Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Miami Florida
747 am EDT Monday Apr 27 2015
Storms expected along the East Coast late morning and this
afternoon. Tempo groups may be added later today as trends
develop. Intermittent IFR conds possible especially considering
some storms could be strong. Guidance not completely in favor of
sea breeze development today, if it does occur, could be around
18z and possibly more from the southeast than east. Convection wanes this
Previous discussion... /issued 423 am EDT Monday Apr 27 2015/
A weak surface ridge continues across the Florida Straits with an elongated
east to west cold front extending across the southeastern states.
The surface ridge will begin to erode today as the cold front
sinks southward into the Florida Peninsula. As the front moves
southward deep layered moisture will return to the region.
Today will start a transition to an active period for convection
lasting through at least Wednesday with latest guidance now
hinting could last into Thursday. The synoptic pattern leading to
this scenario includes a cold front approaching South Florida late
today then stalling around the lake region. Then on Tuesday a
surface low and strong cold front is forecast to rapidly develop
along the Louisiana coast and into the Florida Panhandle Tuesday
night with deep layered moisture across South Florida ahead of the
front. By Wednesday the cold front is forecast to move into North
Florida with the surface low deepening into Georgia with deep
moisture over the region continuing. The cold front is then
forecast to enter central Florida on Thursday with a clearing
trend on Friday. There will also be a transition in the middle to
upper levels during this period with the persistent middle to upper
level ridge across the Gulf transitioning to more zonal flow with
embedded short waves possible through at least Wednesday.
For today...moisture will return to the region...the forecast precipitable water
is 1.7 inches...with chances of showers and thunderstorms
returning. Although west surface winds will continue they will
likely be weak enough for the East Coast sea breeze to develop
thus increasing surface convergence. Unseasonably warm
temperatures today will also contribute to the potential for more
active convection. In addition forecast soundings indicate
increasing middle level westerly winds. So there could be a few
strong thunderstorms with an isolated severe thunderstorm possible
with strong wind gusts and hail.
For Tuesday..regional precipitable waters are forecast to be around 1.7 to 1.8
inches. Forecast soundings reveal middle level westerly winds slowly
strengthening and extending to lower levels as well as a
thermodynamic profile supportive of convection. Although day time
maximum temperatures will be less than today...the dynamical and
thermodynamic factors will be supportive of active convection with
a few strong thunderstorms and an isolated severe thunderstorm
possible with strong wind gusts and hail.
For Wednesday and Thursday...on Wednesday the forecast regional
precipitable water is about 1.8 inches with the potential for widespread
convection across the region continuing. By Thursday the cold
front is forecast to finally enter south central Florida with
scattered showers/thunderstorms forecast and then a clearing trend
finally Thursday night into Friday as the front exits the region.
Stable weather is forecast for the upcoming weekend.
With this wet period expected today through Thursday...locally
heavy rainfall will be possible with the stronger thunderstorms
with minor urban type flooding possible. But also need to note
that as the grounds become more saturated that flood potential
will increase as runoff will occur more easily. So there could be
isolated areas of urban type flooding over the next several days.
Showers and thunderstorms are expected to return to the regional
waters today through Thursday. West to southwest winds generally
in the 10 to 15 knot range expected to continue today although a
transition to easterly winds forecast this evening and tonight. By
Wednesday winds and seas forecast to increase with southwest winds
in the 15 to 20 knot range with Atlantic winds forecast to
increase further to 20 to 23 knot range Wednesday night. Gulf and
Atlantic seas forecast to reach 4 to 6 feet in the off shore
waters Wednesday night.
Preliminary point temps/pops...
West Palm Beach 90 74 86 71 / 50 40 70 60
Fort Lauderdale 91 77 90 74 / 50 30 60 50
Miami 91 76 91 76 / 50 30 50 50
Naples 90 76 88 75 / 20 20 50 50