Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/19

Area Forecast Discussion
National Weather Service Hastings NE
629 PM CDT Sat Oct 5 2019 .SHORT TERM...(This evening through Sunday night) Issued at 310 PM CDT Sat Oct 5 2019 Aloft: RAP dynamic tropopause analyses and WV imagery showed a fairly potent shrtwv trof over the GtPlns. Low-amplitude WNW flow was over the Wrn USA with another shrtwv trof over the Pac NW. The flow over NEB/KS will become W tonight and then WSW after 12Z/Sun as the Pac NW trof crosses the Nrn Rckys and approaches the rgn. This trof will then move thru tomorrow...shifting winds to NW after 18Z. Surface: 1002 mb low pres was over MN. The cool front that moved thru early this AM extended S from the low thru IA-MO to the TX Panhandle. High pres over the Pac NW was nosing into NEB/KS. This high will strengthen to 1034 mb tonight...with a piece of this high breaking off and emerging onto the Cntrl Plns tomorrow. Rest of this afternoon: Sunny and breezy. NW winds 15-25 with occasional G35. Winds will be gradually diminishing. Peak gusts include 51 mph at ODX...50 mph near Sherman Reservoir. LSR`s have been sent. Tonight: Mostly clear in the eve...but becoming mostly cldy after midnight as clds increase ahead of the incoming trof. Frost N and W of the Tri-Cities was removed from the fcst. Clds should keep temps from dropping into the mid 30s and temp-dwpt spread will be 6-9F. Sun: Cldy in the AM. Gradually dcrsg clds from the N after midday. N-cntrl KS will remain mostly cldy thru the day. There could be some very light rain or sprinkles W of Hwy 281 in the afternoon. Highs 61-65F. Sun night: Clear and cold. Almost ideal radiating conds. Went with MOS for lows. May need a Frost Advisory for much of the CWA if I`m reading the situation right. Freeze Warning psbl Valley/Greeley counties. Lows 31-40F. .LONG TERM...(Monday through Saturday) Issued at 310 PM CDT Sat Oct 5 2019 Aloft: The last 3 runs of global mdls (GFS-FV3/EC/UKMET/CMC) are tightly clustered thru next Thu...but spread dvlps Thu night into Fri with the last 3 GFS-FV3 runs on the fcst side of the guidance envelope. A shrtwv trof will strengthen over AK tonight in response to upstream amplification related to a storm moving up the E coast of Russia. This trof will dig/deepen over Wrn Can Mon. It will then sink into the Pac NW Tue with a sig trof dvlpg over the Wrn USA Wed...from MT-Srn CA. This trof will cross NEB/KS Thu with an upr low possibly forming. NW flow in its wake Fri-Sat with dcrsg amplitude as the low or trof moves into the GtLks. Over NEB/KS...low- amplitude WNW flow Mon will become WSW Tue...and then SW Wed until the trof moves thru. Surface: Srn Plns high pres will head into the Ern USA/Can Mon- Tue with breezy return flow/WAA Mon-Wed AM as downslope-warmed air overtakes the rgn. An unseasonably cold air mass will plunge into the NW USA. A strong cold front will cross NEB/KS Wed followed by cold high pres Fri-Sat. Temps: Near normal Mon. A little warmer than normal Tue. Near normal Wed. Then much cooler than normal Thu-Sat with a warming trend. The coldest day will be Thu with much of the CWA not getting out of the 40s! Our fcst high temps for Thu and Fri may not be cold enough because of the climo bias from MOS input into the fcst blend. The consensus of mdl 2m temps suggests our fcst could bust 5-10F too warm for highs both days. Plan on colder than what the fcst currently states. The 00Z EC ensemble mean and 12Z GEFS mean bring the -3C 850 mb isotherm all the way down into N-cntrl KS by 12Z/Fri. The 06Z GEFS brings the -6 isotherm down to I-80. That is 2 SD below normal! Thu will be windy and cold! Fri AM and Sat AM we are looking at widespread sub-frzg lows... espcly Fri AM with widespread mid-upr 20s over most of the CWA. That would end the growing season. Suggest everyone with gardens quickly harvest anything left. Rain/Snow: Sct shwrs/tstms Wed night ahead of the front. Uncertainty really increases. We need to see how the upr trof evolves and if a low dvlps. Rain could then move in from the NW with rain changing to snow...probably N and W of the Tri-Cities. Can`t rule out a little snow elsewhere...but the greatest chance (and it may not be all the great) of accumulating snow will be N and W of the Tri-Cities. The best chance for accumulating snow will be over the Panhandle and Sandhills...N and W of the CWA. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday) Issued at 617 PM CDT Sat Oct 5 2019 Anticipating VFR conditions through the forecast period. Winds should decrease this evening and be variable overnight as surface high pressure builds into the area. High clouds will also push in overnight ahead of a shortwave trough, and these will hang around until early afternoon. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Ewald
National Weather Service Wilmington OH
1001 PM EDT Sat Oct 5 2019 .SYNOPSIS... A cold front will continue to approach from the region from the west tonight, reaching the area Sunday into Sunday night. Another high will build in behind this front and persist through mid week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Mid to high clouds have reached the northwest corner of the fa. They will continue to advance overnight ahead of an approaching cold front. The scattered showers over Indiana will work into western locations late. Southeastern parts of the fa with be affected by an increasing low level after midnight, which will provide enough lift for scattered showers and the chance of some thunder. Lows tonight will range from the upper 50s to the mid 60s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/... Initial s/wv will be out running the frontal boundary Sunday morning. Induced pcpn in the southeast will move east while a chance of showers will continue along the front boundary. By the time the front moves into our eastern/southeast zones during the afternoon, there may be enough diurnal heating and convergence for the likelihood of showers, perhaps a rumble of thunder, there. It will likely temporarily dry out in the northwest behind the front during the afternoon. Highs will range from near 70 northwest to the mid/upper 70s southeast. Another embedded s/wv, mid level energy, is still expected to dig east into the region Sunday night. Our area, particularly the southern/eastern locations, will come under the RR quad of an upper level jet which will provide upper level divergence. Meanwhile, this will help induce a low level jet/convergence which will bring low level forcing/ascent near and over the frontal boundary as it slowly moves southeast. There continues to be a fairly tight gradient in terms of decent rainfall amounts, mainly focused along and southeast of I-71. This is where categorical PoPs will be used with chances decreasing as one moves towards west central Ohio. There could be a rumble of thunder early on across the southeast. Lows will range from the upper 40s northwest to the lower/mid 50s elsewhere. On Monday, as the mid level s/wv moves east across the region, upper level energy and low level forcing will rotate east as well. There will be a decrease in pcpn during the day from west to west with all locations expected to be dry by Monday evening. Clouds will hold on in the east, while skies should become partly cloudy in the west by afternoon. Thus, highs will range from near 60 in the east to near 65 in the west. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... The long term time frame will be quiet through most of the week as a large surface high pressure begins to build into the CWA from the lower Ohio Valley behind the departing frontal system. The high will slide northeast to the Canadian Maritimes by the end of the week. The next impacting system approaches the region from the west Friday into Saturday. Monday night begins with surface high pressure centered near Illinois. Model consensus shows the high shifting quickly toward New England through the day on Tuesday and continuing toward the northeast into mid week, with surface flow swinging around from the northeast to the east on Tuesday, then to the southeast by late Wednesday. While temperatures begin the period below normal on Tuesday, the quick return flow brings them back to above normal levels starting on Wednesday into Thursday. Around this time, an upper level low will be digging southeast from the northern Rockies, then ejecting eastward into the northern Plains and upper Midwest by late Friday. Model solutions show wide differences with this system at 00Z on Saturday, as the GFS has a 519 dm H5 low placed just north of the arrowhead of MN, while the Euro has a 541 dm H5 low 400 miles to the southwest near Sioux Falls, SD. This leads to large differences in frontal placement and sensible weather, with the GFS quickly pushing a cold front through the CWA on Friday morning, with the Euro fropa almost 24 hours later. Used a blend, went with chance PoPs from late Thursday into Saturday. Despite timing differences, models show a sharp cutoff of moisture and clouds behind the front in westerly low level flow. Have this pushing into the CWA later on Saturday to close out the extended period. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Surface high pressure will continue to exit to the east tonight. Conditions will be VFR through 12Z, but high and mid clouds will be on the increase after 06Z. Models are producing some light QPF ahead of the advancing cdfnt in an area of low level convergence and shearing H5 disturbance. Scattered showers are forecast into the western zones shortly after 12Z. Kept them VCSH due to the scattered nature. This line of scattered showers will work through the tafs during the morning hours, pushing southeast of I-71 around 18Z. This will bring dry conditions to the TAFS for the afternoon hours. There are some indications that the low levels could become saturated around the eastern tafs during the afternoon. This could bring some MVFR ceilings. Confidence is not high enough to add them at this time. After 00Z Monday, a second surge of moisture is forecast to lift across the tafs. Added some light prevailing showers to the CVG taf to indicated this. OUTLOOK...MVFR ceilings and visibilities are possible on Sunday night into Monday && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hickman NEAR TERM...Sites SHORT TERM...Hickman LONG TERM...Hogue AVIATION...Sites
Area Forecast Discussion
National Weather Service Lincoln IL
703 PM CDT Sat Oct 5 2019 .SYNOPSIS... Issued at 241 PM CDT Sat Oct 5 2019 A cold front shifting across central and southeast Illinois, will bring scattered showers and isolated thunderstorms, into tonight. The front will stall near the Ohio River on Sunday, keeping unsettled weather south of I-70, into Sunday night. && .UPDATE... Issued at 703 PM CDT Sat Oct 5 2019 Updated the forecast to lower PoPs significantly as the band of showers/thunder that passed through the area late this afternoon is now quickly exiting into Indiana. Behind the band, 00z/7pm radar imagery is showing dry conditions across the remainder of central Illinois. With a cold front still poised to the west across Iowa/Missouri, cannot rule out an isolated shower through the evening...similar to the latest HRRR depiction. Think showers will become a bit more numerous along/ahead of the front after midnight, primarily along and east of the I-57 corridor. Have therefore gone with isolated evening showers across much of the CWA, with scattered shower wording through the night across the E/SE. Once the front passes, skies will clear from west to east overnight. Lows will range from the upper 40s west of the Illinois River where skies will clear the upper 50s south of I-70 where clouds/showers will persist through the entire night. && .SHORT TERM...(This evening through Sunday) ISSUED AT 241 PM CDT Sat Oct 5 2019 A band of showers and thunderstorms has steadily been marching east today and is now entering the far western CWA. This is occurring in a pre- frontal trof and area of focused 925-850mb moisture advection. Models are consistent in weakening moisture advection as the zone of lift shifts east this evening, causing an overall diminishing trend in shower/storm coverage. As a result we have likely pops across the west late this afternoon, lowering to chance pops for shower/isolated thunder this evening central/east. After the initial zone of lift diminishes, an isolated shower is possible until the occluded front sweeps west to east later this evening. Models point to a good clearing trend behind the front, which is currently noted in visible satellite imagery across eastern NEB into SW IA. Upper 40s lows expected west of the IL River due to clear skies, while clouds lingering SE of I-70 to keep mins in the mid/upper 50s. While drier air working in behind the front brings a nice Sunday the central/northern CWA, rain chances linger into Sunday evening south of I-70. This, as the front stalls south of the Ohio River, and to several weak mid level impulses lift northeast. So a few periods of showers and isolated storms possible in the far south which would be beneficial rain. With neutral air advection behind the front, seasonable temps to end the weekend. .LONG TERM...(Monday through Saturday) ISSUED AT 241 PM CDT Sat Oct 5 2019 Monday through excellent stretch of fall weather is on tap. Upper heights rise while flow quickly transitions from northwest Monday to southwest Wednesday. This while surface high pressure dominates for dry conditions. We expected temperatures to warm a couple degrees each day, which would put readings several degrees above normal Wed/Thu. On Thursday a deep longwave trof emerging from the Rockies into the Plains, increases moisture advection ahead of the next strong cold front. So shower and thunderstorm chances return to the forecast, and continue into Friday. Still plenty of model spread on timing the strong cold front, which will end the precip threat. However there is better consensus that an unseasonably cold fall airmass will move into the Midwest behind the front. Temperatures have trended lower for Friday into Saturday. Plenty of details to work out with respect to clearing and winds, but widespread lows in the mid to upper 30s now look likely Saturday morning. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 657 PM CDT Sat Oct 5 2019 Band of showers/thunder has passed well east of the terminals early this evening, with dry conditions noted across much of central Illinois. Since cold front is still well to the west across Iowa/Missouri, cannot rule out a stray shower before it passes. Have therefore included VCSH at all TAF sites. Main aviation concern is a band of MVFR ceilings currently noted west of the Illinois River. Based on HRRR RH progs and satellite timing tools, have lowered ceilings to MVFR at KPIA by 01z...then further east to KCMI by 05z. Once the cold front passes, the low clouds will quickly depart and skies will clear from west to east overnight. Winds will initially be S/SE this evening, then will veer to the W/NW at KPIA by 04z...and further east at KCMI by 06z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SYNOPSIS...25 SHORT TERM...25 LONG TERM...25 AVIATION...Barnes
National Weather Service Jackson KY
1050 PM EDT Sat Oct 5 2019 .UPDATE... Issued at 1050 PM EDT SAT OCT 5 2019 The isolated showers and storms have decreased over the last hour; however, the showers that moved over the Jackson Weather Office were enough for the ASOS to measure 0.02 inches of rain. This halts the streak for days without measureable precipitation for the Jackson Julian Carroll Airport at 37 days. There are more showers and storms upstream in Tennessee that are moving northeast into south-central Kentucky. Have updated PoPs to reflect this trend. Isolated showers may continue through the morning, but the main bulk is expected to occur with frontal passage tomorrow afternoon. Also, ingested the latest observations and blended into the overnight hours. Current temperatures range from the lower 60s to mid 70s across eastern Kentucky. Ran a new ZFP to remove evening wording. Updates have been sent to the web and to NDFD. UPDATE Issued at 818 PM EDT SAT OCT 5 2019 A few isolated showers and thunderstorms have developed along an inverted trough in southeastern Kentucky this evening. The HRRR shows this activity decreasing through 2Z, so have followed this thinking with adjustments in PoPs. Did introduce thunder into the grids during this time as well; therefore, did update the HWO to reflect this. No other major changes were needed beyond ingesting and blending the latest observations. Current temperatures are generally in the lower to upper 70s across eastern Kentucky. As a cold front approaches the Commonwealth and with it, increasing cloud cover and rain chances, not expecting overnight lows to drop as low as they did last night. At this time, valleys in the upper 50s and ridges in the lower 60s seems reasonable. Sent a new ZFP to account for the changes in PoPs. Updates have been sent to NDFD and to the web. && .SHORT TERM...(This evening through Sunday night) Issued at 518 PM EDT SAT OCT 5 2019 Models remain in good agreement for the short term period. To that end the HRRR has even trended back the late afternoon and early evening shower activity across our area, with activity showing up later in the evening and/or during the overnight period. Two features of interest appear in the short term. Weak, almost sheared out short wave energy that will pass through the Ohio Valley tonight and then a long wave trough that will push through the Midwest Sunday into Monday. Satellite and forecast soundings show a decent surge of mid-level moisture aloft overnight tonight. With moisture returning to the area, short wave energy passing through the region should be enough to generate some shower activity late tonight during the pre-dawn hours of Sunday. MOS PoP are categorical across the board for tonight. CAMs also have activity developing overnight. The NBM advertises likely PoPs for late tonight as well. At this point seemed a bit hard to ignore and decided to trend upwards with PoPs. This suggests that there will be a round of shower activity leading up to dawn Sunday and just after. There appears to be a relative lull in activity thereafter until later in the day Sunday as the storm system to our west moves into the Ohio Valley. Best chance for rain still appears to fall within the Sunday night into Monday time frame. PWATS continue to edge upward suggesting that there is a better chance for a well needed soaking rain for our area. The speed of the front through our forecast area continues to look relatively slow but steady, entering eastern Kentucky by late afternoon or early evening Sunday and exiting our area by early afternoon Monday. This will help with rainfall totals in the sense that we need the rain. Widespread totals continue to range between one and two inches. Higher amounts appear to be centered over the northwestern parts of our forecast area while the far southeast may only see around an inch. Thunder still looks possible Sunday afternoon into the early evening. Instability is elevated but appears more robust now. There was also a hint of instability late tonight. However decided to leave thunder out for now as this is only a recent trend. .LONG TERM...(Monday through Saturday) Issued at 412 PM EDT SAT OCT 5 2019 A cold front will slowly be moving through the far SE portion of the state and exiting to our SE during the day Monday. Finally, we will see much needed rain along the frontal boundary throughout the day, quickly cutting off behind the frontal boundary as winds become more northerly and advect drier air into the region. That being said, lingering moisture and upslope flow will continue slight chances across the high terrain into Monday night, before a developing shortwave will continue them again for the same location during the day Tuesday. Precip chances will finally exit the entire CWA by Tuesday night, with broad high pressure taking hold from the Deep South through the Great Lakes and New England. JKL`s location on the SE side of this low will continue to invoke cooler and drier air for the CWA. Then as the high continues to shift NE, we will eventually transition to return flow by Wednesday night into Thursday. A small upper level ridge also moving in for Wednesday and Thursday will help to enhance temperatures theses days. Highs Monday and Tuesday will be in the upper 60s to low 70s behind the front. By Wednesday and Thursday temperatures will modify to the mid and upper 70s. Heights will begin lowering again Thursday night. When the NBM was run, the GFS and ECMWF were in very good agreement about the development of a strong upper level low developing across the central/north-central conus, then quickly progressing eastward. A surface center of low pressure will also be in place, pulling a cold front eastward into the state Thursday night and eastern KY during the day Friday. Based on the agreement, the NBM pops seemed quite low, so the initial idea was to increase them. However, soon after, the new ECMWF run came in, and showed a considerable displacement of the surface low to the SW of the previous run, and resultantly, a major slow down to the frontal passage across the state. While it does still have the passage and precip occurring, it is some 24 to 30 hours later than the GFS. Based on this, did not stray away from what the NBM had for pops as solutions will likely continue to change and therefore confidence remains low until they come back into a better agreement for several runs. The good news is that 1. ether way, it looks like there is at least agreement on another round of much needed rain moving through the CWA. and 2. there is no instability showing up along this front according to the GFS, so did not see any need to include thunder in the forecast. Once this front moves through, the tail end of the forecast period will see another blast of cold air. If the GFS is correct on it`s timing, Saturday morning could see some valley temps dropping into the upper 30s. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) ISSUED AT 822 PM EDT SAT OCT 5 2019 VFR conditions will generally be the story through the period. At this time, a few isolated showers and thunderstorms have developed in southeastern Kentucky, but this is expected to be short-lived. Did include TSRA for LOZ for an hour or so since a storm is progressing northeastward over London currently. Did not mention thunder for the other TAF sites, but will continue to monitor this over the next few hours. Another concern for the overnight will be the development of a low level jet over the central portion of our area, particularly over the JKL site towards dawn. Expecting any LLWS concerns to cease by 14Z, however. As the cold front progresses towards eastern Kentucky tomorrow morning, showers will be on the increase. Some heavier showers are likely in the morning, with a decrease in intensity into the early afternoon. However, as the front passes over eastern Kentucky by late afternoon, showers are expected to intensify. There will even be the potential for some thunderstorms. Although, with this being at the end of the forecast period, have mentioned at least -SHRA for now. Some reductions in VIS are also possible during this time. South/southwest winds will generally be between 5 and 10 knots through the TAF period, outside of any thunderstorms. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CGAL SHORT TERM...RAY LONG TERM...JMW AVIATION...CGAL
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
946 PM CDT Sat Oct 5 2019 .UPDATE... Issued at 936 PM CDT Sat Oct 5 2019 The cold front extends through northeast and central MO into northeast OK at 02z. Within the last hour there has been an explosion of showers between St Louis and Columbia with lesser coverage extending towards central IL. This development appears to be in response to weak forcing associated with a short wave trof now centered through western MO and largely lift/moisture convergence associated with the west-southwesterly LLJ. The precipitation is expected to continue expanding into east central MO and southwest Illinois the remainder of this evening into the overnight hours and then shift slowly southward with the movement of the cold front. While the precipitation has been void of thunder thus far, an axis of MUCAPE between 500-1000 j/kg coincident with the lift should eventually result in scattered thunderstorms as well. The last NAMNEST and several HRRR runs show this evolution. Also late tonight across southeast MO and southern IL there will eventually be a tendency to start seeing an anafront precipitation distribution with a shift in showers behind the front. Glass && .SHORT TERM... (Through Late Sunday Night) Issued at 333 PM CDT Sat Oct 5 2019 Large scale ascent associated with a shortwave trough was occurring near an approaching cold front. This combination will support periods of scattered to numerous rain showers and isolated to scattered thunderstorms across parts of the area through Sunday night. The most likely area for rain will tend to shift southeastward with time in tandem with the cold front. By Sunday morning, the cold front and trough will be oriented such that H85 moisture convergence and right entrance region jet dynamics will lead to increasing precipitation chances across the southern part of the LSX CWA even while precipitation chances continue to decrease across the northern CWA. Precipitation chances will end on Sunday night after the trough axis has passed and the front has moved farther south. Overnight lows tonight will range from near normal across the northwestern half of the LSX CWA (mid/upper 40s) to 5-10 degrees above normal across the southeastern half (upper 50s to near 60). The coolest temperatures are expected farther back within the post-frontal air mass and within expected areas of clearing overnight while the warmest temperatures are expected for those locations which will remain within areas of clouds and precipitation. Temperatures will remain near or slightly below normal across the area for Sunday and Sunday night due to the influence of N/NW winds around the eastern side of a high pressure center. Kanofsky .LONG TERM... (Monday through Next Saturday) Issued at 333 PM CDT Sat Oct 5 2019 The aforementioned high pressure center will shift eastward into the central CONUS and Great Lakes, bringing quiet weather and keeping temperatures near to slightly below normal across most of the area. The high pressure center then moves towards the NE CONUS by the middle of the week, and the resulting flow between this feature and a developing low pressure system over the central CONUS will bring a warmer air mass back into the region. Model guidance is in agreement that this flow of warmer air will act to sharpen a baroclinic zone which then eventually moves through MO/IL as a strong cold front, but there are significant timing differences between the models regarding the speed of the parent cyclone and the cold front. These differences lead to low certainty in the temperature and precipitation forecast for next Thu through Sat. This forecast package reflects a middle-of-the-road approach with a frontal passage on Thu/Thu night, but an earlier or later timing is certainly possible given that this feature has not yet developed and is still 5-7+ days away from affecting our area. Kanofsky && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 621 PM CDT Sat Oct 5 2019 The two main issues tonight are precipitation chances and lower ceilings. As far as precipitation, there is going to be a chance of showers and a spot storm across eastern MO into southwest IL this evening into the overnight hours, first ahead of a cold front and then immediately behind it. Now while there is a chance, I have low confidence in the coverage which may be only isolated to scattered. Thus in the St. Louis area terminals (including KSTL) I just have a VCSH. There is a band of stratus resulting in MVFR flight conditions ahead of the advancing cold front and this will impact KCOU and KUIN this evening with clearing near 03z. The stratus will move into the St. Louis terminals (including KSTL) around 04z and bring a 4 hour or so window of MVFR flight conditions. After the stratus clears the terminals, VFR flight conditions should persist through the remainder of the forecast period. Glass && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
1005 PM EDT Sat Oct 5 2019 .DISCUSSION... A frontal boundary continues to push southward from near JAX extending offshore into the Atlc but is expected to stall over or near Volusia county overnight then wash out on Sunday. Isolated showers will continue to push onshore overnight with higher coverage of showers pushing W/SW from the Atlc toward Volusia county assocd with the frontal boundary. There has been a flare up of convection along the front well offshore St Augustine in an area of enhanced UVV producing occasional lightning strikes. HRRR shows this convection weakening as it approaches Volusia county overnight but an increase in E/NE flow along the Volusia coast should enhance coastal convergence so will maintain highest PoPs (40 percent) for coastal Volusia. The best chance for lightning will be over the Atlc waters overnight but will keep thunder mention for Volusia and NE Brevard. Low temps will be very mild along the coast due to persistent onshore flow in the mid to upper 70s with lower 70s interior. && .AVIATION... Mainly VFR through 00Z. Isold SHRA will push onshore overnight with scattered coverage around DAB. Will handle with VCSH for now but may need to add a TEMPO group for DAB with the possibility of TSRA. && .MARINE... The most significant changes were to start the Small Craft Advisory for offshore Volusia a little earlier at 11 pm and add a Caution headline for the nearshore waters of Volusia and Brevard as well as offshore Treasure coast waters. Frontal boundary is forecast to stall over the Volusia waters later tonight with an increase in shower coverage along with isolated storms. Tonight-Sunday (previous)...East-northeast breeze will increase to 15-20 knots overnight as a weak front approaches the area. Seas of 4- 5 feet this evening will increase up to 7 feet overnight in the offshore waters north of Cape Canaveral. A Small Craft Advisory will be in effect starting late tonight for the offshore waters, then extending into the offshore Treasure Coast waters by Sunday afternoon as seas of 7-8 feet build in. && .PRELIMINARY POINT TEMPS/POPS... DAB 75 84 75 85 / 40 40 40 50 MCO 73 87 73 86 / 10 40 20 60 MLB 77 87 77 86 / 20 40 40 60 VRB 75 86 75 86 / 20 40 40 60 LEE 73 87 73 88 / 10 30 10 50 SFB 73 86 73 86 / 20 40 20 60 ORL 73 87 74 86 / 20 40 20 60 FPR 75 86 74 88 / 20 40 40 60 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...Small Craft Advisory from 10 AM Sunday to 4 PM EDT Monday for Sebastian Inlet to Jupiter Inlet 20-60 nm. Small Craft Advisory from 4 AM Sunday to 4 PM EDT Monday for Volusia-Brevard County Line to Sebastian Inlet 20-60 nm. Small Craft Advisory from 11 PM Saturday to 4 PM EDT Monday for Flagler Beach to Volusia-Brevard County Line 20-60 nm. && $$ Kelly/Combs
Area Forecast Discussion
National Weather Service Marquette MI
748 PM EDT Sat Oct 5 2019 .SHORT TERM...(This evening through Sunday) Issued at 458 PM EDT SAT OCT 5 2019 Water vapor imagery and RAP analysis show a vigorous shortwave lifting across the eastern Dakotas into nw MN. Strong 850-700mb moisture transport and theta-e adv has supported a band of shra spreading e into Upper MI today, though shra have tended to diminish as they outran better dynamics hanging back to the w. Clouds/pcpn/lack of much insolation has kept winds in check today despite 40-50kt low-level jet beginning to shift over the fcst area. Gusts have been into the 20-30mph over land. Over Lake Superior, gusts at the high obs platforms are up into the lower gale range except over far western Lake Superior. Even the n central and eastern buoys are gusting to near gales. Vigorous shortwave will lift across Upper MI/Lake Superior/northern Ontario tonight. As associated occluded front swings across the fcst area and mid-level dry slot arrives, expect shra/dz to end from w to e during the evening and into the early part of the overnight. With cyclonic flow and the edge of deeper moisture brushing the nw fcst area, there could be a few -shra thru the night across nw Upper MI, but it really looks like the overnight will end up dry. Otherwise, main concern will shift to wind for Lake Superior and the Keweenaw. Biggest negative aspect for enhancing winds continues to be lack of meaningful caa to mix low-level winds more efficiently. 850mb temps are only fcst to drop 4 or 5C overnight with a trend to neutral or weak weak waa during Sun morning. Another negative is that the low- level winds are more of a wsw direction rather than the more favorable wnw direction. However, favorable isallobaric wind component (though pres rise/fall couplet is not especially notable at roughly +3/+4 mb/3hr and -4/-5 mb/3hr) and potentially upwards of 40-45kt in the mixed layer suggest conditions across the Keweenaw will be flirting with wind advy (sustained winds of 30mph or more and/or frequent gusts 45mph or greater). Although fcst soundings depict mixed signals on degree of mixing in the low-levels and thus how strong sfc wind gusts may become, seems that a wind advy is probably warranted for northern Houghton and Keweenaw counties overnight into Sun morning. With daytime heating on Sun deepening the mixed layer and with brisk winds of 30-40kt in the low-levels, it will be a breezy day across the fcst area. Gusts to 25-35mph should be the rule, except 30-40mph on the Keweenaw. There may be a decent amount of sunshine during the morning, especially in areas where w to sw winds are downsloping. During the aftn, daytime heating, cold air aloft, mid-level trof over the area, and an approaching shortwave late in the day will likely lead to isold/sct shra development. Over the last 24hrs, models have trended toward more of a signal for shra development. Seems reasonable given the factors mentioned. Some models show maybe a couple of hundred j/kg of MLCAPE. If that materializes, not out of the question that there could be a few rumbles of thunder. High temps will be near to a little above normal in the mid 50s to lower 60s. .LONG TERM...(Sunday night through Saturday) Issued at 350 PM EDT SAT OCT 5 2019 The main forecast concerns for next week are lingering gusty winds over the Keweenaw Peninsula and lingering showers, especially over the north half of Upper Michigan Sunday night into Monday. Attention then turns to a late-season warm up next week ahead of an open wave expected to lift north across the Upper Great Lakes, undergo cyclogenesis and then occlude as it stalls out late in the week/early next weekend. Ahead of the developing surface low, strong warm air advection does look to boost day-time temperatures into the 50s and 60s, with mild overnight lows for this time of year. Thursday night into next weekend is a time period to keep a close eye on as the above mentioned system impacts the region. Still quite a bit of uncertainty that far out, but the system does look like it could be a wind bag and depending on the track of the system, as previously mentioned, we could see the first snowflakes of the season. Certainly, the potent system expected to impact the region late next week/next weekend is something to keep a close eye on. Sunday night into Monday morning - A shortwave digging south across the region will bring with it a brief shot of weak cold air advection. The combination of a lingering strong pressure gradient, pressure rises, and incoming weak cold air advection will allow for gust winds to linger over the west half of Upper Michigan, and near the Great Lakes. The windiest location looks to remain the Keweenaw Peninsula, where wind gusts of 30 to 35 mph will remain possible. As for precipitation, the combination of synoptic lift and colder air moving in from the northwest will bring scattered rain showers. While cold air advection isn`t incredibly strong, there does look to be a subtle, weak lake enhancement signal. Instability doesn`t look impressive, but given the lingering gusty west to northwest winds rain showers should push inland quite a bit across then north half of Upper Michigan. Monday through Thursday - As the main shortwave pulls off to the northeast early next week, surface high pressure center down in the southern/central Plains will build northward into the Great Lakes, essentially shutting down any lingering precipitation on Monday. As the surface ridge continues to move eastward, over the Northeast, we will remain anchored between high pressure to the east, and an elongated open wave/surface trough to our west. This will place us under continued bouts of warm air advection and an enhanced pressure gradient. Therefore, Tuesday through Thursday, expect a late-season warm up accompanied by daily breezy southerly winds. Given the pressure gradient in play, could also see the breezy winds linger during the overnight hours next week as well. Thursday night into next weekend - As longwave troughing exits the northern Rockies and lifts across the Upper Mississippi Valley, the open wave to our west will undergo cyclogenesis, as low pressure looks to quickly develop and deepen as it slowly lifts northeast towards the Minnesota/Lake Superior border. While it is a bit early to discuss specific impacts, as mentioned above there is the potential for this system to generate some strong, gusty winds. Initially even though warm air advection will dominate and try to keep things more on the stable/less mixy side, given the strength of the pressure gradient and the deepening low certainly think we could be looking at a period of gusty southeast to south winds on Thursday/Thursday night. There is quite a bit of uncertainty among the deterministic models as to when the stronger cold air advection will wrap around the system as it occludes; therefore, depending on when we start to see the colder air aloft move in winds will switch around to the southwest and would have additional support for stronger gusts. As for precipitation during this time period, as the low deepens it will bring with it one last surge of warm air advection, deeper moisture and the next best chance for rain. Did back off on the better chances for rain until late Thursday/Friday morning, but as we get closer to the event depending on the speed/track of the system this timing could change further. There are very subtle hints within MUCAPE fields that some limited instability may develop, but for now opted to leave thunder out of the forecast. As mentioned above there is uncertainty in regards to when the system will occlude and start to send that surge of colder air across the area. Based on a few forecast soundings, it isn`t out of the question that we could see some wrap around snow try to work into far western parts of Upper Michigan. Don`t expect any lake component at this point given the predominately southwest flow regime we will remain under into early parts of the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 743 PM EDT SAT OCT 5 2019 Ahead of an approaching occluded front, MVFR conditions with ocnl light shra will likely prevail into the evening hrs at KIWD and KCMX. However, under upsloping southerly winds at KSAW, IFR cigs may prevail there this evening. Low-level jet will be translating across the area thru early evening, but it appears there will be sufficient mixing in the lower 2kft to preclude LLWS in the fcst. With the passage of occluded front tonight, expect improvement from w to e with all terminals becoming VFR by sunrise Sun. Upsloping westerly wind will hold in MVFR cigs longest at KCMX. Passage of front will also bring strong/gusty winds to KCMX under favorable w wind direction. Gusts to 35-40kt are expected at that terminal, but there could be a couple of hrs of higher gusts immediately after fropa. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 458 PM EDT SAT OCT 5 2019 On Lake Superior, winds have been ramping up today, especially across the central and eastern part of the lake where gusts have reached the lower gale range this aftn. As deepening low pres currently over nw MN lifts ne to southern Hudson Bay by Sun evening, associated front will sweep across Lake Superior tonight. Ahead of the front, the s to se winds over central and eastern Lake Superior will continue to increase this evening with gusts reaching up to 40kt. Behind the front, winds will switch to the sw to w and ramp up over western Lake Superior. Gusts to 40-45kt still appear likely over the w half of the lake, but especially btwn nw Upper MI and Isle Royale. Around the w and n side of the Keweenaw, wind gusts may just reach storm force at times btwn 06z-12z Sun. Across eastern Lake Superior, the w to sw winds behind the front will not be as strong as over the w, gusting to 35-40kt. Winds may be a little slower to subside blo gale force Sun aftn/evening, so gale warnings may need to be extended across central and eastern Lake Superior into Sun evening. Winds will diminish more notably overnight Sun night thru Mon as sfc high pres ridge approaches. Winds should be mostly under 15kt by Mon evening. S winds will then increase on Tue with gusts reaching up to 25kt in the aftn. Winds will change little for Wed. The next low pres system will approach on Thu, leading to the potential for stronger winds late Thu into Fri. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Wind Advisory from 2 AM to 11 AM EDT Sunday for MIZ001-003. Lakeshore Flood Advisory from 4 AM to 5 PM EDT Sunday for MIZ001- 003. Lake Superior... Gale Warning until 1 PM EDT Sunday for LSZ248-267. Gale Warning until 9 PM EDT Sunday for LSZ264-266. Gale Warning until 2 PM EDT Sunday for LSZ246-247-265. Gale Warning until 10 AM EDT Sunday for LSZ249>251. Gale Warning until 3 PM EDT Sunday for LSZ245. Gale Warning until 11 PM EDT Sunday for LSZ244. Gale Warning from 1 AM EDT /midnight CDT/ to 1 PM EDT /noon CDT/ Sunday for LSZ241. Gale Warning from midnight EDT /11 PM CDT/ tonight to 6 AM EDT /5 AM CDT/ Sunday for LSZ240. Gale Warning from 1 AM to 11 PM EDT Sunday for LSZ242-243. Gale Warning from midnight EDT /11 PM CDT/ tonight to noon EDT /11 AM CDT/ Sunday for LSZ162. Gale Warning from midnight tonight to 6 PM EDT Sunday for LSZ263. Lake Michigan... Gale Warning until 3 AM EDT Sunday for LMZ248-250. Gale Warning until 1 AM EDT Sunday for LMZ221. && $$ SHORT TERM...Rolfson LONG TERM...Ritzman AVIATION...Voss MARINE...Rolfson