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NWS Technical Forecast Discussion |
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Observed at |
Temperature |
20.8°F |
Hour Change |
-0.1°F |
Humidity |
55% |
Hour Change |
-4% |
Dewpoint |
7.2°F |
Hour Change |
-1.6°F |
Wind |
6 mph from 292° (WNW) |
Wind Gust |
13 mph |
Barometer |
29.708 inHg |
3 Hour Trend |
0.016 inHg |
Today's Rain |
0.00 in |
Rain Rate |
0.00 in/hr |
Rain Last Hour |
0.00 in |
Monthly Rain |
0.22 in |
Yearly Rain |
3.51 in |
Apparent Temp |
11.5°F |
Wind Chill |
12.9°F |
Heat Index |
20.8°F |
Est. Cumulus Base |
3266 feet |
Today's Highs / Lows | |
Temperature |
High: 42℉, Low: 21℉ |
High Temperature |
23.2°F at 12:00 AM |
High Humidity |
62% at 03:43 AM |
High Dewpoint |
10.1°F at 03:43 AM |
High Barometer |
29.708 inHg at 05:45 AM |
High Wind Gust |
28 mph from 284° at 12:05 AM |
High Rain Rate |
0.00 in/hr at 12:00 AM |
Low Wind Chill |
5.3°F at 04:37 AM |
High Heat Index |
23.2°F at 12:00 AM |
Yesterday's Statistics | |
High Temperature |
38.1°F at 12:00 AM |
High Humidity |
82% at 06:35 AM |
High Dewpoint |
27.4°F at 12:00 AM |
High Barometer |
29.763 inHg at 12:04 AM |
High Wind Gust |
24 mph from 318° at 01:39 PM |
Rain |
0.00 in |
High Rain Rate |
0.00 in/hr at 12:00 AM |
Low Wind Chill |
9.0°F at 11:21 PM |
High Heat Index |
38.1°F at 12:00 AM |
000 FXUS61 KBOX 050743 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 243 AM EST Fri Mar 5 2021 .SYNOPSIS... Dry weather persists through the middle of next week. Colder than normal air remains in control through the weekend. The pattern then moderates to warmer than normal conditions for the middle of next week. && .NEAR TERM /TODAY THROUGH 6 PM/... Low pressure sitting over Labrador and Eastern Quebec feeds cold air advection into Southern New England today on gusty northwest winds. Surface pressure gradient will be sufficient to maintain sustained winds of 10-15 kt, while winds aloft in the mixed layer will be 20 to 25 kt...these would be available for gusts. Speaking of the mixed layer, the ECMWF shows the layer reaching 925- mb, while the GFS suggests 900-mb. ECMWF temps at 925-mb are forecast at minus 9C to minus 11C, while the GFS at 900-mb has minus 11C to minus 13C. Converting these temperatures to a standard level suggests max sfc temps of 26F to 35F. If mixing gets closer to 850- mb in a few spots, the max temps in those places could reach 36F to 38F. Cold pool moisture from the upper low will linger during the day, and generate areas of clouds, especially north of the Mass Pike. The surface air will remain rather dry with dew points in the single numbers. && .SHORT TERM /6 PM TONIGHT THROUGH 6 PM SATURDAY/... Low pressure lingers over Eastern Canada into Saturday, maintaining a surface pressure gradient over Srn New England although diminished from the levels of today. There will also be lingering clouds from the cold pool aloft. But with continued dry air at the surface, expect dry weather through Saturday. The wind may keep the air stirred tonight and prevent radiational cooling. With dew points in the single numbers, there should be room for temperatures to drop into the teens. Temps aloft will show similar values to today. Therefore will forecast similar max temps for Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Highlights * The weekend will be dry and cold. Below average temperatures expected through Sunday. More seasonable temperatures on Monday. * Little to no chance of precipitation over the forecast period. * Warm-up on the way starting next Tuesday and extending late into the work week. 50s and even 60s are not out of the question for Wednesday. Saturday night and Sunday... With an upper level low still in place over Nova Scotia and the Canadian Maritimes, several shortwaves will bring a series of cold shots to New England this weekend. These cold spells are not expected to be accompanied by any significant precipitation, but will keep temperatures 5 to 10 degrees colder than average. The upper level low is in sync with a deep trough that extends the 540mb isobar well into the Carolinas Saturday and Sunday. Gusty, northwest flow associated with this trough will keep wind chills in the 10s and 20s, especially Saturday, before the winds relent a bit on Sunday. High temperatures on both Saturday and Sunday are expected to range from the 20s north and west of our metropolitan areas to the mid 30s south and east, extending across the Cape and Islands. Guidance has come into agreement that this cold shot will extend through the weekend before relinquishing its grip early next week. On Saturday night, conditions are ripe for radiational cooling with weakening winds, clear skies, and a remaining snowpack north and west of the I-95 corridor. To account for this low temperatures on Saturday night were lowered using CONSMOS guidance. The deep southern extension of the trough will keep us dry through the weekend. Monday thru Wednesday... On Monday, the ridge that has been so dominant over the western US begins to nudge into our area. Temperatures begin to level out around average, in the upper 30s and low 40s, before the primary wind direction switches from west/northwest to southwest, ushering in more spring-like temperatures for mid-week. High pressure settles over New England with this ridge. Temperatures are likely to top out in the 50s on Tuesday with the potential to reach 60 in several locations away from the immediate coast of Massachusetts and Rhode Island on Wednesday. The Cape and Islands will remain in the 40s to near 50 as SSTs are still hovering around 40 degrees. Warm spring patterns that occur pre-"green up" have a tendency to overperform compared to the highs forecasted by guidance. This tendency is supported by both the NAEFS and ENS Situational Ensemble Tables such that all levels rise above the 90th and 97.5th percentiles on Tuesday and Wednesday respectively. CPC guidance also shows a 60-70% chance of above normal temperatures for the five day period of Mar 9-13th. Given both our seasonal knowledge, and the strong probabilistic trends in guidance, high temperatures were increased on Tuesday and Wednesday using a blend of the GFS and NBM 90th percentile values. Low temperatures overnight Tuesday into Wednesday were adjusted using the NBM 75th percentile guidance. There is a slight chance of precipitation on Tuesday as a shortwave passes to our north, however given that this potential is five days out, it is too soon to determine what localities, if any, will see a brief passing shower. Otherwise, next week looks dry. Guidance is narrowing in on a cold front/chance for more significant precipitation sometime late next week. More attention will need to be paid to this system as Thurs/Fri enter our forecast period as the ECMWF, GFS and Canadian models all differ on exact timing. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... Forecaster Confidence Levels. Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. VFR today with northwest winds gusting to 25 kt. VFR tonight and Saturday with winds diminishing...Saturday gusts will be near 20 kt. KBOS TAF...High confidence in TAF. VFR. KBDL TAF...High confidence in TAF. VFR. Outlook /Saturday Night through Tuesday/... Saturday Night: VFR. Breezy. Sunday through Monday: VFR. && .MARINE... Gusty northwest winds today with potential for 25 to 30 kt gusts. Winds diminish later tonight and Saturday with wind gusts Saturday around 20 kt. Seas 5 to 6 feet on the outer waters today, subsiding to 5 foot seas on the southern outer waters Saturday. Light freezing spray will a factor through Saturday. Favorable conditions include air temps around freezing, sea temps 35F to 40F, and strong gusty northwest winds. Gales will be dropped with this forecast. Expect Small Craft Advisory conditions today and tonight, diminishing below that level on Saturday. .Outlook /Saturday Night through Tuesday/... Saturday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Sunday through Sunday Night: Winds less than 25 kt. Monday: Winds less than 25 kt. Seas locally approaching 5 ft. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 9 PM EST this evening for ANZ230>237. Gale Warning until 4 AM EST early this morning for ANZ250-251- 254. Small Craft Advisory until 7 AM EST Saturday for ANZ255-256. && $$ SYNOPSIS...WTB/KS NEAR TERM...WTB SHORT TERM...WTB LONG TERM...KS AVIATION...WTB/KS MARINE...WTB/KS |