NWS Forecast Discussion
For Fremont, NH
000 FXUS61 KGYX 080317 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1017 PM EST Thu Dec 7 2023 .SYNOPSIS... If you thought last night was cold, well tonight will feature temperatures as cold if not a couple degrees colder. However the cold will be short lived, as a warming trend will begin Friday and last through the weekend. Temperatures will climb into the 50s for many areas by Sunday, but rain will be close behind. A strong storm will bring a combination of a soaking rain and strong wind gusts to the area. It will be a quick moving storm with clearing expected late Monday. Gusty winds continue and colder temperatures return through midweek. && .NEAR TERM /TONIGHT/... 1017 PM Update... Deja vu all over again as stratus continues to bank against the Whites in blocked NW flow late this evening. Have taken the same logic as last night... with RAP low-level moisture depicting these clouds well, and suggesting these clouds hang around in convergent LL flow until the ridge moves overhead by mid-Friday-morning. This brought lows up a bit for the Connecticut River Valley vs the inherited, although the remainder of the area is cooling quickly with flow going calm under clear skies. 635 PM Update...Little to report at this hour. There is some stratus working yet again into the upper Connecticut River Valley this evening, so have incorporated this into the sky and temperature forecast. Overall models aren`t as persistent with overnight stratus toward the north as they were yesterday around this same time in the evening... so overnight lows are intact, with hourly trends incorporating more of last night`s hourly observations. Previously... High pressure remains firmly planted over the region which will help to crash temperatures down once again under clear skies. Up north low temperatures will fall below zero. The foothills and interior will single digits and low teens. Across the south, locations will see mid to upper teens. Clouds may spill over into western New Hampshire tonight, but with a dry airmass overhead there won`t be any worry for precipitation. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... Short wave ridging tomorrow will make for another dry day with light winds. High temperatures will be able to warm into the upper 20s and low 30s in the north and mountains, and mid 30s to near 40 across the south. Ridging moves off to the east and a trough begins to approach the region which will increase cloudiness from west to east as the evening goes on. This will keep temperatures much warmer than we have seen in recent nights. Expect temperatures in the mid to upper teens to the north and 20s to the north. With a dry airmass still overhead and no forcing, there shouldn`t be any concern for precipitation during this period either. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Overview: Brief ridge slips east of the area Sat and will be followed by a deep trof that gradually flattens but remains in place thru the end of the week. Temps remain below normal...and while precip may average above normal over the next week it is mostly expected to fall Sun night into Mon. Impacts: Storm system Sun into Mon will bring a combination of strong winds and heavy rains. The extent of either remains uncertain. At this time a period of strong wind gusts is likely at the coast Mon morning...potentially greater than 60 mph north of PWM. Poor drainage and overland flooding is possible across all of the forecast area...with snow melt determining whether river flooding occurs. See Hydrology section for more details. Forecast Details: S/WV ridge axis moves east of the forecast area Sat allowing deep southwesterly flow will set up over the Eastern Seaboard. This will advect seasonally significant PWAT values into northern New England. At this time the system appears progressive enough to limit QPF to between generally 0.50 to 1.50 inches. I do not see the storm speeding up any from current forecasts...so the trend to monitor will be if it slows down at all or pivots and allows residence time of convective fine line to linger over any areas. The Hydrology section below covers the threats posed by rainfall in more detail. The southerly LLJ will also increase with time into Mon morning and bring a period of strong wind gusts to at least coastal areas. The inland push of milder air and low level lapse rates will be something higher resolution model guidance will start to glimpse over the next 12 to 24 hrs...but at this time forecast wind speeds at 925 mb suggest coastal areas are in line for at least a wind advisory. The LLJ peaks mostly north of Casco Bay...and so the Midcoast zones are more at risk of seeing gusts come closer to high wind criteria. There is far more uncertainty southwest along the coast...where LLJ orientation is more southerly than southeasterly. This may limit the peak gusts and inland extent of winds...especially across the Seacoast. Much of this will also depend on storm track...where overnight guidance was more easterly and kept strongest winds out to sea...07.12z guidance came back west and maintained the wind threat. For now I kept the forecast close to the median NBM forecast...consistent other ensemble guidance on wind speeds/gusts. Beyond the early week storm...CAA continues for much of the week. This will keep winds gusty and colder than normal temps in place. Precip chances will revolve around individual S/WV trofs and upslope flow. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... Short Term...VFR conditions will prevail through Friday. Ceilings thicken as our next system approaches Friday night. Long Term...VFR conditions expected for the majority of the area to star the period Sat. Clouds will thicken and lower thru Sun with widespread IFR or lower conditions in low CIGs and RA thru Mon morning. A period of LLWS is also likely for coastal terminals at least Mon morning. Winds shift to westerly Mon afternoon and will remain gusty into midweek. Clearing is expected quickly Mon south of the mtns...but MVFR CIGs may linger around LEB and HIE in upslope flow. && .MARINE... Short Term...High pressure settling over the waters will keep winds and waves below SCA thresholds. Freezing spray is possible tonight through early tomorrow morning. Long Term...Southerly winds will steadily increase ahead of the next storm system. Storm force gusts will be possible for all waters Sun night into Mon morning. I have used the highest of wave guidance to get seas building to near 15 ft by Mon morning...which may end up being higher if storm force winds are realized. Winds shift to westerly behind the storm and will remain gusts at least SCA thresholds thru the middle of the week. && .HYDROLOGY... A soaking rain is expected to move into the region Sunday and increase in coverage and intensity Sunday night into Monday. The moisture feed into the region pushes PWATs into the climatological max territory (~1.2"), which is 3 standard deviations above normal. Strong SW winds feeding the system will support high rainfall rates, more comparable to the warm season. Heavy rain could result in urban flood concerns and rapid rises on small streams, some of which have recently grown ice. The big ? will be the snowmelt factor, which is too uncertain to ascertain this far out. Coastal areas will likely see a melt out, with notable loss in the coastal plains to the foothills. System will need to be watched closely for potential river flooding. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ UPDATE...Casey NEAR/SHORT TERM...Baron LONG TERM...Legro AVIATION...Baron/Legro MARINE...Baron/Legro HYDROLOGY...Jamison