Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wakefield Virginia
405 PM EDT Monday Jul 6 2015
unsettled weather conditions will finally come to an end later
tonight as a frontal boundary lifts well north of the area. On
Tuesday...there will only be a slight chance for late day showers
and thunderstorms...along with hotter temperatures. A weak cold
front is expected to stall just north of the area Wednesday night
into Friday...and will bring the chance for showers and thunderstorms.
Near term /until 6 am Tuesday morning/...
latest analysis indicating remnant surface frontal boundary now pushing
north of the County Warning Area. Flow aloft is from the south-southwest with upper low
centered from the upper Ohio Valley into Kentucky. A very moist airmass
remains in place with dew points 70-75 f and precipitable waters from 1.60" to
2.00". Current radar showing diminishing coverage of thunderstorms over
the far southeast....with scattered thunderstorms now the norm over the forecast
area. This as the upper low is weakening/filling in/heights
rising. Thus the overall trigger for widespread precipitation this
evening will be lower than yesterday (but still above climo).
Locally heavy rain again will be primary concern...though trends
are suggesting diminishing coverage by sunset as storms fired
rather early today (which tends to lead to them diminishing early
as well). Some gusty winds also possible in any storms but no
severe weather is expected as effective shear values are fairly
low...20 to 25 knots. Will continue to highlight potential for heavy rain in
severe weather potential statement with generally 40-50% probability of precipitation through 9 PM most areas...dropping off
thereafter. Lows in the upper 60s northwest to the lower 70s most other
areas. Patchy fog possible overnight but coverage expected to be
limited so will allow next shift to determine based on areas where
heavy rain occurs.
Short term /6 am Tuesday morning through Thursday/...
the pattern finally looks to be drier Tuesday...as a stronger upper
level low pushes east from central Canada and allows the upper
low over Ohio/WV to weaken/become engulfed into the stronger mean
flow. Weak ridging aloft develops along/off the southeast and middle Atlantic
coast and low level flow turns more to the south-southwest. Along with rising 850
mb temperatures and increasing amts of sunshine...expect more typical
summertime heat with high temperatures into the lower 90s most areas
(for now stayed a tad below guidance for highs due to the very moist
antecedent conds). Hi temperatures at the immediate coast will be in the
80s. Will maintain a 20% pop in the middle/late afternoon/early evening
period most places...even though forcing is weak. Warm/humid Tuesday
night with lows in lower to middle 70s. Wednesday expected to be rain-free
into the middle afternoon...before a cold front from the northwest drifts closer...combining
west/ heating could result in late day storms...especially across the
northern 1/2 of the County Warning Area. Will have 20% probability of precipitation south to 40% north in the
late aftn/evening. Highs upper 80s/around 90 f far north...to the
Lower-Middle 90s elsewhere (locally 85-90 f at the beaches). Heat
indices near 100 f. Models show some continued shortwave energy
overnight across the NE zones...and will maintain chance probability of precipitation into
early am hours Thursday there. Lows 70-75 f. Continued hot Thursday...highs
again 90-95 f (though again will stay on cool side of guidance for
Long term /Thursday night through Monday/...
southeastern U.S. 500 mb ridge will gradually build west into the Southern
Plains this weekend. This will allow northwest flow to develop over the middle-
Atlantic region by late week into the weekend...with a series of
disturbances diving south. Timing of these features will be
difficult...so mainly went with typical diurnal thunderstorm probability of precipitation of 20-30%
each afternoon/evening through the weekend. Seasonable temperatures are expected
through the period with lows in the upper 60s to middle 70s...and highs
in the upper 80s to low 90s...except low/middle 80s at the beaches.
Aviation /20z Monday through Saturday/...
frontal boundary has lifted north of the region this afternoon
with scattered showers increasing in the southerly flow over
southeast Virginia and northeast NC. Scattered showers and isolated
thunderstorms will continue to affect primary ecg/orf/phf from 18z through
23z. Widely scattered showers will develop closer to ric and sby
by late afternoon and into early evening. Scattered heavy rain
showers will result in IFR visibilities of 1 to 2 miles
especially at orf...phf and ecg between 18z to 23z. Scattered
showers and storms will decrease in coverage faster than the past
A more typical Summer pattern expected for Tuesday into Wednesday. Just
isolated late afternoon/evening thunderstorms will be possible those two days.
relatively benign boating conditions are expected tonight
through the coming weekend as a more typical summertime pattern
develops. Isolated thunderstorms will be possible each afternoon...but Small Craft Advisory
conditions are not anticipated. Seas will remain generally 2-4 feet.
Waves on the ches Bay 1-2 feet.