70s and 80s the Rest of the Week

Strong high pressure system over the area, combined that with strong down-sloping winds I think we might take a run at 80 this afternoon folks.

Thursday Morning Update

6:30 am Storm Update

1:00 am storm update

Wind, Rain, and Heavy Snow This Weekend

A lot to talk about with this up-coming storm system this weekend.  A few lingering showers and storms this afternoon and evening.  Tomorrow we will also see another chance of storms in the afternoon with low level convection tops.

Now onto Sunday...

Upper level low positioned to our North West.  This upper level feature will help direct another surface low right through the NorthState area Sunday morning and Sunday afternoon.  The inverted trough in the left hand corner of the image above is the surface low.  It will rotate around the trough tonight, tomorrow, and Sunday morning.

988 surface low just to our southwest Sunday morning.  A very strong low considering most we ever see are well above 1000 mb.  The winds will slingshot up through the valley floor and Chico and points southward will see sustained winds of around 40-45 mph.  Gusts up to 70 mph.  This is already ontop of the unseasonably high rain fall we have been receiving the last 3 weeks.  The ground is already saturated and we will pick up even more rain Sunday.  So I would expect downed trees and even power lines.

The valley floor could easily pick up another .5-1.5 inches of liquid, higher amounts to the south.

Chester reported over 2 feet of snow Thursday night and into Friday.  Higer elevations will pick up an additional foot of snow if not more, foothills, snow levels down to 2000 ft.

HPC Totals Days 1-3

Moist Weekend....Dry Out for the Work Week

Most of the returns you see in the reflectivity is failing to reach the ground....virga basically.  Only the highest DBZ on the radar are actually making it to the sfc. So the dark blues and greens.  Of course pockets of sprinkles could be mixed in as well in the swath of virga.

This is the GFS forecasted sounding 12 hrs out.  You will notice that the entire "weather layer" is saturated and p-wat values are over 2 standard deviations above average.  So a very moist humid Saturday and Saturday night.  Also the winds to the right of the graphic are turning clockwise and strengthening with height. This is a veering wind which gives us WAA (warm air advection). WAA allows for QG lift as well as a warmer air mass throughout the saturated layer. 

Combine this saturated airmass with a forecasted 1011 mb low late tonight, we should have enough forcing to squeeze out about a half inch for the NorthState valley floor.  Snow levels will also be much higher, given the WAA, above 5500 ft.  This system is very pre-spring like and is ushering us out of Winter. 

The North State should clear out Sunday afternoon before our next upper level troph pushes through late Sunday Night.  Could be enough forcing out affront of the troph to allow for additional showers .  If the cold pool sticks around long enough Monday we could also be dealing with a very unstable atmosphere given daytime heating.  Lapse rates could easily climb over 9 and with any surface forcing we could be dealing with storms and small hail early Monday afternoon.  I think the cut off will be 2-3:00 at the latest of Monday if not much earlier.



Beautiful Friday...A couple of Systems This Weekend

Great day outside today, we are getting closer and closer to spring.  850 temps this afternoon were around 5 degrees Celsius and if dropped dry adiabatically, valley temps could have reached into the 70's.  However, High thin clouds overhead reduced solar radiation this afternoon as well as gusty winds.  Still managed to make into the 60's and considering the weather the last 2 weeks, not too bad



Now this weekend we have a couple systems pushing through all the way into early morning hours Monday.

We will begin to see a few widely scattered to isolated insentropic showers limited to the mountains and a few valley communities Saturday afternoon.

The first system brings heavy moisture and arrives Saturday night into early Sunday morning.  We will see a 1012 mb low advect moisture into the region Saturday night.  The High to our southwest will also advect subtropical moisture all the way into NorthState.

You can actually follow the moisture all the way from the ITZ , through Hawaii, around the high and into the NorthState.  A minature pineapple express basically. Precipitate water values will be almost 2 standard deviations above average Saturday night so 700 mb moisture feed should not be an issue. The GFS and the Nam both push this sfc low through pretty quickly so pops will be high but limited in qpf.  Still could be possible to squeeze a quarter to a half an inch out in the valley through Sunday morning.

The next trough will push through Sunday night with a quick trailing cold front.  Still possible to see a negative enough tilt to pull some moisture back into the NorthState.

If we can hold onto the 500 mb cold pool long enough into the afternoon hours on Monday we will have enough daytime heating and extremely high lapse rates to allow for thunderstorms, hail, and heavy downpours.



Dry Friday....Wet Saturday, Sunday

Showers have died out for the night as a piece of energy has moved off to our west.  Yesterday I was thinking we would miss out on the forcing to our northwest but the energy followed more of a west to east phasing.  Most locations missed out on moisture but a few spots, including Redding, saw brief but heavy downpours.  Locations off to our southwest picked up on quite a bit of sunshine and made into the upper 60's.

Now for the Weekend...models have backed off on moisture feed and intensity of the low and high as well as  positioning. The surface low projection is further north and the surface high will be weaker going by the GFS.  I tend to side with the GFS because of better initiation and obs when following short term 500 mb wave progression.  The European so far this winter has done a better job in long term rossby wave forecasting.  All in all it looks like we are going to miss out on the strong conveyer belt of moisture the models were pointing to yesterday.

  

It appears the heaviest of the rain will begin to arrive Saturday night into early morning hours Sunday .  

With the sharp upper level wave approaching into Sunday night into early Monday morning hours we will begin to see another round of showers.  QG lift will be lost to a positive tilt and locations to our south will pick up on the stronger vorticity.

However we might see some moisture kicked back into the NorthState with the wave going negative.  We should see enough cyclonic vorticty to allow for additonal moisture to be pulled back into the valley.

So not as promising as yesterday with signs of a mini pineapple express but still some decent qpf amounts Saturday afternoon through Monday Morning.

Rain Wrapping Up...More to Come

We had quite a bit of rain in the overnight hours into this morning.  This afternoon we had a boundary set up right over Redding with a strong moisture feed.  These downpours were associated with training cells from the southwest.  This boundary is beginning to shift southeast of  Redding so I expect limited rainfall totals for the rest of the evening.

Tomorrow, isolated showers in the early morning hours but I expect the afternoon to be dry.
We will dry out for Friday with temperatures around 60 before we see the arrival of our next system Saturday.  I fully expect the system on Saturday to drop heavy QPF for the entire NorthState.

Now this is the18z GFS, valid at 18z on Saturday.  You will notice the surface low off to our west northwest.  To our south west you will also notice the surface high.  The clockwise motion of the high pressure and the counterclockwise motion of the surface low will funnel moisture into Northern California.  The cross hairs look to be a little south of the NorthState but I still expect heavy qpf amounts.

6 hour precip totals for Saturday afternoon based off the 18z  GFS.

Heavy Rain Arrives Tonight

Partly cloudy to mostly sunny skies this afternoon as of 12:00 pm.  The valley will quickly begin to transition over to cloudy skies and late afternoon showers before the main onset of the heavy rain arrives later tonight.

With a strong short wave off to our west, The NorthState will receive adequate forcing with strong QG forcing out a front the mid level disturbance.  The 12z Nam and GFS put out quite a bit of precip tonight and into the overnight hours.  Still learning the local biases I am not entirely aware of GFS convective feedback issues.  However, this system should have no issues overcoming terrain problems and I fully expect a good soaking rain this evening and into tomorrow night.

HPC has put down 1.5-2.5 inches of QPF for days 1-2, with higher amounts for the highest elevations.

I'll talk about the weekend system in detail tomorrow.