748
FXUS66 KMFR 190523
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
918 PM PDT Thu Apr 18 2024
...Updated AVIATION discussion...
.DISCUSSION...
Quiet weather continues this evening through tonight with some
mid and upper level clouds moving through the forecast area.
Temperatures have trended a bit warmer compared to last night, so
frost and freeze concerns have diminished west of the Cascades.
Read the previous discussion for more information beyond tonight.
-Smith
&&
.AVIATION...19/06Z TAFs...Atmospheric stability will bring continued
VFR levels under clear skies for northern California and southern
Oregon through the TAF period. Winds will be light and variable
across the area overnight before picking up slightly along the
Oregon coast and over areas east of the Cascades on Friday
afternoon. -TAD
&&
.MARINE...Updated 200 PM Thursday, April 18, 2024...A thermal
trough will continue to bring gusty north winds and steep seas to
all waters into tonight. The thermal trough weakens tomorrow and
conditions will improve. Relatively light winds and low seas
continue into Saturday, though a weak cold front will move through
with some rain. Gusty north winds and steep seas are expected to
return later in the weekend. -Spilde/Hermansen
&&
.PREV DISCUSSION... /Issued 216 PM PDT Thu Apr 18 2024/
DISCUSSION...The steady dry and warming trend continues through
the rest of the work week, with high pressure overhead and a
thermal trough developing along the coast. This pattern is
producing a general east wind aloft, and this will then result in
downsloping winds, especially along the south coast near
Brookings, and will allow for strong overnight inversions for
inland valleys. This means that while daytime highs will be above
normal for this time of year, lows in the valleys will be cool. A
few pockets of frost and freeze are possible, but widespread
freezing conditions are not expected west of the Cascades.
A weak system will approach the area Saturday, with a mostly dry
cold front passing through by Saturday night. While precipitation
is possible along the coast, and perhaps into the Umpqua basin
and the Cascades, precipitation amounts will be very light.
Additionally, the main dynamics associated with this system are
very far north, so if the system shifts north at all we could miss
out entirely. Even a southward shift of the surface features
wouldn't help out too much, as all upper level support would still
remain well to the north. Behind the front, temperatures will
cool, with Sunday highs about 10 to 15 degrees cooler than Friday
or Saturday.
High pressure, with dry conditions and warm daytime temperatures
and cool nights (and another chance for frost/freeze conditions)
will return Monday into Tuesday, then the next system arrives by
late Tuesday or Tuesday night, with upper level troughing passing
overhead Wednesday into Thursday. Again, we do not expect this to
be much of a rainmaker. In fact, the frontal passage itself
appears almost completely dry, with more widespread precipitation
arriving behind the front as showers develop within the
instability under the upper level trough. Confidence is low in any
details at this time, given the wide spread in ensemble
solutions, so updates will likely be necessary over the coming
days.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory until 5 AM PDT Friday
for PZZ350-356-370-376.
&&
$$
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