PACJET Projects
HMT 2004
IOP 1: 20 Jan 2001
IOP 2: 23 Jan 2001
IOP 3: 25 Jan 2001
IOP 4: 31 Jan 2001
IOP 5: 1 Feb 2001
IOP 6: 6 Feb 2001
IOP 7: 9 Feb 2001
IOP 8: 10 Feb 2001
IOP 9: 11 Feb 2001
IOP 10: 12 Feb 2001
IOP 11: 17 Feb 2001
IOP 12: 18 Feb 2001
IOP 13: 21 Feb 2001
IOP 14: 24 Feb 2001
IOP 15: 25 Feb 2001
IOP 16: 1 Mar 2001
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2001 - Monterey, CA
July 13-14 2000 (Boulder, CO)
July Workshop Agenda
September 1999 - Monterey, CA
1999 Planning Workshop Figures
June 1998 - CALJET

Program Status for 9 February 2001 : IOP 07

Status | Observations | Forecast Discussion | Flight Plan | Aircraft Status | Soundings Status

Thursday, February 8 Microphysics study flight take-off at 2330 PST.
Friday, February 9 Weather briefing 1000 PST.

Status | Observations | Forecast Discussion | Flight Plan | Aircraft Status | Soundings Status

1527 UTC
1513 UTC leading edge of significant rainband
from 37deg7minN, 123deg14minW
to 37deg44minN, 122deg34minW
to 38deg7minN, 122deg30minW
extends NW from there parallel to coast
echo max 30-35dbz.
1510 UTC Cazadero Sounding
T (C)     Z (m MSL)     p (mb)
  0         1282         864
 -3         1763         813.5
 -8         2630         728.8
-13         3314         666.3
1504 UTC at 38deg34minN, 123deg,21min, 642 mb:
(heading to pt 20; heading: 234deg, at 12000 ft)

winds: 209deg, 27kt
air temp: -15.4degC, dewpt temp: -26.1degC

Will drop a sonde at pt 20.

1448 UTC Graupel shower just as we crossed the coast (at 1448 UTC, at 38deg41minN, 123deg3minW) echo weakens noticeably E of CZD. Echo top west of CZD was ~5km.
1430 UTC at 38deg50minN, 123deg45minW, 975 mb
(moving to pt 18 at 1000 ft, heading: 146deg)

winds: 233deg, 21kt
air temp: 6.9degC, dewpt temp: 4.8degC

1334 UTC At 39deg23minN, 123deg55minW, 974mb:
(moving to pt 13, heading; 178deg, at 1000 ft)
winds: 192deg, 15kt
air temp: 6.2degC, dewpt temp: 4.8degC

Will do the CZD racetrack pattern. After reaching pt 13, will proceed to pt 14 and run the box counterclockwise. Will wait to see if microphysics stacks are worthwhile.

1214 UTC At 40deg34minN, 124deg52minW, 895 mb
(heading toward the South; 160deg)
winds:194deg, 17kt
air temp: 0.6degC , dewpt temp:-0.7degC

Likely will leave the Cape Mendocino area for IOP-7 and will try to sample near CZD. Monterey radar images suggest some precip enhancement N of SFO Bay. Will go to investigate.

1214 UTC At 39deg57minN, 125deg7minW, at 970 mb:
(heading : 235deg, at 1000 ft)
winds:210deg, 16kt
air temp: 6.5degC , dewpt temp: 3.5degC

Currently running a triangle between points 3, 4, and 5.

Features on LF match up well with Eureka 1201 Z radar image.

1147 UTC

1143 UTC At 40deg0minN, 124deg35minW, 849 mb ( 5000 ft):
(porpoise top)
winds: 219deg, 18kt
air temp: -1.8degC , dewpt temp: -2.8deg
1142 UTC

Probable NCFR orientation offshore
38deg47min, 124deg11min to
38deg12min, 124deg32min to
37deg20min, 125deg13min

1140 UTC At 40deg4minN, 124deg48minW, 975 mb ( 500 ft):
(moving to pt 5, heading: 122deg, will porpoise from pt 3 to pt 5)
(porpoise bottom)
winds:216deg, 14kt
air temp: 7.5degC , dewpt temp: 4.2degC
1108 UTC at 39deg57minN, 124deg9minW, 975 mb (1000 ft):
(moving to pt 4 ,heading:325deg)
winds: 148deg, 20kt
air temp: 5.7degC ,dewpt temp: 3.7degC
1035 UTC At 40deg10minN, 124deg43minW, 751 mb:
(moving to pt 10 at 8000 ft)

winds: 234deg, 19kt
air temp: -7.6degC, dewpt temp: -10.6degC

No strong echo activity in current location.

1015 UTC at 40deg28minN, 124deg40minW, 975 mb
(have been spiralling down at pt 8 to 1000 ft, now moving to pt 9, heading: 160deg)

winds: 205deg, 17 kt
air temp: 5.2degC ,dewpt temp: 5.1degC

0953 UTC At 39deg59minN, 123deg43minW, 695 mb
(moving to pt 5 at 10000 ft)

winds: 212deg, 30kt
air temp: -11.6degC, dewpt temp: -13.4degC

0945 UTC Along NCFR, intense bowing segment w/ convex leading edge near 39.5degN, 124.5degW. Highly convective in warm sector seeing much convection to our south. Echo tops: 6-7km max reflectivities: 45-50 dbz

Bright bolt of triggered lightning on front of P-3.

0937 UTC At 40deg0minN, 124deg16min, 904mb
(moving to pt 5; heading: 146deg)

winds: 205deg, 27kt
air temp: 2.2degC, dewpt temp: 2.2degC

0927 UTC At 40deg29minN, 124deg34minW, 905 mb:
winds:214deg, 27kt
air temp: 1.8degC ,dewpt temp: 1.8degC

Getting pelted with graupel (3-4mm diam) at 3000 ft. Copious radar echoes 45-50 dbz (some greater than 50). NCFR immediately to our west. Great data. Winds showed direction of 153-160 deg below 1000 ft, max winds of 37 kt within blocked flow.

0853 UTC At 40deg9minN, 125deg13minW, 912mb
(heading: 339deg, about to hit pt 3)

winds: 244deg, 15.5kt
air temp: 2.5degC, dewpt temp: 0.8degC

0844 UTC Heading 348 degrees, just passed through convective band.

At 39deg36minN, 125deg3minW, 908mb

winds: 230deg, 21.6kt
air temp: 2.2degC, dewpt temp: 1.3degC

0836 UTC Proceeding toward pt 3, ETA at pt 3 0900 UTC.

At 39deg5minN, 124deg52minW, 913mb
winds: 232deg, 26.3kt
air temp: 3.2degC, dewpt temp: 2.4degC

Intense rainband (probable Narrow Cold Frontal Rainband):
orient: 30-210deg
echo top: 8km , echo max: 40-45 dbz

0700 UTC Bodega Bay Sounding
T (C)       Z (m MSL)        p (mb)

  0            1220            875
 -3            1732            821
 -8            2726            723
-13            3693            637

Status | Observations | Forecast Discussion | Flight Plan | Aircraft Status | Soundings Status |

Forecast Discussion
PACJET IOP#07 Short Term Forecast Discussion NWS/PACJET Operations Center, Monterey, CA 1545 UTC February 9, 2001

No lightning indicated.

Moderate rain was measured across the northern SF bay area between 14z and 15z. Hourly rainfall reports were mainly between .10 and .25 in. Maximum recorded amount for the hour was .40 in. at Yorkville in the Russian River Basin.

At 1542Z the intensity of most showers off the coast were between 25 and 35 dbz. However, an embedded echo of 51 dbz was indicated by radar at 36 deg 38minN 122 51minW.


PACJET IOP#07 Short Term Forecast Discussion
NWS/PACJET Operations Center, Monterey, CA
1440 UTC February 9, 2001

A single lightning strike was detected offshore from Monterey at 1420Z. The location was 36N 124.4W.

Showers continue to track across Northern California, but at this time the strongest radar echoes are noted across the San Francisco Bay Region into the Sacramento Valley.

Santa Rosa reported a wind shift from 150 at 05kt to 260 at 03kt at 1420z. Between 13z and 14z Santa Rosa reported 0.17 in. while Hawkeye reported 0.19, Farallon Island with 0.20, Calistoga 2W with 0.24, and Ross and St. Helena 4WSW each with 0.16. Further South rainfall was just beginning to intensify at 14z with hourly amounts of less than 0.10.

Maximum radar reflectivities at 1444Z are noted over the Santa Cruz mountains with a return of 51 dbz 4 mi SW of the McQueen ridge radar site. Radar generated cell movement was from 197 deg. at 36 kts.


1345 UTC February 9, 2001

No lightning indicated.

Moderate rain is being reported at Santa Rosa with 0.09 in. between 13z and 1328Z. Between 12z and 13z rainfall reported included 0.28 in. at Bridgeville in the Van Duzen Basin, 0.16 at Ft. Seward, and another 0.12 at Honeydew.

Besides the showers moving into Northwest California, there is also an area of enhanced precipitation across the Northern San Francisco Bay Area extending into Lake County. 12z-13z amounts included 0.12 in. at Venado and Upper Lake.

Gauges in the Santa Cruz Mtns. all reported totals of 0.04 in. between 12 and 13z except 0.12 at Scotts Valley.

1230 UTC February 9, 2001

No lightning indicated.
The 1224Z Radar image shows a line of showers with return of 20 to 30 dbz extending SSW to NNE through 40.0N 125W. Strongest returns of 35dbz are indicated of Eastern Humboldt county and about 10 mi offshore from Arcata.

The cold front has reached Pt. Reyes with moderate rain indicated for the past hour in the vicinity of Cazadero.

Rainfall reports from 11Z to 12Z include 0.24 in at Miranda, 0.20 at Orick, 0.16 at Ft. Seward, 0.12 at Honeydew, and 0.08 across much of the Russian and Napa River basins.


1130 UTC February 9, 2001

The 1124Z Radar image shows the furthest eastward progression of the cold frontal rain band at 40.4N 123.5W. A region of 20 to 30 dbz echoes extends from Crescent City down to Point Arena. There are a few cells of 35 dbz over Cape Mendocino.

IR imagery shows enhanced cloud tops associated with the cold front extend as far south as Point Arena where the front is currently making landfall. Cloud top temperatures are -35 to -45C.

Honeydew reported 0.12 inches of rain between 10Z and 11Z...the same amount it received between 09Z and 10Z. 0.12 also at Miranda in the Eel River Valley and 0.08 at Orick.


1040 UTC February 9, 2001

First lightning strike detected at 1025Z at 39.8N 124.1W. Cell is moving to the NE with return of 40dbz.

1035Z Radar image shows a maximum return of 50 dbz at 40.52N 124.24W. Echoes of 30 dbz or greater continue to be confined to the vicinity of Cape Mendocino.


0950 UTC February 9, 2001

No lightning strikes detected in the past 3 hours.

0930 Radar image shows a box of mainly 35 to 40 dbz echoes bounded at 40.8N 124.8W to 40.2N 124.8W and extending to the coast. A small maximum of 50 dbz is located at 40.41N 124.62W

0950 Radar indicates this band has of echoes has weakened with echoes as strong as 35 dbz mainly only within 10 mi of Cape Mendocino.

06Z run of the mesoeta depicts negative LI through 15Z only in the region north of Pt. Reyes. At 12Z forecast Maximum CAPE values of 850 J/Kg and LI of -3 are forecast for 38.6N 128W. Nearly as impressive values are forecast for the region from 38.1 129.0 to 39.0 125.6


0840 UTC February 9, 2001

No lightning strikes detected in the past 3 hours. NCFR is oriented N to S from Southern Oregon Coast to about Cape Mendocino 35 mi offshore, before beginning to trail off to the southwest. frontal position is approx. 85 mi W of Pt. Arena

The front is moving E at approximately 25 Kts. Current maximum radar return 45 dbz 28mi due W of Cape Mendocino.

1710 UTC, February 8, 2001

Short Term (Thu - Sat) Discussion

Model 5H initialized okay with the next Gulf of AK vortex that will slide into the western US this period. The base of the vortex looks a little sharper than what the model height analysis is showing. Vort vertification is good.

Model verification over the eastern Pacific for the past several runs shows the models, especially the AVN, have been moving previous vortexes too far east into the western US. 5H verification shows a clear positive bias over the eastern Pacific. Threrefore, although both the Eta & AVN are not too different, we need to dig these systems farther south. Verification of RH & PWs also shows the models too dry over the eastern Pacific.

Will follow the lead of the Eta which brings more energy into central CA this period. The AVN is strong, but farther north with the main 5H vort that pushes into central CA.

Sensible weather features associated with this next vortex should bring frontal precipitation into northern CA later tonight with the front reaching the SFO region around 12 UTC. Post frontal/orographic precipitation will quickly follow the front as onshore flow increases, while mid/upper level dynamics remain strong. The models are depicting strong left exit region upper jet dynamics over central CA. This should support heavy precipitation in the favored orographic regions of the central/northern CA coastal areas and sierra.

Long Term (Sat - Thu) A second strong Gulf of AK vortex is expected to dig into the eastern Pacific very quickly on the heels of Friday's system. The vortex is expected to move to just off the Pacific northwest coast by Sat evening with strong mid/upper level dynamics digging into northern CA. This should bring another round of mod/heavy precipitation into northern CA Sat afternoon/evening and central CA by Sat night. Beyond this time frame, the models are having some difficulty with mid/upper level heights. Yesterday's models brought shortwave energy through the eastern Pacific ridge axis and into CA by late in the week, but today's medium range models are showing very little energy cutting through the base of the eastern Pacific ridge. This latest solution is very similar to what happened last week, which led to several days of dry/warm weather.

Eckert/PACJET Forecaster

Status | Observations | Forecast Discussion | Flight Plan | Aircraft Status | Soundings Status

Flight Plan

Status | Observations | Forecast Discussion | Flight Plan | Aircraft Status | Soundings Status |

Aircraft Status
February 8 Night flight starting at 2300 PST.

Status | Observations | Forecast Discussion | Aircraft Status | Soundings Status |

Sounding Status
8 February
Bodega BayNo soundings.
CazaderoNo soundings.
OaklandSpecial soundings requested every 3 hours from 0 Z Friday - 0 Z Saturday.
RenoNo special soundings requested.
9 February
Bodega BaySoundings as event develops.
CazaderoSoundings as event develops.
OaklandSpecial soundings requested every 3 hours from 0 Z to 0 Z Saturday.
RenoSpecial soundings requested every 3 hours from 12 Z Friday to 12 Z Saturday.