into tonight. Several forecasting challenges today with sharp edge to moderate to heavy rains and the gradual drying or ending of the rain with the cold front. For this morning isc grids update included the mention of heavy rains in the southeast portions of forecast area. Also, elected to slow down the timing of the drying in the west. Initially shaped pops towards WSR-88d trends and then leaned to HRRR for late morning into this afternoon. Made some minor adjustments in temperatures with latest sfc obs and blended in the lamp guidance for late morning into this afternoon. Increased winds and winds gusts slightly across the higher terrain and across the south. More changes later this morning. As of 445 AM EDT Saturday... The northwest edge of the large shield of precipitation associated with Hurricane Matthew had advanced into the foothills and Piedmont of Virginia and North Carolina. A cold front trailed from Lake Erie to Louisiana this morning. Rain extended from central New York into northeast Tennessee ahead of this boundary. Models were in good agreement that precipitation would gradually end from west to east today and tonight. Expect much of the area west of the Blue Ridge to be dry by this evening, with the rain exiting the piedmont by early Sunday morning. From 8AM today through 8AM Sunday rainfall amounts will be heaviest east of a Lynchburg to Martinsville line. The tropical air mass and warm rain process will lead to heavier rainfall in that area. Similar to Friday, clouds and precipitation will translate to only a small rise in temperatures today. Have stayed close to the MAV guidance which was just a few degrees above temperatures at 3AM. The cold front will cross through the area tonight leading in cooler and drier air. Surface points drop enough for temperatures to lower in the 40s in the mountains overnight. 850MB winds increase from the north into the 40 to 50 knot range tonight. Expecting the gusty winds to become more common at higher elevations behind the front late tonight. Wind gusts rise close to advisory criteria at the highest elevations from Grayson county into northwest North Carolina early Sunday morning. && .SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/... As of 330 AM EDT Saturday... Matthew will be looping away from the region on Sunday as low amplitude ridging builds over the eastern US and allows a large area of high pressure to move into the northeast through the first part of next week. This will yield a dry forecast for the Appalachians and central mid Atlantic region through the period. There will be a very tight pressure gradient between departing Matthew and the large high moving in from the west. This will generate very windy conditions, especially at the higher elevations from the mountains of NC into the southern Blue Ridge on Sunday. Guidance is not universal in mixing advisory criteria winds to the surface so will wait for later runs to assess potential for any wind advisories. The high will then wedge down the east side of the Appalachians on Monday and remain as such through Tuesday. Moisture fields indicate that it will be a dry wedge, so aside from keeping temperatures on the cool side there will be little associated sensible weather with the wedge. Lows will be quite chilly Sunday and Monday night with readings in the 30s expected form the Ridge westward, low to mid 40s to the east. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... As of 230 PM EDT Friday... During most of this portion of the forecast, a broad area of high pressure will extend from the Gulf Coast to New England. Limited cloud cover, very limited precipitation, and a warming trend to near/slightly above, normal temperatures expected. Guidance is hinting that two distinct shortwave troughs may move into and through the northern extent of the ridge, one on Thursday, and one on Friday. Each of these could have the potential for bringing some isolated showers into western parts of the area. Currently, the one slated for Friday looks have the best chance of bringing some isolated to scattered showers to parts of the area, and and overall trend towards increasing cloud cover for the whole region. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... As of 745 AM EDT Saturday... Radar showed coverage of light to moderate rain west of the Blue Ridge was gradually diminishing. The western side of the precipitation shield around Hurricane Matthew was becoming fixed from Lynchburg to Martinsville. The precipitation over the mountains will be exiting the region by 18Z. High confidence that the rain may not end at KDAN until after 00Z. Widespread MVFR to IFR ceilings will remain in place until the hurricane moves farther north and the cold front in the Ohio Valley crosses the Mid-Atlantic region tonight. Decent agreement in the models that ceilings would begin to lift after 18Z, generally from west to east with conditions improving to VFR after 00Z/8PM. Winds will increase in the afternoon and overnight in the foothills and piedmont of Virginia and North Carolina. Wind gusts up to 25 knots are possible at KDAN especially after 06Z/2AM. Extended aviation discussion... For Sunday through Wednesday, models are keeping the area mainly dry, although this is subject to change pending the track of Matthew. Most models have Matthew circling off the southeast coast through the middle of next week. For the latest storm track forecast see the latest NHC Advisory for Matthew. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AMS/KK SHORT TERM...MBS LONG TERM...DS/MBS AVIATION...AMS/JH
Area Forecast Discussion
National Weather Service Seattle WA
900 AM PDT Sat Oct 8 2016 .SYNOPSIS...A frontal system will be over Western Washington through tonight. The front will probably move south and hang up over the south part of the Cascades on Sunday. Dry weather will prevail Monday through Wednesday of next week. A Stormy pattern will return for the latter part of next week. && .SHORT TERM...A front over the area today could shift south by about daybreak Sunday. Models have trended faster shifting the rain to the south. See the hydrology section below for a discussion of the rain and the flood watch. The front should be south of the area by midday Sunday for a dry afternoon and Monday will be dry as a ridge of high pressure takes over for a few days. .LONG TERM...An upper ridge will be over the area Tuesday for dry and mostly sunny weather but somewhat chilly early morning temperatures. Clouds will probably begin to increase Wednesday as a front approaches. Wet and blustery weather will return Thursday and Friday as vigorous frontal system move onshore. Schneider && .AVIATION...A warm front will stall over Western Washington today for rain across the area. The flow aloft is westerly. The air mass is moist and stable with mainly IFR to MVFR ceilings across Western WA. The cold front will slowly shift S/SE through the area tonight with rain continuing. 33 KSEA...Light rain or drizzle this morning with MVFR cigs. May see slight improvement to the cigs this afternoon. South winds increasing by 18-20z with gusts to 15 kt. Rain continuing tonight with winds flipping back to northerly by 12z. 33 && .MARINE...A warm front will stall over the region today with south flow increasing over the waters. Small Craft Advisories are in effect. The cold front will slowly shift south through Western Washington tonight...with the flow turning W/NW behind the front. Northerly flow will continue on Monday with high pressure over interior B.C. Offshore flow will prevail on Tuesday with the next weak front arriving on Wednesday. A stronger Pacific storm system will arrive on Thursday. 33 && .HYDROLOGY...A front over the area will bring rain today. Rain will continue tonight but could end by daybreak Sunday for most of Western WA. The 12z NAM shows the heaviest rain today in the Olympics and North Cascades, then tonight in the Olympics and Central Cascades. After midnight tonight the rain ends for the Olympics but the Cascades get another dose--this is the 12z NAM solution only--and then all of Sunday the front is hung up over the South Cascades and it is dry over the rest of Western WA. I have not seen the GFS and UW mesoscale solutions yet, but the HRRR was especially fast in moving the rain south out of the area--it has the front hung up over the South Cascades before midnight tonight. A flood watch is currently in effect for the Skokomish river in Mason county and Stillaguamish River in Snohomish County for a chance of river flooding and we will see what the other models show as they come in today. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...Flood Watch Mason and Snohomish county. PZ...Small Craft Advisory until 9 PM PDT this evening for Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm. Small Craft Advisory until 5 PM PDT this afternoon for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm- Coastal Waters From Cape Flattery To James Island Out 10 Nm- Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Northern Inland Waters Including The San Juan Islands-Puget Sound and Hood Canal. Small Craft Advisory until 11 PM PDT this evening for Admiralty Inlet-Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 3 PM PDT this afternoon for West Entrance U.S. Waters Strait Of Juan De Fuca. && $$ www.weather.gov/seattle You can see an illustrated version of this discussion at www.weather.gov/seattle/gafd/latest_webafd.html
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Area Forecast Discussion
National Weather Service Tucson AZ
415 AM MST SAT OCT 8 2016 .SYNOPSIS...Expect scattered showers and thunderstorms this afternoon and evening. Some strong thunderstorms producing gusty winds and perhaps resulting in blowing dust may occur. A chance of showers and thunderstorms continues Sunday mainly near the New Mexico border. Dry conditions with above normal daytime temperatures will then prevail Monday through next Friday. && .DISCUSSION...Strong high pressure aloft was centered over south Texas early this morning, and a negative-tilted upper trough was moving northeastward across Baja California into Sonora Mexico. An ample supply of mid/upper level moisture prevailed across southeast AZ. However, a fairly dry near-surface environment was ongoing, with dewpoints mostly in the 40s at lower elevations as of 4 AM MST. 08/00Z Univ of AZ WRF-NAM and GFS and several HRRR solutions were similar with depicting the initiation of showers/tstms to occur later today, generally around noon or such. Given the ongoing easterly surface wind regime, appears a low-level convergence axis near the Tucson metro area extending southeastward into southern Cochise County, may eventually be the focusing mechanism for showers/tstms to develop by early this afternoon. Given the dry surface-700mb layer and expected associated DCAPE values of 1200-1400 J/kg, the potential exists for some stronger thunderstorms to produce locally strong wind gusts. Based on the various NWP data sets, opted to increase PoPs generally about 10 percent or so versus the inherited forecast for this afternoon. Thus, expect scattered to perhaps numerous showers/tstms this afternoon, with the best coverage from Tucson eastward to the New Mexico border. There should be enough moisture for a slight chance of showers/tstms this afternoon as far west as western Pima County. As 700-500 mb layer winds veer from sely early this morning to swly this afternoon, storm motions should favor a northeasterly component. As mentioned in the second paragraph, locally strong wind gusts should occur with the stronger tstms. Thus, have maintained patchy blowing dust late this afternoon and early this evening for locales from the northwest portion of the Tucson metro area wwd/nwwd into western Pima County and south-central Pinal County. One caveat worth mentioning: have noted that the 08/06Z Univ of AZ WRF-NAM as well as the 08/09Z HRRR were not quite as strong with the showers/tstms to occur later this afternoon versus several previous solutions. At any rate, am still inclined to favor the scenario already described in terms of spatial/temporal framework, and the potential of strong or possibly severe thunderstorms capable of producing damaging winds. Showers/tstms should dissipate fairly rapidly this evening with the loss of daytime heating, and the various hi-res models suggest that dry conditions may prevail area-wide late tonight into early Sunday morning. Have held to the notion of isolated-scattered showers/tstms Sunday afternoon mainly near the New Mexico border. Thereafter, dry conditions will prevail late Sunday night into next Friday. An amplifying ridge aloft thru mid-week should be displaced by a progressive shortwave trough moving across the area next Thur. 08/00Z GFS/ECWMF then depict the upper ridge to amplify next Friday as the shortwave trough moves east into the central CONUS. High temps today will be about 2-7 degs or so cooler versus Fri, then daytime temps Sun-Fri will remain about 5 degs or so above normal. && .AVIATION...Valid through 09/12Z. SCT -TSRA/-SHRA should develop around 19Z-20Z today, and especially in vicinity of KTUS. TSRA/SHRA will then expand in coverage while moving northeastward across much of southeast AZ into this evening. MVFR conditions due to restricted vsbys/cigs, and wind gusts of 35- 45 kts may also prevail. The bulk of -TSRA/-SHRA is expected to end by 09/06Z. Cloud decks into Sunday morning will generally be 6k-12k ft AGL. Surface wind outside of thunderstorm gusts thru the period ely/sely at 5-15 kts with gusts to 20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Expect scattered showers and thunderstorms this afternoon and evening. The best chance for wetting rain will occur from Tucson east to the New Mexico border. A chance of thunderstorms continues Sunday mainly near the New Mexico border, then dry conditions Monday through next Friday. 20-foot winds this morning and Sunday morning will be east and southeast at 10-15 mph with gusts to 20 mph. Otherwise, 20-foot winds will be terrain driven less than 15 mph. && .TWC Watches/Warnings/Advisories...None. && $$ DISCUSSION...Francis AVIATION/FIRE WEATHER...Lader Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Sunday Issued at 223 PM CDT Sat Oct 8 2016 The latest RAP analysis and satellite/radar imagery show cyclonic flow over the western Great Lakes, between high pressure centered over central Canada, and low pressure over James Bay. Weak shortwave in the northwest flow is sending a band of mid-clouds from North Dakota to western Wisconsin, and should move across central WI into east-central WI later this afternoon. Additional enhanced cu is passing over the Lake Superior region, just north of the U.P. border. As high pressure builds into area late tonight, cloud cover trends and temps are the main forecast concerns. Tonight...Weak shortwave energy will be passing across the region during the evening. Scattered to broken cloud cover resides upstream, but models do show this moisture thinning out during the evening hours, as the clouds move across central and east-central WI. Will increase sky cover through midnight as a result. High pressure will build into the area overnight, promoting good radiational cooling conditions with the clearing skies outside of Vilas county. Low temps should be falling into the upper 20s in the cold spots over N-C WI, and through the 30s elsewhere. With coordination from other offices, will issue frost/freeze headlines for areas north and west of the Fox Valley. Sunday...High pressure will be centered over the area. After a frosty start, should see plenty of sunshine, with scattered clouds over eastern WI developing with the heat of the day. Low level temps will be moderating a few degrees, which put highs into the mid and upper 50s. .LONG TERM...Sunday Night Through Saturday Issued at 223 PM CDT Sat Oct 8 2016 Temperatures will begin to recover Monday on the back side of a departing high pressure system with temperatures rising to 5 to 10 degrees above normal for this time of year. A mid level shortwave and 850 mb theta-e advection will bring the chance for showers to the area Monday night and Tuesday. Despite the forcing there will be a low layer of dry air, therefore rain chances will be fairly small during this period. A cold front with better dynamics and meaningful moisture will arrive Tuesday night and Wednesday, bringing a better chance for showers to the area. Much cooler temperatures are expected behind the front as temperatures fall to around 5 degrees below normal. High pressure will bring clearing skies and light winds to the western Great Lakes, bringing favorable conditions for another round of frost development across central and north-central Wisconsin Wednesday night and Thursday morning. Return flow on the backside of the high will bring a return to near normal temperatures on Friday, with temperatures a few degrees above normal on Saturday. && .AVIATION...for 18Z TAF Issuance Issued at 1209 PM CDT Sat Oct 8 2016 Though high pressure will be moving across the region during the TAF period, a weak upper level disturbance combined with some cumulus will lead to broken conditions at times this afternoon and evening. Cigs should remain vfr at most locations. Clearing is anticipated late tonight. Good flying weather will continue into Sunday, with only diurnal cu popping up over eastern WI. && .GRB WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 3 AM to 8 AM CDT Sunday FOR WIZ005-010>013- 018>021-030-031-035>037-045-073-074. && $$ SHORT TERM.....MPC LONG TERM......Kurimski AVIATION.......MPC
Area Forecast Discussion
National Weather Service Wilmington NC
655 PM EDT Sat Oct 8 2016 .SYNOPSIS... The center of Hurricane Matthew in the vicinity of Cape Fear this evening, will track east northeast, reaching the vicinity of Cape Lookout around midnight. Weakening Matthew will finally track offshore, away from the NC Mainland, Sunday thru early next week. Continued life threatening flash flooding and damaging winds and storm surge flooding north of Cape Fear are expected this evening. In the wake of Matthew, Strong, cool and dry Canadian high pressure will infiltrate the region for much of the upcoming work week, bringing the coolest air of this early Fall season. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... As of 3 PM Saturday...The entire forecast area remains under a flash flood warning with very impressive rainfall totals and numerous reports of flooding rolling in. Saturated ground and tropical storm force gusts have combined for a number of downed tree reports and numerous power outages. Watches and warnings continue as before. The latest NHC warning has Matthew as a category 1 storm, moving ENE from its present location near Myrtle Beach, SC to just south of Cape Fear this evening while weakening to a Tropical Storm. The latest HRRR guidance has center of Matthew about 30 NM directly south of Cape Fear at 6 PM this evening. Matthew has begun to lose its symmetry with an increase in wind shear, with water vapor imagery showing dry air beginning to wrap around the south side of the system. In addition, Matthew seems to be merging with the southern extent of an old frontal boundry. The southern half of the circulation will also continue to ingest rain-cooled air off of South Carolina, and this will continue to concentrate heavy rainfall more preferentially in the northwestern quadrant of the storm where the flow is onshore from the high heat content of the Gulf Stream. As the center of Matthew passes south of Cape Fear, rain-cooled air across interior North Carolina would get pulled south behind the storm. As lapse rates steepen in the lowest 1500-2000 feet of the atmosphere, winds of 60-70 mph may get transported down through this mixed layer to the surface. For many locations north of Myrtle Beach this may be the strongest winds we see from the entire event, and could pose quite a shock as the system will seem to be on its way out to sea by then. After a foot or more of rain, gusts this strong would almost certainly uproot trees causing further power outages and blocked roads. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... As of 3 PM Saturday...With Matthew pulling off to the east and the coolest airmass of this Fall season building in, we should have two days of crisp, breezy and dry weather with dewpoints plunging into the 40s. Temperatures will gradually decrease through the period as cooler air filters across the eastern Carolinas and expect highs on Monday to only reach the upper 60s, with low possibly dropping into the upper 40s well inland. The period may actually start out with a few showers dropping south across the area as Matthew moves off to the east, but expect dry weather to otherwise dominate the period. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 3 PM Saturday...Benign, dry and seasonal weather will persist through the Long Term as a cool NE flow persists with high pressure dominating eastern CONUS. A re-enforcing cold front arriving early on Friday will come through dry and may allow for a further cool-down to keep us at seasonal temperature levels. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 00Z...Hurricane Matthew is SE of KILM at TAF time. High confidence MVFR flight restrictions will improve to VFR and rain end from W-E this evening, with KILM the last to improve around midnight Z. Winds speeds will be strongest at the coastal terminals early this evening. In general wind speeds will decrease as from W-E as Matthew pulls away, but still remain 25-35 kt and gusty overnight. VFR Sunday with NW-N winds 20-25 kt and gusty through the day. EXTENDED OUTLOOK...VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 3 PM Saturday...Hurricane Warnings continue for all waters through the Near Term as Hurricane Matthew continues to move up the coast of the Carolinas and directly over our coastal waters. The latest NHC advisory has Matthew as a category 1 Hurricane. Matthew is forecast to make a turn to the ENE after approaching the Cape Fear this evening. The strongest winds of this event may actually happen this evening as north winds get pulled around the backside of Matthew. Latest obs show seas of 14 ft at the 41110 near-shore buoy, with 21 ft out at 41013. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 3 PM Saturday...Very dangerous boating conditions will continue through the short term as Matthew pulls off to the east of the waters. Although the official NHC forecast has Matthew as a tropical storm by 8 AM Sunday and becoming post-tropical shortly thereafter, the tight gradient between Matthew and a strong high pressure to the west will keep winds and seas elevated. Expect the period to start off with tropical storm-force winds in place, with conditions remaining unfavorable for marine interests through Monday night. LONG TERM /TUESDAY THROUGH WEDNESDAY/... As of 3 PM Saturday...Expect gradual improvement through the period with high pressure extending south from New England and the remnants of Matthew pushing further away from the waters as it gets absorbed by a frontal system. The period may start off rocky for boating interests and it is possible that an advisory may be in place at the beginning of the period. Seas will decrease to 3 to 5 ft later on Tuesday or on Wednesday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Hurricane Warning for SCZ053>056. Flash Flood Watch until 6 AM EDT Sunday for SCZ017-023-024-032- 033-039-053>056. Tropical Storm Warning for SCZ017-023-024-032-033-039. High Rip Current Risk until 6 AM EDT Sunday for SCZ054-056. NC...Hurricane Warning for NCZ105>110. Flash Flood Watch until 6 AM EDT Sunday for NCZ087-096-099- 105>110. Tropical Storm Warning for NCZ087-096-099. High Rip Current Risk until 6 AM EDT Sunday for NCZ106-108-110. MARINE...Hurricane Warning for AMZ250-252-254-256. && $$ SYNOPSIS...DCH NEAR TERM...REK SHORT TERM...REK LONG TERM...REK AVIATION...MRR
Area Forecast Discussion
National Weather Service Miami FL
451 PM EDT Sat Oct 8 2016 .SYNOPSIS... Drier air will continue to filter into Florida this evening, as Matthew pushes further up the North Carolina coastline. There will be a slight chance of showers over the southern tip of Florida through this evening, otherwise expect only a few passing high clouds. Conditions should stay dry into Monday with high temperatures decreasing slightly each day. A more moist northeasterly flow may return by mid next week, brining another chance for shower and storm activity. .DISCUSSION... Water vapor imagery this afternoon showed what is now a low end category 1 Hurricane Matthew traversing northeast up the North Carolina Coast. A frontal boundary, behind this tropical feature, could be seen filtering in dry air over northern and central Florida. A rather stable atmosphere was observed on the 12Z MFL morning sounding in the lower and mid levels. Latest runs of the short term models, such as the HRRR and WRF indicate that a couple of light showers may develop over the Southern tip of Florida through this evening, so maintained slight chances in the forecast package. Maximum temperatures across the region should top out in the lower 90s, a few degrees above the norm for this time of year. The 12Z GFS continues the southward push of the aforementioned front towards south Florida tonight. Mostly dry conditions are forecast for Sunday with PW values lowing to below 1.50". By Monday, cooler weather will be advected into the region along with lower dewpoints in the mid 60s, a short relief from the typical muggy conditions. Tuesday through Friday...NHC has squashed the possibly of Matthew revisiting South Florida. According to the latest forecast track, the storm becomes post tropical and diminishes out at sea. Long range models build high pressure over the northeast Gulf by mid week. This feature would act to develop northeast flow over South Florida and bring a return to the lower and mid level moisture. There will be a chance of showers and storms each afternoon over the entire region, then limit the activity back to the east coast at night. && .MARINE... Winds turn more northerly behind the front on Sunday into Monday, with seas building once again, particularly in the Gulfstream. Waves will slowly start to lower by Tuesday afternoon with a continuing gusty northeast wind. && .PREV DISCUSSION... /issued 147 PM EDT Sat Oct 8 2016/ AVIATION... Not much change in the forecast. A weak front is moving through South Florida. This will help to clear out the cloud cover, and turn the wind to the northwest tonight, and northeast in the morning. VFR conditions will prevail. TAFs show VRB for the wind tonight, as it becomes 5 kts or less, and may not have a steady direction, as it shifts. However, in the morning, it is forecast to pick up to 10 to 12 kts. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 74 88 73 83 / 0 0 10 20 Fort Lauderdale 75 88 75 84 / 0 10 10 20 Miami 76 89 75 85 / 0 10 20 20 Naples 74 91 68 85 / 0 0 10 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...Beach Hazards Statement until 10 PM EDT this evening for FLZ069. AM...None. GM...None. && $$ DISCUSSION...27/JT MARINE...27/JT AVIATION...SI
Area Forecast Discussion
National Weather Service Mount Holly NJ
406 PM EDT Sat Oct 8 2016 .SYNOPSIS... A cold front will slide through the region tonight. At the same time Tropical Cyclone Matthew will start to curve out to the ocean. High pressure will build towards the region through Tuesday before shifting northeast Wednesday. On Thursday, a weak cold front could approach the region. High pressure will then build over the region to start the weekend. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A cold frontal boundary will move eastward into the region tonight with moisture from tropical storm Matthew streaming northward ahead of the front. Drier air will be advecting southward into the region behind the front as well. The main challenge tonight will be the main northward extent of the rain shield from tropical storm Matthew. Modeling still differs quite a bit this afternoon with the ECMWF and RGEM the furthest north and west with the HRRR and RAP furthest southeast. Will continue to lean more in the direction of the modeling that is farther north and west given radar trends this afternoon. With this mind forecast expectations are still for rainfall totals from one to four inches in the southern Delmarva with totals of an inch or two along the SE Jersey coast. With the drier air advecting into the region a sharp cutoff will be present with the rain witch areas north and west of Philadelphia seeing little in rainfall outside of a few scattered showers this evening. The exact location of this divide is still uncertain and may be adjusted as the evening unfolds. Winds will also begin to increase from the north toward sunrise behind the front with cloudy skies. Temperatures will be slow to fall off tonight with lows in the 50`s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... The cold front will allow for an eastward propagation of the rain shied and slow clearing from west to east during the morning across the region. Northerly winds will still be increasing as well. GFS bufkit analysis shows the potential for some wind gusts around 40 mph, close to wind advisory criteria. However, the NAM and ECMWF indicate slightly weaker winds. Still some wind gusts Sunday afternoon may reach 30 mph. With the cool air advection, temperatures should be rather steady on Sunday, particularly in areas that see clouds and rain in the morning. Most locations may not see temperatures much higher than around 60. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... Sunday night...biggest concern through this period remains the potential for patchy frost in the Poconos and NW NJ. However, is is less certain now how quickly winds will drop off Sunday night. Some models have winds staying near or above 10 mph across this area. If this happens, frost is unlikely to develop even with a clear sky and temperatures dropping to the mid 30s. However, suspect that winds will decouple, if even for only a few hours, so have kept mention of patchy frost in the forecast. Monday...Most guidance trended lower with high temperatures during this day...with many showing highs 5 to 10 degrees below normal. Given the strong cold air advection, this seems reasonable. Monday night...With similar conditions to Sunday night, except lighter winds, the threat for patchy frost increases and is possible over portions of the Poconos, NW NJ, and the Lehigh Valley. Will also have to watch how efficient radiational cooling will be in the Pine Barrens: for now I have kept temps in this area in the upper 30s which is slightly lower than guidance, but would not be surprised if temps drop even lower than that. Tuesday through Wednesday...surface high builds close to the region, then slides northeast through the day on Wednesday. Weak southwesterly low level flow should allow for a modest warming trend through this period. Thursday...the exact timing is still uncertain, but it looks like a cold front should slide through the region through this time. Many models don`t show any precip with this front, but given how close the upper level trough will be to our region, think it is possible, so will mention a slight chance of precip through the day on Thursday. Friday and Saturday...For the second time of the week, a surface high is expected build in over the region in the wake of a cold front, leading to tranquil but slightly cooler than normal conditions. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Periods of rain will likely lower ceilings and visibilities throughout much of the night into the MVFR and even IFR category at times. Winds will be light tonight but increase from the north around sunrise to around 10 knots. On Sunday, improvement to VFR is likely during the morning from west to east, perhaps early afternoon for KACY and KMIV. Northerly winds increasing to between 15-20 knots with gusts around 25 knots. Some potential is present for even higher gusts from 30-35 knots but confidence is lower for gusts this strong. Outlook... Sunday night through Wednesday...VFR conditions expected. Thursday...Mostly VFR conditions expected. Small chance of MVFR conditions with showers. && .MARINE... Waveheights will increase this evening and be well above five feet during the day Sunday. Northerly winds will also increase behind a cold front. Indications are for a likelihood of some gale gusts on both the ocean waters and Delaware bay on Sunday. Gale warning now in effect. Outlook... Sunday night...winds will start to subside on the Delaware Bay, but should remain above 25 kt through the overnight hours. On the Coastal Waters, expect gale conditions to continue through much of the overnight before beginning to subside near sunrise. Monday...winds will slowly subside through the day below SCA criteria by the end of the day. However, seas are expected to stay above 5 feet through the day on the Coastal waters. Monday night through Wednesday...Seas should slowly subside through this period. Exactly when they will drop below 5 feet on the coastal waters is still uncertain. Some guidance has elevated seas lingering through the day on Wednesday. On the Delaware Bay, winds and seas should stay below SCA criteria. Thursday...winds and seas should stay below SCA criteria. && .HYDROLOGY... Periods of moderate to heavy rain are expected tonight across the southern Maryland and southern Delaware and continue into Sunday. FFG is fairly low, only around two inches in Sussex DE in six hours due to heavy rain that fell from 9/27-9/30 that totaled up to 14 inches. Modeled rainfall on average is expected to range from 1-4 inches in the flash flood watch area. Our QPF forecast continues to hedge the forecast in the direction of the model guidance that is further north and west with the higher QPF. Lighter rainfall of an inch or two is possibile over southeast New Jersey and the mention of poor drainage flooding is in the HWO for this location. It should be noted that an even heavier core of rainfall with more than 4 inches total is expected to track just southeast of the region. Any additional northwest bump could result in higher QPF. The opposite would be true as well if the system trends further south and east which would shift the rain/little rain cutoff closer to the coast. && .TIDES/COASTAL FLOODING... ETSS guidance shows both Lewes and Atlantic City getting close to minor tidal flooding with the Monday evening high tide. For now, I have not mentioned this in the HWO as it seems unlikely given an unfavorable wind direction and being in between the new and full moon. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...Flash Flood Watch through Sunday morning for DEZ002>004. MD...Flash Flood Watch through Sunday morning for MDZ015-019-020. MARINE...Gale Warning from 6 AM Sunday to 6 AM EDT Monday for ANZ450>455. Gale Warning from 6 AM to 6 PM EDT Sunday for ANZ430-431. && $$ Synopsis...Johnson Near Term...Gaines Short Term...Gaines Long Term...Johnson Aviation...Gaines/Johnson Marine...Gaines/Johnson Hydrology... Tides/Coastal Flooding...
Area Forecast Discussion
National Weather Service Pueblo CO
331 PM MDT Sat Oct 8 2016 .SHORT TERM...(This evening through Sunday) Issued at 330 PM MDT Sat Oct 8 2016 ...Upper Disturbance to move Across Forecast Area Sunday... An upper level disturbance, visible on satellite over Arizona and New Mexico today, will drift across the region through Sunday. This disturbance will bring a chance of showers and thunderstorms to most of the area on Sunday and particularly to areas along and south of Highway 50. Some of the latest HRRR runs are bringing the moisture farther north and more organized than previously. This could bring better chances for precipitation to southern Colorado on Sunday than once thought. However, the convection hasn`t looked overly impressive to the south of us today so not entirely certain of the storm`s overall potential. Latest HRRR runs have the best potential over the southeast plains Sunday. We will see. Primary threats will be lightning and wind gusts to around 40 mph. .LONG TERM...(Sunday night through Saturday) Issued at 330 PM MDT Sat Oct 8 2016 Main longer term meteorological issues continue to be generally low-grade to nil pops...locally gusty gradient winds at times and temperatures. Latest longer term forecast model soundings...computer simulations and PV analysis continue to indicate that basically zonal to southwesterly upper flow will continue over the forecast district into next Saturday with a couple of more upper systems(per PV analysis...etc.) to contend with during the longer term. At the surface it still appears that differing degrees of eastern Colorado lee-side troughing will be noted from Sunday evening into Tuesday morning with next northerly to easterly surface surges impacting primarily eastern sections of the forecast district from later Tuesday morning into Wednesday night. Then...similar to previous thinking...next round of eastern Colorado lee-side surface troughing develops again from later Thursday into next Saturday. At this time...the highest potential of precipiation(including the potential for some higher elevation light snow at times) is anticipated Sunday evening and then again from Tuesday into possibly Thursday...with the highest potential of gusty gradient winds at times expected from Tuesday into Thursday. Finally, above seasonal mid-October minimum and maximum temperatures are expected to continue over the forecast district from Sunday evening into Wednesday morning with near to below seasonal temperatures then anticipated from Wednesday into Thursday in advance of warming conditions again by next Friday and Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 330 PM MDT Sat Oct 8 2016 Upper high pressure will push north of the flight area tonight. As upper high drifts slowly north, moisture will increase from the south, resulting in a few evening thunderstorms, mainly over the mountains south of Highway 50. Increased thunderstorm activity, reaching farther north, is expected for tomorrow. Primary storm threats will be lightning and gusty winds. Generally VFR across flight area next 24 hours, although areas of MVFR, IFR and LIFR flight conditions may be encountered in areas of convective precipitation. Storm chances are too low to put in the KCOS, KPUB and KALS TAF sites over the next 24 hours. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$