Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Newport/Morehead City NC
420 PM EDT Sat may 30 2015
sprawling Bermuda high pressure will extend over the region from
the east through the weekend. A cold front will approach from the
northwest on Monday and gradually stall near the coast middle week.
High pressure builds north of the area late in the week.
Near term /tonight/...
as of 333 PM Sat...the surface ridge will shift slightly farther
away from the region tonight allowing surface winds to shift more
south- southeasterly which will help to increase low level
moisture. The high will remain in place however, which should
yield enough subsidence to inhibit shower development overnight
except for the coastal waters where guidance suggests showers may
develop near the Gulf Stream and move towards the coast late
tonight. Will maintain the slight chance probability of precipitation for the coastal
waters tonight but keep dry elsewhere. Warm and muggy overnight
temperatures again with lows in the middle 60s inland to near 70 coast.
Short term /Sunday/...
as of 333 PM Saturday...similar setup to Sunday as the summerlike
pattern continues with Bermuda high continuing to ridge into east NC.
Have added a 20 pop for areas away from the coast as weak
convergence occurs with inland propagating sea breeze through the
afternoon. Still enough subsidence to prohibit thunder however as
weak capping exists. Temperatures very similar to Saturday and may even
rise a degree or so higher...mid/upr 80s inland to low 80s
Long term /Sunday night through Saturday/...
as of 330 PM Saturday...12z models continue to diverge and only
moderate confidence for Sun night-Tuesday period and below normal
confidence rest of period. Kept dry forecast for Sun night and lowered
probability of precipitation Monday and Monday night. Highest probability of precipitation in 40-50% range Tuesday into
Wednesday...then trended probability of precipitation toward climatology 20-30% rest of period.
Models in general agreement with slower upper low movement Sun night
through Tuesday resulting in slower surface front movement. Main
difference rest of period with GFS indicating upper low opening up
and gradually moving east across area next weekend with surface
cyclogenesis off fla-NC coast. European model (ecmwf) keeps upper low cut off and
pushes it S-southeast into eastern gulfmex Friday-Sat in response to upper ridging
upstream. Used a compromise solution with thinking of surface front
gradually moving into area Tue-Wed...then stalling near coast and
becoming diffuse Fri-Sat. This supports best coverage of
showers/thunderstorms Tuesday-Wednesday with a scattered mainly diurnal threat Thu-Sat.
Monday likely to be warmest day with highs near 90 inland. Highs
mainly low-middle 80s Tuesday-Wednesday with more cloud cover and better precipitation
threat...then warming a few degrees end of week. Lows mainly 60s
inland to around 70 coast.
Aviation /20z Saturday through Thursday/...
short term /through 18z Sunday/...
as of 140 PM Sat...light south-southeasterly winds expected today
with just isolated diurnally driven showers possible this
afternoon and again Sun afternoon...not enough to include in tafs.
Low level parameters indicating a small chance for broken IFR ceilings
and or/visibilities overnight...though based on persistence from last
several nights...will not include in tafs at this time and only hint at
the development with a scattered IFR deck after around 06z.
Long term /Sunday night through Thursday/...
as of 330 PM Saturday...VFR conditions are expected to prevail
through Monday morning with surface ridge extending over area from the
E-NE. A cold front will approach on Monday and move slowly into the area
Tuesday-Wednesday resulting in some periods of sub- VFR conditions with
showers and thunderstorms. Best coverage expected Tuesday afternoon into Wednesday.
short term /through Sunday/...
as of 333 PM Sat...latest observation indicate southeast winds generally around
10 knots across the waters with seas ranging from 2 to 4 feet. High
pressure will continue to dominate the waters with southeast to S winds 5 to
15 knots through Sunday. Local Swan/nwps and wavewatch iv in good
agreement indicating seas mostly 2-3 feet with some 4-5 feet seas
along the outer fringes of the central waters through tonight due
to 9 to 10 second period swells radiating west away from weak
area of low pressure well east of the region.
Long term /Sunday night through Thursday/...
as of 330 PM Saturday...moderate forecast confidence into Tuesday...then
below normal confidence Wednesday-Thursday due to model differences. High
pressure offshore and front approaching from west-northwest expected to produce
southerly flow 10-15 knots Sun night into Tuesday. Front then expected to
stall near coast Wednesday-Thursday with model differences on timing and
location. Forecast will continue to indicate period of NE winds around
10 knots late Wednesday into early Thursday...but low confidence forecast. Seas
mainly 2-3 feet with some 4 feet heights outer portions at times.