Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion 
National Weather Service Miami Florida 
820 am EDT Sat may 25 2013 


Update... 
the morning surface analysis showed a weak frontal boundary 
extending west-southwest across South Florida with moderate 
northeast winds and drier air trailing it to the north. The 
latest radar loop showed a line of mainly isolated showers out 
ahead of this boundary over the adjacent Atlantic waters from 
around Bimini island to Key Biscayne. The latest numerical 
guidance has initialized well with these features and generally 
indicates this boundary continuing south through the area today 
with moderate northeast winds and drier conditions expected to 
fill in behind it. As a result...the best chance for showers today 
will be along the coast and out across the Atlantic waters early 
this morning...then inland and over the southwestern portions of 
the peninsula through the afternoon/evening periods (all mainly 
south of a line from feet Lauderdale to naples). At the East Coast 
beaches...expect strengthening rip currents through the day as the 
onshore winds and surf build in the wake of the frontal boundary. 
Outside of a few minor tweaks based on the morning observations 
and trends...the previous forecast remains on track this morning. 


&& 


Previous discussion... /issued 733 am EDT Sat may 25 2013/ 


Aviation... 
scattered-bkn060-080 will affect the East Coast terminals early this 
morning. A few showers and few-sct020-030 will be around mainly 
around kmia and south. Then, drier air moves into the area as 
winds switch from light northwest to NE and really increase by this 
afternoon...ne15g20-25kt. There is a slight chance of showers and 
even a possible tstorm along the Gulf Coast. Included vcsh at kapf 
for now. 


Previous discussion... /issued 453 am EDT Sat may 25 2013/ 


Discussion... 


A weakening and diffuse frontal boundary continues to move southward 
across south central Florida and adjacent waters. Latest regional 
radar returns indicate a line of showers and thunderstorms 
approaching Martin County and moving southward with additional 
showers and isolated thunderstorms ahead of the line across the 
Atlantic waters to the east of Palm Beach County. 


As the boundary continues southward it is expected to continue to 
spawn additional showers and isolated thunderstorms...mainly forecast 
to affect the eastern half of South Florida as the morning 
progresses. For the afternoon...drier air and a middle to upper level 
ridge are forecast to limit chances of convection but with the 
boundary moving through South Florida at that time isolated to 
scattered showers and a slight chance of thunderstorms are forecast 
for the region with any thunderstorm activity mainly expected across 
the southwestern portions of the peninsula and adjacent Gulf waters 
later in the afternoon with isolated showers elsewhere. 


On Sunday high pressure is forecast to build across the southeast 
U.S. And the Florida Peninsula with mainly stable weather expected. 


Over the weekend there will a gradual cooling trend with 
temperatures across the East Coast metropolitan areas on Sunday forecast to 
be in the lower 80s for the East Coast suburbs to middle 80s inland and the 
Naples metropolitan areas upper 80s to near 90. Temperatures will slowly 
rebound through early next week. 


For the extended forecast...the pressure gradient will increase 
across the region over the weekend as low pressure builds along 
the Atlantic sea board and high pressure builds into the southeast 
U.S. And adjacent Atlantic waters tonight into Sunday. Breezy 
conditions will affect the East Coast metropolitan areas later today and 
during the afternoon hours through the remainder of the weekend 
and well into next week. A surge of moisture is forecast to enter 
the region from the Caribbean on Monday with a chance of showers 
and isolated thunderstorms. Additional moisture is forecast to 
enter the region early next week as a middle to upper level trough is 
forecast to deepen in the eastern Gulf with a chance of showers 
and thunderstorms returning to the region. There is some consensus 
amongst the model guidance that deeper layered tropical moisture 
and a deepening of the middle to upper level trough could occur 
around middle- week next week and persist for a couple of days with 
more widespread convection possible. Will have to wait and see if 
future guidance persists with these synoptic features. 


There will be increasing threat of rip currents for the Atlantic 
coast beaches today into next week as winds and seas respond to the 
increasing pressure gradient forecast to build across the western 
Atlantic. Today a moderate risk is expected but by Sunday as winds 
and seas increase a high risk is expected and is forecast to 
continue into next week. 


Marine... 


The pressure gradient will increase across the region over 
the weekend. Winds across the South Florida Atlantic waters are 
forecast to be in the 15 to 20 knot range through the weekend with 
that trend continuing into next week. Atlantic seas are forecast 
to increase to 3 to 5 feet by Sunday and remain in that range into 
mid-week. 


For the South Florida Gulf waters...winds in the 15 to 20 knot range 
are forecast by early Sunday with off shore seas forecast to be 3 to 
4 feet range with these conditions forecast to possibly continue 
into early next week. 


A pre-cautionary statement is in effect for the Atlantic waters 
and Biscayne Bay today and will likely be necessary through the 
weekend. For the Gulf waters a pre-cautionary statement will 
likely be needed tonight into Sunday. 


Fire weather... 


Minimum relative humidities are forecast for Glades and Hendry counties and 
mainly inland Collier County today and Sunday. 


&& 


Preliminary point temps/pops... 
West Palm Beach 85 73 82 73 / 10 - 10 10 
Fort Lauderdale 86 75 84 76 / 20 - 10 20 
Miami 87 74 83 74 / 20 - 10 20 
Naples 93 68 90 67 / 30 - 10 10 


&& 


Mfl watches/warnings/advisories... 
Florida...none. 
Am...none. 
GM...none. 
&& 


$$ 


Discussion/marine/fire...85/ag 
aviation/radar...10/cd