![National Oceanic and Atmospheric Administration](/build/images/header/noaa.d87e0251.png)
![National Weather Service](/build/images/header/nws.4e6585d8.png)
![United States Department of Commerce](/build/images/header/doc.b38ba91a.png)
Area Forecast Discussion
Issued by NWS Boston, MA
Issued by NWS Boston, MA
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
142 FXUS61 KBOX 181519 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 1119 AM EDT Thu Jul 18 2024 .SYNOPSIS... A cold front moves into southern New England today bringing lower humidity away from the south coast. The front moves offshore tonight with high pressure in control Friday through the weekend. This brings seasonable temperatures and comfortable humidity levels. Dry and pleasant weather this weekend. The pattern turns more active again next week with increasing humidity. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1100 AM Update: Cold front continues to slowly trudge southeastward, its current position about near Buzzards Bay. Dewpoints were falling into the middle 60s on the northwestern, cool side of this boundary and while that is still a little humid it is far better than the humidity levels we`ve seen the last several days. Lower to mid 70s dewpoints were still common over the Cape and Islands so still quite humid there. Regional radar and satellite imagery shows blossoming thunderstorms over the southeastern outer waters southeast of ACK; while those could pose problems for mariners, these should stay far enough southeast to not put any land areas at risk for thunderstorms. Front will probably be slower to egress eastward; while dewpoints will be steadily falling into the lower 60s inland by this afternoon, near the South Coast, Cape and Islands, dewpoints in the mid 60s probably won`t be observed until late in the day or tonight. Otherwise a mix of sun and higher-level clouds today (a few lower cloud decks for the Cape and Islands) but dry weather prevails. Previous discussion: A cold front will slowly make its way across the region through the day before stalling along the south coast. This means that relief from the humidity won`t arrive for most until later today, and overnight for far southeast MA. We`ve still got dewpoints in the low 70s in northern MA and mid 70s in southern MA/RI at 3 AM. Drier air will be filtering in on northwest flow today dropping those dewpoints into the 50s for northwest MA by late morning/early afternoon. That dry air finally pushes over the Cape and islands by tonight. In the mean time, that moist airmass will be conducive to scattered showers and even some thunderstorms along and off the south coast this morning before pushing off by afternoon. Clouds will become increasingly sparse through the day by the same token. Temperatures will be warm but not as warm as days past, with cooler air filtering in in the low and mid levels. Highs max out in the mid to upper 80s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... The real difference will be felt overnight as those lower dewpoints allow for much cooler temperatures than we`ve felt recently, in the 50s and 60s. Friday is the pick of the week as high pressure moves overhead and rising heights aloft allowing for clear skies, cooler temperatures (upper 70s to mid 80s), and a much less humid airmass. Dry and quiet weather to take us into the weekend. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... High pressure over the Great Lakes will extend eastward into SNE. This will leave the region with dry and pleasant conditions through Sunday. High temperatures slowly climb from the mid 80s on Friday and Saturday to the upper 80s on Sunday. Dewpoints Friday start out in the low 60s, but climb into the mid to upper 60s for Saturday and Sunday. Global guidance does show roughly 100-300 J/kg of MUCAPE will be available in western portions of SNE Saturday afternoon. With a little bit of cyclonic vorticity aloft, this could lead to some isolated low topped showers. Saturday will likely be the most cloudy day of the weekend with a rather thick deck of cirrus clouds aloft associated with the weak cyclonic vorticity impulse. Next Week A more active pattern looks to set in again for next week as deep SW flow aloft kicks back in bringing increased moisture back and several weak shortwaves towards SNE. Temperatures through the week look to stay in the mid 80s, but dewpoints will be on the rise again reaching the 70s by Tuesday staying there through the end of the week. Timing these features this far out is difficult given the spread in deterministic and ensemble guidance. Will need to monitor trends in the coming days for severe convection with CSU ML probs showing 5% severe on days 7 & 8. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 15z TAF Update: Today: High confidence. VFR for the majority, but could be occasional MVFR bases over the Cape and Islands thru 17z. NW winds around 10-12 kt with occasional gusts to 20 kt in the interior and into the coastal plain; wind shift from SW to WNW around 10 kt for the Cape and Islands occurs later this afternoon. Tonight...High confidence. VFR. Light NW winds. Friday and Friday night...High confidence. VFR. Light W winds with onshore flow at coasts. Overnight winds become west at all terminals. KBOS TAF...High confidence in TAF. VFR through the period. NW winds have developed around 10-12 kt and should continue that way through tonight, though become NNW at around 10 kt late tonight. Better chance at seabreeze Fri starting during the late morning hours. KBDL TAF...High confidence in TAF. VFR through the period. NW winds around 8-10 kt today into Fri. Outlook /Friday Night through Monday/... Friday Night: VFR. Saturday: VFR. Slight chance SHRA. Saturday Night through Monday: VFR. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Through tonight: High confidence. Winds diminishing, SW becoming NW then N Thu night behind the front. Seas over south coastal waters will be 5-6 feet today, diminishing overnight. Showers and a few t-storms continue into the early afternoon, especially southern waters. Friday: High confidence. Winds 5-10 kts. Seas 2-4 feet. Rip Currents... A rip current statement is in effect into this evening along south coastal beaches due to high risk for rip currents. Leftover 5-6 ft southerly swell will result in dangerous rip currents. Outlook /Friday Night through Monday/... Winds less than 25 kt. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...High Risk for Rip Currents until 8 PM EDT this evening for MAZ020- 021-023-024. RI...High Risk for Rip Currents until 8 PM EDT this evening for RIZ006>008. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ235- 237. Small Craft Advisory until 2 PM EDT Friday for ANZ254>256. && $$ SYNOPSIS...BW/KP NEAR TERM...Loconto/BW SHORT TERM...BW LONG TERM...KP AVIATION...Loconto/BW/KP MARINE...Loconto/BW/KP