Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/19/17
Area Forecast Discussion
National Weather Service Taunton MA
1037 PM EDT Wed Oct 18 2017
.SYNOPSIS...
High pressure will maintain dry weather and warmer than normal
temperatures through the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
1035 PM Update... corrected SREF to HRRR.
At 10 PM, skies were crystal clear across southern New England.
Temperatures had dropped to the mid 40s to lower 50s except mid
50s at the coast. Have lowered temperatures a tad to fit with
current trends. Lows should range from the lower 40s to lower
50s in the larger cities. Some patchy frost possible in
northwest MA.
As noted by previous forecaster, the 23Z North America Rapid
Refresh Ensemble System (NARRE) has continued to emphatically
show development of low cloudiness beginning in eastern CT
around 06Z and then expanding everywhere south of the Mass Pike
by 11Z. The HRRR has the same trend, only later and farther
east, only across RI and southeast MA, mainly after daybreak.
Have decided to increase sky cover grids to 60-70 percent across
eastern CT and RI late tonight and around daybreak, since the
NARRE is often quite good at picking up on these trends.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Tomorrow...
Upper lvl shortwave continues opening trend as it moves across S
New England during the late afternoon/evening hours. The
attendant cold front loses its baroclinicity and is associated
with little to no moisture increase so aside from a few more SCT
clouds are possible, but this fropa passes with little fanfare.
SFC pres gradient response yields an increase, so S-SW flow will
be breezy with a few wind gusts around 25 mph during the
afternoon. Temps a bit milder in spite of the SCT clouds thanks
to weak warm advection aloft ahead of the wave. Looking at
widespread low 70s.
Tomorrow night...
Weak front shifts E. Gradient winds shift to the W but weaken
inland as pres gradient weakens rapidly with the core of a
stronger high pres shifting E. Winds may remain elevated near
shore. The slight increase in moisture thanks to S gradient flow
during the day will limit overnight mins further still,
suggesting more widespread upper 40s to low 50s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
* Above average temps and dry conditions lasting into Monday
* Precipitation chances are increasing for mid-next week.
Pattern Overview/Confidence...
12z guidance is in good agreement for the long term. Passing frontal
system an associated trough will push offshore by Friday morning.
Anomalous ridging will develop across the East Coast pushing heights
and temperatures 2 STD above normal. This strong ridge will last
into early next week before a pattern change appears to take hold of
the area. Digging trough will dip into the Gulf states with the
potential for a closed low peeling off. Another wave will begin to
dive into the Ohio Valley which could result in phasing to a
negatively tilted trough putting much of the East Coast near 3-4 STD
below normal in heights fields. This pattern change will result in
cooler conditions and unsettled weather.
Details...
Temperature Forecast...
Overall trend in the forecast is for above average temperatures
through the period. Cool front will sweep through the region
Thursday night leading to a cooler day on Friday, but still above
average. Anomalous ridge will begin to build for the weekend into
Monday resulting in high temps into the mid 70s. Tuesday`s and even
Wednesday`s temperature forecast is a bit trickier as it is
dependent on the timing of the front. Thus will trend towards a
model consensus until guidance gets a better handling on the FROPA.
Precipitation Forecast...
High pressure will take over the area on Friday through Monday
leading to dry weather. Next chance or precipitation will be around
the Tuesday timeframe when a potent trough will dig into the Ohio
Valley and towards the East Coast. Ensemble guidance is trending
towards a very wet pattern with high PWAT values and strong
southerly LLJ. This is in conjunction with the several waves of low
pressure that will ride along the trough both Tuesday and Wednesday.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Thursday Night/...Generally high
confidence.
VFR through 06Z. Confidence is increasing in the development of
some IFR ceilings developing especially 08-13Z across northern
CT, RI, and southeast MA. Patchy MVFR-IFR in fog in a portion of
those areas. VFR then returns tomorrow and most of tomorrow
night.
SW flow expected today through the daylight tomorrow, then
gradual shift to the W is expected tomorrow evening/overnight.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...Moderate confidence in TAF. Although VFR
dominates there is a moderate risk for some IFR ceilings
developing late tonight into early tomorrow morning.
Outlook /Friday through Monday/...
High Confidence. VFR.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Short Term /through Thursday Night/...High confidence.
Overnight...
Quiet boating weather into tomorrow morning.
Tomorrow and tomorrow night...
S-SW winds increase tomorrow afternoon with gusts to around 25
kt likely over all waters by late afternoon and a slight
increase in outer seas to near 5 ft. These winds persist into
the overnight but slowly diminish as they shift to the W late
tomorrow night. Small Craft Advisories will be issued for all
waters.
Outlook /Friday through Monday/...High confidence.
Great boating weather as high pressure prevails through the
upcoming weekend with sub SCA conditions.
&&
.FIRE WEATHER...
Ahead of a very weak cold front tomorrow (with which no
precipitation is expected) S-SW winds will gust 20-25 mph across
much of the region. Relatively mild conditions (highs in the
low-mid 70s) and continued dry dewpoints in the mid 40s to low
50s will yield min RH values near 30 percent. With an overall
lack of precipitation of late this suggests elevated fire
weather for the day tomorrow.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 2 PM Thursday to 6 AM EDT Friday for
ANZ231>234.
Small Craft Advisory from 2 PM Thursday to midnight EDT
Thursday night for ANZ230-236.
Small Craft Advisory from 4 PM Thursday to 6 AM EDT Friday for
ANZ235-237-255-256.
Small Craft Advisory from 2 PM Thursday to 8 AM EDT Friday for
ANZ250-251-254.
&&
$$
SYNOPSIS...Doody/Dunten
NEAR TERM...Field
SHORT TERM...Doody
LONG TERM...Dunten
AVIATION...Field/Doody/Dunten
MARINE...Field/Doody/Dunten
FIRE WEATHER...Doody
Area Forecast Discussion
National Weather Service Burlington VT
742 PM EDT Wed Oct 18 2017
.SYNOPSIS...
High pressure along the east coast of the United States will
maintain dry conditions across the North Country through Sunday.
With south to southwest winds in place, temperatures will warm
well above seasonal levels for mid to late October beginning
today, and continue through the upcoming weekend. The next
chance of appreciable precipitation occurs by Monday into
Tuesday of next week as a cold front crosses the area from west
to east.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 707 PM EDT Wednesday...Forecast in great shape with
another mild evening across the north country. Surface high pres
is shifting east...while surface boundary approaches the central
Great Lakes. The gradient between these two features will help
to increase sfc winds overnight...especially in the wider
valleys...like cpv/slv. Meanwhile...early this evening...skies
are clear and winds have decoupled in the deeper valleys...along
with very dry air mass has allowed temps to fall quickly. Have
updated to capture rate of fall in hourly grids...but have only
made minor tweaks to overall low temp forecast. Expecting lows
upper 30s/lower 40s slk/nek to l/m 50s cpv/slv with mostly clear
skies.
Previous discussion below:
Going forecast on track. 925mb temps around 12C at BTV per RAP
this afternoon which should yield max temps in the mid 60s in
the valleys lower 60s in the hills this afternoon which is well
covered in the going forecast.
Very quiet wx through the near-term. Generally looking at clear
skies otherwise through tonight. The sfc ridge axis extending
along the east coast of the U.S. and building shortwave ridging
aloft will bring dry weather, but southerly pressure gradient
increases overnight especially west of the Greens with light
south to southwest winds and moderating temperatures. Only a
very small chance for any radiation fog east of the Greens so
left it out. Lows mainly in the 40s for tonight except near 50
in the St. Lawrence and Champlain valleys.
Temperatures moderate further on Thursday under a rather strong
west southwest flow with 850-mb winds 30 to 50 kts leading to
breezy surface winds of around 15 kt with gusts to 25 to 30 kt.
With 925-mb temps around 14C for looking for max temps reaching
the upper 60s to lower 70s.
Another mid-upr level shortwave trough is progged to pass along
the intl border Thursday afternoon. This feature should bring
an increase in mid-upr level clouds, but dry low-level
conditions should preclude any precipitation.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 334 PM EDT Wednesday...A rather dry cold front will pass
through the region Thursday night with some clouds especially in
the northern Green mountains where a sprinkle can`t be ruled
out. 925mb temps drop to about 8C near BTV on Friday for
"cooler" high temps in the mid 50s to lower 60s, still a bit
above normal. High pressure will slide across the mid-Atlantic
states and off the coast lead to quiet weather conditions with
mostly clear skies under broad subsidence. Return SW flow around
the high with warm advection over the weekend will will bring
warming temps each day with upper 60s Saturday to 70 by Sunday.
Each night we`ll radiatively cool and should see temps in the
upper 30s to low 40s.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 352 PM EDT Wednesday...High pressure will be the dominant
feature over the weekend. Surface ridge axis will slide
eastward over the Atlantic seaboard, increasing warm
southwesterly flow. This will result in daytime max temperatures
in the mid 60s to low 70s to close out the weekend. Min
temperatures will see a warming trend heading into the work
week, from mid 40s to mid 50s.
The beginning of the work week will see a pattern change as a
cold front associated with a mid-upper level longwave trough
approaches from the west. The North Country will see an increase
in clouds and potential for rain some time late Monday into
Tuesday. Potential for rain showers will be reinforced,
especially on Tuesday at the mid-upper level trough digs
southward into the Mississippi valley. At the surface, ECMWF and
GFS show closed low pressure system develop and move over SE
Ontario/NW NY by late Tuesday. Increased pressure gradient at
the surface should lead to fairly gusty winds with the potential
for 15-25 mph with gust to 35mph Tuesday into Wednesday.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...VFR conditions expected to persist as low
level southwesterly jet of 20-35kts developing overnight due to
increasing pressure gradient with surface high pressure settled
over the mid-Atlantic states and approaching strong Canadian low
entering Hudsons Bay increases the pressure gradient. Jet
should hinder any fog development under clear skies into
Thursday morning, but also produce some LLWS (23035kt at 020)
overnight at KMSS and KSLK. There`s a chance some intermittent
fog may develop at KSLK before the jet develops...mainly btwn
02Z-04Z as T-Td spread is very narrow to start the night.
Winds will mix to the ground throughout the daytime with S-SW
sustained winds of 10-15kts and gusts 20-35kts expected. Can`t
rule out funneling up the St Lawrence to have isolated higher
gusts.
A cold front associated with the low will bring some high to
mid level clouds toward 18z with a wind shift to west northwest
toward 00Z Fri.
Outlook...
Thursday Night: VFR. Breezy. NO SIG WX.
Friday - Sunday: VFR. NO SIG WX.
Sunday Night: VFR. Slight Chance SHRA.
Monday: VFR. Chance SHRA.
&&
.MARINE...
Southerly winds will increase overnight reaching 15 to 25 kts by
dawn Thursday as a moderately strong pressure gradient develops.
Relatively mild water temps in the upper 50s may mix winds of
30 knots just above the surface early Thursday morning, so could
be a bit higher than 25 knot for a few hours from sunrise to
noon. Winds should slowly diminish late in the afternoon and
then shift to the west northwest 10 to 15 knots Thursday night.
&&
.EQUIPMENT...
KTYX radar at Fort Drum, New York will remain down for
scheduled maintenance through tonight (10/18) and tomorrow
(10/19) as technicians repaint the radome.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Sisson
NEAR TERM...Taber/Sisson
SHORT TERM...Sisson
LONG TERM...KGM
AVIATION...KGM
MARINE...
EQUIPMENT...BTV
Area Forecast Discussion
National Weather Service Marquette MI
727 PM EDT Wed Oct 18 2017
.SHORT TERM...(This evening through Thursday)
Issued at 345 PM EDT WED OCT 18 2017
...Windy into this evening then again on Thu...
Surface low over northern Manitoba down to 973mb at 19z/4-5 standard
deviations below mid October mean is resulting in warm and windy day
across much of Upper Michigan. Temps over portions of western U.P.
have reached over 20F above normal in the middle 70s. Warm spot as
of 3 pm in Upper Michigan is on the Keweenaw near the Upper Entrance
of the Portage Canal. Houghton Co Airport not far behind at 75F.
Pretty warm for mid to late October. Should note the record high for
today in the Houghton area is 80F set in 1910.
Dry airmass ahead of the low and associated cold front is leading to
just a batch of mid clouds over northern Ontario into western Upper
Michigan. Cold front crosses region late tonight with winds shifting
from southwest to west. Based on RAP soundings showing mixed layer
winds over 35 kts/40 mph, current obs and pressure falls crossing
north of Lk Superior into early this evening, expect wind gusts over
40 mph from north central into eastern forecast area. Issued special
weather statement into early evening to cover the strong winds.
West winds ramp back up on Thursday behind the cold front. Strongest
wind gusts 30-40 mph will be across Lk Superior and Keweenaw
Peninsula but 15-30 mph gusts could also occur over rest of forecast
area. Even with cooler airmass compared to today, temps on Thursday
will top out in the low to mid 60s, which is still well above
normal. Min RH values will bottom out in the 20-25 percent range so
fire weather concerns may be elevated especially given the recent
stretch of warm/dry weather.
.LONG TERM...(Thursday night through Wednesday)
Issued at 404 PM EDT WED OCT 18 2017
Thursday night through Friday night: Fairly quiet weather is
expected through this time period as high pressure will remain in
control. Aloft, upper level ridging in place will keep temperatures
above normal through this time period, in fact, many places will be
around 15 to 20 degrees above normal through this time period. For
perspective, average temperatures this time of year area right
around the low 50s.
Saturday into Sunday: An upper level trough is expected to slide
from the Plains eastward through the Upper Great Lakes region
through this time period. At the surface, the associated stroung
surface low is expected to slide north of the area, and remain
mainly over Canada. This will drag a cold front through the Upper
Peninsula Saturday afternoon and night and then to the east of the
area by Sunday evening. Increased moisture and forcing and moisture
ahead of the front will allow for widespread rain showers to spread
across the U.P. Current model trends have roughly a half inch of
precip across the area by the time the precipitation ends Sunday
afternoon. There may be just enough instability around for Saturday
afternoon and Saturday evening ahead of the front for a few
thunderstorms; however, thunderstorm potential does look to be
fairly marginal overall. Temperatures will be about 10 to 15 degrees
above normal through this time period.
The rest of the extended: There will likely be a brief break in the
precipitation Sunday night as a brief ridge builds into the area;
however, another slow moving low pressure system is expected to
slide through for Monday through Wednesday. Aloft, a much deeper
trough will dig into the Upper Great Lakes region. This will allow
enough cold air to slide into the region to cause some snow to mix
in with the rain over the higher terrain of the west. The ground is
still warm and overall QPF is not expected to be that impressive, so
not expecting too much in the way of accumulation. 850mb
temperatures are progged to drop into the -5C to -7C range, creating
delta-T values in the 17 to 19C range. This will be prime for lake
enhancement. The favored areas will have to be pinned down as models
come into better agreement, but it looks like the northwest wind
lake effect prone areas would have the best chance at this point.
Model consnesus was used and appeard to work well for this time
period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 726 PM EDT WED OCT 18 2017
VFR conditions are expected to prevail over the next 24 hours. A
cold front will push east across all terminals tonight veering winds
to the west at KSAW. Breezy winds will likely persist behind the
front.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 345 PM EDT WED OCT 18 2017
South to southwest winds to 30 kts with a few gale gusts to 35 kts
over eastern sections will continue into the evening. Cold front
crossing tonight will shift winds to west and these may gust to 30
kts late tonight into early Thu aftn and once again there may be
gale gusts to 35 kts over east half. Overall, expect winds to stay
25 kts or less Thu night into early next week. Winds could increase
to 30 kts late Fri night into Sat though as pressure gradient
briefly tightens up ahead of low pressure tracking across south
central Canada.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 11 PM EDT this evening for LSZ250-251.
Gale Warning until 8 PM EDT this evening for LSZ248-249.
Lake Michigan...
Gale Warning until 11 PM EDT this evening for LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...KEC
AVIATION...JLB
MARINE...JLA