Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/04/17
Area Forecast Discussion
National Weather Service Caribou ME
912 PM EDT Sat Jun 3 2017
.SYNOPSIS...
A trough of low pressure will move east of the region tonight.
Weak high pressure will briefly build across the region on
Sunday. Low pressure will track south of the area Sunday night
through early next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
9:12 PM Update...An upper low is seen on water vapor satellite
pictures across the western Gulf of Saint Lawrence and Nova
Scotia. Moisture continues to rotate around the low into eastern
Maine. As of 9 PM, area radars are still showing a decent
amount of shower activity, mainly from northern Piscataquis
County south into the Greater Bangor Region. Will make some
adjustments, mainly to the PoP grids to account for this shower
activity. The latest few runs of the HRRR and RAP continue to
show isolated shower activity lingering overnight, mainly across
western and southern portions of the CWA. Also getting some
reports of fog with the visibility reduce to a mile or less
during the past hour at Houlton. Have added in some patchy fog
for the remainder of the night.
Previous discussion...
An upper level low will continue to move east through the Canadian
maritime provinces through Sunday. Latest radar reflectivity
continues to show scattered shower activity, mainly across
eastern Maine. Have only seen a few lightning strikes in the
CWA, mainly across Washington county in down east Maine, where
we even received a report of pea sized hail in Lubec. Expect
this activity to wane quickly by early evening as we lose the
diurnal heating. Otherwise expect partly to mainly cloudy skies
overnight with diminishing winds. Couldn`t rule out some patchy
fog where showers occurred. Will not include in forecast
however, since it should be patchy in nature and rather
localized. Lows tonight should generally be in the low to mid
40s.
The upper low will continue to move east the through the
Canadian maritimes Sunday. The GFS still hints that there could
be enough instability down east for an isolated shower in
association with the departing Maritimes low. Otherwise any
shower activity associated with the next upstream shortwave
approaching from the west should hold off until evening with
mainly dry weather expected across most of the region. Highs on
Sunday should be a few degrees milder than today with highs
generally in the low to mid 60s, but a bit cooler along the
coast.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
A trough of low pressure over eastern Canada will drop south
Sunday night developing surface low pressure over New York
state. The low may bring some light rain into southwestern parts
of our area Sunday night into Monday. High pressure will remain
anchored to our northeast. The main forecast challenge will be
in determining how far north this rain progresses as the low
tracks to our south Monday into Tuesday and the high holds on to
our northeast. Forecast guidance is coming into better
agreement that any rain Monday into Monday night will be mainly
confined to southern and western areas with the north mostly
cloudy but remaining dry. One area of surface low pressure will
slide east on Tuesday while the upper trough hangs back over
the Great Lakes. Precipitation will likely thin out or dissipate
Downeast. The north will have clouds and some breaks of
sunshine Tuesday as high pressure to our north sinks a bit
south into our region.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
The long term remains a complicated and messy forecast, with
models differing greatly from each other, and also with
significant run-to-run inconsistency. However, we can say with
reasonable certainty that the period will start with a cut-off
low over the eastern Great Lakes Tue night, sagging southeast
across the Mid-Atlantic through Thurs. As this feature sags
south, a weak sfc high will scoot by to the north of it and pass
over Maine, giving us some nicer weather later Wed into Thurs.
All models then show the cut-off finally getting picked up by
the westerlies and pushing across or just south of New England
Thurs night through Fri night, and the northern trough kicking
it out may spur some showers or perhaps a few storms Fri eve and
night. The 12z Euro came into more agreement with the GFS on an
upper trough and surface cold front impacting the state later
Saturday, with some showers and storms possible again Sat eve
and night. However, given the significant disagreements and
inconsistencies in model data over the past 24 hours or so, have
kept all POPs to 50 percent of less for now. The latter half of
the week looks to be near to a bit above normal on temps, with
the best chance for temps getting into the mid-70s expected for
Thurs and Fri, when partly to mostly sunny skies and S-SW`ly
winds should help warm things up.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: Still some showers that could reduce the visibility,
especially at KBGR and KBHB during the next few hours.
Otherwise mainly VFR tonight through Sunday. Patchy fog could
result in brief IFR or lower conditions, but coverage will be
patchy and not widespread. Also, some patches of MVFR may drift
across the northern terminals at times tonight with a MVFR
ceiling as of 9 PM at KFVE.
SHORT TERM: VFR conditions are likely Sunday night, possible
lowering to MVFR across the north late. MVFR conditions are
likely Monday into Monday night Downeast with VFR conditions
across the north. Conditions may improve to VFR Downeast on
Tuesday and remain VFR across the north.
&&
.MARINE...
NEAR TERM: The wind and seas will remain below small craft
advisory criteria through Sunday.
SHORT TERM: A SCA may be needed late Monday night into early
Tuesday for northeast winds as low pressure tracks south of the
waters. Otherwise, winds and seas should remain below SCA.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...CB/Duda
Short Term...Bloomer
Long Term...Kredensor
Aviation...CB/Duda/Bloomer
Marine...CB/Duda/Bloomer
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
940 PM EDT Sat Jun 3 2017
.UPDATE...
Mid evening radar trends indicate some showers developing over
northern lower Michigan, out ahead of the main convective line. These
are occurring within the mid level theta-e gradient where moisture
transport is helping build some elevated instability that will
develop into the Saginaw valley and Thumb during the rest of the
evening into the early morning. This is a preview of what can be
expected to continue during the late night through mid Sunday morning
regardless of how the current upstream convective line evolves, the
bulk of which is deeply rooted in surface based instability over
Wisconsin. Expect a transition from surface based to elevated/low
level jet forced activity as the night progresses which will either
support the remnants of the ongoing line and/or produce a new pattern
of elevated convection. The strengthening low level jet and new surge
of moisture transport will be enhanced by the lead edge of the mid
level trough approaching from central Canada. This will also
maintain effective shear around 30 knots and also provide some
background lift and a better mid level lapse rate environment. The
most recent runs of the RAP model advertise 700-500 mb lapse rate
near 7 C/km, in line with hourly mesoanalysis, and 850 mb LI running
in the -2 to -4 C range. The combination of larger scale background
forcing, elevated instability, and adequate wind shear will be
capable of some updraft enhancement capable of hail production on an
isolated basis while wind gust potential will be not out of the
question but limited by a the surface based stable layer. Outside of
a stronger updraft, expect the overall shower pattern will expand to
numerous coverage as these nocturnal processes mature. High res
model output the indicates a weakening trend toward sunrise through
mid Sunday morning as the pattern develops toward the Detroit area
and Ohio border, which also fits the nocturnal convection model of
evolution.
&&
.PREV DISCUSSION...
Issued at 715 PM EDT Sat Jun 3 2017
AVIATION...
Mid level clouds and some virga drifting over lower Michigan are all
that remain of earlier convection that was over the western Great
Lakes. The next round of storms is off to a strong start from the
central U.P. into central Wisconsin which will be the primary
subject of the aviation forecast tonight through Sunday morning.
Generally expect a weaker form of showers/storms to survive into SE
Michigan and arrive in the MBS area around 08Z. That is assuming the
eastward extension of high based showers over northern lower Michigan
during the evening remains there and moves off into northern Lake
Huron leaving the stronger activity to move in later in the night.
The message of the previous forecast is preserved with this issuance
as confidence in storms reaching MBS and FNT remains high, and
possibly even with an IFR restriction, while probability diminishes
toward the DTW area by sunrise as both coverage and intensity will be
waning by then. Residual clouds in the borderline MVFR/VFR range
will linger through the morning in the warm sector of the low
pressure system before the prefrontal trough/cold front moves in with
another chance of storms by early Sunday afternoon. Current timing
would favor south of DTW but strongly dependent on evolution of
clouds/surface heating after the early morning activity.
For DTW... Best timing for thunderstorms in the D21 airspace remains
in the 10-15Z time period. While coverage and intensity of storms
will be in question, there is expected to still be generous coverage
of showers capable of at least MVFR restriction through mid Sunday
morning. Redevelopment Sunday afternoon will be favored just south
of DTW across the southern portion of D21 through Sunday afternoon.
//DTW THRESHOLD PROBABILITIES...
* Low for ceiling aob 5 kft late tonight through Sunday morning.
* Low for thunderstorms impacting the airspace tonight. Moderate
Sunday afternoon.
* Low for wind to reach or exceed crosswind threshold from 270
degrees during peak heating Sunday.
PREV DISCUSSION...
Issued at 329 PM EDT Sat Jun 3 2017
DISCUSSION...
Local environment still characterized late this afternoon by deeper
dry layer depth within relenting surface ridging, capped by
predominant lower amplitude mid level northwest flow. Notable
changes ongoing upstream, as pockets of shortwave energy embedded
within this northwest flow lead in a stronger mid level circulation
now digging into southern Manitoba. Existing convection still
anchored to an initial wave or remnant MCV now lifting southeast into
southwest lower mi will continue to weaken with time despite a local
arrival at the back end of peak heating, given the lack of better
moisture quality /dewpoints still in the 40s/ and consequently
available instability. A few light showers/sprinkles a possibility
from whatever persists as weak ascent slips through this evening,
but of little consequence.
Moisture will increase through the night as the flow veers
southwesterly immediately downstream of the pending stronger height
falls. Convection will organize within a zone of greater
instability and mid level forcing/shear over northern WI and the
U.P. this evening. Some degree of downscale expansion is forecast
initially into northern lower MI tonight. However, the overall
maintenance and longevity of this activity as it lifts deeper into
the lower peninsula will carry increasing uncertainty with time
given the less desirable nocturnal timing. With that said, the
underlying cva/ascent and degree of mid level theta-e advection tied
to the inbound shortwave or general height falls appear sufficient
to support at least a chance for showers/thunderstorms during the
early-mid morning period Sunday /06z-14z/. Should an organized east-
southeast propagating MCS overcome the increasing nocturnal
influence and maintain greater integrity, then a few stronger storms
containing larger hail could emerge within the steeper mid level
lapse rates.
Mid level moisture axis settles into far southeast michigan and
northern Ohio by midday Sunday. Positioning of this feature
seemingly key to the location of eventual renewed convective
development under weak daytime destabilization as a surface trough
works across this moisture plume. A corridor roughly southeast of
Ann Arbor to Mt. Clemens will remain tenuously positioned within the
northern periphery of possible convective initiation with these
features by mid-late afternoon. A well-mixed west-southwest
gradient and at least partial sunshine will lift afternoon
temperatures into the lower 80s. Acknowledging the usual NAM moist
bias on dewpoints and subsequently overhyped instability parameters,
potential for MLCAPE to reach upwards of 1500 J/kg will exist. Thus,
there remains a window for convection to obtain greater vigor under
the background of 30-35 kts of bulk shear, leading to a conditional
threat for severe thunderstorms should development emerge locally
first. Mixed signal yet across the model spectrum, but general
consensus suggests a greater expansion in coverage and organization
may not occur until activity builds into northern Ohio/Lake Erie.
Potential for additional late day/evening convective development
mainly over the Tri-Cities/thumb tied to a weak surface wave and the
eventual southwest release of the marine augmented cold frontal
boundary. Isolated deeper updrafts will bring the threat for
strong wind gusts given the existing wind field. Strong mid level
dcva and increasing mid level lapse rates as the main trough axis
pivots through will then maintain a low chance of showers/embedded
thunder areawide through Sunday night.
Consolidation of the aforementioned exiting trough with a strong mid
level circulation ejecting due south out of eastern Hudson Bay then
results in a deep layer closed system that centers over the eastern
great lakes for the early week period. Southeast Michigan remains
within the cyclonic western expanse of this troughing, ensuring
colder then average conditions exist during this time. Prevailing
north-northeast flow will provide a notable marine influence to
temperatures across the thumb. Shower potential Monday contingent
on remaining beneath a corridor of heighten cva as this system
organizes to our east. Residual low end precip chances remain
forecast at this stage.
The chance for showers will continue into Tuesday as an upper low
centered over the Eastern Great Lakes slowly moves east. Northerly
flow will keep temperatures in the 60s on Tuesday. Ridging then
builds into the region on Wednesday bringing drier conditions and a
gradual warming trend through the mid week period. The next chance
for showers and thunderstorms will arrive late next week as a
shortwave tracks across the region. Temperatures will return to near
average values late next week with highs in the upper 70s.
MARINE...
Brief period of moderate southeast flow will develop late tonight
before weakening and veering to northwesterly through Sunday as low
pressure traverses the waters. Gusty north northwest flow will take
hold Monday into Tuesday as cooler air overspreads the Great Lakes
in the wake of Sunday night`s cold front. Small craft advisories
will likely be needed during this time due to both elevated winds
and waves. Episodes of thunderstorms can also be expected tonight
through Sunday night. The greatest threat will be the potential for
severe wind gusts.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
UPDATE.......BT
AVIATION.....BT
DISCUSSION...MR/JD
MARINE.......JVC
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Peachtree City GA
1133 PM EDT Sat Jun 3 2017
.UPDATE...
The forecast is on track with little changes made to the immediate
short term.
Convection has diminished dramatically over the past hour or two
as diurnal heating has waned and so too the instability. At this
hour, we are monitoring some activity moving across southern
AL. When looking at radar returns and WV imagery, it seems this
is a weak shortwave/mesolow that if tracking northeast would
blossom across our area tomorrow morning. This may lead to more
stratiform rain a bit premature for the current forecast in place.
This activity would also likely hamper overall instability and
temperatures through mid-day. We will continue to monitor the
progress of this impulse as it moves across AL tonight. It seems
the best moisture flux will move into the area during the morning
hours, with plenty of omega. Given these factors and the eroding
ridge aloft we expect to see better coverage of precipitation
across the region tomorrow as compared to today.
A quick look at typical heavy rain ingredients within the next 24
to 36 hours, seeing very high values of PWAT, Mean RH, moisture
flux and sufficient warm cloud depths to be somewhat concerned
with localized flooding; mainly across central GA. This airmass
is somewhat synonymous to the tropics, so heavy downpours may
occur, especially with better convections (likely in the
afternoon). If training becomes an issue, which is may given MBE
vectors, we may need to up our QPF totals.
26
&&
PREV DISCUSSION... /Issued 308 PM EDT Sat Jun 3 2017/
SHORT TERM /Tonight through Sunday Night/...
Rather moist airmass oozing in our direction. PWAT analysis this
afternoon highlighting a plume of rich tropical air with a peak PW
of 2.2 inches over MS/AL that extends south into the GOM with
connections into a southern GOM disturbance. Not much in the way of
lightning associated with any of the in GA or in MS/AL and would
expect with such a tropical airmass that thunderstorms would be less
common. Most of the showers developing this afternoon are firing
along an instability Axis that extends from near AGS westward
through FFC. Have pulled back on the thunder in the grids today
and tomorrow but kept pops high for more showery type weather to
be the rule. High res models including the HRRR are lifting
showers into W GA and NW GA in the early morning hours on Sunday
along the leading edge of this deeper moisture plume that shifts
our way as the broad trof located over the NE states starts to
pull away. Forecast may have to be updated this evening as often
times tropical airmasses will have an early morning uptick in
activity...followed by a lull and then daytime heating will re-
start the process.
Have kept pops in the likely category Sunday per model consensus
with best chance of thunderstorms in the afternoon assuming enough
breaks can form to get some deeper convection developing. Good news
is that high temps will be kept in the lower to middle 80s on sunday
with all the clouds..bad news is that dewpoints will be near 70
most places so you`ll need a towel when outside.
30
LONG TERM /Monday through Saturday/...
Mainly only tweaks to the long term based on the latest guidance.
A wet period still looks in the cards Monday into Tuesday.
BDL
PREVIOUS DISCUSSION...
Extended period begins with likely pops over the state Monday as
frontal boundary associated with parent upper low over the Great
Lakes is dragged into the state. There continues to be better low
level forcing along the front, which combined with more favorable
deep layer shear could promote a few organized strong storms
Monday into Monday night. Monday appears to be our best shot at
anything significant through the extended period with dry air
filtering into the state behind the cold front.
Near normal temperatures are expected through the period,
reinforced by the aforementioned cold front as it brings in drier
and more stable air into the area. Temperatures are expected to
rise into the low 80s, with a gradual warming trend to the mid 80s
by week`s end. Lows will be in the upper 50s and 60s. Have
generally used a guidance blend for the temperatures.
31
AVIATION...
00Z Update...
Scattered convection should dwindle through the next couple hours.
However, there is quite a bit of uncertainty with precipitation
coverage later tonight into tomorrow as most models have varying
solutions. The HRRR seems to handle the current situation the
best, which would mean an increase in coverage by 10Z, continuing
into mid-day. Scattered showers/thunderstorms thereafter.
However, there is a chance that most of the activity will begin a
bit later if the precipitation across SW AL doesn`t move into
west GA late tonight. Also as the winds increase in the morning,
the wind direction is also in question. It is an even split with
the model guidance. As of right now, current thinking is that
winds will be out of the SE by the morning. We may need to adjust
this back to the west if the gradient tightens a bit more than
anticipated. MVFR cigs can be expected by around 15Z and remain
through the rest of the day.
//ATL Confidence...00Z Update...
Low confidence of wind direction and precipitation.
Medium confidence on all other elements.
26
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 88 67 85 67 / 20 20 50 60
Atlanta 86 70 83 69 / 30 20 60 50
Blairsville 82 61 78 63 / 30 20 60 60
Cartersville 87 67 82 67 / 30 20 60 60
Columbus 87 71 86 71 / 40 20 60 40
Gainesville 85 67 82 67 / 20 20 60 60
Macon 88 69 87 70 / 30 20 60 50
Rome 87 67 83 67 / 30 30 60 60
Peachtree City 87 67 84 67 / 30 30 60 50
Vidalia 89 70 88 71 / 30 20 50 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...30
LONG TERM....BDL
AVIATION...26
Area Forecast Discussion
National Weather Service Grand Rapids MI
957 PM EDT Sat Jun 3 2017
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 300 PM EDT Sat Jun 3 2017
A low pressure system will bring scattered showers and a few
thunderstorms overnight and Sunday. However most of the weekend
will be dry. Cooler weather is forecast early next week before
temperatures moderate back to near normal for this time of year
for mid to late week.
&&
.UPDATE...
Issued at 957 PM EDT Sat Jun 3 2017
MUCAPE values across West Michigan have crept up this evening to
around 2000 j/kg near Big and Little Sable Points. The RUC shows
MUCAPE values of 1000-2000 j/kg persisting north of Muskegon
through midnight or so. The RUC shows a 850mb low level jet of
30-40 knots continuing through that time as well across Central
Lower which then progresses south overnight through the entire
forecast area. So, favorable air is expected to continue for the
next few hours for convection across West Central and Central
Lower Michigan off to the north of Grand Rapids. Overnight, as the
convection works into the I-96 corridor a weakening is expected as
the instability wanes.
Strong wind gusts have occurred in Northeast Wisconsin this
evening with an outflow boundary propagating out ahead of the
convection. The outflow moving out ahead of the convection would
lead to a dissipating trend as the inflow is cutoff some. Lake
Michigan may not play a big role here as the air over the lake is
still cold and the convection will likely remain elevated and not
ingest the cold stable lake air.
Bottom line, threat for some marginal wind gusts and hail are
possible through 100am or so north of Muskegon and west of U.S.
Highway 131. Thinking wind gusts of 45 mph or so are possible.
Expecting some showers to move through the I-96 corridor overnight
and into the I-94 corridor late.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 300 PM EDT Sat Jun 3 2017
Main short term fcst concerns involve determining convective
potential late tonight through Sunday night.
Showers over central and southern Lake MI have been dissipating as
they move further east into the drier airmass over our area. The
majority of our fcst area should stay dry late this aftn/early
evening but a few light rain showers and sprinkles will affect our
northwestern fcst area and lakeshore counties.
The combination of the northeastward moving warm front and low
pressure/cold front approaching from the west late tonight will
result in development of scattered showers and a few thunderstorms
overnight. Convection should first develop up around Ludington
late this evening and then gradually overspread the rest of our
fcst area from nw to se overnight.
Convective potential overnight is mitigated by several factors
including weak sfc/elevated instability and lack of stronger
forcing and a fairly weak llj. Convection will potentially be
relatively stronger up around KLDM late this evening before the
band gradually weakens as it advances slowly southeastward
overnight. In fact our southern fcst area may receive little if
any rainfall overnight.
Scattered showers will linger Sunday along with potential for a
few storms. However given cold frontal timing we would expect
potentially stronger convection to develop southeast of our fcst
area as indicated by the day 2 spc convective outlook.
A strong shortwave will dive down from the nnw and bring potential
for scattered showers and perhaps a few thunderstorms Sunday
night. Scattered showers will linger into Monday with the upper
trough axis over the eastern Great Lakes region by then. At this
time we will keep the fcst for Monday night dry with a drier
airmass in place by then. However it is not impossible that
another stronger shortwave dropping down from the north could
bring a few more showers.
.LONG TERM...(Tuesday through Saturday)
Issued at 300 PM EDT Sat Jun 3 2017
The long term period is forecasted to start off cooler than
normal...then a possible warming trend may develop as we go into the
weekend.
A mid level low will be tracking southward through the eastern Great
Lakes Region on Tuesday. Moisture wrapping around this system
combined with some heating could lead to a few showers during the
day. The 925 mb thermal trough will be pulling through so this
should keep high temperatures below normal.
This mid level low pulls away from the area Wednesday into Thursday.
It will be replaced by a ridge. This should result in fair weather
for the area. Near seasonable temperatures are expected.
The temperature are forecasted to be moderating here in MI for the
end of the week and into the weekend as a deep upper low moves
onshore in the Pacific NW. To the east across the Upper Plains...a
large mid level ridge sets up. This pattern supports deep warming
here in the Great Lakes region. Through Friday...the mid level flow
remains NW...which will have to be monitored for possible elevated
convection which the models tend to struggle with...similar to today.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 827 PM EDT Sat Jun 3 2017
A line of showers and storms are located across Northeast
Wisconsin at 00z, about to move out over Green Bay. The storms
will move south and east through the evening and move into Western
Lower Michigan toward 03z of 04z. The storms may still be strong
as they move into the Ludington area around 04z, but will likely
lose strength as the drop further south into the TAF sites.
Therefore, only have VCSH in the TAF at this point as we are
expecting a significant downward trend in intensity after 05z or
so.
Essentially expecting VFR conditions throughout the TAF period.
The only exception may be a brief dip in conditions with the line
of dissipating showers overnight.
&&
.MARINE...
Issued at 300 PM EDT Sat Jun 3 2017
Fairly minimal wind speeds and wave heights are forecast through
Sunday but thunderstorms will pose a hazard to mariners late this
evening and overnight. A decent north flow wind and wave event is
anticipated late Sunday night and Monday with strong cool air
advection.
&&
.HYDROLOGY...
Issued at 106 PM EDT Sat Jun 3 2017
River levels are mostly around normal for this time of year and much
below bankfull. Expecting showers and thunderstorms into Sunday
night, but rain totals should be below a half inch. Additional
storms are possible late in the week. Rivers may experience small
rises, but no flooding is expected through the week.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
UPDATE...Duke
SYNOPSIS...Laurens
SHORT TERM...Laurens
LONG TERM...MJS
AVIATION...Duke
HYDROLOGY...63
MARINE...Laurens
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1010 PM EDT Sat Jun 3 2017
.SYNOPSIS...
A moist southerly flow will develop tonight and continue on Sunday
with showers and storms increasing ahead of an approaching cold
front. Expect the front to cross our region Monday night with
slightly cooler and drier conditions developing through the week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 1010 PM EDT Saturday: Convection continues to wind down
as diurnal heating and thus instability is lost. That said,
the most recent HRRR does favor weak/brief redevelopment across
the lower NC and upper SC piedmont in the immediate near term,
which looks to be underway per recent radar returns. This is
not expected to last long, and any threat of tsra is minimal to
non existent at this point, therefore will clear the HWO shortly.
Otherwise, think chances for patchy overnight fog are a bit elevated
from days past given increase BL moisture, especially for locales
that experience rains this past afternoon/evening such as the GSP
metro area. Beyond that the current fcst remains on track with
only minor tweaks needed to t/td trends.
Previous Discussion: A more robust cumulus field has developed
across the CWFA over the past few hours with the best coverage over
the central and southern mtns. The latest RADAR mosaic has a few,
weak isolated cells trying to develop over the escarpment, but
none have yet to grow very tall. I still anticipate more convective
cells to fire up over the area over the next few hours with better
coverage more likely over the escarpment and higher terrain,
however the latest CAM runs have been on an overall downtrend wrt
to coverage. Limited severe potential exists, especially downburst
winds, but most cells should remain sub-severe. Otherwise, the
upper ridge axis will continue to move farther of the east coast
as another potent upper shortwave digs down over the Western Great
Lakes later tomorrow and into Monday. At the sfc, the weak boundary
is expected to continue to dissipate near our southern zones
through the period as the persistent high shifts eastward. This
will allow more moist SLY flow to overspread the region tomorrow
and Monday. Chances for more widespread convection ramp up thru the
day tomorrow, with increased instability and dewpts. The severe
potential will be better tomorrow than today, however significant
organization still looks unlikely with little in the way of bulk
shear and helicity. Temps will remain above climatology thru the
period, however highs should be a few degrees cooler tomorrow
compared to the past few days.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 230 PM EDT Saturday: A more interesting forecast for the first
part of next week as the model guidance shows more interaction
between a strong short wave digging down from the upper MS River
valley/upper Midwest and an upper low over the Srn Plains. There
are two interesting trends in the model guidance. One trend in
the guidance is toward stronger SW flow at 850 mb out of the old
upper low to our SW on Monday, which brings better shear across the
region during peak heating on Monday afternoon. The operational
model solutions now have shear on the order of 25 kt to go along
with sfc-based CAPE on the order of 1500-2000 J/kg, instead of
the weak shear like they previously depicted. This suggests more
of an opportunity for storm organization a bit farther S than the
Day 3 Outlook based on the previous model cycle. The potential
is still not great enough to mention in an Outlook, but is worth
noting and keeping in mind. The other trend seems to be toward
a larger plume of deep moisture and stronger moisture transport
from the Gulf of Mexico out ahead of the system approaching from
the west Sunday night and Monday. Precipitable Water values in the
guidance now creep up toward 2 inches, which is above 150 pct of
normal. Fcst soundings also show a deep warm cloud layer and the
potential for small MBE velocity. This raises the possibility of
a heavy rain/flash flood threat and would not be surprised to see
the Day 3 Marginal expand in the Excessive Rainfall Outlook.
As for the details of the forecast, the increasing moisture and
forcing suggest retaining at least a chance overnight Sunday
night, then a gradual increase in precip prob on Monday as
heating develops. Will resist going with a categorical at this
time, because of the overall convective nature of the expected
precip. Clouds and precip should keep temps on the cooler side of
normal. The main short wave is expected to cross the region from
the NW on Monday evening and should help to drive a surface front
across the region to the SE as well. Precip chances will drop from
the NW as a result. On Tuesday, there is some debate as to how
far the front makes it to the S. The boundary may hang up close
enough that a passing wave could bring the nrn extent of showers
across the srn third of the region, especially if some low level
convergence sets up in the Savannah R basin. Temps will again be
a bit below normal with the front to the S. Expect any lingering
precip to dry up Tuesday evening.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 150 pm EDT Saturday: At 12Z Wed the upper level trough axis
still west of the Appalachians and should gradually cross our region
Wed night from the NW. Dry air in place under weak surface high
pressure as an upper ridge builds over our part of the nation into
the weekend. While this occurs, a deep upper trough and / or closed
upper low develops over the Pacific NW and upper Rockies. Although
national guidance has a cold front stalling over the Virginias next
weekend, both the GFS and ECMWF suggest the crosses the Carolinas
Saturday night in accordance with the upper trough located off the
East Coast. The GFS has convection breaking out over GA and the
Carolinas late Friday and late Saturday while the EC has some random
convection passing over NC on Saturday. Although plenty of dry air,
there is enough moisture to generate widely scattered convection
with the front approaching so put slight chance POPs in for at least
the NC mtns and foothills.
Coolest day on Wed with temps about 5 degrees below normal and then
just below normal Thursday. Temps back to near normal Friday and
Saturday.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: VFR conditions expected to dominate through
the overnight with the exception of possible fog restrictions
at KAVL given increased moisture, as well as at KGSP/KGMU given
recent rains. Could see the same at KAND as an outflow continue
to move southward possibly spawning new development over the next
few hours. Did start KAND with VCTS, while favoring only VCSH
at the other SC Sites. Otherwise, persistent llv moisture will
keep conditions favorable for weak convection into the evening,
possibly spreading northward into the Piedmont. Not expecting any
shra/tsra at KCLT, however wouldn`t rule out some nearby ground
fog by daybreak if such precip does occur. Moisture will continue
to increase in the llvs through the period given redevelopment
of sly flow thanks to the transient surface ridge, thus did favor
lowered MVFR level few/sct stratus/stratocu on Sunday regionwide,
with cigs certainly possible, especially adjacent to any convection.
Speaking of such, CAM guidance favors convective development across
the western tier of the fcst area first, before spreading east into
the afternoon/evening as deep instability prevails. Therefore all
tafs feature some flavor of prob30s and or prevailing shra/tsra
late in the period with timing based on a CAM consensus.
Outlook: Better coverage of afternoon/evening showers and storms
is expected Sunday afternoon/evening and especially Monday. There
will also be increasing chances for early morning fog and/or low
stratus, especially over the mtn valleys. Drier air and NLY flow
is expected to return behind the cold for Tue and Wed.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT High 100% High 100% High 95% High 100%
KGSP High 100% High 98% High 98% High 100%
KAVL High 100% High 90% High 100% High 100%
KHKY High 100% High 100% High 98% High 100%
KGMU High 100% High 100% High 100% High 100%
KAND High 100% High 95% 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:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...CDG/JPT
SHORT TERM...PM
LONG TERM...DEO
AVIATION...CDG
Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
757 PM CDT Sat Jun 3 2017
.NEAR TERM...(Tonight)
Issued at 757 PM CDT Sat Jun 3 2017
Latest convective trends have been for northward moving outflow to
generate weaker showers over north AL and a few pulse t-storms in
western portions of southern middle TN. With loss of daytime heating,
believe the showers will become more stratiform and decrease in
coverage. That being said, HRRR and other short range guidance
suggest another surge of activity over much of central AL late
tonight as a mesoscale vorticity lobe in southern MS lifts northeast.
The going forecast for an increased in PoP late tonight into Sunday
morning looks good. Locally heavy rainfall appears likely tonight,
mainly over central AL with this feature. We may have to deal with it
more on Sunday morning.
.SHORT TERM...(Tonight through Monday Night)
Issued at 245 PM CDT Sat Jun 3 2017
The overall synoptic pattern will gradually begin transitioning
tonight. An upper level disturbance over W. TX is continues to slowly
push eastward. North of the Great Lakes, another upper level low is
diving southeastward. This low will help guide its southern
counterpart a bit further south as it approaches the ARKLATEX region.
Given this set up, deep south-southwest flow through the midlevels is
expected through tomorrow. Model PW may approach 2 inches in some
locations. The threat of widespread rain with embedded thunderstorms
is expected after sunrise tomorrow and will persist through Monday
afternoon before a front starts to sweep into the region. Areal
average rain totals could reach 2 inches, with locally higher
amounts. Given this potential, there will be a threat of flooding
over the next couple of days, especially in areas of poor drainage.
Temperature-wise: expect conditions to moderate through the
beginning of the week given the increased cloud cover with daily
highs in the upper 70s to low 80s.
.LONG TERM...(Tuesday through Friday)
Issued at 245 PM CDT Sat Jun 3 2017
Models are in fairly good agreement that the front finally pushes
into southern Alabama by early Tuesday morning. There may be just
enough forcing and left over moisture behind the front to produce a
few showers on Tuesday. Mostly cloudy conditions will likely hold on
for most of the morning hours, before clearing. Fairly warm low
temperatures in the lower to mid 60s and afternoon sunshine should
still allow highs to climb into the upper 70s to lower 80s, despite
some cold air advection.
Cooler and drier air will continue to push south behind the front,
particularly Tuesday night into Wednesday, as northerly 925 mb winds
around 20 knots develop. The source region of this advected air
originates from the Great Lakes region. Thus, adjusted forecast
temperatures a bit below blended guidance. Lows between 55 and 60
degree look reasonable given upstream dewpoints forecast by models.
Winds should stay around 5 knots keeping a fog at bay.
This dry and cool pattern will continue through Thursday, with
temperatures starting out in the lower to mid 50s and highs climbing
into the 75 to 80 degree range. A warm up begins Thursday night into
Friday, as more low level moisture returns via southerly flow in the
boundary layer. Enough moisture may return to locations in
northeastern Alabama by Saturday for a few showers or storms to
develop. Temperatures should climb back into the mid 60s for lows and
mid to upper 80s for highs by Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 547 PM CDT Sat Jun 3 2017
Small clusters of thunderstorms and showers in a band from NW through
central AL may impact the KMSL vcnty over the next 1-3 hours. This
may reduce vsby briefly into the MVFR range (~4sm) but possibly IFR
(~1sm). It is less certain that this activity will reach KHSV, so
have held out of their TAF. Activity should wane after sunset, but
could pick back up again toward morning as an additional upper level
disturbance tracks northeast into the area. Lower clouds of
010-020agl (MVFR) may develop as well by 10Z. Showers and
thunderstorms will become numerous on Sunday as daytime heating
progresses. Have included VCTS at both KMSL and KHSV from 15z onward.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...17
SHORT TERM...Barron
LONG TERM...KDW
AVIATION...17
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Northern Indiana
724 PM EDT Sat Jun 3 2017
.SYNOPSIS...
Issued at 328 PM EDT Sat Jun 3 2017
Chances for rain will steadily increase tomorrow as a cold front
approaches the area. Scattered thunderstorms are expected by
afternoon. A few of these storms may be strong to severe with
isolated damaging winds possible. Lows tonight will be in the mid
60s with highs tomorrow in the mid 80s. Cooler and drier conditions
expected for the rest of the week.
&&
.SHORT TERM...(This Evening through Tonight)
Issued at 328 PM EDT Sat Jun 3 2017
Playing chicken with remnant MCV and convection along subtle warm
front draped over western lakes as it tries to push into our area
but encounters increasingly hostile environment. Regional 12Z upper
air soundings tell the story with very dry conditions below 700mb
and relatively warm midlevel temps. Longwave pattern favoring
general height rises with AVA/subsidence and as such, convection is
struggling. Radar mosaic certainly shows weakening trend for
activity over Lake Michigan. Only question will be if any decaying
showers manage to survive into our northwest CWA early this evening.
Last few runs of HRRR and radar mosaic would suggest a slight chance
in at least Berrien/Cass but chance of measuring seems too low to
mention based on latest obs and radar data. Even if precip does
survive, it will be very light and not expecting any thunder,
limiting impact. This activity should dissipate completely around
sunset with loss of diurnal heating and complete shearing out of
midlevel vort max.
Latest guidance trending much drier for most of the overnight period
in our area. As upper low across Central Canada digs SE, convection
currently developing over Northern Wisconsin will grow upscale and
spread E/SE overnight. Best height falls and associated
LLJ/isentropic ascent remain north or our CWA with subtle shortwave
ridging over us for most of the night. Some residual
showers/isolated storms may clip our northern counties in the early
morning hours but better moisture convergence remains along warm
front lifting through Lake Huron and expect just SCT convection at
best. A few rumbles of thunder possible but stable boundary layer
will prevent any gusty winds and warm midlevel temps/limited MUCAPE
suggest a very low hail threat.
&&
.LONG TERM...(Sunday through Saturday)
Issued at 328 PM EDT Sat Jun 3 2017
Main concern for the long term period will be convection/severe
weather potential tomorrow with very little impactful weather
thereafter. Prefrontal troughing/confluence (leftover from overnight
activity) will settle into our CWA tomorrow and diurnal heating
expected to touch off a few showers/storms during the afternoon.
Much will depend on degree of surface moisture pooling/dewpoint
trends during the afternoon. NAM12 70 degree surface dewpoints (and
subsequent SBCAPE values) likely much too high but mid 60s possible
based on upstream obs and other guidance. With moderate insolation
and decent midlevel lapse rates, this still yields around 1000 J/kg
of 0-1km MLCAPE. Primary vort max doesn`t arrive until late in the
day but expect there will be enough low level convergence to touch
off SCT storms by mid-afternoon given little/no capping. Question
will be do they reach severe thresholds. Wind/shear profiles are not
very supportive, around 25 kts 0-6km at best and that is not until
around 00Z in the evening as midlevel wave approaches. 850mb winds
20-25 kts and some low level dry air/DCAPE could support an isolated
damaging wind gust but threat for widespread severe weather is low
given lackluster instability.
Convection exits around 03Z tomorrow evening and expect generally
dry conditions through the rest of the week. Upper low will set up
over northeast CONUS and a few sprinkles possible on the backside
(especially Tue) but our weather will be primarily influenced by
strong midlevel ridge and associated surface high to the northwest.
This also results in highs slightly below normal for early June.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 717 PM EDT Sat Jun 3 2017
Left over convective complex slowly dissipates southeast out of
Lake Michigan with showers that appear to be struggling to reach
the ground. Expecting the region to remain mostly dry overnight
with continuing VFR conditions as convection across the UP dies
upstream. However, a lingering shower can`t be ruled out for early
Sunday. Then, low pressure will be sliding southeast out of the
UP dragging a cold front south that will set up across the region
Sunday. Within an area of 1000 J/kg MLCAPE and meager shear,
storms are expected to fire Sunday afternoon, but overall severity
is in question. Also expect diurnal mixing to occur allowing for
wind gusts around 20 kts during the afternoon.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Roller
Visit us at www.weather.gov/iwx
Follow us on Facebook...Twitter...and YouTube at:
www.facebook.com/NWSNorthernIndiana
www.twitter.com/nwsiwx
www.youtube.com/NWSNorthernIndiana
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
643 PM CDT Sat Jun 3 2017
.SHORT TERM...(This evening through Sunday)
Issued at 332 PM CDT Sat Jun 3 2017
The RAP model and Satellite indicate the upper low across Nern Colo
will drop south this evening. It would appear this process is
occurring as a the upper low across Srn Canada moves east toward the
Great Lakes. The SREF was the basis for rain chances this evening.
Once the upper low moves south late this evening, rain chances will
end.
A fairly dry Pacific high moves in tonight and this will send dew
points back into the the 40s by morning. A blend of the MET/MAV
guidance plus bias correction suggested lows in the 40s and 50s.
None of the models or guidance indicated fog despite the strong
radiational cooling tonight. The subsidence may be too strong and
north winds develop which does not favor moisture pooling. It is
also possible the models are wrong but the forecast will be fog-free.
Sfc high pressure moves overhead Sunday and generally clear skies
should prevail. The deeper moisture will still be across Srn Neb but
no forcing will be available for thunderstorm development. The
guidance blend plus bias corrected produces highs in the 80s with
very light winds.
.LONG TERM...(Sunday night through Saturday)
Issued at 332 PM CDT Sat Jun 3 2017
High pressure ridge will remain nearly stationary from the desert
southwest into up into the Rockies though the end of the week. This
spells weak northwest flow aloft on the eastern periphery of the
ridging across our area. Low level/surface flow will mainly be south
to southeast helping to maintain at least mid 50s dew points through
the end of the week. Afternoon heating will lead to widely scattered
thunderstorms just about each afternoon this week as there is very
little in the way of capping aloft. The best chance will be Tuesday
afternoon when a weak shortwave disturbance slides southeast across
the region.
By Saturday a large upper level low pressure system should be
located across southwest Canada into the Pacific northwest. This
will nudge the upper level ridging east over our area. Chances for
thunderstorms will decrease or end all together by this time as
temperatures aloft warm considerably.
Temperatures wise expect a warm week, with highs mostly in the 80s.
Upper 80s to near 90 are expected by Saturday as the upper level
ridging begins to dominate.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 641 PM CDT Sat Jun 3 2017
Isolated thunderstorms over central Nebraska will continue to
diminish. Light and variable winds expected over night with mostly
clear skies. Visual Flight Rules.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...Taylor
AVIATION...power
Area Forecast Discussion
National Weather Service Elko NV
254 PM PDT Sat Jun 3 2017
.SYNOPSIS...High pressure will provide warm and dry conditions
across the state with highs reaching 90 degrees in many spots on
Sunday. A weak disturbance will bring a few more clouds and the
possibility of thunderstorms Sunday afternoon and evening
primarily north of I-80. Dry conditions will return for most of
next week.
&&
.SHORT TERM...Tonight through Monday. Warm and dry conditions will
persist through Sunday morning. A quick-moving short wave trough
with an accompanying cold front will move across the state
Sunday. Primary forecast hurdle Sunday will be available mid to
upper-level moisture for thunderstorm development across northern
Nevada Sunday afternoon and evening. This is a relatively small
scale feature that the global models are seemingly not resolving
well but NAM and RAP maintain a stronger SW-NE oriented axis of
instability from Eureka county through the Ruby Mountains and into
NE Elko county. Dry sub-layer on Sunday extends up to 550mb with
precipitable water values around 0.50 in should promote limited
dry thunderstorm activity so maintained isolated coverage.
Sunday night and Monday. Cooler temperatures behind the cold front
will move into the state Sunday night and Monday suppressing high
temperatures about 5 degrees from Sunday highs. Otherwise, dry
conditions will exist Monday as ridging builds back over the
state.
.LONG TERM...Monday night through Saturday
Long term period will start with an upper-level ridge building
developing and and ridge axis setting up shop just east of the
region with dry southwest flow for the state. This will allow
temperatures to jump right back up to near record-breaking
territory for Tuesday and Wednesday. Highs will climb up to the
upper 80s to mid 90s while nighttime lows will dip back down into
the upper 40s to 50s.
Starting Thursday a strong upper-level low begins to drop south
out of the Gulf of Alaska towards the Pacific NW Coast. In
response, the upper-level ridge begins to shift east and winds
increase out of the southwest with the tightening pressure
gradient. Increasing moisture will also allow for some high-level
clouds for northwest NW. In response, temperatures start to cool
a little in the northwest, though a tight temperature gradient
will exist from northwest to southeast, so cooling will be little
if any in our southeast region. Models are in fairly good
agreement now with path of the low to our north on Friday and
Saturday and with a cold frontal passage across northern and
central NV on Friday bringing showers and thunderstorms. Lingering
showers on Saturday with possible high mountain snow showers down
to 7000-8000 ft across northern NV. Expect a respite from the
heat as well temps with highs in the 70s to mid 80s for Friday and
Saturday and nighttime lows in the upper 30 to 40s. Winds will
also be quite breezy Friday and Saturday with advisory level
winds possible on Friday with the cold frontal passage.
&&
.AVIATION...VFR conditions through with a few mid to high level
clouds. Breezy winds will dissipate quickly after sundown but
quickly pick back up tomorrow afternoon from the south to
southwest, gusting 20-30kts at times.
&&
.FIRE WEATHER...A weak cold front along with an upper-level
disturbance could generate a few dry lightning strikes across
northern Nevada Sunday. However, limited atmospheric moisture will
limit coverage of dry thunderstorms to isolated on Sunday
afternoon and a mix of dry and wet showers and thunderstorms
by Sunday evening. Afternoon RH values will drop below 15% south
of I-80 over the next few days but winds will remain below red
flag criteria particularly in fire zone 468 where fuels are
critical.
&&
.HYDROLOGY...Snowmelt in the higher elevations continues to
increase due to persistent warm temperatures over the past few
days as indicated by rising stream gage heights.
Lamoille Creek continues to trend towards higher flows. The creek
normally peaks in the evening. However, a weak cold front will
bring cooler temperatures Sunday and Monday to northern Nevada
which may temporarily decrease the rate of snowmelt. An areal
Flood Warning is in effect as Lamoille Creek will fluctuate
around minor flood stage each evening.
The Jarbidge River continues to run high and is expected to rise
again early next week
The Humboldt River at Battle Mountain continues to run high and is
rising. The river could reach flood stage again next week.
The lower Humboldt River from Comus downstream through Winnemucca
to the Humboldt/Pershing County border is running high and could
experience another rise next week near minor flood stage.
Wildhorse Reservoir is still flowing over the spillway. There is
no threat for flooding at this time downstream along the Owyhee
River.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
93/84/84/93
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
634 PM CDT Sat Jun 3 2017
.SHORT TERM...
228 PM CDT
Through Sunday...
Hybrid lake breeze/outflow boundary from morning convection over
Wisconsin continues to push south across portions of the Chicago
metro area dropping temperatures a good five degrees or more over
the suburbs while areas along the lake front have fallen back into
the 60s. Farther west, the boundary has begun to slow its
southward progress over Lee and Dekalb counties but is helping to
kick off a few showers. Moderately unstable conditions are in
place out ahead of the boundary and there is a threat for
additional isolated showers and thunderstorms area wide, but
particularly in the vicinity of the boundary which is the only
notable source of lift. Aloft, weak mid and upper level ridging is
in place and should help keep coverage limited through the
remainder of the afternoon and evening. Weak winds throughout the
column should keep storms from becoming organized and minimize any
severe threat today.
Overnight, a strong upper wave digging into the Upper Midwest
will result in height falls across the region and result in
additional showers and thunderstorms to our north. NAM/ECMWF keep
most of the precipitation north of the CWA, with thunderstorms
dissipating as they near our CWA late tonight into early Sunday
morning. The GFS meanwhile is a little faster and develops
scattered convection after midnight. Given the unfavorable diurnal
timing and better forcing staying just to our north, prefer the
drier solutions for the local CWA but will maintain some slight
chance/low chance PoPs as a nod to the GFS and some of the high-
res models such as the HRRR which also maintain convection into
the local area. Deep layer shear increases some this evening in
advance of the upper wave, but tops out 25-30kt. Given the sub
optimal shear and unfavorable diurnal timing...thinking the severe
threat will continue to be very low this evening and tonight.
Focus will likely shift south of I-80 on Sunday where thunderstorms
will once again redevelop within a moderately unstable environment
likely tied to remnant outflow boundaries. Shear does not improve
any during the day Sunday, so any severe threat will be marginal,
with strong localized downburst the primary severe concern.
Deubelbeiss
&&
.LONG TERM...
133 PM CDT
Sunday night through Saturday...
Pre-frontal trough will be in the process of clearing our
southern CWA Sunday evening, with some lingering threat of
scattered showers and storms. The true synoptic cold front is
expected to pass across the region later Sunday night and the set
the stage for a couple of chilly early June days to kick off the
week, especially near the lake.
Unseasonably strong upper low is progged to dig into the eastern
Great Lakes region and New England early in the week helping
encourage a low to develop and track up the coast. Tightening
pressure gradient between that low and high pressure over Ontario
south into the upper Mississippi Valley will result in brisk
northerly winds Monday. The strong winds blowing down the full
fetch of the lake will keep temps near the lake struggling to
reach the low 60s, with 60s for highs over a good portion of the
Chicago metro area, with lower to mid 70s well inland across and
southern and western CWA. Tuesday will moderate a bit with less
wind and a more typical lake breeze. Could see some post frontal
low cloudiness Sunday night into Monday morning before skies
likely clear out during the afternoon.
Upper trough will move east during the middle and end of the
upcoming work week and allow for a steady moderating trend, though
lake will augment the moderation during the afternoon Wednesday.
By Thursday and especially Friday, it appears as though there will
be enough of an offshore component to likely hold lake breeze at
bay. By Friday, a weak cold front could approach bringing some
threat of showers and thunderstorms, otherwise the entire week
looks dry.
- Izzi
&&
.AVIATION...
For the 00Z TAFs...
Southeast winds gradually becoming southwest through mid-late
evening, and the potential for a period of showers late tonight
are the main aviation concerns this evening.
Combination lake breeze/outflow boundary had pushed through
terminals earlier today. 88D vertical wind profiles depict south-
southeast flow aloft however, and surface observations indicate a
gradual veering of wind direction is already occurring. Southeast
winds early this evening are expected to become southwest by late
evening, with speeds less than 10 kts. Isolated shra/tsra which
have been focused along outflow boundary(ies) west of Chicago
area are expected to dissipate early this evening with the loss of
diurnal heating.
Attention then turns to a weak cold front across the upper
Midwest, which will sag across the area very late tonight into
Sunday. Area of shra/tsra currently along/ahead of the weak front
is expected to weaken significantly overnight while approaching
the forecast area, though may produce some shra/isolated tsra
after 08-09Z. Convective-allowing guidance indicates continued
weakening of this activity as it moves into far northern IL early
Sunday morning. Redevelopment is then expected by early-mid
afternoon along the boundary, which should be south of the
terminals by that time. Have indicated a PROB30 for tsra at GYY,
though expect activity to be south of the other northern IL TAF
sites. Southwest winds to shift northwest behind the front, with a
period of some gusts in the 15-20 kt range possible in the
afternoon.
Ratzer
&&
.MARINE...
133 PM CDT
Main marine concern is the period of unseasonably brisk northerly
winds very late Sunday night through Monday, with a period of 30kt
northerly winds possible Monday, especially closer to the shore
where water temps are warmer and stability weaker. While full
fetch northerly flow will continue through Tuesday, the magnitude
will ease a bit Monday afternoon, but likely remaining upwards of
20kt at times through Tuesday. By the middle and end of the week
more typical June-like stable conditions are expected over the
lake with lighter winds and smaller waves.
- Izzi
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Updated for 00Z aviation forecast discussion.
&&
.SHORT TERM...(Tonight through Monday night)
Issued at 1229 PM CDT Sat Jun 3 2017
Fairly high confidence in the short term.
A ridge axis was bi-secting the fa today from southeast to
northwest. This is creating a difficult informant for storms to
survive. With only showers so far on radar. However surface based
instability does support thunder especially over SEMO with some
development to the north of the ridge axis. Also the dewpoint
gradient is playing a significant role with the main gradient
across PAH FA...with around 60 to the northeast to near 70 along
the MO/AR border. Tonight the models want to increase rain chances
as the dewpoints increase and the high starts to give way to an
approaching trough over the southwest. This trough begins to phase
with another or parent low over the great lakes area. However we
do develop a shallow surface inversion so convection should be
elevated slightly overnight. Still elevated CAPES are low around
100-300 j/kg2. Chances will peak Sunday and Sunday night as a cold
front approaches the area. Models have slowed the passage
slightly with the latest runs but still are in fair concert. The
HRRR would suggest nothing more than a couple showers over SEMO
tonight I am not comfortable following that solution with most all
models showing more widespread chances. The cold front will
actually move through Monday with cooler drier air in its wake.
.LONG TERM...(Tuesday through Saturday)
Issued at 1229 PM CDT Sat Jun 3 2017
Higher than average confidence in the extended with above average
agreement among the models.
Models are in good agreement on a cooler and drier week ahead in
the extended. High pressure will dominate the weather pattern
through the extended. Temperatures will increase through the week.
Rain chances remain below 10 percent for any given period but do
start to increase as we approach next weekend. We stay in a fairly
stable northwest flow through the period. By Saturday a weak cold
front stalls along or just north of the fa. This will bring our
next best chance of rain. However until higher confidence is
gained will leave the forecast dry for now.
&&
.AVIATION...
Issued at 620 PM CDT Sat Jun 3 2017
Isolated to sct convection ongoing at this time and mainly will
impact KCGI for the evening hours. Opted for a VCSH for now. Will
monitor. After sunset, activity should wane a bit but then ramp
back up again after sunrise on Sunday. Best coverage should be in
the afternoon hours due to incoming disturbance aloft to aid in
development of convection. Therefore, went with a PROB30 for
Sunday afternoon. Will see activity linger into Sunday evening as
well.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
Area Forecast Discussion
National Weather Service Shreveport LA
1013 PM CDT Sat Jun 3 2017
.DISCUSSION...
Convection continues, mainly across portions of Deep E TX this
evening. Latest high res model runs show this activity eventually
diminishing later tonight, but more developing across our nwrn
areas. Have increased PoPs across our srn and ern areas, and have
left the higher PoPs ongoing across the nw as previously fcst.
Convection is not widespread, but rain rates under nearly
stationary storms have been in the 1.5-3 in/hr window, so some
localized flooding will continue to be possible under the heavier
downpours.
Otherwise, have made a few tweaks to overnight min temps to lower
just a bit closer to persistence/blended guidance. Updated
products already out. /12/
&&
.PREV DISCUSSION... /issued 849 PM CDT Sat Jun 3 2017/
AVIATION...
For the 04/00Z terminal forecast, scattered showers and
thunderstorms will be providing MVFR/IFR flight categories with
low ceilings and visibility restrictions. Away from the
showers and thunderstorms, there will be periods of VFR.
Will see a return of convection during the late night and
through the morning hours Sunday. Not confident that VFR
conditions will be returning for the afternoon Sunday. Surface
winds will be light and variable to light South less than 7
knots overnight and could see South to Southwest winds of 5-10
knots Sunday. In and near the thunderstorms winds will be
variable around 10-15 knots with gusts to 25-30 knots. /06/
PREV DISCUSSION... /issued 330 PM CDT Sat Jun 3 2017/
DISCUSSION...
Convection has remained scattered this aftn with no real
organization noted. However, a scattered band of convection has
begun to persist, mainly between I-30 and I-20. HRRR also shower
a short tstm segment movg into ne TX this eve. For these reasons,
will go likely pops this eve across nw portions of cwa. the lazy
upper low will slowly shift south across the Red River into ne TX
by late Sunday. Pops will generally be on the increase across the
area as this upper low gains in proximity, especially closer to
the low center, but also coming onshore with increased southerly
flow. Pops to finally begin to taper off gradually as drier air
to the north of the sagging low center infiltrates into the area
by mid week. However, models are fairly transient with areas of
deeper moisture and boundaries with no clear focus on prolonged
rain which could warrant any kind of flood watch, so will not
consider attm. Temps will remain fairly persisted, particularly in
regard to overnight lows, but with cloud based variations with
regard to aftn highs. /07/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 72 83 71 83 / 50 70 50 60
MLU 71 82 72 83 / 50 70 40 60
DEQ 70 83 69 84 / 60 70 50 50
TXK 71 83 69 83 / 50 70 50 50
ELD 70 82 70 84 / 50 70 40 60
TYR 71 84 71 83 / 50 60 50 60
GGG 71 84 71 83 / 50 60 50 60
LFK 72 84 72 84 / 50 70 50 60
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
12/06/07
Area Forecast Discussion
National Weather Service Tucson AZ
335 PM MST Sat Jun 3 2017
.SYNOPSIS...Hot daytime temperatures will prevail during the
upcoming week. A few afternoon thunderstorms may also occur mainly
near the New Mexico border.
&&
.DISCUSSION...A few showers were occurring at this time near the New
Mexico border and across about the southern quarter of Cochise
County. Otherwise, clear skies prevailed across western Pima County
with partly cloudy to mostly cloudy skies east-to-south of Tucson.
Based on the 03/12Z Univ. of AZ WRF-NAM and WRF-GFS and several HRRR
solutions, believe any showers/tstms will end around or shortly
after sunset. Thus, have configured the official PoP/Wx grids for
precip to end by 8 pm MST.
A slight chance of afternoon/evening showers/tstms continues Sunday
east of Tucson, then afternoon/evening showers/tstms Monday and
Tuesday should be confined to mainly near the New Mexico border. The
ECMWF was more robust versus the GFS in showing a slight increase in
precip chances east of Tucson Wednesday into Thursday. Thus, perhaps
a slightly further westward coverage of showers/tstms especially
Wednesday, but any measurable precip still expected to be east of
Tucson.
Thereafter, the GFS/ECMWF were quite similar with shunting deeper
moisture well east of this forecast by next weekend as westerly flow
aloft increases in response to a deepening trough over the Great
Basin. A few showers/tstms may yet occur Friday across the White
Mountains, otherwise dry conditions will prevail Friday into next
Saturday.
Want to emphasize for this forecast period that the main concern is
the hot daytime temperatures expected to occur. Based on the various
NWP solutions, opted to raise the inherited maximum temperatures
generally about 1-2 degrees or so on any given day. For example, the
official forecast currently has Tucson with a high temperature range
of 103-106 degrees Sunday into next Saturday.
&&
.AVIATION...Valid thru 05/00Z.
Isolated -SHRA and perhaps -TSRA mainly near the New Mexico border
and International border southeast of KTUS this evening and Sunday
afternoon. Otherwise, SCT-BKN clouds at 10k-15k ft AGL mainly east
to south of KTUS this evening and Sunday afternoon. Clear skies to
FEW clouds above 15k ft AGL at other times. Surface wind variable in
direction mainly less than 12 kts, though afternoon gusts near 25
kts due to daytime heating. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...A few afternoon thunderstorms will occur mainly near
the New Mexico border during the upcoming week. Most rainfall
amounts will be quite light. However, brief gusty and erratic winds
may occur due to thunderstorm outflows. Otherwise, dry conditions
with 20-foot winds generally less than 15 mph, although afternoon
gusts will occur due to strong daytime heating.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Francis
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson