Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/29/18
Area Forecast Discussion
National Weather Service Caribou ME
1206 AM EDT Mon Oct 29 2018
Low pressure across the eastern Great Lakes this evening will
track across the Gulf of Maine Monday and pass into New
Brunswick Monday night. Weak high pressure will build toward the
area on Tuesday.
.NEAR TERM /THROUGH TODAY/...
Have adjusted temperature, wind, and dew points based on latest
observations. No other changes.
Low pressure will continue tracking west of the region tonight.
The last batch of rain will lift out of northern Maine this
evening leaving cloudy skies and some patchy drizzle. Some dry
working up from southern New England as seen on the latest satl
visible imagery could allow for some brief partial clearing
across interior Downeast and the coast. This would allow for
some fog formation due to the wet ground and cooling overnight.
The 12Z UA picked up on this dry air at 700mbs. Decided to go to
push the fog for the Downeast region overnight as well as parts
of the Maine Central Highlands. The 12Z GFS soundings confirm
this as well as the RAP guidance. Further n, more clouds will
keep the risk of fog formation at bay. Overnight temps are
forecast to be in the upper 30s to lower 40s(coast). The
northern areas could actually see warmer temps than some of the
interior Downeast due to the cloud cover.
Low pres seen on the 12Z UA over Wisconsin this morning is
forecast to move to PA Monday morning and then lift across the
Maine coast later Monday into Monday evening. The 12Z GFS
matched up well w/this morning`s placement of the low. The 12Z
ECMWF and NAM lined up well w/this setup. This low will bring at
least 0.25 inches of rain across the interior Downeast and
coast. The Maine Central Highlands could see some measurable
rainfall w/less amounts across the n and w. The decision was to
raise the rain chances to 60% and went ahead w/40-50% into the
central and ne areas. Further w, rainfall chances drop off to
20% or less. A tad warmer for the daytime temps in the 40s.
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
Weak system Monday night, followed by high pressure Tuesday and
Tuesday night, then followed by another weak system Wednesday.
Considerable uncertainty in the Monday night system, but it
appears a weak surface low will develop in the northern Gulf of
Maine and track northeast through Downeast Maine as a shortwave
trough rounds the base of the main upper low over Quebec.
Doesn`t look like a strong system by any measure, but it could
bring around a quarter inch of rain mainly for Downeast late
Monday to Monday evening. Looks like mainly a cold rain, though
can`t rule out some very light mixed precip over Northern Maine
late Monday night into Tuesday as slightly cooler air moves in
from the northwest with a few persisting showers. Not expecting
any significant impacts.
High pressure briefly moves in late Tuesday into Tuesday
evening. May get partial clearing late Tue/Tue evening, but then
clouds thicken late Tuesday night into Wednesday with the next
weather system. This system again looks quite weak and went only
with a chance of precip for Wednesday. Although can`t rule out
some spots in the north getting mixed precip, any light precip
should go over to rain Wednesday afternoon with little or no
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Overall, looking unsettled Wednesday night through Saturday, and
possibly into Sunday. Deep, moist, mild south/southwest flow
will be over the area as a potent longwave upper level trough
positions itself to our west in the Great Lakes and Ohio Valley.
Quite a bit of uncertainty as to the timing of shortwaves in the
south/southwest flow. Looking very likely we will get rain for
some of the period late Wednesday to Sunday, but pinpointing
exactly when is tough. Did go with the highest PoPs late
Thursday into Friday. Looks mild enough to where the vast
majority of any precip in the extended period will come as rain.
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
NEAR TERM: IFR/LIFR through Monday at the Aroostook County
terminals with times of MVFR at BGR and even VFR at BHB late
this evening, but with conditions likely to lower to IFR to low
end MVFR overnight and during the day Monday.
SHORT TERM: Some IFR possible Monday night, though mainly looks
like MVFR ceilings. Likely MVFR in the north for Tuesday, with
VFR Downeast. Generally VFR Tuesday night to early Wednesday,
followed by MVFR/IFR for the next weather system late Wednesday
NEAR TERM: SCA for Hazardous Seas into Monday. Initial sea state
needed to be raised by 1-2 ft as the local wave guidance was
underdone. Periods of 14-15 second leading to a large swell. No
problems reported w/any overwash this afternoon at high tide.
Seas are forecast to gradually subside overnight into Monday
but will stay well above 6 ft. Therefore, midnight crew may need
to extend the SCA through Monday given the low moving in from
the sw which should stir the seas. Winds will be 10-15 kts
tonight dropping to around 10 kts on Monday.
SHORT TERM: Winds likely remaining just below small craft levels
Monday night through Wednesday, though seas will be hovering
around 5 feet (small craft criteria). Solid small craft
winds/seas likely Thursday/Friday with the next weather system.
Month to date the average temperature at Caribou is running 3.6
degrees below average and ranks as the 8th coolest (Oct 1-27) on
record (POR since 1939). At Bangor, the average temperature is
running 2.3 degrees below average and it ranks as the 13th
coolest (Oct 1-27) on record (POR since 1926).
MARINE...Small Craft Advisory for hazardous seas until 8 AM EDT this
morning for ANZ050>052.
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1159 PM EDT Sun Oct 28 2018
Despite widespread precipitation stripping out of the state, a moist
postfrontal environment persists across Southeast Michigan. Evidence
of this includes a lack of dry dewpoints across the region, and
steady drizzle this evening here at the office. Well mixed
conditions have developed in the northerly flow with gusty winds in
the 10 to 20 knot region. This will continue into the overnight.
Will carry MVFR for the duration of the overnight. Model data,
including the RAP is suggesting a similar mixed layer for the day on
Monday and prefer to keep an MVFR ceiling in place for the afternoon.
.DTW THRESHOLD PROBABILITIES...
* High for ceiling 5000 feet or less tonight through Monday
Issued at 318 PM EDT Sun Oct 28 2018
Showers will diminish over the next few hours as large scale forcing
for ascent shifts well south east. Active fgen along the mid-level
theta-e gradient which is helping to support slightly more organized
activity north of M-59 this afternoon will pivot through the
remainder of the CWA by 03z, carrying just a low chance of remnant
light rain prior to exiting. Water vapor loop reveals a shortwave
trough over far southeast Manitoba that will propagate over the
Lower Peninsula tonight against a background of building mid-level
heights. The brief uptick in lake effect will be of little
consequence as northwest flow steers more organized Lake Michigan
activity into Indiana. However, there is at least non-zero drizzle
potential as cold advection steepens lapse rates in the presence of
remnant boundary layer moisture and the brief period of increased
forcing for ascent. Low confidence due to a lack of shearwise
forcing and, especially, ongoing modest advection, precludes
inclusion in the forecast at this time.
Even as heights build, cyclonic flow aloft and backing boundary
layer flow to the west will remain supportive for persistence of
stratus through most or all of Monday. Forecast soundings indicate
sufficient moisture to fill in any erosion of stratus with diurnally
forced stratocu. Trended high temps downward into the upper 40s
Western US trough will force the downstream mid-level ridge and
attendant surface high through the area Monday night. Increasing
depth to anticyclonic flow and backing wind field to the southwest
will spell an end to any remaining boundary layer stratus as warm
advection brings 850mb temps into the upper single digits and
surface temps well into the 50s. Any higher end potential on temps
will likely be limited by increasing high clouds. Increasingly moist
southwest flow will increase the probability for a lowering cloud
deck again late Tuesday, particularly as the resultant inversion
becomes better defined. At the same time, fgen along the developing
mid-level thermal gradient will become increasingly supported by
right entrance dyanmics late Tuesday night. Existing low-static
stability environment will likely yield a healthy response during
this time worthy of categorical pops as the moisture axis works
through the area late Tues through the overnight. Lows hold firmly
in the mid to upper 40s with ongoing southwest flow at the surface.
Lingering precipitation will be possible across the southern Metro
region throughout Wednesday morning as a cold front finishes pushing
across Michigan. The frontal boundary is expected to stall across
Ohio and will produce a strong baroclinic zone across central Ohio,
which will be the focal point for persistent rainfall throughout
Thursday. Southeast Michigan, specifically across the Metro region
and up into the Thumb, will have the chance to see some of this
precipitation associated with both the stalled frontal boundary and
embedded shortwaves aloft, before an advancing trough pushes the
baroclinic zone towards the northeastern U.S. coast. A thermal
trough that is projected to expand down to Alabama and Georgia will
again bring an extended period of slightly below normal conditions
to Michigan starting Thursday. Temperatures will peak in the upper
40s to lower 50s into weekend, with lows in the 30s. For reference,
highs are in the mid-50s for this time of year.
Upper-level troughing will bring the chance for spotty showers late
Friday into Saturday, with the next best chance to see widespread
rain moving in late Sunday into Monday as a warm front pushes across
Moderate northwest wind follows low pressure exiting Lake Erie
tonight. Direction is a little more toward the west across Lake
Huron and Saginaw Bay and this affects the wave field with lower
values through Monday morning. The Small Craft Advisory remains in
effect but has been trimmed to include the nearshore from Port
Austin to Harbor Beach. Wind and waves will be marginal elsewhere
before high pressure settles in Monday afternoon through Monday
night. Lighter wind then shifts southwest and increases Tuesday
while stability increases with a surge of warmer air moving in ahead
of the next cold front. This will cap wind gusts to around 25 knots
before the frontal passage which is followed by northwest wind
remaining under 20 knots Wednesday.
The next low pressure system pulls a cold front into Lower Michigan
late Tuesday and Tuesday night. Showers and a chance of
thunderstorms bring potential rainfall totals around a half inch
mainly Tuesday night into Wednesday morning before the front exits
eastward. Flooding is not expected given the low rainfall totals for
Lake Huron...Small Craft Advisory until 4 PM EDT Monday for LHZ441-442.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
You can obtain your latest National Weather Service forecasts online
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1046 PM EDT Sun Oct 28 2018
Northwest flow will persist over the region through tonight bringing
mostly cloudy skies and periodic light showers along the Tennessee
border. Conditions will clear on Monday as high pressure moves over
the region and remains in place through midweek. On Thursday, a cold
front will approach from the west, bringing showers and thunderstorms
to the area.
.NEAR TERM /THROUGH MONDAY/...
As of 1030 PM EDT Sunday: The pre-frontal shower band continues to
weaken as it moves east of the mountains, and piedmont PoPs should
rapidly dwindle through midnight. The wind forecast remains on
track, with hourly RAP runs still showing peak 50 kt 850 mb winds
just touching the northern mountains Blue Ridge area through the
early morning hours. Given the slightly backed flow and fairly
shallow mixing layer, the current mountain Wind Advisory still looks
good. Cannot rule out some damaging winds at elevations 5000 feet
and above across the northern mountains, but a short-fuse High Wind
Warning does not appear to be needed at present. Otherwise, the
upper wave and associated surface cold front will move through the
region very quickly early overnight, with just residual northwest
flow moisture in the western mountains. Some very light snow
accumulations along the highest peaks are possible by daybreak in
scattered upslope snow showers.
With dry northwesterly advection behind the front and high pressure
building in, Monday afternoon should be mostly clear with highs
warming a bit over values observed today.
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 200 PM Sun: An upper ridge will translate across the
Southeast during the short term, and a broad sfc high accordingly
will maintain settled weather over the CWFA. The high will be
centered over the mountains Monday night, with very light winds
and generally clear skies. Despite slight warm advection occurring
aloft, radiational cooling will bring temps down into the upper
30s in some parts of the NC Piedmont. A few patches of frost could
occur, though conditions still appear marginal.
A southerly return flow should develop Tuesday as the ridge axis
progresses east. Thicknesses and midlevel temps will rise, bringing
temps back to about normal, and eliminating any frost threat for
Wednesday morning. Weak lift and some moistening can be seen on
isentropic progs for Wednesday; temperatures will warm 1 to 2
categories above normal. PoPs still remain below slight-chance
thru the end of the day, except in the very far west nearest the
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 150 pm Sunday: Although the disagree on the details, the
global models are gradually building toward a consensus regarding
the overall pattern during the medium range, as a series of short
wave troughs is expected to displace a short-lived East Coast upper
ridge by the end of the week. The initial short wave trough
impacting the eastern states is expected to lift west and north of
our area in the Thu/Thu night time frame, which is expected to drag
a fairly well-forced frontal boundary into the area during this
time. Pops are therefore advertised in the likely to categorical
range from Thu evening through Fri morning. Warm/above normal levels
of warmth and humidity in the warm sector could result in sufficient
warm sector instability to support a few thunderstorms during this
time, and it is not out of the question that a high shear/low CAPE
severe convective threat could evolve. Pops gradually ramp down Fri
into the weekend, with lingering shower possibilities, primarily
over the high terrain within a NW flow regime. Temps will return to
levels 5-10 degrees below climo by Friday, continuing through Day 7.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Shower coverage should dwindle as the
boundary continues east across the terminal forecast area into the
early overnight hours. Should thus see mainly scattered VFR clouds
into the early morning hours before skies gradually clear from the
west. S to SW pre-frontal winds will toggle W to NW with fropa late
this evening and early overnight. Any low end gusts should abate
quickly east of the mountains with a shallow mixed layer, but
gustiness will likely persist at KAVL through the period as NW flow
and cold advection increases. Gusts may pick up east of the
mountains through Monday with mixing as dry high pressure arrives
from the west.
Outlook: Drier air will spread into the region the early part of the
week, with VFR conditions lasting through Wednesday. A vigorous
frontal system, with associated increasing moisture, will likely
arrive from the west on Thursday.
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 100% High 100%
KGSP High 100% High 100% High 100% High 100%
KAVL High 100% High 100% High 100% High 100%
KHKY High 100% High 100% High 100% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
GA...Wind Advisory until 11 AM EDT Monday for GAZ010.
NC...Wind Advisory until 11 AM EDT Monday for NCZ033-048>053-058-
Area Forecast Discussion
National Weather Service Sacramento CA
324 PM PDT Sun Oct 28 2018
Breezy off and on winds this week...with elevated fire weather
concerns. Cooler tomorrow with light showers early far north.
Warming and dry mid week into next weekend.
An upper level trough is passing through the Pacific Northwest
today with a weak cold front passing through Northern California.
Precipitation has been light across the forecast area, generally
0.01-0.06" over the mountains of western Shasta and Tehama
counties. The HRRR model suggests any additional rain over our
area into early Monday as the trough exits will be limited to the
same area, with total accumulation 0.10" or less. Heavier
amounts, exceeding over an inch today have been focused along the
coast around the California/Oregon border.
For much of the area the main effects of the trough today have
been some high and mid level clouds and cooler temperatures.
Temperatures at 2 pm were generally 2 to 9 degrees cooler than the
same time yesterday.
The upper level trough will dig southeastward into the Great
Basin on Monday and Tuesday. This will bring a tightening surface
pressure gradient and will result in breezy northerly winds. The
highest winds gusts are expected in the western Sacramento Valley
Tuesday during the the late morning and early afternoon gusts up
to 35 mph possible. Northeasterly down slope winds will develop
for the Sierra as well. These will bring lowering humidity and
combine with the breezy winds to enhance fire weather danger,
especially on Tuesday into early Wednesday.
Upper level ridge will build in on Wednesday with somewhat less
breezy winds and warmer temperatures. Halloween afternoon/evening
looks dry and mild, with Valley highs in the upper 70s to lower
.EXTENDED DISCUSSION (Thursday THROUGH Sunday)
Upper level ridge over the west coast will bring continued warm
and dry conditions to the forecast area Thursday with daytime
highs around 10 degrees above normal. Northerly winds will
develop again though not as strong as earlier in the week. These
will decrease later in the week. Temperatures trend upward
through the week into Saturday. A shortwave disturbance is
projected to drop through the Pacific Northwest next Sunday into
early Monday. This will bring increasing cloud cover and a slight
cool off. This will also may bring a slight threat of showers to far
northern Shasta County early next week, but most of the area
should remain dry. EK
VFR conditions next 24 hours. Winds at TAF sites generally below
10 knots. High mountain ridge gusts up to 40 knots possible.