Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/05/19
Area Forecast Discussion
National Weather Service Columbia SC
747 PM EST Mon Nov 4 2019
.SYNOPSIS...
High pressure will move farther away from the region tonight
with a weak trough off the SE Coast through Tuesday. A front
will move through the area Tuesday with most of the moisture
associated with the trough and ahead of the cold front remaining
east of the forecast area. High pressure will be in the region
Wednesday. A strong cold front will approach Thursday and move
into the area Thursday night into Friday. Cold and dry
conditions will return for the weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Weak disturbance off the SE Coast will slowly deepen and track
northeastward overnight. IR satellite imagery shows extensive
clouds over the region associated with southwesterly flow aloft
ushering Gulf moisture northward. WSR-88D imagery from
surrounding offices shows a few showers off the ILM coast with
the remainder of the region rain free. Isentropic ascent will
increase during the early morning hours and combine with the
Gulf moisture to result in slight chances of showers from the
CSRA through the eastern Midlands. With the extensive cloud
cover radiational cooling will be less than optimal resulting in
overnight lows in the upper 40s to around 50.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
A cold front will merge with a coastal trough Tuesday. Most of
the moisture associated with these features and ahead of upper
troughing will stay east of the forecast area, but latest models
runs have been bringing moisture farther west. Widely scattered
showers are becoming more probable, but rainfall amounts will be
light. Dry high pressure will build back into the forecast area
Tuesday night through Wednesday. Temperatures will be mild
through this period with highs in the upper 60s to mid 70s, and
overnight lows in the mid 40s to low 50s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Thursday should remain dry with warm air advection bringing
temperatures into the low to mid 70s ahead of the next frontal
system. Model are now in much better agreement on the timing of
a strong cold front moving through the region Thursday night
into Friday morning. Current forecast shows a quarter to half an
inch of rain is expected. The front will move east of the area
Friday afternoon, and much colder and drier air will follow. The
coldest conditions of the season so far may occur with freezing
temperatures possible this weekend, especially Friday night and
Saturday night. Zonal flow will return Sunday and Monday, with
slight warming, but still below normal temperatures.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
Pressure ridge centered to the northeast extending into the
area. Air mass remains relatively dry, however moisture will be
increasing overnight in the low-levels. HRRR and lamp guidance
suggest strato-cumulus will increase and lower overnight mainly
from AGS to OGB as weak low pressure develops offshore. Winds
will be light and mainly east or northeast. MVFR ceilings
expected late tonight into Tuesday morning from AGS/DNL to OGB.
Probability of restrictions lower in the CAE area. Isolated
light showers possible. Will maintain VCSH mention through the
afternoon as a weak front moves through.
EXTENDED AVIATION OUTLOOK...The next system will impact the
area late this week bringing the potential for rain and early
morning restrictions.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Charleston SC
1017 PM EST Mon Nov 4 2019
.SYNOPSIS...
High pressure will prevail inland, while a coastal trough
develops near the coast through Tuesday. A cold front will then
pass through Tuesday evening. High pressure will return
Wednesday, before a stronger cold front crosses the area late
week. Chilly high pressure will build in next weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
As of 1010 PM: Recent runs of the CAMs indicate that showers
will develop around dawn Tuesday. I will update the PoPs to
decrease values over land through the rest of tonight. Also,
temperatures have remain a little warmer than forecast, likely
due to thick mid and high clouds.
As of 655 PM: Expansive cloud cover will likely remain across
the forecast area tonight. Latest run of the HRRR indicates that
conditions will remain dry for most of the night, with a few
marine showers during the pre-dawn hours. I will update the
forecast to adjust sky, PoPs, and tweak hourly temperature
trends.
Previous Discussion:
The mid-levels will consist of a trough along the eastern half
of the country. Weak waves within the general flow are expected
to move over or nearby our area tonight. At the surface, weak
high pressure will develop over the central Appalachians.
Meanwhile, a trough will develop along the coast. The trough
will allow moisture to increase across our area. PWATs ~1.8" are
expected across our southern coastal counties by daybreak
Tuesday, with values lower further inland and to the north. The
combination of the moisture, lift from the trough, and the mid-
level waves should help to generate showers across portions of
the area. Both the synoptic and HREF are in decent agreement
showing the greatest risk for showers across the GA coastal
waters after midnight. The showers should increase in
coverage/intensity, moving onshore along the coast. We tried to
capture this the best we could with the hourly POPs, showing
likely for the GA immediate coastline, chance over a large
portion of our area, and a slight chance far inland. QPF should
be barely measurable far inland, a tenth or so along the
immediate coast, and higher over the coastal waters. The QPF
gradient should be fairly tight, so it`s possible the POPs may
need to be adjusted as radar trends develop. Additionally,
instability over the coastal waters should help to generate a
few rumbles of thunder along the immediate coast, especially for
our GA counties. The cloudy skies and warm advection will keep
low temperatures mild for a change, ranging from the 50s far
inland to the lower/mid 60s along the immediate coast.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
Tuesday: Aloft, the area will remain along the southern periphery of
a broad trough of low pressure while high pressure persists to the
south and southeast. At the sfc, a coastal trough/weak low will take
form and linger along the Southeast Coast for much of day, producing
scattered showers closer to the coast and even a few thunderstorms
when instability peaks late morning through the afternoon. Overall
highs should range in the mid/upper 70s under partly to mostly
cloudy skies. A cold front is then expected to push southeast into
the area overnight, putting an end to most precip and/or keeping
precip offshore as the coastal trough/low weakens. Overnight lows
should range in the low/mid 50s away from the coast to upper
50s/lower 60s along the coast.
Wednesday and Thursday: Aloft, mainly a zonal flow will occur until
late Thursday ahead of an approaching cold front. At the sfc, high
pressure will wedge south along the Mid-Atlantic and Southeast
States over land with a prevailing north/northeast wind in place
through much of Wednesday. The flow will likely keep temps cooler
Wednesday afternoon with highs generally ranging in the upper 60s
north to low/mid 70s south. Wednesday night temps should also be a
few degrees cooler than the previous night, ranging around 50 well
inland to mid/upper 50s closer to the coast. By Thursday, high
pressure will begin to weaken ahead of a cold front approaching from
the west. Winds should gradually turn onshore during the afternoon
and temps should warm a few degrees more than the previous day. In
general, highs should range in the mid/upper 70s, warmest away from
the immediate coast.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Models are in good agreement that a strong cold front will cross the
area late Thursday into early Friday. This will bring the highest
rain chances of the period, although it`s worth noting that models
show varying degrees of coverage. GFS is especially wet, as it
depicts a low developing and passing over the area later Friday into
Saturday. The current forecast disregards this scenario and shows
quick drying post-front. Chilly high pressure will build in for the
weekend. Temperatures will be well below climatology and the coolest
we`ve seen of the season thus far. We will need to monitor the
potential for frost/freeze concerns.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
0Z TAFs: A coastal trough will remain just offshore through the
TAF period. MOS and forecast soundings indicate that rounds of
showers and MVFR ceilings are expected to pass over the
terminals during the early daylight hours on Tuesday. The trough
is expected to shift east during the afternoon, resulting in
less shower activity and higher cloud bases.
Extended Aviation Outlook: Mainly VFR through the middle of next
week. There is a low chance for flight restrictions due to low cloud
ceilings and a few showers Tuesday into Wednesday. Greater chances
for flight restrictions are possible late Thursday into Saturday due
to showers along a passing cold front.
&&
.MARINE...
Tonight: Coastal troughing is expected to develop while weak
high pressure develops over the central Appalachians. The
interaction between these two features will lead to east winds
10-15 kt. Seas will range from 2-3 ft within 20 nm and 4-5 ft
further offshore.
Tuesday through Saturday: High pressure will prevail inland on
Tuesday while a coastal trough/weak low lingers near the Southeast
coast. Northeast winds will average 10-15 kt, but increase late as a
cold front shifts over coastal waters with cooler high pressure in
its wake. The pattern should result in an enhanced pressure gradient
and higher winds/building seas on Wednesday. Small Craft Advisories
could be needed for a short period for a portion of the waters,
mainly northern South Carolina waters and offshore Georgia waters.
Some improvement is then expected on Thursday before a strong cold
front sweeps through the area Thursday night into early Friday.
Strong cold air advection behind the front will likely cause winds
and seas to deteriorate rapidly. Small Craft Advisories will likely
be needed for all coastal waters, but there is also a potential for
gale force wind gusts across some of the waters. Gale Watches and/or
Warnings could eventually be needed with peak conditions occurring
Friday night into Saturday.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...
LONG TERM...ETM
AVIATION...NED
MARINE...
Area Forecast Discussion
National Weather Service Quad Cities IA IL
515 PM CST Mon Nov 4 2019
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 347 PM CST Mon Nov 4 2019
RAP analysis had a 1008mb surface low over eastern Ontario and
northwest flow across the Upper Mississippi Valley. A large scale
mid-level trough was present over the Northern Plains and Great
Lakes with the parent 500mb low anchored in northeast Manitoba.
Local temps were again below seasonal averages today. As of the mid
afternoon most locations were in the mid to upper 40s. Macomb was
the warm spot at 50 F and Dubuque and Independence were the coldest
at 43 F.
&&
.SHORT TERM...(This Evening through Tuesday Night)
ISSUED AT 347 PM CST Mon Nov 4 2019
This Evening and Tonight
Models are showing a subtle mid to upper-level trough axis
rolling through the Upper Mississippi Valley tonight into Tuesday
morning. Low-level cold air advection with 850mb temps falling
into the single digits below zero (C) will be accompanied by a
dry air mass -- PWATs are expected to fall to near 0.30 inches
overnight. For this reason, and with the absence of any focused
forcing, most of the CWA will stay dry overnight.
But a signal is there for shallow boundary layer instability this
evening and tonight which could result in sprinkles or flurries,
and possibly a few isolated rain/snow showers. Mentioned slight
chances for isolated showers in the north and northwest, and have
sprinkles/flurries extending further to the east and south through
midnight to 3 AM. Otherwise, chilly tonight in the mid 20s to
lower 30s.
Tuesday
High pressure and a dry air mass will result in quiet conditions
with highs in the mid to upper 30s far north to low to mid 40s
further south.
Tuesday Night
Main Message: Light snow is possible in the north with minor
accumulations and possibly a brief window of slippery pavement,
especially along the highway 20 corridor.
A clipper system and 850mb open wave will develop across the north
Plains on Tuesday and then track through northern Iowa to southern
Lake Michigan Tuesday night into Wednesday morning. Forcing for
ascent with this disturbance will be mainly elevated frontogenesis,
which will lay out a band of accumulating snow over parts of the
Upper Midwest into the Western Great Lakes.
The favored track along or north of the Wisconsin/Illinois border,
and marginal thermal profiles to support all snow in persistent warm
air advection, should focus the "heaviest" snow band to the north of
the CWA.
Potential Snow Amounts:
Southerly surface winds should offset an initial drop in temps
during the evening and first part of the night, and eventually lead
to a slow rise in temps into early Wednesday morning. A model
consensus blend of QPF and thermal profiles restricts most of the
snow accumulation to areas north of highway 30. The highest
amounts with this forecast update, on the order of 0.5" to around
1", are along and north of highway 20. These amounts taper to a
dusting toward highway 30 or just south. Any slight deviation in
the track could affect forecast amounts so stay tuned.
With the positive theta-e advection south of the low , a
transition from snow to a rain/snow mix and even all rain is a
possible trend in precip types from SW to NE, which is reflected
in the latest forecast. Uttech
.LONG TERM...(Wednesday through Monday)
ISSUED AT 347 PM CST Mon Nov 4 2019
Wednesday and Thursday
A cold, modified arctic air mass will filter into the Midwest later
Wednesday and Wednesday night. Several models are now indicating the
possibility for a band of anafrontal precip to develop north of
the surface front as elevated frontogenesis moves across the
area.
In coordination with surrounding offices, added low QPF amounts,
which combined with cooling thermal profiles, generated some
light snow accumulation mainly Wednesday night. Still plenty of
uncertainty on the snow potential at this lead time. On one
extreme the ECMWF is mostly dry, while the CMC and GFS have up to
a few inches. A model blend approach was taken to mention the
chance for light snow and potential light accumulations.
After lows in the teens and 20s Thursday morning, highs will only
rebound into the upper 20s to mid 30s. Brrr! Uttech
Thursday night on...
Thursday night through Saturday night Assessment...high confidence
Quiet, dry, and much colder than normal temperatures will be seen as
Canadian high moves across the Midwest. Daytime high temperatures
will be 10 to 20 degrees below normal.
Sunday Assessment...medium confidence
The global models bring another clipper type system through the
Midwest. This clipper system will pull continental polar or modified
arctic air down into the Midwest for the week of November 10th.
Moisture availability looks to be quite low for this clipper system.
Right now the model consensus has slight chance to low chance pops.
These pops will slowly increase as the week progresses and the track
of the system becomes more certain. Precipitation should be start
out in the form of rain that begins changing to a rain/snow mix by
late afternoon.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
ISSUED AT 514 PM CST Mon Nov 4 2019
VFR conditions are expected to prevail tonight through Tuesday.
Low clouds, just above MVFR thresholds, may produce a few
sprinkles or flurries at DBQ this evening. Tuesday will have
mainly mid and high level cloud cover with light westerly winds at
the surface.
&&
.CLIMATE...
ISSUED AT 326 AM CST Mon Nov 4 2019
Week 2...November 9-15
The Climate Prediction Center has the Great Lakes and mid-
Mississippi Valley at high risk for much below normal temperatures.
The high risk is mainly toward minimum temperatures. A CPC high risk
means that minimum temperatures have a 60 percent chance of being
less than the 15th percentile.
A continental polar or modified arctic air mass will settle into the
Midwest. The lack of a snow field will prevent temperatures from
getting too cold but temperatures will likely be at 20 degrees below
normal.
Thus daily maximum temperatures may approach record cool maxes.
Daily low temperatures could approach records.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Uttech/08
AVIATION...Sheets
CLIMATE...08
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
906 PM CST Mon Nov 4 2019
.UPDATE...
Only minor changes made to the ongoing forecast. Hourly temperature
observations are running 1-2 degrees above the hourly grids so have
made adjustments to bring the grids into line with the observations.
Based on the current observational trends and some of the short range
models have brought overnight lows up a degree in some spots, mainly
along and east of I-35. The other change was to expand the patchy fog
which is expected to develop early Tuesday morning to include areas
of the Edwards Plateau. Short range models like the HRRR are picking
up fog in these areas in during the early morning hours. Otherwise
should be a quiet night with cool overnight lows and increasing
clouds and fog by morning.
&&
.PREV DISCUSSION... /ISSUED 601 PM CST Mon Nov 4 2019/
AVIATION /00Z TAFs/...
VFR conditions this evening under a SCT-BKN high cloud canopy around
FL250 will quickly deteriorate to IFR/LIFR between 07-11Z as a light
wind field ahead of a surface boundary allows for nocturnal stratus
to build to the surface as fog. HRRR guidance and BUFR soundings
remain consistent in first developing these conditions near SAT/SSF
closer to 07Z, spreading towards AUS/DRT by 11Z. Low ceilings should
persist through much of the morning, rising to MVFR with heating
closer to 17-19Z. Additional heating should allow for ceilings to
lift to VFR by the end of the TAF period. As the surface boundary
clears the region midday, expect winds northeast to east 5-10 knots
at the South Central Texas terminals.
PREV DISCUSSION... /ISSUED 315 PM CST Mon Nov 4 2019/
SHORT TERM (Tonight through Tuesday Night)...
Late afternoon temperatures are in the mid 70s to mid 80s across the
region. Some scattered low clouds are noted in the coastal plains and
Highway 77 corridor, with high clouds on the increase across the Rio
Grande plains.
For tonight, we expect fog to develop mainly along and east of the
I-35 corridor. Farther to the northwest, a weak cold front will move
in early Tuesday morning, with the leading edge moving into the
southern Edwards Plateau and western Hill Country around sunrise.
The front weakens as it approaches the I-35 corridor during the late
morning and early afternoon hours. A few weak showers may develop
east of I-35 where moisture levels will be higher. The front
continues to weaken Tuesday night and with southerly flow
strengthening just above the shallow, cool, air mass we should see
some light showers develop over the Hill Country and southern Edwards
Plateau.
LONG TERM (Wednesday through Monday)...
On Wednesday, southerly flow in the low-levels will strengthen across
all areas as the above mentioned front dissipates. Moisture levels
may be slightly higher across the Rio Grande plains, southern Edwards
Plateau and western Hill Country. While any upper air support for
shower and thunderstorm development is rather weak, we will continue
to mention a very low chance (20%) for convection across these areas
on Wednesday.
Rain chances will increase significantly on Thursday as a fairly strong
cold front moves in during the late morning and afternoon hours.
Moisture levels ahead of the front will be fairly impressive for
early November with models indicating precipitable water values as
high as 1.5 inches along the Rio Grande to near 2 inches in the
coastal plains. We should see fairly widespread rainfall amounts in
the 1/4-1/2 inch range across south central Texas. Some higher
amounts will likely occur, especially in the coastal plains. Rain
chances should taper quickly from north to south on Friday as drier
air in the low-levels moves in behind the front.
A dry and cool weekend is in store with highs in the 60s and lower
70s and overnight lows in the upper 30s to mid 50s.
Another fairly strong cold front is set to arrive early next Monday.
Rain chances with this front do not appear too favorable as return
southerly flow in advance of this front will be weak. For now, we
will only mention a 20% chance for showers on Monday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 75 61 76 59 / 0 - - - 10
Austin Bergstrom Intl Airport 59 77 60 78 58 / 0 - - - 10
New Braunfels Muni Airport 61 77 62 78 58 / 0 10 - 10 -
Burnet Muni Airport 56 72 58 73 57 / 0 - - 10 20
Del Rio Intl Airport 61 78 65 80 63 / 0 0 20 20 30
Georgetown Muni Airport 59 74 59 76 56 / 0 - - - 10
Hondo Muni Airport 62 79 63 80 61 / 0 - 10 20 10
San Marcos Muni Airport 60 77 60 78 57 / 0 10 - 10 10
La Grange - Fayette Regional 63 78 61 78 58 / 0 10 - 0 -
San Antonio Intl Airport 64 77 63 78 61 / 0 - - 20 -
Stinson Muni Airport 64 77 64 78 61 / 0 - - 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Aviation...Huffman
Short-Term/Long-Term...Treadway
Area Forecast Discussion
National Weather Service Hastings NE
520 PM CST Mon Nov 4 2019
.SHORT TERM...(This evening through Tuesday Night)
Issued at 307 PM CST Mon Nov 4 2019
...AVIATION UPDATE...
As advertised by the RAP and HRRR, the frontogenetic band of
light rain has persisted south of a line roughly from Lexington to
Kearney to Hebron. Rainfall totals have been very light, with
many locations only seeing sprinkles. Expect rain to gradually
push southward through the late afternoon before dissipating
early this evening as high pressure slides in from the north.
Winds will go light and variable tonight, but mostly cloudy skies
will keep temperatures from falling any lower than the low 30s or
upper 20s.
Late tonight into Tuesday morning, some models (especially HRRR
and RAP) continue advertise another chance for precipitation
mainly over northern portions of the forecast area. This will be
associated with the warm air advection on the back side of the
surface high and will be aided by a 100+ kt upper level jet nosing
into the area. Precipitation type is the biggest challenge. Most
soundings appear to be initially supportive of light snow, but
warming low-level temperatures and decreasing saturation aloft
could allow for a mix of drizzle/rain as precipitation ends
Tuesday morning. In the official forecast, I went with mostly all
snow which is more supported by the short-term models. Luckily,
amounts should be fairly light with only a half inch of snow
expected, at most. Most locations will only see flurries or
sprinkles.
By mid-morning on Tuesday, we will see rising heights aloft,
which will lead to clearing skies. Coupled with southwesterly
surface winds, temperatures should be able to return to the 50s
and low 60s across the area. Tuesday night should also remain
relatively warm with lows in the upper 20s to mid 30s.
.LONG TERM...(Wednesday through Monday)
Issued at 307 PM CST Mon Nov 4 2019
The temperature roller-coaster continues as a cold front passes
through on Wednesday. Temperatures could still reach the 50s by
early afternoon in southern portions of the area, but most of the
area will see falling temps in the afternoon with increasing
northerly winds. This should be a mostly dry frontal passage but
the latest GFS and NAM do hint at some sprinkles or flurries
Wednesday evening and overnight.
The area should then get a good push of cold air for Wednesday
night into Thursday as the GFS shows a 1040mb high moving into
the region Thursday morning. Highs on Thursday will only reach
the 30s for most.
Temperatures then rebound once again Friday and Saturday as the
700mb trough slides off to the east coast. Highs on Saturday
should reach the 60s and maybe even the low 70s for some areas
with westerly downsloping winds.
A stronger arctic outbreak is expected to impact the area on
Sunday after yet another cold front moves through the area. Model
ensembles have come into better agreement on timing of the front.
As a result, forecasted highs for Sunday have dropped by almost
20 degrees since yesterday. As of now, highs are expected to only
be in the 30s. Dry conditions are forecast through this time, as
predictability and timing of any jet streaks or frontogenetic
bands remain uncertain. That being said, some light snow or
flurries is never out of the question with a strong front like
this.
The question then becomes how long this cold pattern will last.
It seems likely that we will have at least a day or two of
temperatures well below normal to start next week. Ensembles then
hint at a bit of a warmup for the middle of the week. The GEFS and
EPS ensembles then diverge a bit on their solutions for the
middle of the month. The former continues to bring more cold air
into the area by the middle of the month, while the latter shows
more of a warming trend for mid to late November.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday)
Issued at 517 PM CST Mon Nov 4 2019
VFR to MVFR ceilings are forecast for this TAF period. Looking at
upstream obs and guidance, a MVFR ceiling looks to move into the
area tomorrow morning. Winds will become southerly tomorrow with
gustier winds expected for EAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Beda
Area Forecast Discussion
National Weather Service Goodland KS
459 PM MST Mon Nov 4 2019
.SHORT TERM...(This evening through Wednesday night)
Issued at 203 PM MST Mon Nov 4 2019
The short term forecast focus is on the low probability of
precipitation for the remainder of late this afternoon and
evening and again Wednesday night as temperatures bounce up and
down with periodic intrusions of colder air every couple of days.
The broad upper trough remains generally in place over the U.S.
with the amplified flow flattening a bit prior to a
reamplification after mid week as a series of short wave troughs
carves through the upper trough. The position of the upper trough
leaves the central high plains region exposed to cold air
intrusions in the wake of each short wave trough circulating
through the large scale trough.
The colder air, low clouds, and northeast flow around the surface
high in place today moves out of the area tonight. There will be
isolated sprinkles to light rain showers associated with the weak
short wave trough currently moving through Nebraska and clipping
the northeast portion of the forecast area. Southwest surface flow
and warmer air move into the area on Tuesday helping temperature
rise into the 60s.
Another cold front moves through the area early Wednesday with a surge
of colder air following through the day and overnight Wednesday
night along with northeast upslope near surface flow. Moisture
above 700mb is very limited while the airmass below 700mb is
showing up to be near saturation Wednesday night into early
Thursday morning. The GFS usually produces some kind of
precipitation when in an upslope setup when there is moisture
available, but is showing up as dry across the forecast area
similar to the ECMWF. The NAM is, however, developing some very
light QPF in the cold air as it moves through the region. Could
definitely see some low clouds with this type of setup producing
less than VFR conditions at the TAF sites. Along with the low
level saturation, there could also be some fog or very light
precipitation that may eventually show up as a freezing drizzle.
Am not confident in the area seeing any fog or freezing drizzle at
this point, so have decided to leave it out while also bumping up
PoPs a bit to stay within forecast tolerance of forecast areas
over eastern Colorado.
.LONG TERM...(Thursday through Monday)
Issued at 1249 PM MST Mon Nov 4 2019
Synopsis... Mostly quiet weather is expected across the Tri-State
area in the long term with very little if any chances for
precipitation. A passing cold front on Thursday will bring cloudier
skies and high temperatures in the 40s. Clearing skies for Friday
and Saturday will allow temperatures to increase back up the 60s.
Another passing cold front Sunday will bring another big temperature
swing with temperatures struggling to get into the 40s in the
afternoon with cooler temperatures stick around through early next
week.
Discussion... Significant upper-level ridging centered over the far
southwestern portion of the United States and strong upper-level
troughing centered over the Great Lakes region will lead to a
relatively quiet pattern for the Central High Plains. As such, the
current long term forecast for Thursday through Monday currently has
almost no chances for precipitation across the forecast area. The
only exception would be a chance for some freezing drizzle Thursday
morning in east-central Colorado and a chance for some light
rain/snow showers in far northern Yuma County Sunday evening. Both
slight chances of precip are associated with passing cold fronts
from stronger surface lows forming over the Upper Midwest.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 455 PM MST Mon Nov 4 2019
Somewhat complicated and uncertain aviation forecast through
tonight. Satellite imagery shows area of low clouds persisting
across the Tri-State border area, though KGLD is on the southern
edge. Latest hires models suggest these clouds will persist
through tonight, possibly expand in coverage, with slowly lowering
ceilings. In addition, with dew point depressions already rather
low, fog may develop overnight, but radiational cooling will be
limited by the clouds, so confidence in fog development not great
at this time. Latest runs of the HRRR do show fog developing,
however, mainly from Goodland to Garden City, so will mention fog
at KGLD but not at KMCK overnight. As southwest surface winds
increase and become breezy Tuesday morning, low clouds and fog
will dissipate at both terminals.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...LOCKHART
LONG TERM...PATTON
AVIATION...024
Area Forecast Discussion
National Weather Service Melbourne FL
930 PM EST Mon Nov 4 2019
.DISCUSSION...
Update...Small Craft Advisory issued for offshore waters from
Flagler Beach to Sebastian Inlet.
Tonight...Impressive low level convergence ongoing across parts of
northeastern Brevard County. A low level boundary (oriented from
southwest to northeast) is located from central Merritt Island to
Playalinda Beach, extending at least 10-20 miles offshore. Southeast
flow at the surface is feeding moisture and generating lift along
the boundary, at the same time southwesterly flow aloft is
advecting storms towards the northeast off the boundary. This is a
typical flooding setup with low level flow perpendicular to the
mean 850mb-300mb flow atop a low level boundary, all in the
presence of deep moisture that if fueling high rainfall rates. RAP
analysis also indicates high 850mb moisture transport into the low
level boundary.
Since 6 PM EST, the KMLB Doppler Radar has tracked this boundary
as it developed offshore and slowly shifted onshore around the
KSC/Merritt Island Wildlife Refuge areas. Around 3-5 inches of
rain has already fallen, mostly unpopulated areas around KSC.
However, heavy rainfall in southern Merritt Island, and over
mainland Brevard County could lead to 1-2 inches of rain over the
next couple of hours.
Elsewhere it will be mostly cloudy overnight with passing showers
at times. Low temperatures will be around 70 degrees inland, and
in the low to mid 70s along the coast.
&&
.AVIATION...
Most of the showers and storms from earlier today have dissipated,
with the only convection now around the Cape in Brevard County.
Overnight expect vicinity showers, with some light rain at times,
and occasional MVFR ceilings. These lower ceilings might become
more prevalent towards sunrise - may need to add TEMPO groups for
this in the 06Z TAFs. Afternoon showers and isolated lightning
storms are in the forecast for Tuesday.
&&
.MARINE...
Tonight...Recent observations from Buoy 9 suggest seas of 6-7 feet
and southeast winds around 20 knots are ongoing across the
offshore waters from Flagler Beach to Sebastian Inlet. Thus, a
Small Craft Advisory has been issued through Tuesday morning.
Elsewhere, small craft should exercise caution due to breezy winds
around 15 knots and seas up to 6 feet, especially once you move
away from the immediate coast.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 80 71 83 69 / 30 60 50 20
MCO 83 71 85 70 / 30 10 50 10
MLB 83 74 85 72 / 40 40 50 20
VRB 84 73 85 72 / 50 40 40 30
LEE 82 71 85 69 / 20 20 50 10
SFB 82 70 85 70 / 30 30 50 10
ORL 82 70 85 72 / 30 20 50 10
FPR 84 74 86 70 / 50 40 40 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 7 AM EST Tuesday for Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Volusia-Brevard County
Line to Sebastian Inlet 20-60 nm.
&&
$$
SHORT TERM...Rodriguez
LONG TERM....Cristaldi
AVIATION...Rodriguez
Area Forecast Discussion
National Weather Service Marquette MI
655 PM EST Mon Nov 4 2019
.SHORT TERM...(This evening through Tuesday)
Issued at 352 PM EST MON NOV 4 2019
Water vapor imagery and RAP analysis show a mid-level trof over
central N America with axis extending s from Manitoba. Shortwave
that brought snow to portions of the fcst area last night is moving
into southern Quebec. Upstream, next feature of interest is a weak
shortwave over se Manitoba. Ahead of this wave, an area of -sn has
been shifting out of ne MN across western Lake Superior and now far
western Upper MI. To the e, sharp trof/mesolow type feature over se
Lake Superior has been supporting pcpn streaming into Alger/northern
Schoolcraft/Luce counties. Wetbulb zero heights btwn 1200-1700ft
suggest most of this pcpn over the e is falling as shra.
Tonight, as Manitoba shortwave swings across the area, 12hr 500mb
height falls of 30-60m and weak deep layer forcing are indicated.
This will support a period of lake enhancement under wnw low-level
winds. CAA will also get underway tonight with passage of cold
front. 850mb temps across Lake Superior are fcst to fall from -8C w
and -5C e this evening to -15C w and -11C e by 12z Tue. Short period
of lake enhancement will occur largely before caa drops dgz more
firmly down into the upper portion of the lake induced convective
layer. While this will hold down snow-to-water ratios, some decent
snowfall rates will likely occur around the time of fropa. Overall,
expect a general 1-3 inch snowfall over the western snowbelts
tonight. Highest terrain locations such Painesdale to Twin Lakes,
around the Porcupine Mtns, and possibly around Herman in eastern
Baraga County may end up near 4 inches by 12z. To the e, more of a
rain/snow mix until later tonight will hold snow accumulations down
to an inch or two by 12z Tue in the snowbelts e of Munising.
Better period of LES over the e will occur Tue, especially during
the morning hrs before drying/subsidence begins to work into the
area from the w. Expect accumulations of 1-3in e of Munising in the
12-18z time frame with another 1-2in from 18z-24z. May end up
needing an advy for that area on Tue as current fcst snow
accumulations late tonight thru Tue aftn are around 5in in a small
area from the interior of eastern Alger County/far ne Schoolcraft
County e to around Pine Stump Junction. Out w, fcst soundings show a
return of fairly pronounced mixed layer/inverted-v profile blo the
cloud deck on Tue which will work to cut down on snowfall despite a
decent inversion height around 6kft. With DGZ completely occupying
the convective cloud layer, expect a fluffy 1-2 inches of snow where
LES is most persistent. With winds beginning to back in the aftn
across western Lake Superior, LES will shift n during the aftn hrs,
ending at least in Gogebic County. Will be a cold day with highs
mostly in the mid/upper 20s w and lwr 30s east. Across the Keweenaw
and elsewhere where wnw are onshore off Lake Superior, it will be
blustery with winds gusting 25-35mph. The brisk winds across Lake
Superior, generating to 8-11ft waves, will lead to some minor beach
erosion on beaches e of Munising on Tue.
.LONG TERM...(Tuesday night through Monday)
Issued at 308 PM EST MON NOV 4 2019
Tomorrow night, slight surface ridging nudges northward into the U.P.
Lows tomorrow night are tricky. There should still be enough
gradient flow to maintain a few knots of wind and prevent a
surprise PBL decouple (and subsequent temperature plummet). This is
certainly what the raw guidance shows, anyway. However, it`s natural
to get nervous with light winds and clear skies (away from the
lakes) in winter. There`s always a chance the valleys of the
interior west get colder than expected. So for low temps, tried to
hedge towards the colder statistical guidance in cloud-free areas
and towards warmer raw guidance in cloudy areas, resulting in lows
ranging from the lower teens in the coldest spots of Iron County to
the mid or even upper 20s right along the Lake Superior shoreline.
For Wednesday, models continue to depict a very weak mid-level short
wave in broad cyclonic, almost zonal flow racing eastward through MN
into WI, shearing out as it does so. Still, with good baroclinicity
in the vicinity (about a 12 C spread in 850 mb temps from S to N
across WI) there should be enough of an fgen band for a couple
inches of snow... somewhere. The trend in the last 6 runs or so of
the GFS has been slightly south, reducing our risk for any
accumulating (synoptically forced/system) snow. Meanwhile in the W
wind LES belts, expect periods of snow showers to continue,
especially east where the bands will benefit from having the longer
fetch over water. NAM and GFS both depict a convergence band
dropping southward onshore from Munising on east at some point on
Wednesday but disagree on timing. Given the environment (lake-based
CAPE up to 700 J/kg, inversion heights to 11 kft, 850 mb deltaT`s up
to 21 C), this band will probably produce prolific snow where/when
it moves on shore. For now, went with the 90th percentile QPF and
ratios around 20:1 resulting in 1-3" for the spine of the Keweenaw
and 2-4" east of Munising, but these could both end up being low
estimates (especially east).
The next cold air dump is still scheduled for Wednesday night into
Thursday with 850 mb temps returning to around -16 C meaning more
prolific LES in the WNW and NW wind snow belts. Again went with the
90th percentile QPF in the LES areas and 20:1 SLRs. This resulted in
another 2-4" west and 3-6" east (over the 24 hour period Wed night
through Thu) but as we get closer and this next LES event comes into
the range of the CAMS, expect to see these accumulations fine-tuned
and increased (perhaps significantly in some more localized areas).
As winds veer to more NW Thursday night and eventually NNW by Friday
morning, this may finally bring LES into areas that haven`t seen too
much of it yet like western Alger County and perhaps even as far
west as the city of Marquette. However this NNW flow LES will be
short-lived as height rises and associated subsidence/warming aloft
take over during the day on Friday. (Previously it looked like
another s/w and cold air shot Friday, so you can see how timing out
these fast waves in NW flow is hardly an exact science!)
By Saturday, it`s time for another shot of cold air, this one
possibly the coldest yet of the season. Looking at this morning`s
06z GEFS plumes for 850 mb T, the ensemble mean gets down to -17.5 C
(brrr!) and the majority of members back down to at least -16 C by
early next week, with both the GFS and EC 12z deterministic runs
getting down to -20 C! The ensembles still show about a 36-hour
spread in when exactly that next burst of cold air arrives, however,
so some timing uncertainty lingers. Regardless, the general trend is
certainly clear: continuing cold and lake-effect snow in the NW wind
LES belts right into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 644 PM EST MON NOV 4 2019
Lake-enhanced snow showers continue to dominate across Upper
Michigan, with these showers anticipated to continue off and on at
all three terminals tonight. KSAW may see a break with perhaps
only vicinity showers during the heart of the overnight hours into
tomorrow morning, but could see another round around midday
Tuesday. By mid-morning, KIWD should see a clearing of the snow,
with KCMX likely stuck under the constant bands of snow showers
throughout much of the TAF period. Look for west winds to prevail
as they pickup tonight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 352 PM EST MON NOV 4 2019
NW winds will increase to 30kt from w to e across Lake Superior this
evening. Given the increasingly colder air moving over the
relatively warm waters, making for more efficient mixing, some gale
force gusts are also expected, mainly over the central and east
portion of the lake. No change in winds is expected during the day
Tue. With cold air dominating the Upper Lakes Wed/Thu, 20-30kt winds
will prevail more often than not across Lake Superior. Stronger
winds may occur late Wed and also Thu aftn with gale force gusts a
possibility over the e half of Lake Superior. High pres ridge
passing early Fri will provide a period of lighter winds under 20kt.
Winds will then increase to at least 20-30kt again for Sat as the
next cold front passes.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...RJC
AVIATION...lg
MARINE...Rolfson