Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/18/17

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
533 PM MDT Sun Sep 17 2017 .AVIATION... 00Z TAF CYCLE Current round of showers and storms will persist into the evening hours before diminishing. Terminals most likely to be impacted by storms are KLVS, KSAF and KTCC and generally in that order. Strong/erratic wind gusts to near 40kts will be the most likely impact, with low probability of MVFR conditions. MVFR cigs may develop at KTCC overnight, but forecast confidence too low to include in TAF. Otherwise, storms will trend down significantly Monday afternoon, with gusty southwest winds forecast. 11 && .PREV DISCUSSION...347 PM MDT Sun Sep 17 2017... .SYNOPSIS... A weak cold front has backed into northeastern New Mexico, and has led to scattered storms developing over the eastern plains of the state. Some of the storms have turned strong to severe, and are expected to continue into the early evening. Most storms are expected to diminish by midnight with some low clouds redeveloping over northeastern New Mexico through Monday morning. Less moisture and instability will be available for storms on Monday, limiting storms with just a few stray cells possible in the southeastern third of the state. Thereafter, a drying trend is expected Tuesday and Wednesday with temperatures running near normal in western and central parts of New Mexico and readings climbing slightly above average in the eastern sections of the state. Precipitation chances will then begin increasing Wednesday night into the remainder of the week as a deep trough of low pressure closes in on the Land of Enchantment. && .DISCUSSION... Active weather is in progress over New Mexico with a relative weak long wave trough over the western U.S. and a couple of smaller scale embedded short waves lifting east northeastward into AZ and the Four Corners. This is providing large scale ascent that has assisted shower/storm development since this morning. In addition, the cold front invaded the northeastern quadrant of NM, providing a boost in moisture and consequently fueling the area with steeper temperature lapse rates, higher CAPE, and more significant bulk shear in the form of veering wind profiles. Storms have exploited these parameters with a crop of few severe cells. Hail and gusty downburst winds will be the primary threat through the early evening. The HRRR model, which has seemed to outperform other synoptic models with convection lately, carries the best axis of instability eastward in quick fashion and takes storms into TX/OK before sunset. This seems reasonable, but the HRRR redevelops additional storms over northeastern NM through the late evening, likely forced by short wave energy aloft rolling off of the Sangre de Cristos. This will need to be monitored through the evening hours, but scattered coverage has been left in the POP forecast through midnight. Into Monday, the flow aloft becomes a bit less perturbed and weakens some while retaining a westerly component. Moisture will decrease some, as will temperature lapse rates/instability. This should limit storm coverage significantly, however given the recent poor performance with synoptic modeling of convection in NM, have opted to leave some isolated storms in roughly the southeastern third of the state. Temperatures will run near to slightly above average. The drying trend persists into Tuesday and through the daytime Wednesday with PWATs falling back too low to support storm development. Temperature lapse rates will also lessen through this stretch, inhibiting storms. Surface temperatures should remain near to slightly above average on Tuesday, but should fall back a few degrees into Wednesday. Unsettled weather will then unfold Wednesday night into the remainder of the week as a deep long wave trough carves itself over the western U.S. drawing moisture into the NM plains from the south southeast and generating dynamics into some central to western portions of the state. 52 && .FIRE WEATHER... ...Critical fire weather conditions possible Tuesday... Scattered storms have fired off over the central and northern mtns and are quickly moving to the NE. The backdoor front slid down the eastern plains reaching as far as Clovis and the east slopes of the central mtn chain. Increased instability behind the front, CAPE values 2000-2700 J/kg with 0-6km shear up to 40-50 kts has prompted a slight risk of severe storms over the eastern plains through the evening hours. Storms will be capable of producing gusts up to 60kts and large hail. Garden variety isold to scattered storms will be present west of the ctrl mtns, still capable of producing gusty erratic winds up to 40kts. Monday could see lingering moisture across the E with some morning low clouds and fog possible over the NE plains. Drier westerly flow will continue to mix down over the west, and begin to erode moisture across the east later in the afternoon. MinRH`s over the NW plateau will fall to the teens, however winds will be the limiting factor for any critical fire weather. Tuesday will see the dryness expand further east with stronger winds as an upper trough moves over the northern Rockies. Several hours of critical fire weather are likely across the west and eastern plains, the majority of zone 104 and much of zones 105 and 108. The one limiting factor at the moment is remaining decent soil moisture still being observed on the NASA SPoRT imagery. With today`s expected additional rainfall across the east, soil moisture should be even further improved. MixHgts will be a bit lower across the NE where Haines 5 and fair ventrates will also exist. Another weak backdoor bdry is still forecast to pass into far NE New Mexico Wednesday, keeping MixHgts lower, with Haines 5, and pockets of bad to fair Ventrates. With the pressure gradient lessening as the aforementioned trough moves away, winds will be lighter, with only a small improvement in MinRHs as MaxT`s fall closer to normal. Southerly return flow will improve moisture across the east and central areas Thursday as another strong trough moves into the Pacific NW. This will help improve sfc moisture helping to spark afternoon scattered convection Thursday and into the weekend with storm coverage being limited more to eastern NM by the weekend. SW breezy winds pick up ahead of the trough Thursday and Friday. 24 && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$ 52
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1153 PM EDT Sun Sep 17 2017 .AVIATION... Another round of showers and isolated thunderstorms is expected along the cold front moving very slowly through SE Michigan during the night. This activity will be mainly south and east of FNT down through the DTW corridor and could last through mid morning as the front stalls while low pressure ripples along it. Evening observations over northern Michigan also show mounting coverage of IFR/MVFR stratus behind the northerly wind shift. This part of the boundary will bring the best chance of stratus spreading southward over the region. A clearing trend will then develop during late morning through afternoon as high pressure builds into the northern Great Lakes into Monday evening. For DTW... Timing and coverage of additional showers and isolated thunderstorms, mainly in the FNT to PTK area, will be such that short term updates will be the best approach for forecast refinement at DTW. VFR will then hold until borderline VFR/MVFR develops during the morning associated with the cold front and northerly wind shift. Clouds then diminish mid to late afternoon. //DTW THRESHOLD PROBABILITIES... * Medium for ceiling 5000 ft or less toward sunrise through mid afternoon. * Low for thunderstorms during the morning. && .PREV DISCUSSION... Issued at 938 PM EDT Sun Sep 17 2017 UPDATE... Clusters of showers and thunderstorms lingering along the primary cold front are holding on near reservoirs of weak surface based instability near Saginaw Bay and south of the Indiana border. Expect the weakening trend to continue through midnight while the next upper wave approaches. The wave can be seen in satellite imagery moving in from northern Illinois at press time and which is expected to produce a surface reflection along the cold front during the night. Backing mid level flow and a slight uptick in low level jet forcing will combine with some lift due to frontogenesis and DCVA to produce another round of showers and isolated thunderstorms toward sunrise. The latest model guidance supports scattered coverage - chance POPs generally along and east of a line from Port Austin to Howell through about mid Monday morning. Without the boost from daytime heating, any new thunderstorms will be on the ordinary side of the spectrum which will limit hazards to a brief heavy downpour. PREV DISCUSSION... Issued at 301 PM EDT Sun Sep 17 2017 DISCUSSION... Warm mid September day across southeast Michigan, as temperatures have pushed into the mid 80s. The 12z DTX sounding showed a significant warm layer around 650 MB, which may be too much to overcome to generate much in the way of showers and thunderstorms this evening, especially with surface dew pts mostly in the lower 60s. 18Z SPC analysis does show SBCAPES of 1000-1500 J/KG over western Lower Michigan, but quickly tapering off as one heads east. The front is attempting to generate activity at the present time, but mainly over northern Lower Michigan, closer to upper level support, and approaching northern Indiana where better instability resides. Planning on continuing with scattered/chance pops. On the flip side, there does look to be an upper level PV filament streaking out of northern Missouri, which tracks through the State tonight, which could be enough to support an uptick in activity despite the loss of surface/daytime heating, as a repositioning/ modest increase in the low level jet occurs overhead. 17z HRRR also suggesting an increase in activity late tonight. Regardless, main moisture axis exiting southeast Michigan around 12z, leading to a dry day on Monday as 850-700 mb Theta-E min/surface ridging become established, with PW values dropping under 1 inch. Another surge of moisture to arrive late Monday night/Tuesday Morning, as upper level energy comes out of the Four Corners region this afternoon, and an upper wave/trough seen tracking along or close to the southern Michigan border on Tuesday, per 12z Canadian/NAM. Still, looks to be getting just marginally unstable north of the Michigan border, with surface ridging holding on, suggesting just low chance pops warranted at the moment. A good deal of clouds and light early flow in low levels expected to hold maxes in the 70s both Monday and Tuesday. Main story in the extended timeframe is the expansive ridging over the eastern CONUS bringing a continuation to the above normal temperatures into next weekend. A large trough will be situated over western portions of the CONUS where it will stay through the forecast period. As ridging and surface high pressure remain over the Great Lakes region, southerly winds will bring temperatures into the 80s for all of this week. MARINE... A series of fronts are forecast to cross through the Great Lakes region this evening and through the overnight period. The first front will be the focus for some scattered showers and thunderstorms during the afternoon and evening time frame for the open waters of Lake Huron. Post frontal winds will be shifting to a more westerly direction around 5-15 kts. The secondary front will come during the overnight hours in a more northerly direction and remain around 15 kts. The long fetch of northerly winds overnight could lead to some higher waves along the shoreline of the Thumb on Monday morning. At this moment conditions should remain under criteria for a small craft advisory. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....BT UPDATE.......BT DISCUSSION...SF/SP MARINE.......AA You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Grand Forks ND
925 PM CDT Sun Sep 17 2017 .UPDATE... Issued at 924 PM CDT Sun Sep 17 2017 Increased cloud cover a bit with advancing mid/high clouds otherwise forecast ok. UPDATE Issued at 626 PM CDT Sun Sep 17 2017 No changes necessary. && .SHORT TERM...(This evening through Monday) Issued at 240 PM CDT Sun Sep 17 2017 Shower chances in the southern CWA late tonight/early tomorrow will be the main forecast issue for the period. The upper low over southern Canada continues to move slowly off to the northeast. Clouds have been slowly clearing out with some lingering stratocu over northwestern MN and the Devils Lake Basin. The clearing trend should continue into this evening as the low pressure system pulls further away from the area and diurnal cu dissipates. Temps should fall off quickly after sunset this evening, but then slow down as a surface trough developing to our west shifts winds back to the south and clouds come in with the next shortwave trough. Most spots should stay in the 40s although a few locations in the far northeastern counties with latest onset of clouds and south winds could drop into the upper 30s. The shortwave currently over WY will move into the upper midwest late tonight and tomorrow. At this point, it seems that the track of the system will keep the best precip chances to the south and east of us. However, the RAP continues to drop some precip in our southern counties as that shortwave comes through. Model soundings have most of the moisture around 700 mb or above, so not super impressed with precip chances but will keep a slight shower mention going. The shortwave will move quickly off to the east Monday and skies should start to clear out, during the morning in the ND counties but not until afternoon further east. With the south fetch to the winds and at least some sunshine tomorrow, highs will be near the 70 mark across the west but slightly cooler in the eastern counties. .LONG TERM...(Monday night through Sunday) Issued at 240 PM CDT Sun Sep 17 2017 A mild and breezy Monday evening is expected with overnight lows in the low 50s and southeasterly winds under mostly clear skies. A cold front is anticipated to move through central and eastern North Dakota Tuesday afternoon and into Tuesday evening, reaching northwestern Minnesota overnight Tuesday. Thunderstorms are expected with the passage of this cold front including the chance for severe thunderstorms Tuesday afternoon and early Tuesday evening. However, questions remain about the northward extent of CAPE and favorable shear supportive of severe storms. Wednesday and Thursday should both be quiet days with partly cloudy skies, high temperatures in the upper 60s on Wednesday and mid 70s on Thursday. Rain chances will return to the forecast late Thursday night into the day on Friday. Friday highs should reach the low 70s with Saturday seeing highs in the mid to upper 60s across the region. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 626 PM CDT Sun Sep 17 2017 VFR through the period. Will see an increase in mid level clouds later tonight with some light showers or sprinkles over the far south however likely to remain south of FAR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Voelker SHORT TERM...JR LONG TERM...AM AVIATION...Voelker
Area Forecast Discussion
National Weather Service Northern Indiana
729 PM EDT Sun Sep 17 2017 .SYNOPSIS... Issued at 350 PM EDT Sun Sep 17 2017 There is a chance of showers and a few thunderstorms tonight as a cold front slowly approaches the area. Chances of rain will diminish late tonight into Monday morning as this frontal boundary stalls across central Indiana. An upper level disturbance will approach the Great Lakes and Ohio Valley Monday night into Tuesday providing another chance of showers and isolated thunderstorms. Low temperatures tonight will range from the upper 50s northwest to the lower to mid 60s southeast. High temperatures on Monday will range from the mid and upper 70s across the north, to the lower 80s south. && .SHORT TERM...(This Evening through Monday) Issued at 350 PM EDT Sun Sep 17 2017 Chances of showers and storms tonight and Monday will continue to be the primary short term forecast concern. Isolated showers have developed this afternoon in association with pre-frontal trough type feature from west central Indiana into northeast Indiana. Greater coverage of scattered showers and isolated thunderstorms also noted over past hour or two across northeast Illinois, roughly from Lansing to east of Bloomington in proximity of advancing cool front. Expecting these two general areas to continue to be focus for additional showers and thunderstorms this afternoon with greatest coverage expected to focus across western portions of the forecast area with approach of better pooled moisture axis/cold front. Surface based instability in the 1000-1500 J/kg should be sufficient for at least isolated thunder through the evening hours. Effective shear values will remain generally below 20 knots through the evening supporting more of a pulsey nature to any stronger cores capable of producing brief heavier rain showers and perhaps some wind gusts to 30 mph across the west through early evening. Did maintain slight chance of showers across the far northwest for a time behind the front late this evening/early overnight with some indications over earlier HRRR runs this afternoon of some development associated with approach of low level trough/weak convergence axis. A lull in precip chances is expected to develop late tonight into Monday morning as frontal boundary drops just south of the area and stalls out. Current indications suggest a south to north moisture gradient should set up in association with this stalling frontal boundary. Difficult to discern a clear forcing mechanism for precip chances with low level boundary, and will maintain just low chance PoPs through the day, focused mainly across southern portions of the area. Highs will be cooler on Monday ranging from the upper 70s north to the lower 80s south. && .LONG TERM...(Monday Night through Sunday) Issued at 350 PM EDT Sun Sep 17 2017 It still appears though the best chance of showers/storms this period will be Monday night into Tuesday as isentropic lift/WAA ramp up in vicinity of stalled boundary as next upper level short wave approaches from the Rockies. Local area will remain at nose of modest low level jet through Wednesday, but mid level height rises in wake of Tuesday system lends to much lower confidence in precip chances Tuesday and beyond. Guidance remains in general agreement of significant amplification of eastern CONUS ridge and continued much above normal temperatures for the Thursday through next weekend period. While cannot completely discount weak perturbations in southwest flow tracking across the western Great Lakes for late this period, tried to maintain a mainly dry forecast for much of the Days 5-7 period given ridge amplification and considerable uncertainty in short wave track. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 725 PM EDT Sun Sep 17 2017 Scattered line of showers with a few tsra now mainly east of KSBN and approaching KFWA. A few shra still possible at KSBN this evening but chances of a restriction are small. KFWA still has a chance of a VCTS for a few hours but even these chances are low given recent radar trends. Outflow boundary pushing east and still some chances for development so left vcts at KFWA for a few hours. Some fog potential tonight but will depend on clouds and amount of clearing. Stayed with MVFR for now at KFWA given uncertainty. Light winds at KSBN could certainly support some development there with clearing as well but will hold off introduction of any restrictions given cloud cover concerns. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...Marsili SHORT TERM...Marsili LONG TERM...Marsili AVIATION...Lashley Visit us at Follow us on Facebook...Twitter...and YouTube at:
East Central Florida Forecast Discussion
National Weather Service Melbourne FL
900 PM EDT Sun Sep 17 2017 .DISCUSSION... ...Large swells from Jose will produce dangerous boating and beach conditions early this week... Ltst soundings along with the Air Force 915 MHZ profiler network indicate the mid afternoon surge of Nly winds ascd with a passing sfc trough around 20 kt. Sub BL flow will show decoupling now through the next few hours, as has already occurred at the somewhat inland location of DAB airport. Beachfront sites should register winds of 10 to 15 mph overnight. PWAT near 1.30 inches indicate effects of mid level drying. from prev disc... Winds above the surface will increase and veer to NNE/NE tonight bringing low-topped ISOLD-SCT shower activity across the coastal waters and possibly along the immediate east coast late. Ltst HRRR guid onboard with current satellite/radar indicated showers brushing the coast during the early Monday hours. Lows will drop into the L70s for the interior and M70s along the coast. A high risk for rip currents and high surf will keep a presence at east central Florida beaches overnight with beach erosion possible near the next high tide from 6-8 AM. Monday...Lower than normal rain chances continue as drier air mass remains over central Florida. Low-level moisture will moderate somewhat as winds veer to a more north-northeasterly onshore component. Believe MOS PoPs are still too high especially for the Treasure Coast area. Carrying only slight chance of showers mainly for coastal areas for any onshore moving showers from the Atlantic. Highs in the upper 80s to around 90 and lows in the low to mid 70s. && .AVIATION...Mostly VFR. Northerly wind component, occasionally gusty along the coast through early Monday will become lighter and back to the northwest. Isold SHRA`s moving onshore from the ATLC may affect cstl terminals aft 06Z tonight through Mon morning. && .MARINE...Seas became fully arisen early today and continue in the 8-10 ft range over the open waters away from the immediate coast with seas 6-8 ft near shore. Northerly winds of 15-20 kts over the open Atlc will slowly decrease to around 15 kts overnight. An advisory for seas remains in effect for all marine legs due to the overall hazardous conditions. Expect an increase in marine shower activity through the night with showers approaching the east coast after midnight. && .HYDROLOGY...River levels along the Saint Johns are forecast to continue a slow rise or remain stationary near Cocoa, Geneva, Sanford, Deland and Astor early this week as runoff into the basin moves slowly downstream. River levels in minor to moderate flood stage are occurring at these locations. The Saint Johns River above Lake Harney near Geneva is forecast to remain in major flood stage into Monday. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...High Surf Advisory until 10 AM EDT Monday for Coastal Volusia County-Indian River-Martin-Northern Brevard County-Southern Brevard County-St. Lucie. AM...Small Craft Advisory for hazardous seas until 11 PM EDT Monday for Flagler Beach to Volusia-Brevard County Line 0-20 nm- Sebastian Inlet to Jupiter Inlet 0-20 nm-Volusia-Brevard County Line to Sebastian Inlet 0-20 nm. Small Craft Advisory for hazardous seas until 11 AM EDT Tuesday for Flagler Beach to Volusia-Brevard County Line 20-60 nm- Sebastian Inlet to Jupiter Inlet 20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60 nm. && $$ JP