Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus62 kkey 180909 
afdkey

Area forecast discussion
National Weather Service Key West Florida
409 am EST Thu Jan 18 2018

Discussion...
currently...
surface analysis reveals a cold front is pushing through South
Florida and into the Florida Keys this early morning. Strong cold
air advection behind the front has dropped temperatures into the
20s and 30s across north and central Florida, and 40s in South
Florida. Locally, temperatures range from the low to upper 50s
across the island chain, and dew points have dropped into the 40s,
with the Marathon ASOS reporting a TD of 34 degrees as of 4am EDT. Both
kbyx and kamx are completely void of precip echos due a moisture-
starved and low-instability environment. Across our marine
district, cman stations report strong breezes out of the north
approaching 25 knots. GOES-16 nighttime microphysics composite
reveals a high cirrus streaming across the Florida Keys and some
stratocu across the offshore Gulf, with much of central and North
Florida remain clear well behind the front.

Short term (today through tomorrow night)...
the cold front will continue to drop temperatures and dew points
significantly this morning as Continental air creeps down The
Spine of Florida and bleeds into the island chain. Strong cold air
advection out of the north will give the Keys the rare
opportunity for dew points to dip into the 30s today (as already
observed), and highs will struggle to reach 60 degrees, with
conditions remaining windy. Forecast soundings indicate high-
cirrus will likely remain across the island chain - otherwise,
expect a mostly sunny day as the ASOS indicates low ceilings have
already cleared Key West. This afternoon and overnight, the New-
England low pressure system pulls well off the coastline, dragging
our cold front away as the Gulf-Coast high sinks southeast into
the Florida Panhandle. This will effectively shut- off the northerly
fetch of cold air advection down the peninsula, veering winds to the northeast
through Friday night as the anti-cyclone sinks deeper into North
Florida. As a result, temperatures will moderate upward toward 70
degrees Friday, with lows near 60 Friday night. Rain chances?
Nill, though some spotty showers won't be out of the question with
the easterly flow along the warmer waters of The Straits of
Florida Friday night.

&&

Long term (saturday through Wednesday night)...
the anticyclone remains across north/central Florida weakens and
shifts to the western Atlantic this weekend as an upper trough,
cut off from the overall jet stream, sneaks through the
southeastern US. Low level moisture creeps upward from the south
and west accordingly, which gently increases cloud-cover and rain
chances early next week. In the extended period (mid-late week),
there is a potential for another front shifting into the Florida
Peninsula.

&&

Marine...
small craft advisories are in effect for all waters surrounding
the Florida Keys. Strong breezes are expected to gradually relax
this afternoon. High pressure will continue to build southeastward
from the Mississippi Valley today, reaching North Florida by
Friday. High pressure will intensify across the western North
Atlantic Saturday and Saturday night.

&&

Aviation...
until 00z/19th, VFR conditions will prevail at island
terminals. North winds near 15 knots with gusts of around 25
knots will result in significant cross winds. North to northeast
winds will slacken to 10 to 13 knots with occasional gusts between
18 and 20 knots by mid afternoon, before slackening further by
evening.

&&

Climate...
in 1981, the daily record low temperature of 48 degrees
was recorded in Key West. Temperature records have been kept since
1872.

&&

Preliminary point temps/pops...
Key West 59 56 70 63 / 0 - - -
Marathon 59 56 69 63 / 0 - - -

&&

Key watches/warnings/advisories...
Florida...none.
GM...Small Craft Advisory until 11 am EST this morning for gmz031>035-
042>044-052>055-072>075.

&&

$$

Public/marine/fire...mclovin
aviation/nowcasts....apa

National Weather Service Glossary of Abbreviations